WorldWideScience

Sample records for cdm based mimo

  1. MIMO Based Multimedia Communication System

    OpenAIRE

    Kandar, D.; Dhar, Sourav; Bera, Rabindranath; Sarkar, C. K.

    2009-01-01

    High data rate is required for multimedia communication. But the communication at high data rate is always challenging. In this work we have successfully performed data chatting, Voice chatting and high quality video transmission between two distant units using MIMO adapter, Direct sequence spread spectrum system and MATLAB/SIMULINK platform.

  2. A nonlinear CDM based damage growth law for ductile materials

    Science.gov (United States)

    Gautam, Abhinav; Priya Ajit, K.; Sarkar, Prabir Kumar

    2018-02-01

    A nonlinear ductile damage growth criterion is proposed based on continuum damage mechanics (CDM) approach. The model is derived in the framework of thermodynamically consistent CDM assuming damage to be isotropic. In this study, the damage dissipation potential is also derived to be a function of varying strain hardening exponent in addition to damage strain energy release rate density. Uniaxial tensile tests and load-unload-cyclic tensile tests for AISI 1020 steel, AISI 1030 steel and Al 2024 aluminum alloy are considered for the determination of their respective damage variable D and other parameters required for the model(s). The experimental results are very closely predicted, with a deviation of 0%-3%, by the proposed model for each of the materials. The model is also tested with predictabilities of damage growth by other models in the literature. Present model detects the state of damage quantitatively at any level of plastic strain and uses simpler material tests to find the parameters of the model. So, it should be useful in metal forming industries to assess the damage growth for the desired deformation level a priori. The superiority of the new model is clarified by the deviations in the predictability of test results by other models.

  3. FPGA based Smart Wireless MIMO Control System

    International Nuclear Information System (INIS)

    Ali, Syed M Usman; Hussain, Sajid; Siddiqui, Ali Akber; Arshad, Jawad Ali; Darakhshan, Anjum

    2013-01-01

    In our present work, we have successfully designed, and developed an FPGA based smart wireless MIMO (Multiple Input and Multiple Output) system capable of controlling multiple industrial process parameters such as temperature, pressure, stress and vibration etc. To achieve this task we have used Xilin x Spartan 3E FPGA (Field Programmable Gate Array) instead of conventional microcontrollers. By employing FPGA kit to PC via RF transceivers which has a working range of about 100 meters. The developed smart system is capable of performing the control task assigned to it successfully. We have also provided a provision to our proposed system that can be accessed for monitoring and control through the web and GSM as well. Our proposed system can be equally applied to all the hazardous and rugged industrial environments where a conventional system cannot work effectively

  4. FPGA based Smart Wireless MIMO Control System

    Science.gov (United States)

    Usman Ali, Syed M.; Hussain, Sajid; Akber Siddiqui, Ali; Arshad, Jawad Ali; Darakhshan, Anjum

    2013-12-01

    In our present work, we have successfully designed, and developed an FPGA based smart wireless MIMO (Multiple Input & Multiple Output) system capable of controlling multiple industrial process parameters such as temperature, pressure, stress and vibration etc. To achieve this task we have used Xilin x Spartan 3E FPGA (Field Programmable Gate Array) instead of conventional microcontrollers. By employing FPGA kit to PC via RF transceivers which has a working range of about 100 meters. The developed smart system is capable of performing the control task assigned to it successfully. We have also provided a provision to our proposed system that can be accessed for monitoring and control through the web and GSM as well. Our proposed system can be equally applied to all the hazardous and rugged industrial environments where a conventional system cannot work effectively.

  5. Measurement-Based Performance Evaluation of Advanced MIMO Transceiver Designs

    Directory of Open Access Journals (Sweden)

    Schneider Christian

    2005-01-01

    Full Text Available This paper describes the methodology and the results of performance investigations on a multiple-input multiple-output (MIMO transceiver scheme for frequency-selective radio channels. The method relies on offline simulations and employs real-time MIMO channel sounder measurement data to ensure a realistic channel modeling. Thus it can be classified in between the performance evaluation using some predefined channel models and the evaluation of a prototype hardware in field experiments. New aspects for the simulation setup are discussed, which are frequently ignored when using simpler model-based evaluations. Example simulations are provided for an iterative ("turbo" MIMO equalizer concept. The dependency of the achievable bit error rate performance on the propagation characteristics and on the variation in some system design parameters is shown, whereas the antenna constellation is of particular concern for MIMO systems. Although in many of the considered constellations turbo MIMO equalization appears feasible in real field scenarios, there exist cases with poor performance as well, indicating that in practical applications link adaptation of the transmitter and receiver processing to the environment is necessary.

  6. Full-duplex MIMO system based on antenna cancellation technique

    DEFF Research Database (Denmark)

    Foroozanfard, Ehsan; Franek, Ondrej; Tatomirescu, Alexandru

    2014-01-01

    The performance of an antenna cancellation technique for a multiple-input– multiple-output (MIMO) full-duplex system that is based on null-steering beamforming and antenna polarization diversity is investigated. A practical implementation of a symmetric antenna topology comprising three dual......-polarized patch antennas operating at 2.4 GHz is described. The measurement results show an average of 60 dB self-interference cancellation over 200 MHz bandwidth. Moreover, a decoupling level of up to 22 dB is achieved for MIMO multiplexing using antenna polarization diversity. The performance evaluation...

  7. Characteristic analysis on UAV-MIMO channel based on normalized correlation matrix.

    Science.gov (United States)

    Gao, Xi jun; Chen, Zi li; Hu, Yong Jiang

    2014-01-01

    Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition number of UAV-MIMO channel matrix, the channel capacity, and other characteristic parameters. The simulation results show that this channel correlation matrix can be applied to describe the changes of UAV-MIMO channel characteristics under different parameter settings comprehensively. This analysis method provides a theoretical basis for improving the transmission performance of UAV-MIMO channel. The development of MIMO technology shows practical application value in the field of UAV communication.

  8. Characteristic Analysis on UAV-MIMO Channel Based on Normalized Correlation Matrix

    Science.gov (United States)

    Xi jun, Gao; Zi li, Chen; Yong Jiang, Hu

    2014-01-01

    Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition number of UAV-MIMO channel matrix, the channel capacity, and other characteristic parameters. The simulation results show that this channel correlation matrix can be applied to describe the changes of UAV-MIMO channel characteristics under different parameter settings comprehensively. This analysis method provides a theoretical basis for improving the transmission performance of UAV-MIMO channel. The development of MIMO technology shows practical application value in the field of UAV communication. PMID:24977185

  9. Performance Analysis of Virtual MIMO Relaying Schemes Based on Detect–Split–Forward

    KAUST Repository

    Al-Basit, Suhaib M.

    2014-10-29

    © 2014, Springer Science+Business Media New York. Virtual multi-input multi-output (vMIMO) schemes in wireless communication systems improve coverage, throughput, capacity, and quality of service. In this paper, we propose three uplink vMIMO relaying schemes based on detect–split–forward (DSF). In addition, we investigate the effect of several physical parameters such as distance, modulation type and number of relays. Furthermore, an adaptive vMIMO DSF scheme based on VBLAST and STBC is proposed. In order to do that, we provide analytical tools to evaluate the performance of the propose vMIMO relaying scheme.

  10. Predicting Protein Secondary Structure Using Consensus Data Mining (CDM) Based on Empirical Statistics and Evolutionary Information.

    Science.gov (United States)

    Kandoi, Gaurav; Leelananda, Sumudu P; Jernigan, Robert L; Sen, Taner Z

    2017-01-01

    Predicting the secondary structure of a protein from its sequence still remains a challenging problem. The prediction accuracies remain around 80 %, and for very diverse methods. Using evolutionary information and machine learning algorithms in particular has had the most impact. In this chapter, we will first define secondary structures, then we will review the Consensus Data Mining (CDM) technique based on the robust GOR algorithm and Fragment Database Mining (FDM) approach. GOR V is an empirical method utilizing a sliding window approach to model the secondary structural elements of a protein by making use of generalized evolutionary information. FDM uses data mining from experimental structure fragments, and is able to successfully predict the secondary structure of a protein by combining experimentally determined structural fragments based on sequence similarities of the fragments. The CDM method combines predictions from GOR V and FDM in a hierarchical manner to produce consensus predictions for secondary structure. In other words, if sequence fragment are not available, then it uses GOR V to make the secondary structure prediction. The online server of CDM is available at http://gor.bb.iastate.edu/cdm/ .

  11. MIMO Based Eigen-Space Spreading

    National Research Council Canada - National Science Library

    Eltawil, Ahmed

    2004-01-01

    .... Combination of this powerful technique with orthogonal frequency division multiplexing (OFDM) based modulation and traditional time and frequency spreading techniques results in a highly secure mode of communications...

  12. MIMO Performance and Decoupling Network: Analysis of Uniform Rectangular array Using Correlated-Based Stochastic Models

    OpenAIRE

    Obour Agyekum Kwame O-B; Maxwell Oppong Afriyie; Paul Oswald Kwasi Anane; Affum Emmanuel Ampoma; Matthew Seddoh Akatey

    2017-01-01

    We explore the dependency of MIMO performance on azimuthal spread (AS) and elevation spread (ES) using correlated-based stochastic models (CBSMs). We represent the transmitter as uniform rectangular array (URA), and derive an analytical function for spatial correlation, in terms of maximum power when phase gradient of the incident wave follows a Student’s t-distribution. We model the correlated-based stochastic MIMO system to investigate the usefulness of the analytical function, under the co...

  13. MIMO transmit scheme based on morphological perceptron with competitive learning.

    Science.gov (United States)

    Valente, Raul Ambrozio; Abrão, Taufik

    2016-08-01

    This paper proposes a new multi-input multi-output (MIMO) transmit scheme aided by artificial neural network (ANN). The morphological perceptron with competitive learning (MP/CL) concept is deployed as a decision rule in the MIMO detection stage. The proposed MIMO transmission scheme is able to achieve double spectral efficiency; hence, in each time-slot the receiver decodes two symbols at a time instead one as Alamouti scheme. Other advantage of the proposed transmit scheme with MP/CL-aided detector is its polynomial complexity according to modulation order, while it becomes linear when the data stream length is greater than modulation order. The performance of the proposed scheme is compared to the traditional MIMO schemes, namely Alamouti scheme and maximum-likelihood MIMO (ML-MIMO) detector. Also, the proposed scheme is evaluated in a scenario with variable channel information along the frame. Numerical results have shown that the diversity gain under space-time coding Alamouti scheme is partially lost, which slightly reduces the bit-error rate (BER) performance of the proposed MP/CL-NN MIMO scheme. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Bidirectional MIMO Channel Tracking Based on PASTd and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Shayevitz Ofer

    2010-01-01

    Full Text Available Abstract We consider a bidirectional time division duplex (TDD multiple-input multiple-output (MIMO communication system with time-varying channel and additive white Gaussian noise (AWGN. A blind bidirectional channel tracking algorithm, based on the projection approximation subspace tracking (PAST algorithm, is applied in both terminals. The resulting singular value decomposition (SVD of the channel matrix is then used to approximately diagonalize the channel. The proposed method is applied to an orthogonal frequency-division multiplexing-(OFDM-MIMO setting with a typical indoor time-domain reflection model. The computational cost of the proposed algorithm, compared with other state-of-the-art algorithms, is relatively small. The Kalman filter is utilized for establishing a benchmark for the obtained performance of the proposed tracking algorithm. The performance degradation relative to a full channel state information (CSI due to the application of the tracking algorithm is evaluated in terms of average effective rate and the outage probability and compared with alternative tracking algorithms. The obtained results are also compared with a benchmark obtained by the Kalman filter with known input signal and channel characteristics. It is shown that the expected degradation in performance of frequency-domain algorithms (which do not exploit the smooth frequency response of the channel is only minor compared with time-domain algorithms in a range of reasonable signal-to-noise ratio (SNR levels. The proposed bidirectional frequency-domain tracking algorithm, proposed in this paper, is shown to attain communication rates close to the benchmark and to outperform a competing algorithm. The paper is concluded by evaluating the proposed blind tracking method in terms of the outage probability and the symbol error rate (SER versus. SNR for binary phase shift keying (BPSK and 4-Quadrature amplitude modulation (QAM constellations.

  15. Color-Space-Based Visual-MIMO for V2X Communication.

    Science.gov (United States)

    Kim, Jai-Eun; Kim, Ji-Won; Park, Youngil; Kim, Ki-Doo

    2016-04-23

    In this paper, we analyze the applicability of color-space-based, color-independent visual-MIMO for V2X. We aim to achieve a visual-MIMO scheme that can maintain the original color and brightness while performing seamless communication. We consider two scenarios of GCM based visual-MIMO for V2X. One is a multipath transmission using visual-MIMO networking and the other is multi-node V2X communication. In the scenario of multipath transmission, we analyze the channel capacity numerically and we illustrate the significance of networking information such as distance, reference color (symbol), and multiplexing-diversity mode transitions. In addition, in the V2X scenario of multiple access, we may achieve the simultaneous multiple access communication without node interferences by dividing the communication area using image processing. Finally, through numerical simulation, we show the superior SER performance of the visual-MIMO scheme compared with LED-PD communication and show the numerical result of the GCM based visual-MIMO channel capacity versus distance.

  16. A real option-based model to valuate CDM projects under uncertain energy policies for emission trading

    International Nuclear Information System (INIS)

    Park, Taeil; Kim, Changyoon; Kim, Hyoungkwan

    2014-01-01

    Highlights: • A real option-based model for the valuation of CDM projects is proposed. • This study investigates the impact of energy policies on the value of CDM projects. • Level of target emission and its schedule should be carefully designed. • Government subsidy facilitates the implementation of CDM projects. • Period for free emission allowance prevents promoting CDM projects. - Abstract: Emission trading has been considered a primary policy tool for emission reduction. Governments establish national targets for emission reduction and assign emission reduction goals to private entities to accomplish the targets. To attain the goal, private entities should perform offset projects that can produce emission credits or buy emission credits from the market. However, it is not easy for private entities to decide to implement the projects because energy policies associated with emission trading keep changing; thus, the future benefits of the offset projects are quite uncertain. This study presents a real option-based model to investigate how uncertain energy policies affect the financial viability of an offset project. A case study showed that the establishment of a target emission was attractive to the government because it could make the CDM project financially viable with a small amount of government subsidy. In addition, the level of the government subsidy could determine the investment timing for the CDM project. In this context, governments should be cautious in designing energy policies, because even the same energy policies could have different impacts on private entities. Overall, this study is expected to assist private entities in establishing proper investment strategies for CDM projects under uncertain energy policies

  17. Design and evaluation of an IDM-based MIMO FSO system over Gamma-Gamma turbulence channels

    Science.gov (United States)

    Zhang, Chenglei; Zhou, Xiaolin; Zheng, Xiaowei; Du, Jianhong

    2011-12-01

    In this paper, we design an interleave-division-multiplexing (IDM) based multiple-input multiple-output (MIMO) free-space optics (FSO) communication system. The system overcomes problems harassing conventional optical MIMO systems such as restrictions of antenna number and high complexity in receiver. An iterative on-off keying (OOK) modulated IDM MIMO detection algorithm is developed. Expression of an upper bound of frame-error-rate (FER) is derived. In addition, we evaluate the BER performance of the proposed optical MIMO scheme in various FSO scenarios. Simulations confirm that the proposed scheme can effectively increase the feasibility of FSO communications over Gamma-Gamma turbulence-induced fading channels.

  18. Codebook-based interference alignment for uplink MIMO interference channels

    KAUST Repository

    Lee, Hyun Ho

    2014-02-01

    In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multipleoutput (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base stations (BSs) through reliable backhaul links so that global channel knowledge is available for all BSs, which enables BS to compute the transmit precoder and inform its quantized index to the associated user via limited rate feedback link.We present an upper bound on the rate loss of the proposed scheme and derive the scaling law of the feedback load tomaintain a constant rate loss relative to IA with perfect channel knowledge. Considering the impact of overhead due to training, cooperation, and feedback, we address the effective degrees of freedom (DOF) of the proposed scheme and derive the maximization of the effective DOF. From simulation results, we verify our analysis on the scaling law to preserve the multiplexing gain and confirm that the proposed scheme is more effective than the conventional IA scheme in terms of the effective DOF. © 2014 KICS.

  19. Energy Efficiency Comparison of MIMO-Based and Multihop Sensor Networks

    Directory of Open Access Journals (Sweden)

    Athanasios G. Kanatas

    2008-03-01

    Full Text Available Wireless sensor networks (WSNs demand the implementation of energy-aware techniques and low-complexity protocols in all layers. Recently, a MIMO-based structure has been proposed to offer enhanced energy savings in WSNs. In this paper, we examine and compare MIMO-based WSN with a multihop transmission in terms of energy efficiency. The results depend on the network density, the channel conditions, and the distance to the destination node. We reach analytical expressions to calculate threshold values of these parameters, which determine the areas where the MIMO-based structure outperforms multihop transmission. Moreover, we present a detailed analysis of the dissipated power during a sensor node_s operation, to prove that as microelectronics develops, the MIMO-based architecture will outperform the equivalent multihop structure for most of the cases examined. Finally, we implement a simple cooperative node selection algorithm to achieve higher energy gains in the MIMO approach, and we examine how this algorithm affects the calculated thresholds.

  20. Energy Efficiency Comparison of MIMO-Based and Multihop Sensor Networks

    Directory of Open Access Journals (Sweden)

    Bravos George

    2008-01-01

    Full Text Available Abstract Wireless sensor networks (WSNs demand the implementation of energy-aware techniques and low-complexity protocols in all layers. Recently, a MIMO-based structure has been proposed to offer enhanced energy savings in WSNs. In this paper, we examine and compare MIMO-based WSN with a multihop transmission in terms of energy efficiency. The results depend on the network density, the channel conditions, and the distance to the destination node. We reach analytical expressions to calculate threshold values of these parameters, which determine the areas where the MIMO-based structure outperforms multihop transmission. Moreover, we present a detailed analysis of the dissipated power during a sensor node_s operation, to prove that as microelectronics develops, the MIMO-based architecture will outperform the equivalent multihop structure for most of the cases examined. Finally, we implement a simple cooperative node selection algorithm to achieve higher energy gains in the MIMO approach, and we examine how this algorithm affects the calculated thresholds.

  1. Sustainable Development Impacts of NAMAs: An integrated approach to assessment of co-benefits based on experience with the CDM

    DEFF Research Database (Denmark)

    Olsen, Karen Holm

    Sustainable development priorities provide the context for Nationally Appropriate Mitigation Actions (NAMAs) by developing countries. While methods exist to assess the sustainable development (SD) co-benefits of Clean Development Mechanism (CDM) projects, no approach has yet been developed...... and a comparison of similarities and differences between NAMAs and CDM. Five elements of a new approach towards assessment of NAMAs SD impacts are suggested based on emerging approaches and methodologies for monitoring, reporting and verification (MRV) of greenhouse gas reductions and SD impacts of NAMAs....

  2. Assessing Measurement Distances for OTA Testing of Massive MIMO Base Station at 28 GHz

    DEFF Research Database (Denmark)

    Kyösti, Pekka; Fan, Wei; Kyrolainen, Jukka

    2017-01-01

    This paper discusses physical dimensions for a multi probe anechoic chamber based (MPAC) over-the-air (OTA) setup aiming for base station (BS) testing. The target frequency of the simulated massive multiple-input-multiple-output (MIMO) BS arrays is 28 GHz. The assessment is performed with two...... metrics. The first metric is a new power metric based on assumptions of a code book of fixed beams and planar waves. The second one is the multi-user (MU) MIMO sum rate capacity. The intention is to evaluate physical dimensions in metres with respect to different BS array sizes. Simulation results...

  3. Novel Base Station MIMO Antennas with Enhanced Spectral Efficiencies Using Angular Reuse

    Directory of Open Access Journals (Sweden)

    Miguel Mora-Andreu

    2015-01-01

    Full Text Available The true polarization diversity (TPD technique is combined with the spatial diversity technique in novel MIMO antenna array geometries with a large number of elements. The use of a large number of elements requires some angular reuse within the array for polarization diversity. With designs compatible with existing base station antenna array configurations, the novel geometries with combining diversity schemes are shown to be able to achieve near the maximum spectral efficiencies. True polarization diversity (TPD schemes are found to be an excellent complement to more conventional spatial diversity schemes for obtaining optimum MIMO array performance in base station antennas.

  4. MMSE-NP-RISIC-Based Channel Equalization for MIMO-SC-FDE Troposcatter Communication Systems

    Directory of Open Access Journals (Sweden)

    Zedong Xie

    2016-01-01

    Full Text Available The impact of intersymbol interference (ISI on single-carrier frequency-domain equalization with multiple input multiple output (MIMO-SC-FDE troposcatter communication systems is severe. Most of the channel equalization methods fail to solve it completely. In this paper, given the disadvantages of the noise-predictive (NP MMSE-based and the residual intersymbol interference cancellation (RISIC equalization in the single input single output (SISO system, we focus on the combination of both equalization schemes mentioned above. After extending both of them into MIMO system for the first time, we introduce a novel MMSE-NP-RISIC equalization method for MIMO-SC-FDE troposcatter communication systems. Analysis and simulation results validate the performance of the proposed method in time-varying frequency-selective troposcatter channel at an acceptable computational complexity cost.

  5. MIMO processing based on higher-order Poincaré spheres

    Science.gov (United States)

    Fernandes, Gil M.; Muga, Nelson J.; Pinto, Armando N.

    2017-08-01

    A multi-input multi-output (MIMO) algorithm based on higher-order Poincaré spheres is demonstrated for space-division multiplexing (SDM) systems. The MIMO algorithm is modulation format agnostic, robust to frequency offset and does not require training sequences. In this approach, the space-multiplexed signal is decomposed in sets of two tributary signals, with each set represented in a higher-order Poincaré sphere. For any arbitrary complex modulation format, the samples of two tributaries can be represented in a given higher-order Poincaré sphere with a symmetry plane. The crosstalk along propagation changes the spatial orientation of this plane and, therefore, it can be compensated by computing and realigning the best fit plane. We show how the transmitted signal can be successfully recovered using this procedure for all possible combinations of tributaries. Moreover, we analyze the convergence speed for the MIMO technique considering several optical-to-noise ratios.

  6. A Practical, Hardware Friendly MMSE Detector for MIMO-OFDM-Based Systems

    Science.gov (United States)

    Kim, Hun Seok; Zhu, Weijun; Bhatia, Jatin; Mohammed, Karim; Shah, Anish; Daneshrad, Babak

    2008-12-01

    Design and implementation of a highly optimized MIMO (multiple-input multiple-output) detector requires cooptimization of the algorithm with the underlying hardware architecture. Special attention must be paid to application requirements such as throughput, latency, and resource constraints. In this work, we focus on a highly optimized matrix inversion free [InlineEquation not available: see fulltext.] MMSE (minimum mean square error) MIMO detector implementation. The work has resulted in a real-time field-programmable gate array-based implementation (FPGA-) on a Xilinx Virtex-2 6000 using only 9003 logic slices, 66 multipliers, and 24 Block RAMs (less than 33% of the overall resources of this part). The design delivers over 420 Mbps sustained throughput with a small 2.77-microsecond latency. The designed [InlineEquation not available: see fulltext.] linear MMSE MIMO detector is capable of complying with the proposed IEEE 802.11n standard.

  7. Design of an Ultra-wideband Pseudo Random Coded MIMO Radar Based on Radio Frequency Switches

    Directory of Open Access Journals (Sweden)

    Su Hai

    2017-02-01

    Full Text Available A Multiple-Input Multiple-Output (MIMO ultra-wideband radar can detect the range and azimuth information of targets in real time. It is widely used for geological surveys, life rescue, through-wall tracking, and other military or civil fields. This paper presents the design of an ultra-wideband pseudo random coded MIMO radar that is based on Radio Frequency (RF switches and implements a MIMO radar system. RF switches are employed to reduce cost and complexity of the system. As the switch pressure value is limited, the peak power of the transmitting signal is 18 dBm. The ultra-wideband radar echo is obtained by hybrid sampling, and pulse compression is computed by Digital Signal Processors (DSPs embedded in an Field-Programmable Gate Array (FPGA to simplify the signal process. The experiment illustrates that the radar system can detect the range and azimuth information of targets in real time.

  8. Aspheric lens based imaging receiver for MIMO visible light communication

    Science.gov (United States)

    Ju, Qiuqi; Liang, Zhongcheng; Liu, Xueming; Yang, Tingting; Wang, Jin

    2014-10-01

    Visible light communication (VLC) has been regarded as a promising solution in short-range intelligent communication system. Nowadays, the research is focused on integrating the multi-input multi-output (MIMO) technique in the VLC system, to achieve a larger transmission capacity and stronger transmission reliability. However, one important issue should be addressed due to the use of MIMO technology: the multipath inter-symbol interference. The multipath intersymbol interference comes from the reflection of the signal in the room and channel crosstalk between different channels. In this paper, we propose a novel optical system used in the MIMO VLC system to reduce multipath interference dramatically. Signals from different LEDs can be separated by using parabolic lens plated with reflecting film. This structure can reduce the reflection effect effectively as well. We present the simulation results to observe the distribution of optical power on the imaging plane for various receiving positions and low correlation between all channels. We can find that the optical power density becomes stronger than non-imaging system and the interference is sharply decreased, thus the SNR and BER are also optimized. Analysis about the optical system is given in this paper.

  9. Spatial Frequency Scheduling for Uplink SC-FDMA based Linearly Precoded LTE Multiuser MIMO Systems

    DEFF Research Database (Denmark)

    Lin, Zihuai; Xiao, Pei; Sørensen, Troels Bundgaard

    2010-01-01

    This paper investigates the performance of the 3GPP Long Term Evolution (LTE) uplink Single Carrier (SC) Frequency Division Multiple Access (FDMA) based linearly precoded multiuserMultiple InputMultiple Output (MIMO) systems with frequency domain packet scheduling. A mathematical expression...

  10. Performance Testing of Massive MIMO Base Station with Multi-Probe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Zhang, Fengchun; Fan, Wei; Ji, Yilin

    2018-01-01

    The utilization of massive multiple-input multipleoutput (MIMO) antenna arrays at the base station (BS) side has been identified as an enabling technique for 5G communication systems. To evaluate the true end-to-end performance of BS's, an over-the-air (OTA) radiated method is required. In this p...

  11. Downlink Linear Precoders Based on Statistical CSI for Multicell MIMO-OFDM

    Directory of Open Access Journals (Sweden)

    Ebrahim Baktash

    2017-01-01

    Full Text Available With 5G communication systems on the horizon, efficient interference management in heterogeneous multicell networks is more vital than ever. This paper investigates the linear precoder design for downlink multicell multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM systems, where base stations (BSs coordinate to reduce the interference across space and frequency. In order to minimize the overall feedback overhead in next-generation systems, we consider precoding schemes that require statistical channel state information (CSI only. We apply the random matrix theory to approximate the ergodic weighted sum rate of the system with a closed form expression. After formulating the approximation for general channels, we reduce the results to a more compact form using the Kronecker channel model for which several multicarrier concepts such as frequency selectivity, channel tap correlations, and intercarrier interference (ICI are rigorously represented. We find the local optimal solution for the maximization of the approximate rate using a gradient method that requires only the covariance structure of the MIMO-OFDM channels. Within this covariance structure are the channel tap correlations and ICI information, both of which are taken into consideration in the precoder design. Simulation results show that the rate approximation is very accurate even for very small MIMO-OFDM systems and the proposed method converges rapidly to a near-optimal solution that competes with networked MIMO and precoders based on instantaneous full CSI.

  12. Measurements of MIMO Indoor Channels at 1800 MHz with Multiple Indoor and Outdoor Base Stations

    Directory of Open Access Journals (Sweden)

    Jaldén Niklas

    2007-01-01

    Full Text Available This paper proposes several configurations for multiple base stations in indoor MIMO systems and compares their performance. The results are based on channel measurements realized with a MIMO testbed. The receiver was moved along several routes and floors on an office building. Both outdoor and indoor locations are considered for the transmitters or base stations, which allow the analysis of not only indoor but also outdoor-to-indoor environment. The use of 2 base stations with different system level combinations of the two is analyzed. We show that the configuration with base station selection provides almost as good performance as a full water-filling scheme when the 2 base stations are placed at different locations. Also the spatial correlation properties for the different configurations are analyzed and the importance of considering path loss when evaluating capacity is highlighted.

  13. An Integrated 4-element Slot-Based MIMO and an UWB Sensing Antenna System for CR Platforms

    KAUST Repository

    Hussain, Rifaqat

    2017-12-08

    This paper presents a novel integrated antenna system for cognitive radio (CR) applications. The design consists of a compact 4- element reconfigurable annular slot based multiple-input-multiple-output (MIMO) antenna system integrated within an ultra-wide-band (UWB) sensing antenna. All the antenna elements are planar in structure and designed on a single substrate (RO-4350) with dimensions 60×120×1.5 mm3. The frequency reconfigurable slot based MIMO antenna system is tuned over a wide frequency band from 1.77 GHz to 2.51 GHz while the UWB sensing antenna is covering from 0.75~7.65 GHz The proposed antenna system is suitable for CR enabled wireless devices. The envelope correlation coefficient (ECC) did not exceed 0.248 in the entire operating band of the MIMO antenna part. The maximum measured gain of the MIMO antenna is 3.2 dBi with maximum efficiency of 81%.

  14. Free-space optical communications using orbital-angular-momentum multiplexing combined with MIMO-based spatial multiplexing.

    Science.gov (United States)

    Ren, Yongxiong; Wang, Zhe; Xie, Guodong; Li, Long; Cao, Yinwen; Liu, Cong; Liao, Peicheng; Yan, Yan; Ahmed, Nisar; Zhao, Zhe; Willner, Asher; Ashrafi, Nima; Ashrafi, Solyman; Linquist, Roger D; Bock, Robert; Tur, Moshe; Molisch, Andreas F; Willner, Alan E

    2015-09-15

    We explore the potential of combining the advantages of multiple-input multiple-output (MIMO)-based spatial multiplexing with those of orbital angular momentum (OAM) multiplexing to increase the capacity of free-space optical (FSO) communications. We experimentally demonstrate an 80 Gbit/s FSO system with a 2×2 aperture architecture, in which each transmitter aperture contains two multiplexed data-carrying OAM modes. Inter-channel crosstalk effects are minimized by the OAM beams' inherent orthogonality and by the use of 4×4 MIMO signal processing. Our experimental results show that the bit-error rates can reach below the forward error correction limit of 3.8×10(-3) and the power penalties are less than 3.6 dB for all channels after MIMO processing. This indicates that OAM and MIMO-based spatial multiplexing could be simultaneously utilized, thereby providing the potential to enhance system performance.

  15. An Optimization Model of Carbon Sinks in CDM Forestry Projects Based on Interval Linear Programming

    Directory of Open Access Journals (Sweden)

    Wenjin Zhao

    2012-06-01

    Full Text Available This study describes the first general optimization model for complex systems with uncertain parameters and decision variables represented as intervals in CDM forestry projects. We work through a specific example of the optimization method developed for a Clean Development Mechanism (CDM forestry project in Inner Mongolia, China. This model is designed to optimize the carbon sink capacity of the new forests, and can deal with uncertainties in the carbon sink capacity, average annual rainfall, ecological parameters, and biological characteristics of tree species. The uncertain inputs are presented in the form of intervals, as are several of the optimized output variables. Compared with the project’s originally recommended scheme, the optimized model will absorb and fix between 1,142 and 885,762 tonnes of extra carbon dioxide. Moreover, the ecological and environmental benefits of the project are also raised to various extents.

  16. Closed form fourier-based transmit beamforming for MIMO radar

    KAUST Repository

    Lipor, John J.

    2014-05-01

    In multiple-input multiple-output (MIMO) radar setting, it is often desirable to design correlated waveforms such that power is transmitted only to a given set of locations, a process known as beampattern design. To design desired beam-pattern, current research uses iterative algorithms, first to synthesize the waveform covariance matrix, R, then to design the actual waveforms to realize R. In contrast to this, we present a closed form method to design R that exploits discrete Fourier transform and Toeplitz matrix. The resulting covariance matrix fulfills the practical constraints and performance is similar to that of iterative methods. Next, we present a radar architecture for the desired beampattern that does not require the synthesis of covariance matrix nor the design of correlated waveforms. © 2014 IEEE.

  17. Design and Implementation of a FPGA and DSP Based MIMO Radar Imaging System

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2015-06-01

    Full Text Available The work presented in this paper is aimed at the implementation of a real-time multiple-input multiple-output (MIMO imaging radar used for area surveillance. In this radar, the equivalent virtual array method and time-division technique are applied to make 16 virtual elements synthesized from the MIMO antenna array. The chirp signal generater is based on a combination of direct digital synthesizer (DDS and phase locked loop (PLL. A signal conditioning circuit is used to deal with the coupling effect within the array. The signal processing platform is based on an efficient field programmable gates array (FPGA and digital signal processor (DSP pipeline where a robust beamforming imaging algorithm is running on. The radar system was evaluated through a real field experiment. Imaging capability and real-time performance shown in the results demonstrate the practical feasibility of the implementation.

  18. Measurements on MIMO-FRET Nano-Networks Based on Alexa Fluor Dyes

    Science.gov (United States)

    Wojcik, Krzysztof; Solarczyk, Kamil; Kulakowski, Pawel

    2015-05-01

    Nano-communication has gained significant attention in the last few years, as a means to establish information transfer between future nano-machines. Comparing with other communication techniques for nano-scale (calcium ions signaling, molecular or catalytic nanomotors, pheromones propagation, bacteria-based communication), the phenomenon called Forster Resonance Energy Transfer (FRET) offers significantly smaller propagation delays and high channel throughput. In this paper, we report our recent experiments on FRET-based nano-networks performed in the Laboratory of Cell Biophysics of the Jagiellonian University, Krakow. We propose to use Alexa Fluor dyes as nano transmitters and receivers, as they enable to create multiple-input multi-output (MIMO) FRET communication channels and thus enhance FRET efficiency. We measure FRET efficiency values, calculate bit error rates for the measured scenarios and extend the calculations to consider a general case of MIMO (n,m) FRET channels.

  19. Performance Evaluation of Closed-Loop Spatial Multiplexing Codebook Based on Indoor MIMO Channel Measurement

    Directory of Open Access Journals (Sweden)

    Junjun Gao

    2012-01-01

    Full Text Available Closed-loop MIMO technique standardized in LTE can support different layer transmissions through precoding operation to match the channel multiplexing capability. However, the performance of the limited size codebook still needs to be evaluated in real channel environment for further insights. Based on the wideband MIMO channel measurement in a typical indoor scenario, capacity loss (CL of the limited size codebook relative to perfect precoding is studied first in two extreme channel conditions. The results show that current codebook design for single layer transmission is nearly capacity lossless, and the CL will increase with the number of transmitted layers. Furthermore, the capacity improvement of better codebook selection criterions is very limited compared to CL. Then we define the maximum capacity boost achieved by frequency domain layer adaption (FDLA and investigate its sensitivity to SNR and channel condition. To survey the effect of frequency domain channel variation on MIMO-OFDM system, we define a function to measure the fluctuation levels of the key channel metrics within a subband and reveal the inherent relationship between them. Finally, a capacity floor resulted as the feedback interval increases in frequency domain.

  20. A Practical, Hardware Friendly MMSE Detector for MIMO-OFDM-Based Systems

    Directory of Open Access Journals (Sweden)

    Babak Daneshrad

    2008-04-01

    Full Text Available Design and implementation of a highly optimized MIMO (multiple-input multiple-output detector requires cooptimization of the algorithm with the underlying hardware architecture. Special attention must be paid to application requirements such as throughput, latency, and resource constraints. In this work, we focus on a highly optimized matrix inversion free 4×4 MMSE (minimum mean square error MIMO detector implementation. The work has resulted in a real-time field-programmable gate array-based implementation (FPGA- on a Xilinx Virtex-2 6000 using only 9003 logic slices, 66 multipliers, and 24 Block RAMs (less than 33% of the overall resources of this part. The design delivers over 420 Mbps sustained throughput with a small 2.77-microsecond latency. The designed 4×4 linear MMSE MIMO detector is capable of complying with the proposed IEEE 802.11n standard.

  1. Fourier-Based Transmit Beampattern Design Using MIMO Radar

    KAUST Repository

    Lipor, John

    2014-05-01

    In multiple-input multiple-output (MIMO) radar settings, it is often desirable to transmit power only to a given location or set of locations defined by a beampattern. Transmit waveform design is a topic that has received much attention recently, involving synthesis of both the signal covariance matrix,, as well as the actual waveforms. Current methods involve a two-step process of designing via iterative solutions and then using to generate waveforms that fulfill practical constraints such as having a constant-envelope or drawing from a finite alphabet. In this paper, a closed-form method to design for a uniform linear array is proposed that utilizes the discrete Fourier transform (DFT) coefficients and Toeplitz matrices. The resulting covariance matrix fulfills the practical constraints such as positive semidefiniteness and the uniformelemental power constraint and provides performance similar to that of iterative methods, which require a much greater computation time. Next, a transmit architecture is presented that exploits the orthogonality of frequencies at discrete DFT values to transmit a sum of orthogonal signals from each antenna. The resulting waveforms provide a lower mean-square error than current methods at a much lower computational cost, and a simulated detection scenario demonstrates the performance advantages achieved.

  2. Primer on CDM programme of activities

    Energy Technology Data Exchange (ETDEWEB)

    Hinostroza, M. (UNEP Risoe Centre, Roskilde (Denmark)); Lescano, A.D. (A2G Carbon Partners (Peru)); Alvarez, J.M. (Ministerio del Ambiente del Peru (Peru)); Avendano, F.M. (EEA Fund Management Ltd. (United Kingdom)

    2009-07-01

    As an advanced modality introduced in 2005, the Programmatic CDM (POA) is expected to address asymmetries of participation, especially of very small-scale project activities in certain areas, key sectors and many countries with considerable potential for greenhouse gas emission reductions, not reached by the traditional single-project-based CDM. Latest experiences with POAs and the recently finalized official guidance governing the Programmatic CDM are the grassroots of this Primer, which has the purpose of supporting the fully understanding of rules and procedures of POAs by interpreting them and analyzing real POA cases. Professional and experts from the public and private entities have contributed to the development of this Primer, produced by the UNEP Risoe Centre, as part of knowledge support activities for the Capacity Development for the CDM (CD4CDM) project. The overall objective of the CD4CDM is to develop the capacities of host countries to identify, design, approve, finance, implement CDM projects and commercialize CERs in participating countries. The CDM4CDM is funded by the Netherlands Ministry of Foreign Affairs. (author)

  3. Measurement Verification of Plane Wave Synthesis Technique Based on Multi-probe MIMO-OTA Setup

    DEFF Research Database (Denmark)

    Fan, Wei; Carreño, Xavier; Nielsen, Jesper Ødum

    2012-01-01

    Standardization work for MIMO OTA testing methods is currently ongoing, where a multi-probe anechoic chamber based solution is an important candidate. In this paper, the probes located on an OTA ring are used to synthesize a plane wave field in the center of the OTA ring. This paper investigates...... the extent to which we can approach the synthesized plane wave in practical measurement systems. Both single plane wave with certain AoA and multiple plane waves with different AoAs and power weightings are synthesized and measured. Deviations of the measured plane wave and the simulated plane wave field...

  4. A Genetic Algorithm-based Antenna Selection Approach for Large-but-Finite MIMO Networks

    KAUST Repository

    Makki, Behrooz

    2016-12-29

    We study the performance of antenna selectionbased multiple-input-multiple-output (MIMO) networks with large but finite number of transmit antennas and receivers. Considering the continuous and bursty communication scenarios with different users’ data request probabilities, we develop an efficient antenna selection scheme using genetic algorithms (GA). As demonstrated, the proposed algorithm is generic in the sense that it can be used in the cases with different objective functions, precoding methods, levels of available channel state information and channel models. Our results show that the proposed GAbased algorithm reaches (almost) the same throughput as the exhaustive search-based optimal approach, with substantially less implementation complexity.

  5. A Leakage-Based MMSE Beamforming Design for a MIMO Interference Channel

    DEFF Research Database (Denmark)

    Sun, Fan; De Carvalho, Elisabeth

    2012-01-01

    We propose a low complexity design of the linear transmit filters for a MIMO interference channel. This design is based on a minimum mean squared error (MMSE) approach incorporating the signal and the interference leakage for each transmitter. Unlike the previous methods, it allows a closed......-form expression of the regularization factor for the MMSE transmit filter. Hence, it requires a lower computational complexity compared to the conventional MMSE approach that is optimally achieved by solving a polynomial equation to find the regularization factor. Furthermore, the mean squared error (MSE...

  6. CDM Country Guide for Thailand

    International Nuclear Information System (INIS)

    2006-01-01

    Under the Integrated Capacity Strengthening for the CDM (ICS-CDM) programme, IGES presents the CDM Country Guides, a series of manuals on CDM project development for Cambodia, China, India, Indonesia, the Philippines, and Thailand. These guidebooks aim at facilitating CDM project developments in Asia by providing essential information to both project developers and potential investors. This volume is on Thailand

  7. Receiver Architectures for MIMO-OFDM Based on a Combined VMP-SP Algorithm

    DEFF Research Database (Denmark)

    Manchón, Carles Navarro; Kirkelund, Gunvor Elisabeth; Riegler, Erwin

    2011-01-01

    Iterative information processing, either based on heuristics or analytical frameworks, has been shown to be a very powerful tool for the design of efficient, yet feasible, wireless receiver architectures. Within this context, algorithms performing message-passing on a probabilistic graph, such as......Iterative information processing, either based on heuristics or analytical frameworks, has been shown to be a very powerful tool for the design of efficient, yet feasible, wireless receiver architectures. Within this context, algorithms performing message-passing on a probabilistic graph......, such as the sum-product (SP) and variational message passing (VMP) algorithms, have become increasingly popular. In this contribution, we apply a combined VMP-SP message-passing technique to the design of receivers for MIMO-ODFM systems. The message-passing equations of the combined scheme can be obtained from...... the equations of the stationary points of a constrained region-based free energy approximation. When applied to a MIMO-OFDM probabilistic model, we obtain a generic receiver architecture performing iterative channel weight and noise precision estimation, equalization and data decoding. We show that this generic...

  8. Efficient Closed-Loop Schemes for MIMO-OFDM-Based WLANs

    Directory of Open Access Journals (Sweden)

    Jiang Yi

    2006-01-01

    Full Text Available The single-input single-output (SISO orthogonal frequency-division multiplexing (OFDM systems for wireless local area networks (WLAN defined by the IEEE 802.11a standard can support data rates up to 54 Mbps. In this paper, we consider deploying two transmit and two receive antennas to increase the data rate up to 108 Mbps. Applying our recent multiple-input multiple-output (MIMO transceiver designs, that is, the geometric mean decomposition (GMD and the uniform channel decomposition (UCD schemes, we propose simple and efficient closed-loop MIMO-OFDM designs for much improved performance, compared to the standard singular value decomposition (SVD based schemes as well as the open-loop V-BLAST (vertical Bell Labs layered space-time based counterparts. In the explicit feedback mode, precoder feedback is needed for the proposed schemes. We show that the overhead of feedback can be made very moderate by using a vector quantization method. In the time-division duplex (TDD mode where the channel reciprocity is exploited, our schemes turn out to be robust against the mismatch between the uplink and downlink channels. The advantages of our schemes are demonstrated via extensive numerical examples.

  9. CDM Country Guides

    International Nuclear Information System (INIS)

    2005-01-01

    Under the Integrated Capacity Strengthening for the Clean Development Mechanism (ICS-CDM) programme, IGES presents the CDM Country Guides, a series of manuals on CDM project development for Cambodia, China, India, Indonesia, the Philippines, and Thailand. These guidebooks aim at facilitating CDM project developments in Asia by providing essential information to both project developers and potential investors. Chapter 1, Introduction, is a summary of issues that developers and investors in CDM projects should be aware of. Includes tips for readers to effectively use the guidebook to find specific information. Chapter 2, Country Profile, comprises a profile that provides a broad picture of the country, including social, economic, and political information, as well as an overview of the country's energy situation, which is important for project development and investment. Chapter 3, The CDM Project Cycle, gives an explanation of the general CDM project cycle, which includes identifying a project, issuance of carbon credits, requirements, and stakeholders for each process. Chapter 4, Possible CDM Projects in the Country, is an overview of the country's potential resources and sectoral or project type categories that hold potential for CDM projects. Chapter 5, Government Authorities, gives a comprehensive picture of the CDM-related institutional framework and its inter-organisational relationships. Chapter 6, CDM Project Approval Procedures and Requirements Steps, informs about obtaining project approval and its requirements (e.g., country-specific provisions on additionality, sustainable development criteria, and environmental impact assessment) in the host country. Chapter 7, Laws and Regulations, is an overview of basic investment-related laws, environmental and property law, and sector-specific regulations relevant to CDM project activities. Chapter 8, Fiscal and Financing Issues, gives practical information on the financial market in the host country (both

  10. Switched-Observer-Based Adaptive Neural Control of MIMO Switched Nonlinear Systems With Unknown Control Gains.

    Science.gov (United States)

    Long, Lijun; Zhao, Jun

    2017-07-01

    In this paper, the problem of adaptive neural output-feedback control is addressed for a class of multi-input multioutput (MIMO) switched uncertain nonlinear systems with unknown control gains. Neural networks (NNs) are used to approximate unknown nonlinear functions. In order to avoid the conservativeness caused by adoption of a common observer for all subsystems, an MIMO NN switched observer is designed to estimate unmeasurable states. A new switched observer-based adaptive neural control technique for the problem studied is then provided by exploiting the classical average dwell time (ADT) method and the backstepping method and the Nussbaum gain technique. It effectively handles the obstacle about the coexistence of multiple Nussbaum-type function terms, and improves the classical ADT method, since the exponential decline property of Lyapunov functions for individual subsystems is no longer satisfied. It is shown that the technique proposed is able to guarantee semiglobal uniformly ultimately boundedness of all the signals in the closed-loop system under a class of switching signals with ADT, and the tracking errors converge to a small neighborhood of the origin. The effectiveness of the approach proposed is illustrated by its application to a two inverted pendulum system.

  11. A cross-layer resource allocation scheme for spatial multiplexing-based MIMO-OFDMA systems

    Directory of Open Access Journals (Sweden)

    Al-Shatri Hussein

    2011-01-01

    Full Text Available Abstract We investigate the resource allocation problem for the downlink of a multiple-input multiple-output orthogonal frequency division multiple access (MIMO-OFDMA system. The sum rate maximization itself cannot cope with fairness among users. Hence, we address this problem in the context of the utility-based resource allocation presented in earlier papers. This resource allocation method allows to enhance the efficiency and guarantee fairness among users by exploiting multiuser diversity, frequency diversity, as well as time diversity. In this paper, we treat the overall utility as the quality of service indicator and design utility functions with respect to the average transmission rate in order to simultaneously provide two services, real-time and best-effort. Since the optimal solutions are extremely computationally complex to obtain, we propose a suboptimal joint subchannel and power control algorithm that converges very fast and simplifies the MIMO resource allocation problem into a single-input single-output resource allocation problem. Simulation results indicate that using the proposed method achieves near-optimum solutions, and the available resources are distributed more fairly among users.

  12. On the capacity of MIMO-OFDM based diversity and spatial multiplexing in Radio-over-Fiber system

    Science.gov (United States)

    El Yahyaoui, Moussa; El Moussati, Ali; El Zein, Ghaïs

    2017-11-01

    This paper proposes a realistic and global simulation to predict the behavior of a Radio over Fiber (RoF) system before its realization. In this work we consider a 2 × 2 Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) RoF system at 60 GHz. This system is based on Spatial Diversity (SD) which increases reliability (decreases probability of error) and Spatial Multiplexing (SMX) which increases data rate, but not necessarily reliability. The 60 GHz MIMO channel model employed in this work based on a lot of measured data and statistical analysis named Triple-S and Valenzuela (TSV) model. To the authors best knowledge; it is the first time that this type of TSV channel model has been employed for 60 GHz MIMO-RoF system. We have evaluated and compared the performance of this system according to the diversity technique, modulation schemes, and channel coding rate for Line-Of-Sight (LOS) desktop environment. The SMX coded is proposed as an intermediate system to improve the Signal to Noise Ratio (SNR) and the data rate. The resulting 2 × 2 MIMO-OFDM SMX system achieves a higher data rate up to 70 Gb/s with 64QAM and Forward Error Correction (FEC) limit of 10-3 over 25-km fiber transmission followed by 3-m wireless transmission using 7 GHz bandwidth of millimeter wave band.

  13. DFT based spatial multiplexing and maximum ratio transmission for mm-wawe large MIMO

    DEFF Research Database (Denmark)

    Phan-Huy, D.-T.; Tölli, A.; Rajatheva, N.

    2014-01-01

    By using large point-to-point multiple input multiple output (MIMO), spatial multiplexing of a large number of data streams in wireless communications using millimeter-waves (mm-waves) can be achieved. However, according to the antenna spacing and transmitter-receiver distance, the MIMO channel...

  14. Simultaneous Wireless Information and Power Transfer for MIMO Interference Channel Networks Based on Interference Alignment

    Directory of Open Access Journals (Sweden)

    Anming Dong

    2017-09-01

    Full Text Available This paper considers power splitting (PS-based simultaneous wireless information and power transfer (SWIPT for multiple-input multiple-output (MIMO interference channel networks where multiple transceiver pairs share the same frequency spectrum. As the PS model is adopted, an individual receiver splits the received signal into two parts for information decoding (ID and energy harvesting (EH, respectively. Aiming to minimize the total transmit power, transmit precoders, receive filters and PS ratios are jointly designed under a predefined signal-to-interference-plus-noise ratio (SINR and EH constraints. The formulated joint transceiver design and power splitting problem is non-convex and thus difficult to solve directly. In order to effectively obtain its solution, the feasibility conditions of the formulated non-convex problem are first analyzed. Based on the analysis, an iterative algorithm is proposed by alternatively optimizing the transmitters together with the power splitting factors and the receivers based on semidefinite programming (SDP relaxation. Moreover, considering the prohibitive computational cost of the SDP for practical applications, a low-complexity suboptimal scheme is proposed by separately designing interference-suppressing transceivers based on interference alignment (IA and optimizing the transmit power allocation together with splitting factors. The transmit power allocation and receive power splitting problem is then recast as a convex optimization problem and solved efficiently. To further reduce the computational complexity, a low-complexity scheme is proposed by calculating the transmit power allocation and receive PS ratios in closed-form. Simulation results show the effectiveness of the proposed schemes in achieving SWIPT for MIMO interference channel (IC networks.

  15. Root-MUSIC Based Angle Estimation for MIMO Radar with Unknown Mutual Coupling

    Directory of Open Access Journals (Sweden)

    Jianfeng Li

    2014-01-01

    Full Text Available Direction of arrival (DOA estimation problem for multiple-input multiple-output (MIMO radar with unknown mutual coupling is studied, and an algorithm for the DOA estimation based on root multiple signal classification (MUSIC is proposed. Firstly, according to the Toeplitz structure of the mutual coupling matrix, output data of some specified sensors are selected to eliminate the influence of the mutual coupling. Then the reduced-dimension transformation is applied to make the computation burden lower as well as obtain a Vandermonde structure of the direction matrix. Finally, Root-MUSIC can be adopted for the angle estimation. The angle estimation performance of the proposed algorithm is better than that of estimation of signal parameters via rotational invariance techniques (ESPRIT-like algorithm and MUSIC-like algorithm. Furthermore, the proposed algorithm has lower complexity than them. The simulation results verify the effectiveness of the algorithm, and the theoretical estimation error of the algorithm is also derived.

  16. Maximum Likelihood-Based Methods for Target Velocity Estimation with Distributed MIMO Radar

    Directory of Open Access Journals (Sweden)

    Zhenxin Cao

    2018-02-01

    Full Text Available The estimation problem for target velocity is addressed in this in the scenario with a distributed multi-input multi-out (MIMO radar system. A maximum likelihood (ML-based estimation method is derived with the knowledge of target position. Then, in the scenario without the knowledge of target position, an iterative method is proposed to estimate the target velocity by updating the position information iteratively. Moreover, the Carmér-Rao Lower Bounds (CRLBs for both scenarios are derived, and the performance degradation of velocity estimation without the position information is also expressed. Simulation results show that the proposed estimation methods can approach the CRLBs, and the velocity estimation performance can be further improved by increasing either the number of radar antennas or the information accuracy of the target position. Furthermore, compared with the existing methods, a better estimation performance can be achieved.

  17. Sliding mode disturbance observer-based control of a twin rotor MIMO system.

    Science.gov (United States)

    Rashad, Ramy; El-Badawy, Ayman; Aboudonia, Ahmed

    2017-07-01

    This work proposes a robust tracking controller for a helicopter laboratory setup known as the twin rotor MIMO system (TRMS) using an integral sliding mode controller. To eliminate the discontinuity in the control signal, the controller is augmented by a sliding mode disturbance observer. The actuator dynamics is handled using a backstepping approach which is applicable due to the continuous chattering-free nature of the command signals generated using the disturbance observer based controller. To avoid the complexity of analytically differentiating the command signals, a first order sliding mode differentiator is used. Stability analysis of the closed loop system and the ultimate boundedness of the tracking error is proved using Lyapunov stability arguments. The proposed controller is validated by several simulation studies and is compared to other schemes in the literature. Experimental results using a hardware-in-the-loop system validate the robustness and effectiveness of the proposed controller. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  18. MIMO Lyapunov Theory-Based RBF Neural Classifier for Traffic Sign Recognition

    Directory of Open Access Journals (Sweden)

    King Hann Lim

    2012-01-01

    Full Text Available Lyapunov theory-based radial basis function neural network (RBFNN is developed for traffic sign recognition in this paper to perform multiple inputs multiple outputs (MIMO classification. Multidimensional input is inserted into RBF nodes and these nodes are linked with multiple weights. An iterative weight adaptation scheme is hence designed with regards to the Lyapunov stability theory to obtain a set of optimum weights. In the design, the Lyapunov function has to be well selected to construct an energy space with a single global minimum. Weight gain is formed later to obey the Lyapunov stability theory. Detail analysis and discussion on the proposed classifier’s properties are included in the paper. The performance comparisons between the proposed classifier and some existing conventional techniques are evaluated using traffic sign patterns. Simulation results reveal that our proposed system achieved better performance with lower number of training iterations.

  19. Wireless Distributed Antenna MIMO

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to system applications of multicore optical fibers. One embodiment relates to a base transceiver station for a wireless telecommunication system comprising a plurality of antenna units arranged in a MIMO configuration and adapted for transmission and/or reception...

  20. Remote sensing using MIMO systems

    Science.gov (United States)

    Bikhazi, Nicolas; Young, William F; Nguyen, Hung D

    2015-04-28

    A technique for sensing a moving object within a physical environment using a MIMO communication link includes generating a channel matrix based upon channel state information of the MIMO communication link. The physical environment operates as a communication medium through which communication signals of the MIMO communication link propagate between a transmitter and a receiver. A spatial information variable is generated for the MIMO communication link based on the channel matrix. The spatial information variable includes spatial information about the moving object within the physical environment. A signature for the moving object is generated based on values of the spatial information variable accumulated over time. The moving object is identified based upon the signature.

  1. Seamless Translation of Optical Fiber PolMux-OFDM into a 2x2 MIMO Wireless Transmission Enabled by Digital Training-Based Fiber-Wireless Channel Estimation

    DEFF Research Database (Denmark)

    Pang, Xiaodan; Zhao, Ying; Deng, Lei

    2011-01-01

    We propose and demonstrate a 2 × 2 multiple-input multiple-output (MIMO) wireless over fiber transmission system. Seamless translation of two orthogonal frequency division multiplexing (OFDM) signals on dual optical polarization states into wireless MIMO transmission at 795.5 Mbit/s net data rate...... is enabled by using digital training-based channel estimation. A net spectral efficiency of 2.55 bit/s/Hz is achieved....

  2. High-Dimensional Analysis of Convex Optimization-Based Massive MIMO Decoders

    KAUST Repository

    Ben Atitallah, Ismail

    2017-04-01

    A wide range of modern large-scale systems relies on recovering a signal from noisy linear measurements. In many applications, the useful signal has inherent properties, such as sparsity, low-rankness, or boundedness, and making use of these properties and structures allow a more efficient recovery. Hence, a significant amount of work has been dedicated to developing and analyzing algorithms that can take advantage of the signal structure. Especially, since the advent of Compressed Sensing (CS) there has been significant progress towards this direction. Generally speaking, the signal structure can be harnessed by solving an appropriate regularized or constrained M-estimator. In modern Multi-input Multi-output (MIMO) communication systems, all transmitted signals are drawn from finite constellations and are thus bounded. Besides, most recent modulation schemes such as Generalized Space Shift Keying (GSSK) or Generalized Spatial Modulation (GSM) yield signals that are inherently sparse. In the recovery procedure, boundedness and sparsity can be promoted by using the ℓ1 norm regularization and by imposing an ℓ∞ norm constraint respectively. In this thesis, we propose novel optimization algorithms to recover certain classes of structured signals with emphasis on MIMO communication systems. The exact analysis permits a clear characterization of how well these systems perform. Also, it allows an automatic tuning of the parameters. In each context, we define the appropriate performance metrics and we analyze them exactly in the High Dimentional Regime (HDR). The framework we use for the analysis is based on Gaussian process inequalities; in particular, on a new strong and tight version of a classical comparison inequality (due to Gordon, 1988) in the presence of additional convexity assumptions. The new framework that emerged from this inequality is coined as Convex Gaussian Min-max Theorem (CGMT).

  3. Maximizing Channel Capacity based on Antenna and MIMO Channel Characteristics and its Application to Multimedia Data Transmission

    Science.gov (United States)

    Pottkotter, Andrew

    Communication transmission between electronic devices is evolving at an ever faster pace. There are now more electronic handheld devices that we communicate with on a daily basis. The allotted bandwidth and speed for these devices are limited by hardware, software, handshaking capabilities between each electronic application. The demand for information at high data rates without the loss of reliability has evolved antenna technology and digital signal processing into more complex systems utilizing multiple processors and multiple antennas. This paper discusses the various techniques used to increase data speed, enhance channel capacity, and reliability of application specific devices with respect to the Multiple-Input-to-Multiple-Output (MIMO) based methods. MIMO based applications can improve the data speed, channel capacity, and reliability of the system with maximum limitations based on hardware, coding schemes, and handshaking abilities between devices.

  4. BER Analysis of Various Channel Equalization Schemes of a QO-STBC Encoded OFDM based MIMO CDMA System

    OpenAIRE

    Husnul Ajra; Md. Zahid Hasan; Md. Shohidul Islam

    2014-01-01

    Quasi Orthogonal Space Time Block Code (QO-STBC) can provide full-rate transmission and low decoding complexity. This paper deals with channel estimation for Quasi Orthogonal Space Time Block Code (QO-STBC) encoded Orthogonal Frequency Division Multiplexing (OFDM) based Multiple Input multiple Output (MIMO) Code Division Multiple Access (CDMA) system. Using the QO-STBC coding property, we analysis the weight performance that reduce the computational complexity of system. The design of channel...

  5. 2D Unitary ESPRIT Based Super-Resolution Channel Estimation for Millimeter-Wave Massive MIMO with Hybrid Precoding

    KAUST Repository

    Liao, Anwen

    2017-11-01

    Millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) with hybrid precoding is a promising technique for the future 5G wireless communications. Due to a large number of antennas but a much smaller number of radio frequency (RF) chains, estimating the high-dimensional mmWave massive MIMO channel will bring the large pilot overhead. To overcome this challenge, this paper proposes a super-resolution channel estimation scheme based on two-dimensional (2D) unitary ESPRIT algorithm. By exploiting the angular sparsity of mmWave channels, the continuously distributed angle of arrivals/departures (AoAs/AoDs) can be jointly estimated with high accuracy. Specifically, by designing the uplink training signals at both base station (BS) and mobile station (MS), we first use low pilot overhead to estimate a low-dimensional effective channel, which has the same shift-invariance of array response as the high-dimensional mmWave MIMO channel to be estimated. From the low-dimensional effective channel, the superresolution estimates of AoAs and AoDs can be jointly obtained by exploiting the 2D unitary ESPRIT channel estimation algorithm. Furthermore, the associated path gains can be acquired based on the least squares (LS) criterion. Finally, we can reconstruct the high-dimensional mmWave MIMO channel according to the obtained AoAs, AoDs, and path gains. Simulation results have confirmed that the proposed scheme is superior to conventional schemes with a much lower pilot overhead.

  6. CDM 20 years after

    NARCIS (Netherlands)

    Lööf, H.; Mairesse, J.; Mohnen, P.

    2017-01-01

    In year 1998, the seminal paper Research Innovation and Productivity: An Econometric Analysis at the Firm Level was published in this journal. The empirical framework, following on ideas in the research of Zvi Griliches at the NBER and commonly labeled CDM (the acronym of the three authors’ names,

  7. DFT-Based Closed-form Covariance Matrix and Direct Waveforms Design for MIMO Radar to Achieve Desired Beampatterns

    KAUST Repository

    Bouchoucha, Taha

    2017-01-23

    In multiple-input multiple-out (MIMO) radar, for desired transmit beampatterns, appropriate correlated waveforms are designed. To design such waveforms, conventional MIMO radar methods use two steps. In the first step, the waveforms covariance matrix, R, is synthesized to achieve the desired beampattern. While in the second step, to realize the synthesized covariance matrix, actual waveforms are designed. Most of the existing methods use iterative algorithms to solve these constrained optimization problems. The computational complexity of these algorithms is very high, which makes them difficult to use in practice. In this paper, to achieve the desired beampattern, a low complexity discrete-Fourier-transform based closed-form covariance matrix design technique is introduced for a MIMO radar. The designed covariance matrix is then exploited to derive a novel closed-form algorithm to directly design the finite-alphabet constant-envelope waveforms for the desired beampattern. The proposed technique can be used to design waveforms for large antenna array to change the beampattern in real time. It is also shown that the number of transmitted symbols from each antenna depends on the beampattern and is less than the total number of transmit antenna elements.

  8. Observer-Based Robust Adaptive Fuzzy Control for MIMO Nonlinear Uncertain Systems with Delayed Output

    Directory of Open Access Journals (Sweden)

    Chiang Cheng Chiang

    2013-01-01

    Full Text Available An observer-based robust adaptive fuzzy control scheme is presented to tackle the problem of the robust stability and the tracking control for a class of multiinput multioutput (MIMO nonlinear uncertain systems with delayed output. Because the nonlinear system functions and the uncertainties of the controlled system including structural uncertainties are supposed to be unknown, fuzzy logic systems are utilized to approximate these nonlinear system functions and the upper bounded functions of the uncertainties. Moreover, the upper bound of uncertainties caused by these fuzzy modeling errors is also estimated. In addition, the state observer based on state variable filters is designed to estimate all states which are not available for measurement in the controlled system. By constructing an appropriate Lyapunov function and using strictly positive-real (SPR stability theorem, the proposed robust adaptive fuzzy controller not only guarantees the robust stability of a class of multivariable nonlinear uncertain systems with delayed output but also maintains a good tracking performance. Finally, some simulation results are illustrated to verify the effectiveness of the proposed control approach.

  9. An Interference Cancellation Scheme for High Reliability Based on MIMO Systems

    Directory of Open Access Journals (Sweden)

    Jae-Hyun Ro

    2018-03-01

    Full Text Available This article proposes a new interference cancellation scheme in a half-duplex based two-path relay system. In the conventional two-path relay system, inter-relay-interference (IRI which severely degrades the error performances at a destination occurs because a source and a relay transmit signals simultaneously at a specific time. The proposed scheme removes the IRI at a relay for higher signal-to-interference plus noise ratio (SINR to receive interference free signal at a destination, unlike the conventional relay system, which removes IRI at a destination. To handle the IRI, the proposed scheme uses multiple-input multiple-output (MIMO signal detection at the relays and it makes low-complexity signal processing at a destination which is a usually mobile user. At the relays, the proposed scheme uses the low-complexity QR decomposition-M algorithm (QRD-M to optimally remove the IRI. Also, for obtaining diversity gain, the proposed scheme uses cyclic delay diversity (CDD to transmit the signals at a source and the relays. In simulation results, the error performance for the proposed scheme is better when the distance between one relay and another relay is low unlike the conventional scheme because the QRD-M detects received signal in order of higher post signal-to-noise ratio (SNR.

  10. An approach to design controllers for MIMO fractional-order plants based on parameter optimization algorithm.

    Science.gov (United States)

    Xue, Dingyü; Li, Tingxue

    2017-04-27

    The parameter optimization method for multivariable systems is extended to the controller design problems for multiple input multiple output (MIMO) square fractional-order plants. The algorithm can be applied to search for the optimal parameters of integer-order controllers for fractional-order plants with or without time delays. Two examples are given to present the controller design procedures for MIMO fractional-order systems. Simulation studies show that the integer-order controllers designed are robust to plant gain variations. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Digital Beam Forming and Compressive Sensing Based DOA Estimation in MIMO Arrays

    NARCIS (Netherlands)

    Belfiori, F.; Anitori, L.; Rossum, W.L. van; Otten, M.P.G.; Hoogeboom, P.

    2011-01-01

    The paper presents different processing schemes that have been investigated in order to evaluate the direction of arrival (DOA) with a multiple-input multiple-output (MIMO) radar. Conventional digital beam forming (DBF) and super resolution algorithm (MUSIC) have been applied. The results provided

  12. Performance Testing of Massive MIMO Base Station with Multi-Probe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Zhang, Fengchun; Fan, Wei; Ji, Yilin

    2018-01-01

    . In this paper, we present a sectorized multi-probe anechoic chamber (MPAC) configuration equipped with a switch box for massive MIMO BS OTA testing. Simulations were performed for a BS equipped with an 88 planar array of half-wavelength element spacing at 3:5 GHz, where 1 m measurement range and 8 active OTA...

  13. IMC based Smith predictor design with PI+CI structure : Control of delayed MIMO systems

    NARCIS (Netherlands)

    Shakibjoo, A.D.; Vasegh, N.; Hossein Nia Kani, S.H.

    2016-01-01

    In this study a novel structure for time-delay MIMO systems controller design is introduced. In this method decoupled Smith predictor (SP) controller is designed using Internal Model Control structure (IMC). In order to approximate decoupled system, step response model approximation is employed and

  14. Channelization Issues with Fairness Considerations for MU-MIMO Precoding Based UTRA-LTE/TDD Systems

    DEFF Research Database (Denmark)

    Rahman, Muhammad Imadur; Wang, Yuanye; Das, Suvra

    2008-01-01

    In a pre-coded Multi User Multiple Input Multiple Output (MU-MIMO) system, the channelization can be done either by using any of the two basic access techniques, namely Orthogonal Frequency Division Multiple Access (OFDMA) and Space Division Multiple Access (SDMA), or by combining them. From reso...

  15. Developed feedback from the Swedish CDM and JI program; Utvecklad aaterrapportering fraan det svenska CDM- och JI-programmet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    The Swedish Energy Agency is responsible for the Swedish government program for the Clean Development Mechanism (CDM) and Joint Implementation (JI). CDM and JI is the Kyoto Protocol's two project-based flexible mechanisms. This program focuses on participation in individual CDM- and JI-projects and on participation in multilateral CDM- and JI- funds. In the report the Swedish Energy Agency, on behalf of the Government, presents a proposal for developed reporting for the CDM- and JI-program. Furthermore, issues related to how CDM and JI can assist in meeting the Swedish climate objective by 2020 are discussed. Also, the role for potential new flexible mechanisms under UN Climate Convention is mentioned.

  16. Potential impacts of CCS on the CDM

    International Nuclear Information System (INIS)

    Bakker, S; Mikunda, T.; Rivera Tinoco, R.

    2011-02-01

    CO2 capture and storage can ensure that stringent climate change mitigation targets are achieved more cost-effectively. However, in order to ensure a substantial role for CCS, deployment of CCS is required on a significant global scale by 2020. Currently, the CDM is the only international instrument that could provide a financial incentive for CCS in developing countries. In December 2010 it was decided that CCS could in principle be eligible under the CDM, provided a number of issues are resolved, including non-permanence, liability, monitoring and potential perverse outcomes. The latter issue relates to the concern that that CCS projects could flood the CDM market, thereby crowding out other technologies that could be considered more sustainable. This report, therefore, aims to quantify the possible impact of CCS on the CDM market, in order to assess the relevance of the CDM market objection. However, the analysis in the report is also valid for the role of CCS in other types of international support mechanisms. The first result of this study is a marginal abatement cost curve (MAC) for CCS in developing countries for 2020. Based on existing MAC studies, the IEA CCS Roadmap and an overview of ongoing and planned CCS activities, we compiled three scenarios for CCS in the power, industry and upstream sector, as shown below. The major part of the potential below $30/tCO2eq (70 - 100 MtCO2/yr) is in the natural gas processing sector. Using the MACs for the CDM market, we estimate the economic potential for CCS projects to be 4-19% of the CDM credit supply in 2020. The potential impact inclusion of CCS in the CDM may have is assessed by using several possible CER supply and demand scenarios, as well as scenarios related to market price responsiveness and the role of CDM in the post-2012 carbon market. The impact is estimated to be between $0 and $4 per tonne of CO2-eq, with three out of four scenarios indicating the lower part of this range.

  17. A Two-Stage Space-Time Adaptive Processing Method for MIMO Radar Based on Sparse Reconstruction

    Science.gov (United States)

    Liu, Hanwei; Zhang, Yongshun; Guo, Yiduo; Wang, Qiang

    2017-10-01

    To effectively suppress clutter and blocking interference for MIMO radar, a two-stage STAP method based on sparse reconstruction is proposed. As interference is sparse in spatial domain, the subspace of it is estimated with only one snapshot by using Orthogonal Matching Pursuit (OMP) algorithm, and the array data is projected onto the complementary subspace of interference. In the sequel, matched-filtering is applied to the output data followed by clutter suppression with temporal and spatial freedom. The clutter suppression is utilized directly to reduced-dimension STAP (RD-STAP) algorithms. Simulation results demonstrate that the proposed method outperforms traditional methods and reduces sample requirement.

  18. The promise of downlink MU-MIMO for high-capacity next generation mobile broadband networks based on IEEE 802.16 m

    Directory of Open Access Journals (Sweden)

    Papathanassiou Apostolos

    2011-01-01

    Full Text Available Abstract The dramatic increase of the demand for mobile broadband services poses stringent requirements on the performance evolution of currently deployed mobile broadband networks, such as Mobile WiMAX Release 1 and 3GPP LTE Release 8. Although the combination of single-user multiple-input multiple-output (SU-MIMO and orthogonal frequency division multiple access (OFDMA provide the appropriate technologies for improving the downlink performance of third generation (3G code division multiple access (CDMA-based mobile radio systems and, thus, address the current mobile internet requirements, a fundamental paradigm shift is required to cope with the constantly increasing mobile broadband data rate and spectral efficiency requirements. Among the different technologies available for making the paradigm shift from current to next-generation mobile broadband networks, multiuser MIMO (MU-MIMO constitutes the most promising technology because of its significant performance improvement advantages. In this article, we analyze the performance of MU-MIMO under a multitude of deployment scenarios and system parameters through extensive system-level simulations which are based on widely used system-level evaluation methodologies. The target mobile broadband system used in the simulations is IEEE 802.16 m which was recently adopted by ITU-R as an IMT-Advanced technology along with 3GPP LTE-Advanced. The results provide insights into different aspects of MU-MIMO with respect to system-level performance, parameter sensitivity, and deployment scenarios, and they can be used by the mobile broadband network designer for maximizing the benefits of MU-MIMO in a scenario with specific deployment requirements and goals.

  19. Reinforcement learning design-based adaptive tracking control with less learning parameters for nonlinear discrete-time MIMO systems.

    Science.gov (United States)

    Liu, Yan-Jun; Tang, Li; Tong, Shaocheng; Chen, C L Philip; Li, Dong-Juan

    2015-01-01

    Based on the neural network (NN) approximator, an online reinforcement learning algorithm is proposed for a class of affine multiple input and multiple output (MIMO) nonlinear discrete-time systems with unknown functions and disturbances. In the design procedure, two networks are provided where one is an action network to generate an optimal control signal and the other is a critic network to approximate the cost function. An optimal control signal and adaptation laws can be generated based on two NNs. In the previous approaches, the weights of critic and action networks are updated based on the gradient descent rule and the estimations of optimal weight vectors are directly adjusted in the design. Consequently, compared with the existing results, the main contributions of this paper are: 1) only two parameters are needed to be adjusted, and thus the number of the adaptation laws is smaller than the previous results and 2) the updating parameters do not depend on the number of the subsystems for MIMO systems and the tuning rules are replaced by adjusting the norms on optimal weight vectors in both action and critic networks. It is proven that the tracking errors, the adaptation laws, and the control inputs are uniformly bounded using Lyapunov analysis method. The simulation examples are employed to illustrate the effectiveness of the proposed algorithm.

  20. Optical and millimeter-wave radio seamless MIMO transmission based on a radio over fiber technology.

    Science.gov (United States)

    Kanno, Atsushi; Kuri, Toshiaki; Hosako, Iwao; Kawanishi, Tetsuya; Yoshida, Yuki; Yasumura, Yoshihiro; Kitayama, Ken-ichi

    2012-12-31

    Multi-input multi-output (MIMO) transmission of two millimeter-wave radio signals seamlessly converted from polarization-division-multiplexed quadrature-phase-shift-keying optical signals is successfully demonstrated, where a radio access unit basically consisting of only optical-to-electrical converters and a radio receiver performs total signal equalization of both the optical and the radio paths and demodulation with digital signal processing (DSP). Orthogonally polarized optical components that are directly converted to two-channel radio components can be demultiplexed and demodulated with high-speed DSP as in optical digital coherent detection. 20-Gbaud optical and radio seamless MIMO transmission provides a total capacity of 74.4 Gb/s with a forward error correction overhead of 7%.

  1. Leakage based precoding for multi-user MIMO-OFDM systems

    KAUST Repository

    Sadek, Mirette

    2011-08-01

    In downlink multi-user multiple-input multiple-output (MIMO) transmissions, several precoding schemes have been proposed to decrease interference among users. Notable among these precoding schemes is one that uses the signal-to-leakage-plus-noise ratio (SLNR) as an optimization criterion. In this paper, leveraging the efficiency of the SLNR optimization, we generalize this precoding scheme to MIMO orthogonal frequency division multiplexing (OFDM) multi-user systems where the OFDM is used to overcome the inter-symbol- interference (ISI) introduced by multipath channels. We also introduce a channel compensation technique that reconstructs the channel at the transmitter for every time instant given a significantly lower channel feedback rate by the receiver. © 2006 IEEE.

  2. Design of Wideband MIMO Car-to-Car Channel Models Based on the Geometrical Street Scattering Model

    Directory of Open Access Journals (Sweden)

    Nurilla Avazov

    2012-01-01

    Full Text Available We propose a wideband multiple-input multiple-output (MIMO car-to-car (C2C channel model based on the geometrical street scattering model. Starting from the geometrical model, a MIMO reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS and non-LOS (NLOS propagation environments. The proposed channel model assumes an infinite number of scatterers, which are uniformly distributed in two rectangular areas located on both sides of the street. Analytical solutions are presented for the space-time-frequency cross-correlation function (STF-CCF, the two-dimensional (2D space CCF, the time-frequency CCF (TF-CCF, the temporal autocorrelation function (ACF, and the frequency correlation function (FCF. An efficient sum-of-cisoids (SOCs channel simulator is derived from the reference model. It is shown that the temporal ACF and the FCF of the SOC channel simulator fit very well to the corresponding correlation functions of the reference model. To validate the proposed channel model, the mean Doppler shift and the Doppler spread of the reference model have been matched to real-world measurement data. The comparison results demonstrate an excellent agreement between theory and measurements, which confirms the validity of the derived reference model. The proposed geometry-based channel simulator allows us to study the effect of nearby street scatterers on the performance of C2C communication systems.

  3. MIMO-OFDM Chirp Waveform Diversity Design and Implementation Based on Sparse Matrix and Correlation Optimization

    Directory of Open Access Journals (Sweden)

    Wang Wen-qin

    2015-02-01

    Full Text Available The waveforms used in Multiple-Input Multiple-Output (MIMO Synthetic Aperture Radar (SAR should have a large time-bandwidth product and good ambiguity function performance. A scheme to design multiple orthogonal MIMO SAR Orthogonal Frequency Division Multiplexing (OFDM chirp waveforms by combinational sparse matrix and correlation optimization is proposed. First, the problem of MIMO SAR waveform design amounts to the associated design of hopping frequency and amplitudes. Then a iterative exhaustive search algorithm is adopted to optimally design the code matrix with the constraints minimizing the block correlation coefficient of sparse matrix and the sum of cross-correlation peaks. And the amplitudes matrix are adaptively designed by minimizing the cross-correlation peaks with the genetic algorithm. Additionally, the impacts of waveform number, hopping frequency interval and selectable frequency index are also analyzed. The simulation results verify the proposed scheme can design multiple orthogonal large time-bandwidth product OFDM chirp waveforms with low cross-correlation peak and sidelobes and it improves ambiguity performance.

  4. A 2 x 2 imaging MIMO system based on LED Visible Light Communications employing space balanced coding and integrated PIN array reception

    DEFF Research Database (Denmark)

    Li, Jiehui; Xu, Yinfan; Shi, Jianyang

    2016-01-01

    In this paper, we proposed a 2 x 2 imaging Multi-Input Multi-Output (MIMO)-Visible Light Communication (VLC) system by employing Space Balanced Coding (SBC) based on two RGB LEDs and integrated PIN array reception. We experimentally demonstrated 1.4-Gbit/s VLC transmission at a distance of 2.5 m...

  5. Single-Side Two-Location Spotlight Imaging for Building Based on MIMO Through-Wall-Radar

    Directory of Open Access Journals (Sweden)

    Yong Jia

    2016-09-01

    Full Text Available Through-wall-radar imaging is of interest for mapping the wall layout of buildings and for the detection of stationary targets within buildings. In this paper, we present an easy single-side two-location spotlight imaging method for both wall layout mapping and stationary target detection by utilizing multiple-input multiple-output (MIMO through-wall-radar. Rather than imaging for building walls directly, the images of all building corners are generated to speculate wall layout indirectly by successively deploying the MIMO through-wall-radar at two appropriate locations on only one side of the building and then carrying out spotlight imaging with two different squint-views. In addition to the ease of implementation, the single-side two-location squint-view detection also has two other advantages for stationary target imaging. The first one is the fewer multi-path ghosts, and the second one is the smaller region of side-lobe interferences from the corner images in comparison to the wall images. Based on Computer Simulation Technology (CST electromagnetic simulation software, we provide multiple sets of validation results where multiple binary panorama images with clear images of all corners and stationary targets are obtained by combining two single-location images with the use of incoherent additive fusion and two-dimensional cell-averaging constant-false-alarm-rate (2D CA-CFAR detection.

  6. Guidebook to financing CDM projects

    Energy Technology Data Exchange (ETDEWEB)

    Kamel, S.

    2007-07-01

    One of the challenges facing Clean Development Mechanism (CDM) projects today is their limited ability to secure financing for the underlying greenhouse gas emission reduction activities, particularly in the least developed countries. Among the key reasons for this is the fact that most financial intermediaries in the CDM host countries have limited or no knowledge of the CDM Modalities and Procedures. Moreover, approaches, tools and skills for CDM project appraisal are lacking or are asymmetrical to the skills in comparable institutions in developed countries. Consequently, developing country financial institutions are unable to properly evaluate the risks and rewards associated with investing or lending to developers undertaking CDM projects, and therefore have, by-and-large, refrained from financing these projects. In addition, some potential project proponents lack experience in structuring arrangements for financing a project. This Guidebook - commissioned by the UNEP Risoe Centre as part of the activities of the Capacity Development for CDM (CD4CDM) project (http://www.cd4cdm.org) - addresses these barriers by providing information aimed at both developing country financial institutions and at CDM project proponents. It should be noted that while the Guidebook was developed particularly with the CDM in mind, most sections will also be relevant for Joint Implementation (JI) project activities. For more detailed information on JI modalities and procedures please consult: http://ji.unfccc.int The purpose of this Guidebook is two-fold: 1) To guide project developers on obtaining financing for the implementation of activities eligible under the CDM; and 2) To demonstrate to developing country financial institutions typical approaches and methods for appraising the viability of CDM projects and for optimally integrating carbon revenue into overall project financing. The target audiences for the Guidebook are therefore, primarily: 1) CDM project proponents in

  7. Employment impacts of CDM projects in China's power sector

    International Nuclear Information System (INIS)

    Wang, Can; Zhang, Weishi; Cai, Wenjia; Xie, Xi

    2013-01-01

    There are continuous debates around the question of whether CDM really contributes to sustainable development (SD) in host countries. Employment impact is an essential indicator of SD. Based on an input-out approach this research builds a quantitative assessment model to evaluate the employment impacts of CDM. Both direct and indirect jobs creation and job losses of CDM projects in the power sector registered by the end of 2011 are calculated by project types and power grids where the project is located. Results of this study show that, although the above mentioned CDM projects causes about 99,000 net direct job losses, they also create about 3.08 million indirect jobs, resulting in the gross employment of CDM to be about 2.98 million. Thereof, hydro projects induce both direct and indirect job losses, which comes to approximately 0.89 million. Solar projects have the most potential since they own the highest indirect jobs created by one GWh generation, about 104 jobs/GWh. - Highlights: • An input–output model was built for assessment of CDM projects' employment impact; • CDM projects create direct and indirect jobs while cause some losses in short. • Significant indirect job gains of CDM projects were found; • Solar projects cause 104 jobs/GWh in average, ranking as the highest contributor

  8. Opportunistic Error Correction for MIMO

    NARCIS (Netherlands)

    Shao, X.; Slump, Cornelis H.

    In this paper, we propose an energy-efficient scheme to reduce the power consumption of ADCs in MIMO-OFDM systems. The proposed opportunistic error correction scheme is based on resolution adaptive ADCs and fountain codes. The key idea is to transmit a fountain-encoded packet over one single

  9. A Multiuser MIMO Transmit Beamformer Based on the Statistics of the Signal-to-Leakage Ratio

    Directory of Open Access Journals (Sweden)

    Chalise BatuK

    2009-01-01

    Full Text Available A multiuser multiple-input multiple-output (MIMO downlink communication system is analyzed in a Rayleigh fading environment. The approximate closed-form expressions for the probability density function (PDF of the signal-to-leakage ratio (SLR, its average, and the outage probability have been derived in terms of the transmit beamformer weight vector. With the help of some conservative derivations, it has been shown that the transmit beamformer which maximizes the average SLR also minimizes the outage probability of the SLR. Computer simulations are carried out to compare the theoretical and simulation results for the channels whose spatial correlations are modeled with different methods.

  10. The Learning Process and Technological Change in Wind Power: Evidence from China's CDM Wind Projects

    Science.gov (United States)

    Tang, Tian; Popp, David

    2016-01-01

    The Clean Development Mechanism (CDM) is a project-based carbon trade mechanism that subsidizes the users of climate-friendly technologies and encourages technology transfer. The CDM has provided financial support for a large share of Chinese wind projects since 2002. Using pooled cross-sectional data of 486 registered CDM wind projects in China…

  11. CDM Convective Forecast Planning guidance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The CDM Convective Forecast Planning (CCFP) guidance product provides a foreast of en-route aviation convective hazards. The forecasts are updated every 2 hours and...

  12. Low complexity MIMO receivers

    CERN Document Server

    Bai, Lin; Yu, Quan

    2014-01-01

    Multiple-input multiple-output (MIMO) systems can increase the spectral efficiency in wireless communications. However, the interference becomes the major drawback that leads to high computational complexity at both transmitter and receiver. In particular, the complexity of MIMO receivers can be prohibitively high. As an efficient mathematical tool to devise low complexity approaches that mitigate the interference in MIMO systems, lattice reduction (LR) has been widely studied and employed over the last decade. The co-authors of this book are world's leading experts on MIMO receivers, and here they share the key findings of their research over years. They detail a range of key techniques for receiver design as multiple transmitted and received signals are available. The authors first introduce the principle of signal detection and the LR in mathematical aspects. They then move on to discuss the use of LR in low complexity MIMO receiver design with respect to different aspects, including uncoded MIMO detection...

  13. Deployment and Implementation Strategies for Massive MIMO in 5G

    DEFF Research Database (Denmark)

    Panzner, Berthold; Zirwas, Wolfgang; Dierks, Stefan

    2015-01-01

    Massive MIMO has emerged as one technology enabler for the next generation mobile communications 5G. The gains promised by massive MIMO are augured to overcome the capacity crunch in today's mobile networks and to pave the way for the ambitious targets of 5G. The challenge to realize massive MIMO...... for 5G is a successful and cost-efficient integration in the overall network concept. This work highlights deployment and implementation strategies for massive MIMO in the context of 5G indoor small cell scenarios. Different massive MIMO deployment scenarios are analyzed for a standard 3GPP indoor...... to spatial streams is varied stepwise from equality to a factor of ten. For implementation of massive MIMO in 5G networks trends in beamforming techniques, mutually coupled subarrays, over the calibration procedure and estimated ADC performance in 2020 time-frame are discussed. Based on the debate the paper...

  14. Model-Free Primitive-Based Iterative Learning Control Approach to Trajectory Tracking of MIMO Systems With Experimental Validation.

    Science.gov (United States)

    Radac, Mircea-Bogdan; Precup, Radu-Emil; Petriu, Emil M

    2015-11-01

    This paper proposes a novel model-free trajectory tracking of multiple-input multiple-output (MIMO) systems by the combination of iterative learning control (ILC) and primitives. The optimal trajectory tracking solution is obtained in terms of previously learned solutions to simple tasks called primitives. The library of primitives that are stored in memory consists of pairs of reference input/controlled output signals. The reference input primitives are optimized in a model-free ILC framework without using knowledge of the controlled process. The guaranteed convergence of the learning scheme is built upon a model-free virtual reference feedback tuning design of the feedback decoupling controller. Each new complex trajectory to be tracked is decomposed into the output primitives regarded as basis functions. The optimal reference input for the control system to track the desired trajectory is next recomposed from the reference input primitives. This is advantageous because the optimal reference input is computed straightforward without the need to learn from repeated executions of the tracking task. In addition, the optimization problem specific to trajectory tracking of square MIMO systems is decomposed in a set of optimization problems assigned to each separate single-input single-output control channel that ensures a convenient model-free decoupling. The new model-free primitive-based ILC approach is capable of planning, reasoning, and learning. A case study dealing with the model-free control tuning for a nonlinear aerodynamic system is included to validate the new approach. The experimental results are given.

  15. Covariance-based Spatial Channel Structure Emulation for MIMO OTA Testing

    DEFF Research Database (Denmark)

    Tsakalaki, Elpiniki; Alrabadi, Osama; Fan, Wei

    2014-01-01

    The paper presents a general framework for recreating the spatial channel structure in a MIMO over-the-air (OTA) multiprobe anechoic chamber testing setup. The idea is to find the power weights of the spatial taps (antenna probes) that minimize a certain distance between the spatial channel covar...... among the antennas-under-test by considering the whole spatial covariance structure. The simulation results validate the improved performance of the suggested approach in terms of emulation accuracy compared to the key emulation methods proposed in the literature....... covariance matrix corresponding to the desired (continuous) channel and the covariance related to the emulated (discrete) channel within the test area. Unlike previous methods that merely rely on the spatial correlation coefficient, the proposed approach properly accounts for emulating the power imbalance...

  16. Reduced complexity FFT-based DOA and DOD estimation for moving target in bistatic MIMO radar

    KAUST Repository

    Ali, Hussain

    2016-06-24

    In this paper, we consider a bistatic multiple-input multiple-output (MIMO) radar. We propose a reduced complexity algorithm to estimate the direction-of-arrival (DOA) and direction-of-departure (DOD) for moving target. We show that the calculation of parameter estimation can be expressed in terms of one-dimensional fast-Fourier-transforms which drastically reduces the complexity of the optimization algorithm. The performance of the proposed algorithm is compared with the two-dimension multiple signal classification (2D-MUSIC) and reduced-dimension MUSIC (RD-MUSIC) algorithms. It is shown by simulations, our proposed algorithm has better estimation performance and lower computational complexity compared to the 2D-MUSIC and RD-MUSIC algorithms. Moreover, simulation results also show that the proposed algorithm achieves the Cramer-Rao lower bound. © 2016 IEEE.

  17. Linear precoding based on polynomial expansion: reducing complexity in massive MIMO

    KAUST Repository

    Mueller, Axel

    2016-02-29

    Massive multiple-input multiple-output (MIMO) techniques have the potential to bring tremendous improvements in spectral efficiency to future communication systems. Counterintuitively, the practical issues of having uncertain channel knowledge, high propagation losses, and implementing optimal non-linear precoding are solved more or less automatically by enlarging system dimensions. However, the computational precoding complexity grows with the system dimensions. For example, the close-to-optimal and relatively “antenna-efficient” regularized zero-forcing (RZF) precoding is very complicated to implement in practice, since it requires fast inversions of large matrices in every coherence period. Motivated by the high performance of RZF, we propose to replace the matrix inversion and multiplication by a truncated polynomial expansion (TPE), thereby obtaining the new TPE precoding scheme which is more suitable for real-time hardware implementation and significantly reduces the delay to the first transmitted symbol. The degree of the matrix polynomial can be adapted to the available hardware resources and enables smooth transition between simple maximum ratio transmission and more advanced RZF. By deriving new random matrix results, we obtain a deterministic expression for the asymptotic signal-to-interference-and-noise ratio (SINR) achieved by TPE precoding in massive MIMO systems. Furthermore, we provide a closed-form expression for the polynomial coefficients that maximizes this SINR. To maintain a fixed per-user rate loss as compared to RZF, the polynomial degree does not need to scale with the system, but it should be increased with the quality of the channel knowledge and the signal-to-noise ratio.

  18. Multi-User MIMO Across Small Cells

    DEFF Research Database (Denmark)

    Finn, Danny; Ahmadi, Hamed; Cattoni, Andrea Fabio

    2014-01-01

    The main contribution of this work is the proposal and assessment of the MU-MIMO across Small Cells concept. MU-MIMO is the spatial multiplexing of multiple users on a single time-frequency resource. In small cell networks, where the number of users per cell is low, finding suitable sets of users...... to be co-scheduled for MU-MIMO is not always possible. In these cases we propose MU-MIMO-based cell reassignments of users into adjacent cells to enable MU-MIMO operation. From system level simulations we found that, when the initial number of users per small cell is four, cell reassignment results in a 21.......7% increase in the spectral efficiency gain attributed to MU-MIMO, and a higher percentage increase when the initial number of users per cell is lower. Going forward, we will extend this work to also consider energy savings through switching off small cells which are emptied by the reassignment process....

  19. MIMO Communication for Cellular Networks

    CERN Document Server

    Huang, Howard; Venkatesan, Sivarama

    2012-01-01

    As the theoretical foundations of multiple-antenna techniques evolve and as these multiple-input multiple-output (MIMO) techniques become essential for providing high data rates in wireless systems, there is a growing need to understand the performance limits of MIMO in practical networks. To address this need, MIMO Communication for Cellular Networks presents a systematic description of MIMO technology classes and a framework for MIMO system design that takes into account the essential physical-layer features of practical cellular networks. In contrast to works that focus on the theoretical performance of abstract MIMO channels, MIMO Communication for Cellular Networks emphasizes the practical performance of realistic MIMO systems. A unified set of system simulation results highlights relative performance gains of different MIMO techniques and provides insights into how best to use multiple antennas in cellular networks under various conditions. MIMO Communication for Cellular Networks describes single-user,...

  20. 2x2 MIMO-OFDM Gigabit fiber-wireless access system based on polarization division multiplexed WDM-PON

    DEFF Research Database (Denmark)

    Deng, Lei; Pang, Xiaodan; Zhao, Ying

    2012-01-01

    We propose a spectral efficient radio over wavelength division multiplexed passive optical network (WDM-PON) system by combining optical polarization division multiplexing (PDM) and wireless multiple input multiple output (MIMO) spatial multiplexing techniques. In our experiment, a training...

  1. Channel Statistics for MIMO Handsets in Data Mode

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Yanakiev, Boyan; Barrio, Samantha Caporal Del

    2014-01-01

    The presented work is based on a large dual- band, dual-base outdoor-to-indoor multiple-input multiple- output (MIMO) channel measurement campaign, involving ten different realistic MIMO handsets, held in data mode by eight test users. Various different use cases (UCs) are measured. Statistics...

  2. CDM potential of bagasse cogeneration in India

    International Nuclear Information System (INIS)

    Purohit, Pallav; Michaelowa, Axel

    2007-01-01

    So far, the cumulative capacity of renewable energy systems such as bagasse cogeneration in India is far below their theoretical potential despite government subsidy programmes. One of the major barriers is the high investment cost of these systems. The Clean Development Mechanism (CDM) provides industrialized countries with an incentive to invest in emission reduction projects in developing countries to achieve a reduction in CO 2 emissions at lowest cost that also promotes sustainable development in the host country. Bagasse cogeneration projects could be of interest under the CDM because they directly displace greenhouse gas emissions while contributing to sustainable rural development. This study assesses the maximum theoretical as well as the realistically achievable CDM potential of bagasse cogeneration in India. Our estimates indicate that there is a vast theoretical potential of CO 2 mitigation by the use of bagasse for power generation through cogeneration process in India. The preliminary results indicate that the annual gross potential availability of bagasse in India is more than 67 million tonnes (MT). The potential of electricity generation through bagasse cogeneration in India is estimated to be around 34 TWh i.e. about 5575 MW in terms of the plant capacity. The annual CER potential of bagasse cogeneration in India could theoretically reach 28 MT. Under more realistic assumptions about diffusion of bagasse cogeneration based on past experiences with the government-run programmes, annual CER volumes by 2012 could reach 20-26 million. The projections based on the past diffusion trend indicate that in India, even with highly favorable assumptions, the dissemination of bagasse cogeneration for power generation is not likely to reach its maximum estimated potential in another 20 years. CDM could help to achieve the maximum utilization potential more rapidly as compared to the current diffusion trend if supportive policies are introduced

  3. Interference Alignment-based Precoding and User Selection with Limited Feedback in Two-cell Downlink Multi-user MIMO Systems

    Directory of Open Access Journals (Sweden)

    Yin Zhu

    2016-05-01

    Full Text Available Interference alignment (IA is a new approach to address interference in modern multiple-input multiple-out (MIMO cellular networks in which interference is an important factor that limits the system throughput. System throughput in most IA implementation schemes is significantly improved only with perfect channel state information and in a high signal-to-noise ratio (SNR region. Designing a simple IA scheme for the system with limited feedback and investigating system performance at a low-to-medium SNR region is important and practical. This paper proposed a precoding and user selection scheme based on partial interference alignment in two-cell downlink multi-user MIMO systems under limited feedback. This scheme aligned inter-cell interference to a predefined direction by designing user’s receive antenna combining vectors. A modified singular value decomposition (SVD-based beamforming method and a corresponding user-selection algorithm were proposed for the system with low rate limited feedback to improve sum rate performance. Simulation results show that the proposed scheme achieves a higher sum rate than traditional schemes without IA. The modified SVD-based beamforming scheme is also superior to the traditional zero-forcing beamforming scheme in low-rate limited feedback systems. The proposed partial IA scheme does not need to collaborate between transmitters and joint design between the transmitter and the users. The scheme can be implemented with low feedback overhead in current MIMO cellular networks.

  4. Why only few CDM projects?

    DEFF Research Database (Denmark)

    Brandt, Urs Steiner; Svendsen, Gert Tinggaard

    2013-01-01

    CDM projects have large potentials but also face significant obstacles that have so far limited their applicability. Two serious problems that an effective contracting faces are the presence of private information and the lack of sufficiently precise output measures. In a principal-agent framewor...

  5. Energy Balance Routing Algorithm Based on Virtual MIMO Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jianpo Li

    2014-01-01

    Full Text Available Wireless sensor networks are usually energy limited and therefore an energy-efficient routing algorithm is desired for prolonging the network lifetime. In this paper, we propose a new energy balance routing algorithm which has the following three improvements over the conventional LEACH algorithm. Firstly, we propose a new cluster head selection scheme by taking into consideration the remaining energy and the most recent energy consumption of the nodes and the entire network. In this way, the sensor nodes with smaller remaining energy or larger energy consumption will be much less likely to be chosen as cluster heads. Secondly, according to the ratio of remaining energy to distance, cooperative nodes are selected to form virtual MIMO structures. It mitigates the uneven distribution of clusters and the unbalanced energy consumption of the whole network. Thirdly, we construct a comprehensive energy consumption model, which can reflect more realistically the practical energy consumption. Numerical simulations analyze the influences of cooperative node numbers and cluster head node numbers on the network lifetime. It is shown that the energy consumption of the proposed routing algorithm is lower than the conventional LEACH algorithm and for the simulation example the network lifetime is prolonged about 25%.

  6. Analogue MIMO Detection

    Directory of Open Access Journals (Sweden)

    McNamara Darren

    2006-01-01

    Full Text Available In this contribution we propose an analogue receiver that can perform turbo detection in MIMO systems. We present the case for a receiver that is built from nonlinear analogue devices, which perform detection in a "free-flow" network (no notion of iterations. This contribution can be viewed as an extension of analogue turbo decoder concepts to include MIMO detection. These first analogue implementations report reductions of few orders of magnitude in the number of required transistors and in consumed energy, and the same order of improvement in processing speed. It is anticipated that such analogue MIMO decoder could bring about the same advantages, when compared to traditional digital implementations.

  7. A FPGA-Based, Granularity-Variable Neuromorphic Processor and Its Application in a MIMO Real-Time Control System.

    Science.gov (United States)

    Zhang, Zhen; Ma, Cheng; Zhu, Rong

    2017-08-23

    Artificial Neural Networks (ANNs), including Deep Neural Networks (DNNs), have become the state-of-the-art methods in machine learning and achieved amazing success in speech recognition, visual object recognition, and many other domains. There are several hardware platforms for developing accelerated implementation of ANN models. Since Field Programmable Gate Array (FPGA) architectures are flexible and can provide high performance per watt of power consumption, they have drawn a number of applications from scientists. In this paper, we propose a FPGA-based, granularity-variable neuromorphic processor (FBGVNP). The traits of FBGVNP can be summarized as granularity variability, scalability, integrated computing, and addressing ability: first, the number of neurons is variable rather than constant in one core; second, the multi-core network scale can be extended in various forms; third, the neuron addressing and computing processes are executed simultaneously. These make the processor more flexible and better suited for different applications. Moreover, a neural network-based controller is mapped to FBGVNP and applied in a multi-input, multi-output, (MIMO) real-time, temperature-sensing and control system. Experiments validate the effectiveness of the neuromorphic processor. The FBGVNP provides a new scheme for building ANNs, which is flexible, highly energy-efficient, and can be applied in many areas.

  8. A FPGA-Based, Granularity-Variable Neuromorphic Processor and Its Application in a MIMO Real-Time Control System

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2017-08-01

    Full Text Available Artificial Neural Networks (ANNs, including Deep Neural Networks (DNNs, have become the state-of-the-art methods in machine learning and achieved amazing success in speech recognition, visual object recognition, and many other domains. There are several hardware platforms for developing accelerated implementation of ANN models. Since Field Programmable Gate Array (FPGA architectures are flexible and can provide high performance per watt of power consumption, they have drawn a number of applications from scientists. In this paper, we propose a FPGA-based, granularity-variable neuromorphic processor (FBGVNP. The traits of FBGVNP can be summarized as granularity variability, scalability, integrated computing, and addressing ability: first, the number of neurons is variable rather than constant in one core; second, the multi-core network scale can be extended in various forms; third, the neuron addressing and computing processes are executed simultaneously. These make the processor more flexible and better suited for different applications. Moreover, a neural network-based controller is mapped to FBGVNP and applied in a multi-input, multi-output, (MIMO real-time, temperature-sensing and control system. Experiments validate the effectiveness of the neuromorphic processor. The FBGVNP provides a new scheme for building ANNs, which is flexible, highly energy-efficient, and can be applied in many areas.

  9. A New Cooperative MIMO Scheme Based on SM for Energy-Efficiency Improvement in Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Yuyang Peng

    2014-01-01

    Full Text Available Improving the energy efficiency in wireless sensor networks (WSN has attracted considerable attention nowadays. The multiple-input multiple-output (MIMO technique has been proved as a good candidate for improving the energy efficiency, but it may not be feasible in WSN which is due to the size limitation of the sensor node. As a solution, the cooperative multiple-input multiple-output (CMIMO technique overcomes this constraint and shows a dramatically good performance. In this paper, a new CMIMO scheme based on the spatial modulation (SM technique named CMIMO-SM is proposed for energy-efficiency improvement. We first establish the system model of CMIMO-SM. Based on this model, the transmission approach is introduced graphically. In order to evaluate the performance of the proposed scheme, a detailed analysis in terms of energy consumption per bit of the proposed scheme compared with the conventional CMIMO is presented. Later, under the guide of this new scheme we extend our proposed CMIMO-SM to a multihop clustered WSN for further achieving energy efficiency by finding an optimal hop-length. Equidistant hop as the traditional scheme will be compared in this paper. Results from the simulations and numerical experiments indicate that by the use of the proposed scheme, significant savings in terms of total energy consumption can be achieved. Combining the proposed scheme with monitoring sensor node will provide a good performance in arbitrary deployed WSN such as forest fire detection system.

  10. Design and Prototyping Flow of Flexible and Efficient NISC-Based Architectures for MIMO Turbo Equalization and Demapping

    Directory of Open Access Journals (Sweden)

    Mostafa Rizk

    2016-08-01

    Full Text Available In the domain of digital wireless communication, flexible design implementations are increasingly explored for different applications in order to cope with diverse system configurations imposed by the emerging wireless communication standards. In fact, shrinking the design time to meet market pressure, on the one hand, and adding the emerging flexibility requirement and, hence, increasing system complexity, on the other hand, require a productive design approach that also ensures final design quality. The no instruction set computer (NISC approach fulfills these design requirements by eliminating the instruction set overhead. The approach offers static scheduling of the datapath, automated register transfer language (RTLsynthesis and allows the designer to have direct control of hardware resources. This paper presents a complete NISC-based design and prototype flow, from architecture specification till FPGA implementation. The proposed design and prototype flow is illustrated through two case studies of flexible implementations, which are dedicated to low-complexity MIMO turbo-equalizer and a universal turbo-demapper. Moreover, the flexibility of the proposed prototypes allows supporting all communication modes defined in the emerging wireless communication standards, such LTE, LTE-Advanced, WiMAX, WiFi and DVB-RCS. For each prototype, its functionality is evaluated, and the resultant performance is verified for all system configurations.

  11. Designing Waveform Sets with Good Correlation and Stopband Properties for MIMO Radar via the Gradient-Based Method

    Directory of Open Access Journals (Sweden)

    Liang Tang

    2017-05-01

    Full Text Available Waveform sets with good correlation and/or stopband properties have received extensive attention and been widely used in multiple-input multiple-output (MIMO radar. In this paper, we aim at designing unimodular waveform sets with good correlation and stopband properties. To formulate the problem, we construct two criteria to measure the correlation and stopband properties and then establish an unconstrained problem in the frequency domain. After deducing the phase gradient and the step size, an efficient gradient-based algorithm with monotonicity is proposed to minimize the objective function directly. For the design problem without considering the correlation weights, we develop a simplified algorithm, which only requires a few fast Fourier transform (FFT operations and is more efficient. Because both of the algorithms can be implemented via the FFT operations and the Hadamard product, they are computationally efficient and can be used to design waveform sets with a large waveform number and waveform length. Numerical experiments show that the proposed algorithms can provide better performance than the state-of-the-art algorithms in terms of the computational complexity.

  12. Designing Waveform Sets with Good Correlation and Stopband Properties for MIMO Radar via the Gradient-Based Method.

    Science.gov (United States)

    Tang, Liang; Zhu, Yongfeng; Fu, Qiang

    2017-05-01

    Waveform sets with good correlation and/or stopband properties have received extensive attention and been widely used in multiple-input multiple-output (MIMO) radar. In this paper, we aim at designing unimodular waveform sets with good correlation and stopband properties. To formulate the problem, we construct two criteria to measure the correlation and stopband properties and then establish an unconstrained problem in the frequency domain. After deducing the phase gradient and the step size, an efficient gradient-based algorithm with monotonicity is proposed to minimize the objective function directly. For the design problem without considering the correlation weights, we develop a simplified algorithm, which only requires a few fast Fourier transform (FFT) operations and is more efficient. Because both of the algorithms can be implemented via the FFT operations and the Hadamard product, they are computationally efficient and can be used to design waveform sets with a large waveform number and waveform length. Numerical experiments show that the proposed algorithms can provide better performance than the state-of-the-art algorithms in terms of the computational complexity.

  13. Towards Very Large Aperture Massive MIMO

    DEFF Research Database (Denmark)

    Oliveras Martínez, Àlex; De Carvalho, Elisabeth; Nielsen, Jesper Ødum

    2014-01-01

    Massive MIMO is a new technique for wireless communications that claims to offer very high system throughput and energy efficiency in multi-user scenarios. The cost is to add a very large number of antennas at the base station. Theoretical research has probed these benefits, but very few measurem......Massive MIMO is a new technique for wireless communications that claims to offer very high system throughput and energy efficiency in multi-user scenarios. The cost is to add a very large number of antennas at the base station. Theoretical research has probed these benefits, but very few...... measurements have showed the potential of Massive MIMO in practice. We investigate the properties of measured Massive MIMO channels in a large indoor venue. We describe a measurement campaign using 3 arrays having different shape and aperture, with 64 antennas and 8 users with 2 antennas each. We focus...... on the impact of the array aperture which is the main limiting factor in the degrees of freedom available in the multiple antenna channel. We find that performance is improved as the aperture increases, with an impact mostly visible in crowded scenarios where the users are closely spaced. We also test MIMO...

  14. Acoustic MIMO signal processing

    CERN Document Server

    Huang, Yiteng; Chen, Jingdong

    2006-01-01

    A timely and important book addressing a variety of acoustic signal processing problems under multiple-input multiple-output (MIMO) scenarios. It uniquely investigates these problems within a unified framework offering a novel and penetrating analysis.

  15. Multiuser MIMO Systems

    National Research Council Canada - National Science Library

    Poor, H. V

    2004-01-01

    .... This talk will discuss implications of using MIMO systems in multiple-access networks. The main focus of the talk will be on receiver signal processing for such systems and in particular on multiuser detection and related issues...

  16. The Learning Process and Technological Change in Wind Power: Evidence from China's CDM Wind Projects

    OpenAIRE

    Tian Tang; David Popp

    2014-01-01

    The Clean Development Mechanism (CDM) is a project-based carbon trade mechanism that subsidizes the users of climate-friendly technologies and encourages technology transfer. The CDM has provided financial support for a large share of Chinese wind projects since 2002. Using pooled cross-sectional data of 486 registered CDM wind projects in China from 2002 to 2009, we examine the determinants of technological change in wind power from a learning perspective. We estimate the effects of differen...

  17. Performance Analysis of Capacity of MIMO Systems under Multiuser Interference Based on Worst-Case Noise Behavior

    Directory of Open Access Journals (Sweden)

    Jorswieck E. A.

    2004-01-01

    Full Text Available The capacity of a cellular multiuser MIMO system depends on various parameters, for example, the system structure, the transmit and receive strategies, the channel state information at the transmitter and the receiver, and the channel properties. Recently, the main focus of research was on single-user MIMO systems, their channel capacity, and their error performance with space-time coding. In general, the capacity of a cellular multiuser MIMO system is limited by additive white Gaussian noise, intracell interference from other users within the cell, and intercell interference from users outside the considered cell. We study one point-to-point link, on which interference acts. The interference models the different system scenarios and various parameters. Therefore, we consider three scenarios in which the noise is subject to different constraints. A general trace constraint is used in the first scenario. The noise covariance matrix eigenvalues are kept fixed in the second scenario, and in the third scenario the entries on the diagonal of the noise covariance matrix are kept fixed. We assume that the receiver as well as the transmitter have perfect channel state information. We solve the corresponding minimax programming problems and characterize the worst-case noise and the optimal transmit strategy. In all scenarios, the achievable capacity of the MIMO system with worst-case noise is equal to the capacity of some MIMO system in which either the channels are orthogonal or the transmit antennas are not allowed to cooperate or in which no channel state information is available at the transmitter. Furthermore, the minimax expressions fulfill a saddle point property. All theoretical results are illustrated by examples and numerical simulations.

  18. Analysis of CDM projects’ potential benefits

    Directory of Open Access Journals (Sweden)

    José Affonso dos Reis Junior

    2015-11-01

    Full Text Available Objective – The main goal of this study is to identify and assess, within sustainability reports, information concerning potential carbon credits obtained through projects carried out under Clean Development Mechanism (CDM assumptions, as well as to assess CDM project experts’ perceptions of obstacles to entering carbon credit markets. Design/methodology/approach – exploratory, descriptive, bibliographical and documental research, and interviews. Theoretical basis - Research was based on the concepts of sustainability, especially as to environmental responsibility (CSR; cost-benefit analysis was also considered, since selling carbon credits can be a way of mitigating the trade off between immediate shareholder satisfaction and investment in CSR. Findings – The perceptions of representatives from carbon credit projects’ certifying companies was examined by means of a series of interviews – concluding that savings in costs, business marketing and certifications are even greater motivators than carbon credits themselves. We estimated that, through energy efficiency, the projects discussed in 2011 sustainability reports would be capable of saving approximately 538 million reais in costs. In addition, 40 million reais, considering the rate of the euro and of securities on December 31, 2014, would be gained through the sale of carbon credits. Practical implications – Thus, this research helps to demonstrate the significant potential for further financial gains that companies may obtain through energy efficiency and habitat restructuring, whether by taking advantage of CO2 reduction brought about by such projects, or by developing new projects that continue to benefit economy, society and the environment.

  19. Quasi-minimal active disturbance rejection control of MIMO perturbed linear systems based on differential neural networks and the attractive ellipsoid method.

    Science.gov (United States)

    Salgado, Iván; Mera-Hernández, Manuel; Chairez, Isaac

    2017-11-01

    This study addresses the problem of designing an output-based controller to stabilize multi-input multi-output (MIMO) systems in the presence of parametric disturbances as well as uncertainties in the state model and output noise measurements. The controller design includes a linear state transformation which separates uncertainties matched to the control input and the unmatched ones. A differential neural network (DNN) observer produces a nonlinear approximation of the matched perturbation and the unknown states simultaneously in the transformed coordinates. This study proposes the use of the Attractive Ellipsoid Method (AEM) to optimize the gains of the controller and the gain observer in the DNN structure. As a consequence, the obtained control input minimizes the convergence zone for the estimation error. Moreover, the control design uses the estimated disturbance provided by the DNN to obtain a better performance in the stabilization task in comparison with a quasi-minimal output feedback controller based on a Luenberger observer and a sliding mode controller. Numerical results pointed out the advantages obtained by the nonlinear control based on the DNN observer. The first example deals with the stabilization of an academic linear MIMO perturbed system and the second example stabilizes the trajectories of a DC-motor into a predefined operation point. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Antenna Pattern Impact on MIMO OTA Testing

    DEFF Research Database (Denmark)

    Fan, Wei; Nielsen, Jesper Ødum; Franek, Ondrej

    2013-01-01

    This paper investigates the impact of the DUT antenna pattern on the test area performance for multi-probe based MIMO OTA setup in terms of received voltage and spatial correlation. The plane wave synthesis (PWS) technique has been proposed for vertical polarization in the literature, where...

  1. MIMO OTA Testing

    DEFF Research Database (Denmark)

    Kotterman, Wim; Pedersen, Gert F.; Szini, Istvan Janos

    2016-01-01

    The main goal of the TopicalWorking Group on MIMO OTAis to gather all the relevant research across theWorking Groups in the IC1004Action for backingup choices to be made in standardisation on technologies for OTA testing of multi-antenna devices.As no standards are conceived in European cooperation....... The targeted application of MIMO OTA in standardisation is the conformance testing cycle, currently targeting RF performance only and not production testing. In this Chapter, contributions over the project duration are documented and resumed in a coherent way....

  2. Printed MIMO antenna engineering

    CERN Document Server

    Sharawi, Mohammad S

    2014-01-01

    Wireless communications has made a huge leap during the past two decades. The multiple-input-multiple-output (MIMO) technology was proposed in the 1990's as a viable solution that can overcome the data rate limit experienced by single-input-single-output (SISO) systems. This resource is focused on printed MIMO antenna system design. Printed antennas are widely used in mobile and handheld terminals due to their conformity with the device, low cost, good integration within the device elements and mechanical parts, as well as ease of fabrication.A perfect design companion for practicing engineers

  3. Implementing CDM projects. A guidebook to host country legal issues; CDM - Clean Development Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Curnow, P. (Baker and McKenzie, London (United Kingdom)); Hodes, G. (UNEP Risoe Centre on Energy, Climate and Sustainable Development, DTU, Roskilde (Denmark))

    2009-08-15

    The Clean Development Mechanism (CDM) continues to evolve organically, and many legal issues remain to be addressed in order to maximise its effectiveness. This Guidebook explains through case studies how domestic laws and regulatory frameworks in CDM Host Countries interact with international rules on carbon trading, and how the former can be enhanced to facilitate the implementation and financing of CDM projects. (author)

  4. A 3-D circuit model to evaluate CDM performance of Ics

    NARCIS (Netherlands)

    Sowariraj, M.S.B.; de Jong, P.C.; Salm, Cora; Mouthaan, A.J.; Kuper, F.G.

    2005-01-01

    This paper presents a physical description of the static charge flow through an IC during a CDM event. Based on this description, an equivalent 3-D circuit to model the complete IC under CDM stress is proposed. The model takes into account various factors like package parasitics, substrate

  5. Integrating ecological restoration into CDM forestry projects

    International Nuclear Information System (INIS)

    Ma, Maohua; Haapanen, Toni; Singh, Ram Babu; Hietala, Reija

    2014-01-01

    Highlights: • Concerns and issues in sustainability of CDM forestry projects are reviewed. • Ecological restoration is suggested to be integrated in the CDM framework. • As an ecosystem supporting service, soil restoration on degraded land is of primary importance. • Regenerating forests naturally rather than through monoculture plantations is suggested. • Potential social impacts of ecological restoration are discussed. - Abstract: The Clean Development Mechanism (CDM) is proposed to reduce greenhouse gas emissions and promote sustainable development. CDM forestry projects should contribute to mitigation of climate change through afforestation and reforestation (A/R) activities on degraded land in developing countries. However, like other types of CDM projects, the forestry projects have encountered a number of concerns and critiques. Appropriate approaches and concrete aims to achieve long-term sustainability have been lacking, and reforms have therefore been called for. The aims of this paper are to examine the published information relevant to these concerns, and frame appropriate approaches for a more sustainable CDM. In this review, as a first step to tackle some of these issues, ecological restoration is suggested for integration into the CDM framework. Essentially, this involves the restoration of ecosystem supporting service (soil restoration), upon which forests regenerate naturally rather than establishing monoculture plantations. In this way, forestry projects would bring cost-effective opportunities for multiple ecosystem services. Potential approaches, necessary additions to the monitoring plans, and social impacts of ecological restoration in CDM projects are discussed

  6. The impact of discounting emission credits on the competitiveness of different CDM host countries

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Paula; Michaelowa, Axel [Institute of Political Science and Center for Comparative and International Studies, University of Zurich, Hirschengraben 56, 8001 Zurich (Switzerland)

    2010-11-15

    Discounting the value of emission credits has been proposed as a possible approach for addressing some of the shortcomings of the Clean Development Mechanism (CDM). It could be used to compensate for non-additional CDM projects; to increase the incentive for advanced developing countries to move from the CDM to own mitigation commitments; and to improve the competitiveness of less developed countries as hosts for CDM projects. We assess the impact of discounting on the distribution of CDM projects in host countries, with a special focus on Least Developed Countries (LDCs). CDM-specific abatement cost curves are built for 4 regions: China, India, other advanced Asian countries and LDCs. Abatement costs are estimated using the information provided in the project documentation of 108 projects from 17 subtypes in 16 host countries. Abatement potentials are derived from the current CDM pipeline for each region. For LDCs, we additionally include an optimistic potential estimation by adding to the current pipeline the potential found by a World Bank study for LDCs in Sub-Saharan Africa. We then assess the effect of two emission credit discounting schemes on these abatement cost curves. Credit discounting is differentiated by host countries, based on an index composed of per capita GDP and per capita emissions. In the first scheme, it only affects the most advanced CDM host countries; in the second one it also affects China. We find that discounting has an impact on the competitiveness of individual CDM host countries in the carbon market, as it affects their abatement cost curves. It could become an instrument for incentivising advanced developing countries to leave the CDM and engage in other farther-reaching climate-related commitments, as a result of the resulting emission credit cost increases. However, even with discounting, LDCs remain unimportant in terms of abatement potential if the financial, technical and institutional barriers to CDM development in these

  7. Emulating Spatial Characteristics of MIMO Channels for OTA Testing

    DEFF Research Database (Denmark)

    Fan, Wei; Carreño, Xavier; Sun, Fan

    2013-01-01

    This paper discusses over the air (OTA) testing for multiple input multiple output (MIMO) capable terminals with emphasis on channel spatial characteristics emulation. A novel technique to obtain optimum power weights for the OTA probes based on convex optimization is proposed. The proposed...... performance compared with existing techniques in the literature. This improvement is further demonstrated by measurement results in a practical MIMO OTA setup....

  8. Distributed MIMO-ISAR Sub-image Fusion Method

    Directory of Open Access Journals (Sweden)

    Gu Wenkun

    2017-02-01

    Full Text Available The fast fluctuation associated with maneuvering a target’s radar cross-section often affects the imaging performance stability of traditional monostatic Inverse Synthetic Aperture Radar (ISAR. To address this problem, in this study, we propose an imaging method based on the fusion of sub-images of frequencydiversity-distributed multiple Input-Multiple Output-Inverse Synthetic Aperture Radar (MIMO-ISAR. First, we establish the analytic expression of a two-dimensional ISAR sub-image acquired by different channels of distributed MIMO-ISAR. Then, we derive the distance and azimuth distortion factors of the image acquired by the different channels. By compensating for the distortion of the ISAR image, we ultimately realize distributed MIMO-ISAR fusion imaging. Simulations verify the validity of this imaging method using distributed MIMO-ISAR.

  9. Can the Clean Development Mechanism (CDM) deliver?

    International Nuclear Information System (INIS)

    Subbarao, Srikanth; Lloyd, Bob

    2011-01-01

    The paper investigates whether the Clean Development Mechanism (CDM) under the Kyoto Protocol has played a significant role in the development of rural communities, specifically investigating uptake of small-scale renewable energy projects. The investigation involved an assessment of 500 registered small-scale CDM projects under the Kyoto Protocol in terms of their potential impact on the envisaged sustainable development goals for rural communities. Five case studies from the Indian subcontinent were also examined. The paper concludes that the CDM in its current state and design has typically failed to deliver the promised benefits with regard to development objectives in rural areas. Successful projects were found to have had good community involvement and such projects were typically managed by cooperative ventures rather than money making corporations. The paper puts forward a new framework for the assessment of such benefits in the hope that future projects can be better assessed in this regard. The key problem, however, remains on how to deal with the inherent contradiction between development and sustainability. - Research Highlights: → Role of CDM towards sustainable development of rural communities. → Assessment of 500 registered small-scale CDM projects. → CDM in its current state and design has typically failed to deliver. → A new framework for sustainable development assessment of small-scale CDM projects. → Inherent contradiction between development and sustainability.

  10. A Generalized Spatial Correlation Model for 3D MIMO Channels based on the Fourier Coefficients of Power Spectrums

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2015-05-07

    Previous studies have confirmed the adverse impact of fading correlation on the mutual information (MI) of two-dimensional (2D) multiple-input multiple-output (MIMO) systems. More recently, the trend is to enhance the system performance by exploiting the channel’s degrees of freedom in the elevation, which necessitates the derivation and characterization of three-dimensional (3D) channels in the presence of spatial correlation. In this paper, an exact closed-form expression for the Spatial Correlation Function (SCF) is derived for 3D MIMO channels. This novel SCF is developed for a uniform linear array of antennas with nonisotropic antenna patterns. The proposed method resorts to the spherical harmonic expansion (SHE) of plane waves and the trigonometric expansion of Legendre and associated Legendre polynomials. The resulting expression depends on the underlying arbitrary angular distributions and antenna patterns through the Fourier Series (FS) coefficients of power azimuth and elevation spectrums. The novelty of the proposed method lies in the SCF being valid for any 3D propagation environment. The developed SCF determines the covariance matrices at the transmitter and the receiver that form the Kronecker channel model. In order to quantify the effects of correlation on the system performance, the information-theoretic deterministic equivalents of the MI for the Kronecker model are utilized in both mono-user and multi-user cases. Numerical results validate the proposed analytical expressions and elucidate the dependence of the system performance on azimuth and elevation angular spreads and antenna patterns. Some useful insights into the behaviour of MI as a function of downtilt angles are provided. The derived model will help evaluate the performance of correlated 3D MIMO channels in the future.

  11. Unified Stochastic Geometry Model for MIMO Cellular Networks with Retransmissions

    KAUST Repository

    Afify, Laila H.

    2016-10-11

    This paper presents a unified mathematical paradigm, based on stochastic geometry, for downlink cellular networks with multiple-input-multiple-output (MIMO) base stations (BSs). The developed paradigm accounts for signal retransmission upon decoding errors, in which the temporal correlation among the signal-to-interference-plus-noise-ratio (SINR) of the original and retransmitted signals is captured. In addition to modeling the effect of retransmission on the network performance, the developed mathematical model presents twofold analysis unification for MIMO cellular networks literature. First, it integrates the tangible decoding error probability and the abstracted (i.e., modulation scheme and receiver type agnostic) outage probability analysis, which are largely disjoint in the literature. Second, it unifies the analysis for different MIMO configurations. The unified MIMO analysis is achieved by abstracting unnecessary information conveyed within the interfering signals by Gaussian signaling approximation along with an equivalent SISO representation for the per-data stream SINR in MIMO cellular networks. We show that the proposed unification simplifies the analysis without sacrificing the model accuracy. To this end, we discuss the diversity-multiplexing tradeoff imposed by different MIMO schemes and shed light on the diversity loss due to the temporal correlation among the SINRs of the original and retransmitted signals. Finally, several design insights are highlighted.

  12. Dynamic CDM strategies in an EHR environment.

    Science.gov (United States)

    Bieker, Michael; Bailey, Spencer

    2012-02-01

    A dynamic charge description master (CDM) integrates information from clinical ancillary systems into the charge-capture process, so an organization can reduce its reliance on the patient accounting system as the sole source of billing information. By leveraging the information from electronic ancillary systems, providers can eliminate the need for paper charge-capture forms and see increased accuracy and efficiency in the maintenance of billing information. Before embarking on a dynamic CDM strategy, organizations should first determine their goals for implementing an EHR system, include revenue cycle leaders on the EHR implementation team, and carefully weigh the pros and cons of CDM design decisions.

  13. Approximation-Based Adaptive Tracking Control for MIMO Nonlinear Systems With Input Saturation.

    Science.gov (United States)

    Zhou, Qi; Shi, Peng; Tian, Yang; Wang, Mingyu

    2015-10-01

    In this paper, an approximation-based adaptive tracking control approach is proposed for a class of multiinput multioutput nonlinear systems. Based on the method of neural network, a novel adaptive controller is designed via backstepping design process. Furthermore, by introducing Nussbaum function, the issue of unknown control directions is handled. In the backstepping design process, the dynamic surface control technique is employed to avoid differentiating certain nonlinear functions repeatedly. Moreover, in order to reduce the number of adaptation laws, we do not use the neural networks to directly approximate the unknown nonlinear functions but the desired control signals. Finally, we provide two examples to illustrate the effectiveness of the proposed approach.

  14. On Dimensions of OTA Setups for Massive MIMO Base Stations Radiated Testing

    DEFF Research Database (Denmark)

    Kyösti, Pekka; Fan, Wei; Pedersen, Gert F.

    2016-01-01

    The development of base stations (BS) with large aperture antenna arrays, enabled partially by the utilization of cmWave and mmWave frequency bands, will require radiated testing in fading conditions. In this paper, the objective is to investigate the suitable measurement distances and physical...

  15. Mimo radar waveform design for spectrum sharing with cellular systems a Matlab based approach

    CERN Document Server

    Khawar, Awais; Clancy, T Charles

    2016-01-01

    This book discusses spectrum sharing between cellular systems and radars. The book addresses a novel way to design radar waveforms that can enable spectrum sharing between radars and communication systems, without causing interference to communication systems, and at the same time achieving radar objectives of target detection, estimation, and tracking. The book includes a MATLAB-based approach, which provides reader with a way to learn, experiment, compare, and build on top of existing algorithms.

  16. A Bayesian matching pursuit based scheduling algorithm for feedback reduction in MIMO broadcast channels

    KAUST Repository

    Shibli, Hussain J.

    2013-06-01

    Opportunistic schedulers rely on the feedback of all users in order to schedule a set of users with favorable channel conditions. While the downlink channels can be easily estimated at all user terminals via a single broadcast, several key challenges are faced during uplink transmission. First of all, the statistics of the noisy and fading feedback channels are unknown at the base station (BS) and channel training is usually required from all users. Secondly, the amount of network resources (air-time) required for feedback transmission grows linearly with the number of users. In this paper, we tackle the above challenges and propose a Bayesian based scheduling algorithm that 1) reduces the air-time required to identify the strong users, and 2) is agnostic to the statistics of the feedback channels and utilizes the a priori statistics of the additive noise to identify the strong users. Numerical results show that the proposed algorithm reduces the feedback air-time while improving detection in the presence of fading and noisy channels when compared to recent compressed sensing based algorithms. Furthermore, the proposed algorithm achieves a sum-rate throughput close to that obtained by noiseless dedicated feedback systems. © 2013 IEEE.

  17. Mean value-based power allocation and ratio selection for MIMO cognitive radio systems

    KAUST Repository

    Tourki, Kamel

    2013-06-01

    In this paper, we consider a spectrum sharing cognitive radio system with ratio selection using a mean value-based power allocation strategy. We first provide the exact statistics in terms of probability density function and cumulative density function of the secondary channel gain as well as of the interference channel gain. These statistics are then used to derive exact closed form expression of the secondary outage probability. Furthermore, asymptotical analysis is derived and generalized diversity gain is deduced. We validate our analysis with simulation results in a Rayleigh fading environment. © 2013 IEEE.

  18. Multiple-Parameter Estimation Method Based on Spatio-Temporal 2-D Processing for Bistatic MIMO Radar

    Directory of Open Access Journals (Sweden)

    Shouguo Yang

    2015-12-01

    Full Text Available A novel spatio-temporal 2-dimensional (2-D processing method that can jointly estimate the transmitting-receiving azimuth and Doppler frequency for bistatic multiple-input multiple-output (MIMO radar in the presence of spatial colored noise and an unknown number of targets is proposed. In the temporal domain, the cross-correlation of the matched filters’ outputs for different time-delay sampling is used to eliminate the spatial colored noise. In the spatial domain, the proposed method uses a diagonal loading method and subspace theory to estimate the direction of departure (DOD and direction of arrival (DOA, and the Doppler frequency can then be accurately estimated through the estimation of the DOD and DOA. By skipping target number estimation and the eigenvalue decomposition (EVD of the data covariance matrix estimation and only requiring a one-dimensional search, the proposed method achieves low computational complexity. Furthermore, the proposed method is suitable for bistatic MIMO radar with an arbitrary transmitted and received geometrical configuration. The correction and efficiency of the proposed method are verified by computer simulation results.

  19. Multiple-Parameter Estimation Method Based on Spatio-Temporal 2-D Processing for Bistatic MIMO Radar.

    Science.gov (United States)

    Yang, Shouguo; Li, Yong; Zhang, Kunhui; Tang, Weiping

    2015-12-14

    A novel spatio-temporal 2-dimensional (2-D) processing method that can jointly estimate the transmitting-receiving azimuth and Doppler frequency for bistatic multiple-input multiple-output (MIMO) radar in the presence of spatial colored noise and an unknown number of targets is proposed. In the temporal domain, the cross-correlation of the matched filters' outputs for different time-delay sampling is used to eliminate the spatial colored noise. In the spatial domain, the proposed method uses a diagonal loading method and subspace theory to estimate the direction of departure (DOD) and direction of arrival (DOA), and the Doppler frequency can then be accurately estimated through the estimation of the DOD and DOA. By skipping target number estimation and the eigenvalue decomposition (EVD) of the data covariance matrix estimation and only requiring a one-dimensional search, the proposed method achieves low computational complexity. Furthermore, the proposed method is suitable for bistatic MIMO radar with an arbitrary transmitted and received geometrical configuration. The correction and efficiency of the proposed method are verified by computer simulation results.

  20. RF Transceiver Design for MIMO Wireless Communications

    CERN Document Server

    Mohammadi, Abbas

    2012-01-01

    This practical resource offers a thorough examination of RF transceiver design for MIMO communications.  Offering a practical view on MIMO wireless systems, this book extends fundamental concepts on classic wireless transceiver design techniques to MIMO transceivers. This helps reader gain a very comprehensive understanding of the subject. This in-depth volume describes many theoretical and implementation challenges on MIMO transceivers and provides the practical solutions for these issues. This comprehensive book provides thorough descriptions of MIMO theoretical concepts, MIMO single carrier and OFDM modulation, RF transceiver design concepts, power amplifier, MIMO transmitter design techniques and their RF impairments, MIMO receiver design methods, RF impairments study including nonlinearity, DC-offset, I/Q imbalance and phase noise and their compensation in OFDM and MIMO techniques. In addition, it provides the most practical techniques to realize RF front-ends in MIMO systems. This book is supported wit...

  1. Low-Bit Rate Feedback Strategies for Iterative IA-Precoded MIMO-OFDM-Based Systems

    Science.gov (United States)

    Teodoro, Sara; Silva, Adão; Dinis, Rui; Gameiro, Atílio

    2014-01-01

    Interference alignment (IA) is a promising technique that allows high-capacity gains in interference channels, but which requires the knowledge of the channel state information (CSI) for all the system links. We design low-complexity and low-bit rate feedback strategies where a quantized version of some CSI parameters is fed back from the user terminal (UT) to the base station (BS), which shares it with the other BSs through a limited-capacity backhaul network. This information is then used by BSs to perform the overall IA design. With the proposed strategies, we only need to send part of the CSI information, and this can even be sent only once for a set of data blocks transmitted over time-varying channels. These strategies are applied to iterative MMSE-based IA techniques for the downlink of broadband wireless OFDM systems with limited feedback. A new robust iterative IA technique, where channel quantization errors are taken into account in IA design, is also proposed and evaluated. With our proposed strategies, we need a small number of quantization bits to transmit and share the CSI, when comparing with the techniques used in previous works, while allowing performance close to the one obtained with perfect channel knowledge. PMID:24678274

  2. Low-Bit Rate Feedback Strategies for Iterative IA-Precoded MIMO-OFDM-Based Systems

    Directory of Open Access Journals (Sweden)

    Sara Teodoro

    2014-01-01

    Full Text Available Interference alignment (IA is a promising technique that allows high-capacity gains in interference channels, but which requires the knowledge of the channel state information (CSI for all the system links. We design low-complexity and low-bit rate feedback strategies where a quantized version of some CSI parameters is fed back from the user terminal (UT to the base station (BS, which shares it with the other BSs through a limited-capacity backhaul network. This information is then used by BSs to perform the overall IA design. With the proposed strategies, we only need to send part of the CSI information, and this can even be sent only once for a set of data blocks transmitted over time-varying channels. These strategies are applied to iterative MMSE-based IA techniques for the downlink of broadband wireless OFDM systems with limited feedback. A new robust iterative IA technique, where channel quantization errors are taken into account in IA design, is also proposed and evaluated. With our proposed strategies, we need a small number of quantization bits to transmit and share the CSI, when comparing with the techniques used in previous works, while allowing performance close to the one obtained with perfect channel knowledge.

  3. Distributed MIMO chaotic radar based on wavelength-division multiplexing technology.

    Science.gov (United States)

    Yao, Tingfeng; Zhu, Dan; Ben, De; Pan, Shilong

    2015-04-15

    A distributed multiple-input multiple-output chaotic radar based on wavelength-division multiplexing technology (WDM) is proposed and demonstrated. The wideband quasi-orthogonal chaotic signals generated by different optoelectronic oscillators (OEOs) are emitted by separated antennas to gain spatial diversity against the fluctuation of a target's radar cross section and enhance the detection capability. The received signals collected by the receive antennas and the reference signals from the OEOs are delivered to the central station for joint processing by exploiting WDM technology. The centralized signal processing avoids precise time synchronization of the distributed system and greatly simplifies the remote units, which improves the localization accuracy of the entire system. A proof-of-concept experiment for two-dimensional localization of a metal target is demonstrated. The maximum position error is less than 6.5 cm.

  4. Alternate transmission relaying based on interference alignment in 3-relay half-duplex MIMO systems

    KAUST Repository

    Park, Seongho

    2012-09-01

    In a half-duplex relaying, the capacity pre-log factor 1/2 is a major drawback in spectral efficiency. This paper proposes a linear precoding/decoding scheme and an alternate relaying protocol in a dual-hop half-duplex system where three relays help the communication between the source and the destination. In our proposed scheme, we consider a phase incoherent method in relays in which the source alternately transmits message signals to the different relays. In addition, we propose a linear interference alignment scheme which can suppress the inter-relay interference resulting from the phase incoherence of relaying. Based on our analysis of degrees of freedom and our simulation results, we show that our proposed scheme achieves additional degrees of freedom compared to the conventional half-duplex relaying. © 2012 IEEE.

  5. Checking Capacity for MIMO Configurations

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2007-01-01

    Wireless system capacity can be added by increasing the number of antennas in a MIMO setup or by carefully optimizing the performance of a smaller number of antennas.......Wireless system capacity can be added by increasing the number of antennas in a MIMO setup or by carefully optimizing the performance of a smaller number of antennas....

  6. Adaptive Backstepping-Based Neural Tracking Control for MIMO Nonlinear Switched Systems Subject to Input Delays.

    Science.gov (United States)

    Niu, Ben; Li, Lu

    2017-04-17

    This brief proposes a new neural-network (NN)-based adaptive output tracking control scheme for a class of disturbed multiple-input multiple-output uncertain nonlinear switched systems with input delays. By combining the universal approximation ability of radial basis function NNs and adaptive backstepping recursive design with an improved multiple Lyapunov function (MLF) scheme, a novel adaptive neural output tracking controller design method is presented for the switched system. The feature of the developed design is that different coordinate transformations are adopted to overcome the conservativeness caused by adopting a common coordinate transformation for all subsystems. It is shown that all the variables of the resulting closed-loop system are semiglobally uniformly ultimately bounded under a class of switching signals in the presence of MLF and that the system output can follow the desired reference signal. To demonstrate the practicability of the obtained result, an adaptive neural output tracking controller is designed for a mass-spring-damper system.

  7. Performance analysis of an OAM multiplexing-based MIMO FSO system over atmospheric turbulence using space-time coding with channel estimation.

    Science.gov (United States)

    Zhang, Yan; Wang, Ping; Guo, Lixin; Wang, Wei; Tian, Hongxin

    2017-08-21

    The average bit error rate (ABER) performance of an orbital angular momentum (OAM) multiplexing-based free-space optical (FSO) system with multiple-input multiple-output (MIMO) architecture has been investigated over atmospheric turbulence considering channel estimation and space-time coding. The impact of different types of space-time coding, modulation orders, turbulence strengths, receive antenna numbers on the transmission performance of this OAM-FSO system is also taken into account. On the basis of the proposed system model, the analytical expressions of the received signals carried by the k-th OAM mode of the n-th receive antenna for the vertical bell labs layered space-time (V-Blast) and space-time block codes (STBC) are derived, respectively. With the help of channel estimator carrying out with least square (LS) algorithm, the zero-forcing criterion with ordered successive interference cancellation criterion (ZF-OSIC) equalizer of V-Blast scheme and Alamouti decoder of STBC scheme are adopted to mitigate the performance degradation induced by the atmospheric turbulence. The results show that the ABERs obtained by channel estimation have excellent agreement with those of turbulence phase screen simulations. The ABERs of this OAM multiplexing-based MIMO system deteriorate with the increase of turbulence strengths. And both V-Blast and STBC schemes can significantly improve the system performance by mitigating the distortions of atmospheric turbulence as well as additive white Gaussian noise (AWGN). In addition, the ABER performances of both space-time coding schemes can be further enhanced by increasing the number of receive antennas for the diversity gain and STBC outperforms V-Blast in this system for data recovery. This work is beneficial to the OAM FSO system design.

  8. Fundamental Bounds on MIMO Antennas

    Science.gov (United States)

    Ehrenborg, Casimir; Gustafsson, Mats

    2018-01-01

    Antenna current optimization is often used to analyze the optimal performance of antennas. Antenna performance can be quantified in e.g., minimum Q-factor and efficiency. The performance of MIMO antennas is more involved and, in general, a single parameter is not sufficient to quantify it. Here, the capacity of an idealized channel is used as the main performance quantity. An optimization problem in the current distribution for optimal capacity, measured in spectral efficiency, given a fixed Q-factor and efficiency is formulated as a semi-definite optimization problem. A model order reduction based on characteristic and energy modes is employed to improve the computational efficiency. The performance bound is illustrated by solving the optimization problem numerically for rectangular plates and spherical shells.

  9. Error Rate Improvement in Underwater MIMO Communications Using Sparse Partial Response Equalization

    Science.gov (United States)

    2006-09-01

    input multiple output (MIMO) ISI channels has been proposed in [2], where the authors have designed a MIMO PRE based on the MMSE criterion. The target... invariant during the transmission of a code word (frame) and changes independently from one frame to the next, and (2) the channel is known perfectly

  10. Evaluation of massive MIMO systems using time-reversal beamforming technique

    DEFF Research Database (Denmark)

    Mbeutcha, Marie; Fan, Wei; Hejselbæk, Johannes

    2016-01-01

    In this paper, we investigate the performance of a massive MIMO system using the time-reversal beamforming technique. The massive MIMO channels are simulated with ray-tracing at 3.5 GHz with a 200 MHz-bandwidth. We use a 64-element uniform cylindrical array as base station (BS) and we equip two...

  11. A SDP based design of relay precoding for the power minimization of MIMO AF-relay networks

    KAUST Repository

    Rao, Anlei

    2015-09-11

    Relay precoding for multiple-input and multiple-output (MIMO) relay networks has been approached by either optimizing the efficiency performance with given power consumption constraints or minimizing the power consumption with quality-of-service (QoS) requirements. For the later type design, previous works has worked on minimizing the approximated power consumption. In this paper, exact power consumption for all relays is derived into a quadratic form by diagonalizing the minimum-square error (MSE) matrix, and the relay precoding matrix is designed by optimizing this quadratic form with the help of semidefinite programming (SDP) relaxation. Our simulation results show that such a design can achieve a gain of around 3 dB against the previous design, which optimized the approximated power consumption. © 2015 IEEE.

  12. Two-Dimensional Direction-of-Arrival Estimation for Trilinear Decomposition-Based Monostatic Cross MIMO Radar

    Directory of Open Access Journals (Sweden)

    Fangqing Wen

    2013-01-01

    Full Text Available A low complexity monostatic cross multiple-in multiple-out (MIMO radar scheme is proposed in this paper. The minimum-redundancy linear array (MRLA is introduced in the cross radar to improve the efficiency of the array elements. The two-dimensional direction-of-arrival (DOA estimation problem links to the trilinear model, which automatically pairs the estimated two-dimensional angles, requiring neither eigenvalue decomposition of received signal covariance matrix nor spectral peak searching. The proposed scheme performs better than the uniform linear arrays (ULA configuration under the same conditions, and the proposed algorithm has less computational complexity than that of multiple signal classification (MUSIC algorithm. Simulation results show the effectiveness of our scheme.

  13. Getting on track : finding a path for transportation in the CDM : final report

    Energy Technology Data Exchange (ETDEWEB)

    Browne, J.; Zegras, C. [International Institute for Sustainable Development, Winnipeg, MB (Canada); Sanhueza, E. [Cambio Climatico y Desarollo (Chile); Silsbe, E.; Winkelman, S. [Centre for Clean Air Policy (United States)

    2005-07-01

    The transportation sector is responsible for almost 25 per cent of global carbon dioxide emissions. This share is increasing annually, particularly in developing countries. This report presented the findings of a study examining possible scenarios for using the Clean Development Mechanism (CDM) as a tool to promote sustainable development in Chile's transportation sector. Mobility challenges, a strong modelling capacity, commitment to CDM and excellent data sets made Chile an ideal location in which to test transportation solutions. It was noted that projects in the transportation sector of the CDM have been slower to develop than those in other sectors. It was suggested that demand-side initiatives face significant methodological and financial barriers. This project examined 3 case studies that revealed how the CDM can be used to address both technological and demand-side solutions for reducing emissions from Santiago's transportation sector. Case study 1 examined the potential greenhouse gas (GHG) benefits of switching bus technologies from diesel to hybrid and analyzed its feasibility as a CDM project. Case study 2 involved bicycle initiatives and assessed the methodological challenges associated with developing bike-ways and networks. Case study 3 focused on location efficiency and involved the measurement of change in travel demand and GHG reduction from encouraging infill development, as well as discussing how the CDM could be used as an incentive for more location efficient urban development. It was concluded that the CDM should accommodate travel demand reduction efforts as well as policy-based and sectoral approaches. It was suggested that the project-based framework required by the current CDM rules is limiting and makes quantification complicated. In addition, most transportation projects do not fit well within the CDM as it currently functions. It was recommended that consideration of emissions reductions should be integrated into long term

  14. Hierarchical Codebook Design for Massive MIMO

    Directory of Open Access Journals (Sweden)

    Xin Su

    2015-02-01

    Full Text Available The Research of Massive MIMO is an emerging area, since the more antennas the transmitters or receivers equipped with, the higher spectral efficiency and link reliability the system can provide. Due to the limited feedback channel, precoding and codebook design are important to exploit the performance of massive MIMO. To improve the precoding performance, we propose a novel hierarchical codebook with the Fourier-based perturbation matrices as the subcodebook and the Kerdock codebook as the main codebook, which could reduce storage and search complexity due to the finite a lphabet. Moreover, t o f urther r educe t he search complexity and feedback overhead without noticeable performance degradation, we use an adaptive selection algorithm to decide whether to use the subcodebook. Simulation results show that the proposed codebook has remarkable performance gain compared to the conventional Kerdock codebook, without significant increase in feedback overhead and search complexity.

  15. Modified MIMO Cube for Enhanced Channel Capacity

    Directory of Open Access Journals (Sweden)

    Lajos Nagy

    2012-01-01

    Full Text Available This paper deals with the optimization of MIMO antenna elements' position in modified MIMO cube for getting maximal channel capacity in indoor environment. The dependence of the channel capacity on the antenna orientation was analyzed by simulations. We have also examined the effect of the frequency dependence of the antenna system (in case of conjugate matching and nonconjugate matching for the channel capacity. Based on the simulation results in the created and measured antenna system, the antennas were at a right angle to each other. At the two chosen different structures, we measured the antenna parameters and the channel capacity. In this paper, we present the results of the measurements which clearly confirm our simulations. We will point out the differences between the two antenna structures.

  16. CDM: Taking stock and looking forward

    International Nuclear Information System (INIS)

    Ellis, Jane; Winkler, Harald; Corfee-Morlot, Jan; Gagnon-Lebrun, Frederic

    2007-01-01

    The Kyoto Protocol's clean development mechanism (CDM) was established in 1997 with the dual purposes of assisting non-Annex I Parties in achieving sustainable development and assisting Annex I Parties in achieving compliance with their quantified greenhouse gas (GHG) emission commitments. This paper looks at the development of the CDM portfolio as well as achievements of the CDM to date in the context of wider private and public flows of investment into developing countries. These achievements include the development of 325 (by May 2005) proposed CDM projects which are together expected to generate more than 79 Mt CO 2 -eq credits/year during 2008-2012, increasing awareness of climate change mitigation options among possible investors and others that may facilitate transactions (i.e. governments), and the strengthening of climate-relevant institutions within countries. The paper also draws lessons from this experience to date, and outlines what changes may be needed to transform the CDM concept to a broader scale after the end of the first commitment period in 2012

  17. CR-Calculus and adaptive array theory applied to MIMO random vibration control tests

    Science.gov (United States)

    Musella, U.; Manzato, S.; Peeters, B.; Guillaume, P.

    2016-09-01

    Performing Multiple-Input Multiple-Output (MIMO) tests to reproduce the vibration environment in a user-defined number of control points of a unit under test is necessary in applications where a realistic environment replication has to be achieved. MIMO tests require vibration control strategies to calculate the required drive signal vector that gives an acceptable replication of the target. This target is a (complex) vector with magnitude and phase information at the control points for MIMO Sine Control tests while in MIMO Random Control tests, in the most general case, the target is a complete spectral density matrix. The idea behind this work is to tailor a MIMO random vibration control approach that can be generalized to other MIMO tests, e.g. MIMO Sine and MIMO Time Waveform Replication. In this work the approach is to use gradient-based procedures over the complex space, applying the so called CR-Calculus and the adaptive array theory. With this approach it is possible to better control the process performances allowing the step-by-step Jacobian Matrix update. The theoretical bases behind the work are followed by an application of the developed method to a two-exciter two-axis system and by performance comparisons with standard methods.

  18. Trojan horse or horn of plenty? Reflections on allowing CCS in the CDM

    International Nuclear Information System (INIS)

    Coninck, Heleen de

    2008-01-01

    The discussion around allowing CO 2 capture and geological storage (CCS) into the Kyoto Protocol's Clean Development Mechanism (CDM) is important, as the CDM is currently the only structural incentive for reducing greenhouse gas emissions in the developing world. Without the potential incentives given by the CDM, CCS in developing countries will only take place sporadically in niche sectors. The debate around CCS in the CDM has developed into a highly polarised discussion, with a deep divide between proponents and opponents and no view on reconciliation between the various perspectives. Environmental organisations and several developing-country parties in the climate negotiations are increasingly vehemently opposed against CCS in the CDM, and industrialised countries, several large fossil-fuel-dependent developing countries and industry view CCS as a natural option under the CDM, provided some surmountable technical and procedural barriers are taken care of. This paper argues that the efforts of those trying to bring the discussion to a close by solving technical and procedural issues around CCS in the CDM will not lead to agreement because of underlying convictions of all stakeholders. Six convictions are identified and discussed. Based on the discussion of the convictions of both opponents and proponents, research needs and a potential negotiation package are suggested. The research needs are primarily in the field of the CDM market impacts of CCS, the issue of enhanced oil emission accounting, and sustainable development aspects, and particularly whether developing countries could actually benefit from technological leadership in the field of CCS, or whether they will be worse off. Devoting attention to the identified convictions could provide information for a more acceptable negotiation package on CCS in the CDM

  19. Key Technologies in Massive MIMO

    Directory of Open Access Journals (Sweden)

    Hu Qiang

    2018-01-01

    Full Text Available The explosive growth of wireless data traffic in the future fifth generation mobile communication system (5G has led researchers to develop new disruptive technologies. As an extension of traditional MIMO technology, massive MIMO can greatly improve the throughput rate and energy efficiency, and can effectively improve the link reliability and data transmission rate, which is an important research direction of 5G wireless communication. Massive MIMO technology is nearly three years to get a new technology of rapid development and it through a lot of increasing the number of antenna communication, using very duplex communication mode, make the system spectrum efficiency to an unprecedented height.

  20. A Quasi-ARX Model for Multivariable Decoupling Control of Nonlinear MIMO System

    Directory of Open Access Journals (Sweden)

    Lan Wang

    2012-01-01

    Full Text Available This paper proposes a multiinput and multioutput (MIMO quasi-autoregressive eXogenous (ARX model and a multivariable-decoupling proportional integral differential (PID controller for MIMO nonlinear systems based on the proposed model. The proposed MIMO quasi-ARX model improves the performance of ordinary quasi-ARX model. The proposed controller consists of a traditional PID controller with a decoupling compensator and a feed-forward compensator for the nonlinear dynamics based on the MIMO quasi-ARX model. Then an adaptive control algorithm is presented using the MIMO quasi-ARX radial basis function network (RBFN prediction model and some stability analysis of control system is shown. Simulation results show the effectiveness of the proposed control method.

  1. Long-term prospects of CDM and JI; Langfristige Perspektiven von CDM und JI

    Energy Technology Data Exchange (ETDEWEB)

    Cames, Martin; Anger, Niels; Boehringer, Christoph; Harthan, Ralph O.; Schneider, Lambert [Oeko-Institut, Berlin (Germany)

    2007-07-15

    This study analyses whether Germany should use the flexible mechanisms under the Kyoto protocol or whether it should continue to achieve its greenhouse gas reduction targets by dint of domestic policies and measures. It estimates the future potential of the project-based Kyoto mechanisms (CDM and JI) and the impacts of its use on the German and the global economy, using an integrated-assessment model. In a Delphi survey, the expectations of international experts on the future prospects of the project-based Kyoto mechanisms are assessed. The study finishes with an analysis of options for promoting the use of the flexible mechanisms in Germany and concludes that the Federal Government of Germany should establish a project-based mechanisms fund of 25 to 50 million Kyoto units to cover the compliance uncertainties due to unexpected temperature or business cycle variations. (orig.) [German] Diese Studie untersucht, ob Deutschland die flexiblen Mechanismen unter dem Kyoto-Protokoll nutzen sollte oder weiterhin seine Treibhausgasreduktionsziele durch inlaendische Politiken und Massnahmen erreichen sollte. Das kuenftige Potenzial der projektbezogenen Kyoto-Mechanismen (CDM und JI) wird untersucht und die Auswirkungen von deren Nutzung auf die deutsche und globale Wirtschaft werden mit einem Integrated-Assessment-Modell abgeschaetzt. In einer Delphi-Befragung werden die Erwartungen internationaler Experten in Hinblick auf die kuenftigen Perspektiven der projektbezogenen Kyoto- Mechanismen ermittelt. Abschliessend werden Moeglichkeiten zur Foerderung der Nutzung der flexiblen Mechanismen in Deutschland analysiert, mit der Schlussfolgerung, dass die Bundesregierung einen 25 bis 50 Millionen Kyoto-Einheiten umfassenden Fonds fuer projektbezogene Mechanismen einrichten sollte, um die Unsicherheiten bei der Erfuellung des Kyoto-Ziels infolge unerwarteter Temperaturschwankungen oder einer Aenderung der Konjunkturentwicklung abzudecken. (orig.)

  2. MimoSA: a system for minimotif annotation

    Directory of Open Access Journals (Sweden)

    Kundeti Vamsi

    2010-06-01

    Full Text Available Abstract Background Minimotifs are short peptide sequences within one protein, which are recognized by other proteins or molecules. While there are now several minimotif databases, they are incomplete. There are reports of many minimotifs in the primary literature, which have yet to be annotated, while entirely novel minimotifs continue to be published on a weekly basis. Our recently proposed function and sequence syntax for minimotifs enables us to build a general tool that will facilitate structured annotation and management of minimotif data from the biomedical literature. Results We have built the MimoSA application for minimotif annotation. The application supports management of the Minimotif Miner database, literature tracking, and annotation of new minimotifs. MimoSA enables the visualization, organization, selection and editing functions of minimotifs and their attributes in the MnM database. For the literature components, Mimosa provides paper status tracking and scoring of papers for annotation through a freely available machine learning approach, which is based on word correlation. The paper scoring algorithm is also available as a separate program, TextMine. Form-driven annotation of minimotif attributes enables entry of new minimotifs into the MnM database. Several supporting features increase the efficiency of annotation. The layered architecture of MimoSA allows for extensibility by separating the functions of paper scoring, minimotif visualization, and database management. MimoSA is readily adaptable to other annotation efforts that manually curate literature into a MySQL database. Conclusions MimoSA is an extensible application that facilitates minimotif annotation and integrates with the Minimotif Miner database. We have built MimoSA as an application that integrates dynamic abstract scoring with a high performance relational model of minimotif syntax. MimoSA's TextMine, an efficient paper-scoring algorithm, can be used to

  3. Diversity and Multiplexing Technologies by 3D Beams in Polarized Massive MIMO Systems

    Directory of Open Access Journals (Sweden)

    Xin Su

    2016-01-01

    Full Text Available Massive multiple input, multiple output (M-MIMO technologies have been proposed to scale up data rates reaching gigabits per second in the forthcoming 5G mobile communications systems. However, one of crucial constraints is a dimension in space to implement the M-MIMO. To cope with the space constraint and to utilize more flexibility in 3D beamforming (3D-BF, we propose antenna polarization in M-MIMO systems. In this paper, we design a polarized M-MIMO (PM-MIMO system associated with 3D-BF applications, where the system architectures for diversity and multiplexing technologies achieved by polarized 3D beams are provided. Different from the conventional 3D-BF achieved by planar M-MIMO technology to control the downtilted beam in a vertical domain, the proposed PM-MIMO realizes 3D-BF via the linear combination of polarized beams. In addition, an effective array selection scheme is proposed to optimize the beam-width and to enhance system performance by the exploration of diversity and multiplexing gains; and a blind channel estimation (BCE approach is also proposed to avoid pilot contamination in PM-MIMO. Based on the Long Term Evolution-Advanced (LTE-A specification, the simulation results finally confirm the validity of our proposals.

  4. Phase Noise Effect on MIMO-OFDM Systems with Common and Independent Oscillators

    Directory of Open Access Journals (Sweden)

    Xiaoming Chen

    2017-01-01

    Full Text Available The effects of oscillator phase noises (PNs on multiple-input multiple-output (MIMO orthogonal frequency division multiplexing (OFDM systems are studied. It is shown that PNs of common oscillators at the transmitter and at the receiver have the same influence on the performance of (single-stream beamforming MIMO-OFDM systems, yet different influences on spatial multiplexing MIMO-OFDM systems with singular value decomposition (SVD based precoding/decoding. When each antenna is equipped with an independent oscillator, the PNs at the transmitter and at the receiver have different influences on beamforming MIMO-OFDM systems as well as spatial multiplexing MIMO-OFDM systems. Specifically, the PN effect on the transmitter (receiver can be alleviated by having more transmit (receive antennas for the case of independent oscillators. It is found that the independent oscillator case outperforms the common oscillator case in terms of error vector magnitude (EVM.

  5. Low Complexity MIMO Detection

    CERN Document Server

    Bai, Lin

    2012-01-01

    Methods of signal detection are becoming an ever more vital component of wireless services, as providers lean towards using multiple antennae to compensate for limitations in the available wireless spectrum. The co-authors of this book are two of the world’s leading authorities on so-called MIMO (multiple-input, multiple-output) systems, and here they share the key findings of their years of research. They detail a range of important techniques for signal detection when multiple transmitted and received signals are available. They then review and explain some conventional MIMO detection schemes, including the ML, linear, and SIC detectors, and show why these methodologies are less than optimal compared to the more versatile list decoding and lattice reduction-aided detection systems. In the second part of the book, the authors move on to discuss various user selection schemes in multiuser systems.   Its finely tuned balance of theoretical analysis and practical applications makes this book required reading...

  6. MIMO Radar - Diversity Means Superiority

    National Research Council Canada - National Science Library

    Li, Jian

    2007-01-01

    We consider a multiple-input multiple-output (MIMO) radar system where both the transmitter and receiver have multiple well-separated subarrays with each subarray containing closely-spaced antennas...

  7. Massive MIMO meets small cell backhaul and cooperation

    CERN Document Server

    Yang, Howard H

    2017-01-01

    This brief explores the utilization of large antenna arrays in massive multiple-input-multiple-output (MIMO) for both interference suppression, where it can improve cell-edge user rates, and for wireless backhaul in small cell networks, where macro base stations can forward data to small access points in an energy efficient way. Massive MIMO is deemed as a critical technology for next generation wireless technology. By deploying an antenna array that has active elements in excess of the number of users, massive MIMO not only provides tremendous diversity gain but also powers new aspects for network design to improve performance. This brief investigates a better utilization of the excessive spatial dimensions to improve network performance. It combines random matrix theory and stochastic geometry to develop an analytical framework that accounts for all the key features of a network, including number of antenna array, base station density, inter-cell interference, random base station deployment, and network tra...

  8. MIMO to LS-MIMO: A road to realization of 5G

    Science.gov (United States)

    Koppati, Naveena; Pavani, K.; Sharma, Dinesh; Sharma, Purnima K.

    2017-07-01

    MIMO means multiple inputs multiple outputs. As it refers MIMO is a RF technology used in many new technologies these days to increase link capacity and spectral efficiency. MIMO is used in Wi-Fi, LTE, 4G, 5G and other wireless technologies. This paper describes the earlier history of MIMO-OFDM and the antenna beam forming development in MIMO and types of MIMO. Also this treatise describes several decoding algorithms. The MIMO combined with OFDM increases the channel capacity. But the main problem is in estimating the transmitted signal from the received signal. So the channel knowledge is to be known in estimating the channel capacity. The advancement in MIMO-OFDM is Massive MIMO which is beneficial in providing additional data capacity in the increased traffic environment is described. In this memoir various application scenarios of LS-MIMO which increases the capacity are discussed.

  9. Dual Band Notched EBG Structure based UWB MIMO/Diversity Antenna with Reduced Wide Band Electromagnetic Coupling

    Science.gov (United States)

    Jaglan, Naveen; Kanaujia, Binod Kumar; Gupta, Samir Dev; Srivastava, Shweta

    2017-10-01

    A dual band-notched MIMO/Diversity antenna is proposed in this paper. The proposed antenna ensures notches in WiMAX band (3.3-3.6 GHz) besides WLAN band (5-6 GHz). Mushroom Electromagnetic Band Gap (EBG) arrangements are employed for discarding interfering frequencies. The procedure followed to attain notches is antenna shape independent with established formulas. The electromagnetic coupling among two narrowly set apart Ultra-Wide Band (UWB) monopoles is reduced by means of decoupling bands and slotted ground plane. Monopoles are 90° angularly parted with steps on the radiator. This aids to diminish mutual coupling and also adds in the direction of impedance matching by long current route. S21 or else mutual coupling of fewer than 15 dB is established over antenna operating range. Two-port envelope correlation coefficient is lower than 0.02 in UWB range of 3.1 GHz-10.6 GHz. The shifting in notch frequencies by varying variables in formulas is also reported. The suggested antenna is designed on low budget FR-4 substrate with measurements as (58 × 45 × 1.6) mm3. Simulated and measured results of fabricated antenna are found to be in close agreement.

  10. Design and Implementation of a DSP-Based MIMO System Prototype for Real-Time Demonstration and Indoor Channel Measurements

    Directory of Open Access Journals (Sweden)

    Jeffrey H. Reed

    2005-09-01

    Full Text Available The design and implementation of the Virginia Tech Space-Time Advanced Radio (VT-STAR, a multiple antenna element space-time (ST processing prototype testbed, is presented. The testbed is a research tool for comparing practical and theoretical performance metrics (e.g., throughput, link reliability in different wireless channel conditions. The prototype builds around software-defined radio (SDR concepts on a DSP platform and provides the flexibility to implement various forms of ST techniques. Different components of the system are described in detail, including the software implementation, I/O schemes with custom hardware, and data transfer mechanisms between the DSP and the host PC. Two different example realizations are presented, a real-time demonstration and an offline measurement tool. Finally, some representative measurement results obtained in indoor environments are presented. These results show VT-STAR to be a promising tool for performing MIMO experiments and generating channel measurements that can complement simulation studies in this area.

  11. Etude Climat no. 37 '10 lessons from 10 years of the CDM'

    International Nuclear Information System (INIS)

    Shishlov, Igor; Bellassen, Valentin

    2012-01-01

    Among the publications of CDC Climat Research, 'Climate Reports' offer in-depth analyses on a given subject. This issue addresses the following points: The Clean Development Mechanism (CDM) is the first and by far the largest carbon offset instrument in the world. To date, it is the only market based on an environmental commodity which managed to attract several billions of euros of private capital on an annual basis. Being the first-of-a-kind climate change mitigation instrument, the CDM followed a 'learning by doing' pattern undergoing numerous reforms throughout its more than 10-year history. Although the post-2012 fate of the mechanism remains uncertain, one should not 'throw out the baby with the bath water' as the lessons from the CDM experience may be useful not only for the CDM reform but also for new market instruments

  12. GDINA and CDM Packages in R

    Science.gov (United States)

    Rupp, André A.; van Rijn, Peter W.

    2018-01-01

    We review the GIDNA and CDM packages in R for fitting cognitive diagnosis/diagnostic classification models. We first provide a summary of their core capabilities and then use both simulated and real data to compare their functionalities in practice. We found that the most relevant routines in the two packages appear to be more similar than…

  13. Understanding the CDM's contribution to technology transfer

    International Nuclear Information System (INIS)

    Schneider, Malte; Holzer, Andreas; Hoffmann, Volker H.

    2008-01-01

    Developing countries are increasingly contributing to global greenhouse gas emissions and, consequently, climate change as a result of their rapid economic growth. In order to reduce their impact, the private sector needs to be engaged in the transfer of low-carbon technology to those countries. The Clean Development Mechanism (CDM) is currently the only market mechanism aimed at triggering changes in the pattern of emissions-intensive activities in developing countries and is likely to play a role in future negotiations. In this paper, we analyse how the CDM contributes to technology transfer. We first develop a framework from the literature that delineates the main factors which characterise technology transfer. Second, we apply this framework to the CDM by assessing existing empirical studies and drawing on additional expert interviews. We find that the CDM does contribute to technology transfer by lowering several technology-transfer barriers and by raising the transfer quality. On the basis of this analysis, we give preliminary policy recommendations

  14. Beyond Multiplexing Gain in Large MIMO Systems

    DEFF Research Database (Denmark)

    Cakmak, Burak; Müller, Ralf R.; Fleury, Bernard Henri

    Given the common technical assumptions in the literature on MIMO channel modeling, we derive generic results for MIMO systems in the large system limit LSL. Consider a $\\ phi T\\ times T $ MIMO system with $ T $ tending to infinity. By increasing the antenna ratio $\\ phi $ when $\\ phi\\ geq 1$, the...... an accurate approximation of it that is easy to calculate....

  15. Impact of MIMO Co-Channel Interference

    DEFF Research Database (Denmark)

    Rahman, Muhammad Imadur; De Carvalho, Elisabeth; Prasad, Ramjee

    2007-01-01

    to cellular interference of some specific Multiple Input Multiple Output (MIMO) schemes on the same and other MIMO schemes. The goal is to study the impact of interference from MIMO schemes at a user located in the cell edge. Semi-Analytical evaluations of Signal to Interference and Noise Ratio (SINR) is done...

  16. Stakeholder participation in CDM and new climate mitigation mechanisms: China CDM case study

    DEFF Research Database (Denmark)

    Dong, Yan; Olsen, Karen Holm

    2017-01-01

    exists on how LSC is practised, and synergies between climate mechanisms are largely unexplored. This study explores how international LSC rules are practised at national and local levels. It aims to better shape future LSC in climate mechanisms by learning from the case of China. First, LSC policies......Stakeholder participation is recognized as a key principle for effective climate governance. Climate mechanisms such as the Clean Development Mechanism (CDM), REDD +, and the Green Climate Fund (GCF) provide guidelines for local stakeholder consultation (LSC). However, little empirical research...... in CDM, REDD +, and GCF are identified. Relevant rules in China’s local policies are analysed. To understand the interaction between CDM policies and China’s local LSC rules, a selection of Chinese CDM Projects Design Documents (PDDs) are analysed, providing an overall impression of the stakeholder...

  17. Multiuser Beamforming with Limited Feedback for FDD Massive MIMO Systems

    Directory of Open Access Journals (Sweden)

    Senyao Zheng

    2016-01-01

    Full Text Available This paper discusses the multiuser beamforming in FDD massive MIMO systems. It first introduces the feature of FDD massive MIMO systems to implement multiuser beamforming schemes. After that, considering the realistic implementation of multiuser beamforming scheme in FDD massive MIMO systems, it introduces the knowledge of channel quantization. In the main part of the paper, we introduce two traditional multiuser beamforming schemes and analyse their merits and demerits. Based on these, we propose a novel multiuser beamforming scheme to flexibly combine the merits of the traditional beamforming schemes. In the final part of the paper, we give some simulation results to compare the beamforming schemes mentioned in the paper. These simulation results show the superiority of the proposed beamforming scheme.

  18. Optimization of Training Signal Transmission for Estimating MIMO Channel under Antenna Mutual Coupling Conditions

    Directory of Open Access Journals (Sweden)

    Xia Liu

    2010-01-01

    Full Text Available This paper reports investigations on the effect of antenna mutual coupling on performance of training-based Multiple-Input Multiple-Output (MIMO channel estimation. The influence of mutual coupling is assessed for two training-based channel estimation methods, Scaled Least Square (SLS and Minimum Mean Square Error (MMSE. It is shown that the accuracy of MIMO channel estimation is governed by the sum of eigenvalues of channel correlation matrix which in turn is influenced by the mutual coupling in transmitting and receiving array antennas. A water-filling-based procedure is proposed to optimize the training signal transmission to minimize the MIMO channel estimation errors.

  19. Active fault detection in MIMO systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    The focus in this paper is on active fault detection (AFD) for MIMO systems with parametric faults. The problem of design of auxiliary inputs with respect to detection of parametric faults is investigated. An analysis of the design of auxiliary inputs is given based on analytic transfer functions...... from auxiliary input to residual outputs. The analysis is based on a singular value decomposition of these transfer functions Based on this analysis, it is possible to design auxiliary input as well as design of the associated residual vector with respect to every single parametric fault in the system...... such that it is possible to detect these faults....

  20. CDM sustainable development impacts developed for the UNEP project 'CD4CDM'

    Energy Technology Data Exchange (ETDEWEB)

    Olhoff, Anne; Markandya, Anil; Halsnaes, Kirsten; Taylor, Tim

    2004-07-01

    The Clean Development Mechanism (CDM), an innovative cooperative mechanism under the Kyoto Protocol, is designed with the dual aim of assisting developing countries in achieving sustainable development (SD) and of assisting industrialised countries in achieving compliance with their greenhouse gas (GHG) emission reduction commitments. The SD dimension is not merely a requirement of the CDM; it should be seen as a main driver for developing country interest in participating in CDM projects. This is so, since apart from GHG emission reductions CDM projects will have a number of impacts in the host countries, including impacts on economic and social development and on the local environment. Furthermore, the selecting of the SD criteria and the assessment of the SD impacts are sovereign matters of the host countries in the current operationalisation of the Kyoto Protocol. National authorities can thus use the SD dimension to evaluate key linkages between national development goals and CDM projects, with the aim of selecting and designing CDM projects so that they create and maximise synergies with local development goals. (au)

  1. Distributed Joint Cluster Formation and Resource Allocation Scheme for Cooperative Data Collection in Virtual MIMO-Based M2M Networks

    Directory of Open Access Journals (Sweden)

    Xi Luan

    2015-01-01

    Full Text Available An efficient data collection scheme plays an important role for the real-time intelligent monitoring in many machine-to-machine (M2M networks. In this paper, a distributed joint cluster formation and resource allocation scheme for data collection in cluster-based M2M networks is proposed. Specifically, in order to utilize the advantages of cooperation, we first propose a hierarchical transmission model which contains two communication phases. In the first phase, the intracluster information sharing is carried out by all the nodes within the same cluster. Then these nodes transmit the total information to the BS cooperatively with virtual-MIMO (VMIMO protocol in the second phase. To grasp the properties and advantages of this cooperative transmission strategy, the theoretical analysis results are provided. The key issue in this system is to form the clusters and allocate resources efficiently. Since the optimization problem on this issue is an NP-hard problem, a feasible joint scheme for the cluster formation and resource allocation is proposed in this paper, which is carried out via coalition formation game with a distributed algorithm. This scheme can reduce the complexity while keeping an attractive performance. Simulation results show the properties of the proposed scheme and its advantages when comparing with the noncooperative scheme for the data collection in a practical scenario.

  2. 3D Channel Model Emulation in a MIMO OTA Setup

    DEFF Research Database (Denmark)

    Fan, Wei; Kyösti, Pekka; Sun, Fan

    2013-01-01

    This paper presents a new channel reconstruction technique for 3D geometry-based channels in a multi-probe based MIMO OTA setup. The proposed method provides a general channel reconstruction framework for any spherical power spectrum. The channel reconstruction is formed as convex optimization...

  3. MU-MIMO in LTE Systems

    DEFF Research Database (Denmark)

    Duplicy, Jonathan; Badic, Biljana; Balraj, Rajarajan

    2011-01-01

    focus is on making Multi-User Multiple-Input Multiple-Output (MUMIMO) practically realizable. This article presents an overview of the different MU-MIMO schemes included / being studied in 3GPP standardization; from LTE (Long Term Evolution) to LTE-Advanced. MU-MIMO system concepts and implementation...... for LTE Release 8 are provided. Interestingly, it is shown that MU-MIMO only offers marginal performance gains with respect to singleuser MIMO. This arises from the limited MU-MIMO features included in Release 8 and calls for improved schemes for the upcoming releases....

  4. Physical layer security in fiber-optic MIMO-SDM systems: An overview

    Science.gov (United States)

    Guan, Kyle; Cho, Junho; Winzer, Peter J.

    2018-02-01

    Fiber-optic transmission systems provide large capacities over enormous distances but are vulnerable to simple eavesdropping attacks at the physical layer. We classify key-based and keyless encryption and physical layer security techniques and discuss them in the context of optical multiple-input-multiple-output space-division multiplexed (MIMO-SDM) fiber-optic communication systems. We show that MIMO-SDM not only increases system capacity, but also ensures the confidentiality of information transmission. Based on recent numerical and experimental results, we review how the unique channel characteristics of MIMO-SDM can be exploited to provide various levels of physical layer security.

  5. Analyzing Capacity of Cooperative MIMO using Beamforming in Measured Channel Data

    DEFF Research Database (Denmark)

    Rahimi, Maryam; De Carvalho, Elisabeth; Pedersen, Gert Frølund

    2012-01-01

    This paper focuses on capacity in cooperative base stations MIMO in a realistic MIMO channel measurement. Two widely separated base stations have been assumed in this work and measurement has been done simultaneously from both base stations to four users. The effect of beamforming on capacity...... in different scenarios in this novel measurement setup has been investigated. The results shows great increase in capacity after cooperation consideration and optimization applied....

  6. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...... isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated...

  7. Review of monitoring uncertainty requirements in the CDM

    International Nuclear Information System (INIS)

    Shishlov, Igor; Bellassen, Valentin

    2014-10-01

    In order to ensure the environmental integrity of carbon offset projects, emission reductions certified under the Clean Development Mechanism (CDM) have to be 'real, measurable and additional', which is ensured through the monitoring, reporting and verification (MRV) process. MRV, however, comes at a cost that ranges from several cents to EUR1.20 and above per ton of CO 2 e depending on the project type. This article analyzes monitoring uncertainty requirements for carbon offset projects with a particular focus on the trade-off between monitoring stringency and cost. To this end, we review existing literature, scrutinize both overarching monitoring guidelines and the 10 most-used methodologies, and finally we analyze four case studies. We find that there is indeed a natural trade-off between the stringency and the cost of monitoring, which if not addressed properly may become a major barrier for the implementation of offset projects in some sectors. We demonstrate that this trade-off has not been systematically addressed in the overarching CDM guidelines and that there are only limited incentives to reduce monitoring uncertainty. Some methodologies and calculation tools as well as some other offset standards, however, do incorporate provisions for a trade-off between monitoring costs and stringency. These provisions may take the form of discounting emissions reductions based on the level of monitoring uncertainty - or more implicitly through allowing a project developer to choose between monitoring a given parameter and using a conservative default value. Our findings support the introduction of an uncertainty standard under the CDM for more comprehensive, yet cost-efficient, accounting for monitoring uncertainty in carbon offset projects. (authors)

  8. CO2 underground storage and potential of CDM

    International Nuclear Information System (INIS)

    Shigetomi, N.; Shibuya, Y.; Nakano, M.; Akai, M.

    2005-01-01

    Carbon dioxide (CO 2 ) underground storage technologies are being used as a means to mitigate the increase in CO 2 concentration in the atmosphere. Indonesia is an oil producing and exporting country. Its reserve-production ratio which is estimated based on the current production volume is approximately 19 years. Energy demand in the future is expected to be on the rise in Indonesia. In addition, in light of the interest in enhanced oil recovery (EOR), CO 2 underground storage is also being explored. Activities to initiate the Clean Development Mechanism (CDM), which is one of the Kyoto Mechanisms, have also been actively promoted in developing countries. This paper examined an EOR operation which used CO 2 separated and recovered from waste gas at coal-fired power plants which have the highest CO 2 emission rates among human-induced CO 2 emission sources in Indonesia. The paper discussed EOR, its characteristics and features as well as case studies with specific sites in order to clarify issues and conditions for promoting CO 2 underground storage technologies into CDM. It was concluded that it is necessary to conduct additional studies on the profitability of the operation while conducting verification at the CO 2 separation and recovery site and the CO 2 storage site and consulting with relevant stakeholders of EOR operation. In addition, it was suggested that procedures should be put in place to promote the EOR operation into a CDM project by coordinating with the host country and offering it incentives. 3 refs., 1 tab., 2 figs

  9. The PN.S Elliptical Galaxy Survey: a standard ΛCDM halo around NGC 4374? : A standard ΛCDM halo around NGC 4374?

    NARCIS (Netherlands)

    Napolitano, N. R.; Romanowsky, A. J.; Capaccioli, M.; Douglas, Nigel; Arnaboldi, M.; Coccato, L.; Gerhard, O.; Kuijken, K.; Merrifield, M. R.; Bamford, S. P.; Cortesi, A.; Das, P.; Freeman, K. C.

    As part of our current programme to test ΛCDM predictions for dark matter (DM) haloes using extended kinematical observations of early-type galaxies, we present a dynamical analysis of the bright elliptical galaxy NGC 4374 (M84) based on ˜450 planetary nebulae (PNe) velocities from the

  10. Design of 5G Full Dimension Massive MIMO Systems

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2017-10-13

    This work discusses full-dimension multiple-inputmultiple- output (FD-MIMO) technology, which is currently an active area of research and standardization in wireless communications for evolution towards Fifth Generation (5G) cellular systems. FD-MIMO utilizes an active antenna system (AAS) with a two-dimensional (2D) planar array structure, that not only allows a large number of antenna elements to be packed within feasible base station form factors but also provides the ability of adaptive electronic beamforming in the threedimensional (3D) space. However, the compact structure of largescale planar arrays drastically increases the spatial correlation in FD-MIMO systems. In order to account for its effects, the generalized spatial correlation functions for channels constituted by individual elements and overall antenna ports in the AAS are derived. Exploiting the quasi-static channel covariance matrices of users, the problem of determining the optimal downtilt weight vector for antenna ports, which maximizes the minimum signalto- interference ratio of a multi-user multiple-input-single-output system, is formulated as a fractional optimization problem. A quasi-optimal solution is obtained through the application of semi-definite relaxation and Dinkelbach’s method. Finally, the user-group specific elevation beamforming scenario is devised, which offers significant performance gains as confirmed through simulations. These results have direct application in the analysis of 5G FD-MIMO systems.

  11. Field-Theoretical Investigations of the Influence of Mutual Coupling Effects on the Capacity of MIMO Wireless Links

    Science.gov (United States)

    Ndoumbè Mbonjo Mbonjo, H.; Wu, G.; Hansen, V.

    2005-05-01

    We present a MIMO channel model which takes into account mutual coupling effects at the receiver and transmitter array in order to assess the influence of mutual coupling effects on the capacity of MIMO channels. We evaluate the mutual impedances using a general approach based on the electric field integral equation (EFIE) and its implementation by the method of moments (MOM). We compute the capacity of a 2x2-MIMO system in a one path scenario for square half wavelength patch antenna elements and half wavelength dipole antenna elements. The capacity of the MIMO system with and without coupling increases compared to the single antenna transmission for the patch antenna elements. On the contrary for half wavelength dipole antenna elements we have found that the MIMO system degenerates to a one-transmitting, one-receiving antenna system due to mutual coupling.

  12. Technology choice and CDM projects in China: case study of a small steel company in Shandong Province

    International Nuclear Information System (INIS)

    Kaneko, Shinji; Yonamine, Asaka; Jung, Tae Yong

    2006-01-01

    Corporate motives and strategies of both investing and hosting country affect the outcomes of a clean development mechanism (CDM) project-who introduces what technology to whom-and result in large differences in economic viability and the CO 2 emission reductions. This is particularly true for steel industry in which steel making consists of many detailed and complex processes, a given strategy could produce cumulative effects of the individual technologies used, leading to large energy savings overall. The objective of this study is to demonstrate some analytical methods that can be used to quantitatively evaluate the impacts of technology selection on the profit performance of CDM projects. Specifically, in this study we analyze a CDM project to introduce energy saving technology from Japan to a small steel manufacturer in China's Shandong Province, and conduct a simulation of the quantitative relationships between various technology options and profitability. Based on these results, we examine the environmental and economic significance of technology selection for CDM projects. To take this further, we then reconsider the profitability of a project as typical FDI activity (i.e., without the CDM), and by comparing this outcome with the CDM case, we clarify the significance and potential of the CDM

  13. Navigating the global carbon market. An analysis of the CDM's value chain and prevalent business models

    International Nuclear Information System (INIS)

    Schneider, Malte; Hendrichs, Holger; Hoffmann, Volker H.

    2010-01-01

    From a slow start, the clean development mechanism (CDM) market has recently experienced enormous growth. However, the CDM market has been increasingly criticised, resulting in a lively debate about how to reform, complement, or replace it. In order to increase transparency and assist policy-makers in better understanding the current market, we depart from the traditional project-level perspective on CDM and analyse commercial activities by utilising data from UNEP Risoe's CDM Bazaar. To this end, we first establish a seven-step value chain by conducting a factor analysis on the commercial activities indicated in the Bazaar and, second, identify nine prevalent business models with a cluster analysis of all 495 participating organisations. Based on these analyses, we discuss potential impacts on the value chain of different policy scenarios that rely on carbon credits as incentive. We find that the importance of specific regulatory CDM know-how and general business activities such as finance varies strongly with the different policy scenarios. Our analysis serves to sensitise policy-makers and business about implications of different regulatory designs. (author)

  14. Phase Noise Effect on MIMO-OFDM Systems with Common and Independent Oscillators

    DEFF Research Database (Denmark)

    Chen, Xiaoming; Wang, Hua; Fan, Wei

    2018-01-01

    of (single-stream) beamforming MIMO-OFDM systems, yet different influences on spatial multiplexing MIMOOFDM systems with singular value decomposition (SVD) based precoding/decoding. When each antenna is equipped with an independent oscillator, the PNs at the transmitter and at the receiver have different...... influences on beamforming MIMO-OFDM systems as well as spatial multiplexing MIMO-OFDM systems. Specifically, the PN effect at the transmitter (receiver) can be alleviated by having more transmit (receive) antennas for the case of independent oscillators. It is found that the independent oscillator case......In this paper, the effects of oscillator phase noises (PNs) on multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems are studied. It is shown that PNs of common oscillators at the transmitter and at the receiver have the same influence on the performance...

  15. Phase Noise Effect on MIMO-OFDM Systems with Common and Independent Oscillators

    DEFF Research Database (Denmark)

    Chen, Xiaoming; Wang, Hua; Fan, Wei

    2018-01-01

    In this paper, the effects of oscillator phase noises (PNs) on multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems are studied. It is shown that PNs of common oscillators at the transmitter and at the receiver have the same influence on the performance...... of (single-stream) beamforming MIMO-OFDM systems, yet different influences on spatial multiplexing MIMOOFDM systems with singular value decomposition (SVD) based precoding/decoding. When each antenna is equipped with an independent oscillator, the PNs at the transmitter and at the receiver have different...... influences on beamforming MIMO-OFDM systems as well as spatial multiplexing MIMO-OFDM systems. Specifically, the PN effect at the transmitter (receiver) can be alleviated by having more transmit (receive) antennas for the case of independent oscillators. It is found that the independent oscillator case...

  16. The analysis of MAI in large scale MIMO-CDMA system

    Science.gov (United States)

    Berceanu, Madalina-Georgiana; Voicu, Carmen; Halunga, Simona

    2016-12-01

    Recently, technological development imposed a rapid growth in the use of data carried by cellular services, which also implies the necessity of higher data rates and lower latency. To meet the users' demands, it was brought into discussion a series of new data processing techniques. In this paper, we approached the MIMO technology that uses multiple antennas at the receiver and transmitter ends. To study the performances obtained by this technology, we proposed a MIMO-CDMA system, where image transmission has been used instead of random data transmission to take benefit of a larger range of quality indicators. In the simulations we increased the number of antennas, we observed how the performances of the system are modified and, based on that, we were able to make a comparison between a conventional MIMO and a Large Scale MIMO system, in terms of BER and MSSIM index, which is a metric that compares the quality of the image before transmission with the received one.

  17. Multi-Target Angle Tracking Algorithm for Bistatic Multiple-Input Multiple-Output (MIMO Radar Based on the Elements of the Covariance Matrix

    Directory of Open Access Journals (Sweden)

    Zhengyan Zhang

    2018-03-01

    Full Text Available In this paper, we consider the problem of tracking the direction of arrivals (DOA and the direction of departure (DOD of multiple targets for bistatic multiple-input multiple-output (MIMO radar. A high-precision tracking algorithm for target angle is proposed. First, the linear relationship between the covariance matrix difference and the angle difference of the adjacent moment was obtained through three approximate relations. Then, the proposed algorithm obtained the relationship between the elements in the covariance matrix difference. On this basis, the performance of the algorithm was improved by averaging the covariance matrix element. Finally, the least square method was used to estimate the DOD and DOA. The algorithm realized the automatic correlation of the angle and provided better performance when compared with the adaptive asymmetric joint diagonalization (AAJD algorithm. The simulation results demonstrated the effectiveness of the proposed algorithm. The algorithm provides the technical support for the practical application of MIMO radar.

  18. Multi-Target Angle Tracking Algorithm for Bistatic Multiple-Input Multiple-Output (MIMO) Radar Based on the Elements of the Covariance Matrix.

    Science.gov (United States)

    Zhang, Zhengyan; Zhang, Jianyun; Zhou, Qingsong; Li, Xiaobo

    2018-03-07

    In this paper, we consider the problem of tracking the direction of arrivals (DOA) and the direction of departure (DOD) of multiple targets for bistatic multiple-input multiple-output (MIMO) radar. A high-precision tracking algorithm for target angle is proposed. First, the linear relationship between the covariance matrix difference and the angle difference of the adjacent moment was obtained through three approximate relations. Then, the proposed algorithm obtained the relationship between the elements in the covariance matrix difference. On this basis, the performance of the algorithm was improved by averaging the covariance matrix element. Finally, the least square method was used to estimate the DOD and DOA. The algorithm realized the automatic correlation of the angle and provided better performance when compared with the adaptive asymmetric joint diagonalization (AAJD) algorithm. The simulation results demonstrated the effectiveness of the proposed algorithm. The algorithm provides the technical support for the practical application of MIMO radar.

  19. A new recipe for Λ CDM

    International Nuclear Information System (INIS)

    Sahni, Varun; Sen, Anjan A.

    2017-01-01

    It is well known that a canonical scalar field is able to describe either dark matter or dark energy but not both. We demonstrate that a non-canonical scalar field can describe both dark matter and dark energy within a unified setting. We consider the simplest extension of the canonical Lagrangian L ∝ X α - V(φ) where α ≥ 1 and V is a sufficiently flat potential. In this case the kinetic term in the Lagrangian behaves just like a perfect fluid, whereas the potential term mimicks dark energy. For very large values, α >> 1, the equation of state of the kinetic term drops to zero and the universe expands as if filled with a mixture of dark matter and dark energy. The velocity of sound in this model and the associated gravitational clustering are sensitive to the value of α. For very large values of α the clustering properties of our model resemble those of cold dark matter (CDM). But for smaller values of α, gravitational clustering on small scales is suppressed, and our model has properties resembling those of warm dark matter (WDM). Therefore our non-canonical model has an interesting new property: its expansion history resembles Λ CDM, while its clustering properties are akin to those of either cold or warm dark matter. (orig.)

  20. Sequential decoders for large MIMO systems

    KAUST Repository

    Ali, Konpal S.

    2014-05-01

    Due to their ability to provide high data rates, multiple-input multiple-output (MIMO) systems have become increasingly popular. Decoding of these systems with acceptable error performance is computationally very demanding. In this paper, we employ the Sequential Decoder using the Fano Algorithm for large MIMO systems. A parameter called the bias is varied to attain different performance-complexity trade-offs. Low values of the bias result in excellent performance but at the expense of high complexity and vice versa for higher bias values. Numerical results are done that show moderate bias values result in a decent performance-complexity trade-off. We also attempt to bound the error by bounding the bias, using the minimum distance of a lattice. The variations in complexity with SNR have an interesting trend that shows room for considerable improvement. Our work is compared against linear decoders (LDs) aided with Element-based Lattice Reduction (ELR) and Complex Lenstra-Lenstra-Lovasz (CLLL) reduction. © 2014 IFIP.

  1. Can CDM bring technology transfer to China?-An empirical study of technology transfer in China's CDM projects

    International Nuclear Information System (INIS)

    Wang Bo

    2010-01-01

    China has undertaken the greatest number of projects and reported the largest emission reductions on the global clean development mechanism (CDM) market. As technology transfer (TT) was designed to play a key role for Annex II countries in achieving greenhouse gas emission reductions, this study examines various factors that have affected CDM and TT in China. The proportion of total income derived from the certified emissions reductions (CER) plays a key role in the project owners' decision to adopt foreign technology. Incompatibility of CDM procedures with Chinese domestic procedures, technology diffusion (TD) effects, Chinese government policy and the role of carbon traders and CDM project consultants all contribute to the different degrees and forms of TT. International carbon traders and CDM consultants could play a larger role in TT in China's CDM projects as investors and brokers in the future.

  2. ESD full chip simulation: HBM and CDM requirements and simulation approach

    Directory of Open Access Journals (Sweden)

    E. Franell

    2008-05-01

    Full Text Available Verification of ESD safety on full chip level is a major challenge for IC design. Especially phenomena with their origin in the overall product setup are posing a hurdle on the way to ESD safe products. For stress according to the Charged Device Model (CDM, a stumbling stone for a simulation based analysis is the complex current distribution among a huge number of internal nodes leading to hardly predictable voltage drops inside the circuits.

    This paper describes an methodology for Human Body Model (HBM simulations with an improved ESD-failure coverage and a novel methodology to replace capacitive nodes within a resistive network by current sources for CDM simulation. This enables a highly efficient DC simulation clearly marking CDM relevant design weaknesses allowing for application of this software both during product development and for product verification.

  3. Performance Analysis of Cooperative Virtual MIMO Systems for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Adnan Al-Anbuky

    2013-05-01

    Full Text Available Multi-Input Multi-Output (MIMO techniques can be used to increase the data rate for a given bit error rate (BER and transmission power. Due to the small form factor, energy and processing constraints of wireless sensor nodes, a cooperative Virtual MIMO as opposed to True MIMO system architecture is considered more feasible for wireless sensor network (WSN applications. Virtual MIMO with Vertical-Bell Labs Layered Space-Time (V-BLAST multiplexing architecture has been recently established to enhance WSN performance. In this paper, we further investigate the impact of different modulation techniques, and analyze for the first time, the performance of a cooperative Virtual MIMO system based on V-BLAST architecture with multi-carrier modulation techniques. Through analytical models and simulations using real hardware and environment settings, both communication and processing energy consumptions, BER, spectral efficiency, and total time delay of multiple cooperative nodes each with single antenna are evaluated. The results show that cooperative Virtual-MIMO with Binary Phase Shift Keying-Wavelet based Orthogonal Frequency Division Multiplexing (BPSK-WOFDM modulation is a promising solution for future high data-rate and energy-efficient WSNs.

  4. MIMO over ESPAR with 16-QAM Modulation

    DEFF Research Database (Denmark)

    Han, Bo; Barousis, V.I.; Papadias, C.B.

    2013-01-01

    MIMO systems have become an indispensable part of modern wireless standards, e.g. LTE advanced. However, in applications with strict energy and size constraints, an alternative MIMO scheme with reduced hardware complexity would be attractive. Towards this direction, parasitic antennas with a sing...

  5. MIMO System Setup and Parameter Estimation

    NARCIS (Netherlands)

    Warnas, J; Shao, X.; Schiphorst, Roelof; Slump, Cornelis H.

    2008-01-01

    There is a rat race in wireless communication to achieve higher spectral efficiency. One technique to achieve this is the use of multiple antenna systems i.e. MIMO systems. In this paper we describe a wireless 4x4 Multiple Input Multiple Output (MIMO) testbed in the 2.2 GHz band including results

  6. REVIEW OF WIRELESS MIMO CHANNEL MODELS | Anioke ...

    African Journals Online (AJOL)

    The need to increase spectral efficiency has led to the design of multiple antenna systems for both transmit and receive sides otherwise known as MIMO. Channel modeling forms an integral part of this design. Therefore it is very important to investigate and understand existing MIMO channel models. This paper provides a ...

  7. Comparison of mimo radar concepts: Detection performance

    NARCIS (Netherlands)

    Rossum, W.L. van; Huizing, A.G.

    2007-01-01

    In this paper, four different array radar concepts are compared: pencil beam, floodlight, monostatic MIMO, and multistatic MIMO. The array radar concepts show an increase in complexity accompanied by an increase in diversity. The comparison between the radar concepts is made by investigating the

  8. REVIEW OF WIRELESS MIMO CHANNEL MODELS

    African Journals Online (AJOL)

    user

    The need to increase spectral efficiency has led to the design of multiple antenna systems for both transmit and receive sides otherwise known as MIMO. Channel modeling forms an integral part of this design. Therefore it is very important to investigate and understand existing MIMO channel models. This paper provides a ...

  9. Study on a resource allocation scheme in multi-hop MIMO-OFDM systems over lognormal-rayleigh compound channels

    Directory of Open Access Journals (Sweden)

    LIU Jun

    2015-10-01

    Full Text Available For new generation wireless communication networks,this paper studies the optimization of the capacity and end-to-end throughput of the MIMO-OFDM based multi-hop relay systems.A water-filling power allocation method is proposed to improve the channel capacity and the throughput of the MIMO-OFDM system based multi-hop relay system in the Lognormal-Rayleigh shadowing compound channels.Simulations on the capacity and throughput show that the water-filling algorithm can improve the system throughput effectively in the MIMO-OFDM multi-hop relay system.

  10. Stakeholder preferences towards the sustainable development of CDM projects: Lessons from biomass (rice husk) CDM project in Thailand

    International Nuclear Information System (INIS)

    Parnphumeesup, Piya; Kerr, Sandy A.

    2011-01-01

    This research applies both quantitative and qualitative methods to investigate stakeholder preferences towards sustainable development (SD) priorities in Clean Development Mechanism (CDM) projects. The CDM's contribution to SD is explored in the context of a biomass (rice husk) case study conducted in Thailand. Quantitative analysis ranks increasing the usage of renewable energy as the highest priority, followed by employment and technology transfer. Air pollution (dust) is ranked as the most important problem. Preference weights expressed by experts and local resident are statistically different in the cases of: employment generation; emission reductions; dust; waste disposal; and noise. Qualitative results, suggest that rice husk CDM projects contribute significantly to SD in terms of employment generation, an increase in usage of renewable energy, and transfer of knowledge. However, rice husk biomass projects create a potential negative impact on air quality. In order to ensure the environmental sustainability of CDM projects, stakeholders suggest that Thailand should cancel an Environmental Impact Assessment (EIA) exemption for CDM projects with an installed capacity below 10 MW and apply it to all CDM projects. - Highlights: → Stakeholders rank increasing the usage of renewable energy as the highest priority. → Biomass (rice husk) CDM projects create a potential negative impact on air quality. → Rice husk CDM projects cannot give an extra income to farmers. → Preference weights expressed by experts and local residents are statistically different.

  11. CDM. Information and guidebook - Developed for the UNEP project 'CD4CDM'[Clean development nedianism

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.K. (ed.)

    2003-12-01

    Since the Clean Development Mechanism (CDM) was defined at Conference of the Parties 3 in Kyoto 1997, it took the international community another 4 years to reach the Marrakesh Accords in which the modalities and procedures to implement the CDM was elaborated. Even if more detailed rules, procedures and modalities have to be further developed a general framework to implement the CDM and other Kyoto mechanisms are now in place. This guidebook is produced to support the UNEP project 'Capacity Development for the Clean Development Mechanism'. Focus is on the CDM project cycle, the Project Design Document (PDD), and related issues such as sustainable development goals, financing and market intelligence. The appendices present frequently asked questions and answers, a short overview of existing guidelines and a possible future list of eligible CDM projects categories. (BA)

  12. Channel Phase Error Compensation for MIMO-SAR

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-01-01

    Full Text Available Multi-input multioutput (MIMO is a novel technique to achieve high-resolution as well as wide swath in synthetic aperture radar (SAR systems. Channel imbalance is inevitable in multichannel systems that it declines the imaging quality. Generally, the imbalance cannot be fully compensated by simple internal calibration in a MIMO-SAR system. In this paper, a new algorithm based on raw data is presented to remove the channel phase error. Based on the error source, this approach models the phase error as two parts: the transmit phase error and the receive phase error. The receive phase error is removed using cost function at the azimuth processing stage, whereas the transmit phase error is estimated with correlation. Point target simulations confirm the influence of channel phase error and the validation of the proposed approach. Besides, the performance is also investigated.

  13. Adaptive Multi-Node Multiple Input and Multiple Output (MIMO) Transmission for Mobile Wireless Multimedia Sensor Networks

    Science.gov (United States)

    Cho, Sunghyun; Choi, Ji-Woong; You, Cheolwoo

    2013-01-01

    Mobile wireless multimedia sensor networks (WMSNs), which consist of mobile sink or sensor nodes and use rich sensing information, require much faster and more reliable wireless links than static wireless sensor networks (WSNs). This paper proposes an adaptive multi-node (MN) multiple input and multiple output (MIMO) transmission to improve the transmission reliability and capacity of mobile sink nodes when they experience spatial correlation. Unlike conventional single-node (SN) MIMO transmission, the proposed scheme considers the use of transmission antennas from more than two sensor nodes. To find an optimal antenna set and a MIMO transmission scheme, a MN MIMO channel model is introduced first, followed by derivation of closed-form ergodic capacity expressions with different MIMO transmission schemes, such as space-time transmit diversity coding and spatial multiplexing. The capacity varies according to the antenna correlation and the path gain from multiple sensor nodes. Based on these statistical results, we propose an adaptive MIMO mode and antenna set switching algorithm that maximizes the ergodic capacity of mobile sink nodes. The ergodic capacity of the proposed scheme is compared with conventional SN MIMO schemes, where the gain increases as the antenna correlation and path gain ratio increase. PMID:24152920

  14. Efficient channel estimation in massive MIMO systems - a distributed approach

    KAUST Repository

    Al-Naffouri, Tareq Y.

    2016-01-21

    We present two efficient algorithms for distributed estimation of channels in massive MIMO systems. The two cases of 1) generic, and 2) sparse channels is considered. The algorithms estimate the impulse response for each channel observed by the antennas at the receiver (base station) in a coordinated manner by sharing minimal information among neighboring antennas. Simulations demonstrate the superior performance of the proposed methods as compared to other methods.

  15. Tracking control of DC motors via mimo nonlinear fuzzy control

    International Nuclear Information System (INIS)

    Harb, Ahmad M.; Smadi, Issam A.

    2009-01-01

    This paper proposed a nonlinear controller for speed tracking of separately excited DC motors (SEDCM's) using the multi-input multi-output (MIMO) fuzzy logic controller (FLC's). Based on a nonlinear mathematical model of SEDCM, a FLC is designed to achieve high performance speed tracking through rejection load disturbance. Computer simulations are presented to show speed tracking performance and the effectiveness of the proposed controller.

  16. Sparse Bayesian Learning Based Three-Dimensional Imaging Algorithm for Off-Grid Air Targets in MIMO Radar Array

    Directory of Open Access Journals (Sweden)

    Zekun Jiao

    2018-02-01

    Full Text Available In recent years, the development of compressed sensing (CS and array signal processing provides us with a broader perspective of 3D imaging. The CS-based imaging algorithms have a better performance than traditional methods. In addition, the sparse array can overcome the limitation of aperture size and number of antennas. Since the signal to be reconstructed is sparse for air targets, many CS-based imaging algorithms using a sparse array are proposed. However, most of those algorithms assume that the scatterers are exactly located at the pre-discretized grids, which will not hold in real scene. Aiming at finding an accurate solution to off-grid target imaging, we propose an off-grid 3D imaging method based on improved sparse Bayesian learning (SBL. Besides, the Bayesian Cramér-Rao Bound (BCRB for off-grid bias estimator is provided. Different from previous algorithms, the proposed algorithm adopts a three-stage hierarchical sparse prior to introduce more degrees of freedom. Then variational expectation maximization method is applied to solve the sparse recovery problem through iteration, during each iteration joint sparsity is used to improve efficiency. Experimental results not only validate that the proposed method outperforms the existing off-grid imaging methods in terms of accuracy and resolution, but have compared the root mean square error with corresponding BCRB, proving effectiveness of the proposed method.

  17. An empirical case study of the transfer of GHG mitigation technologies from Annex 1 countries to Malaysia under the Kyoto Protocol’s Clean Development Mechanism (CDM)

    DEFF Research Database (Denmark)

    Hansen, Ulrich Elmer

    2011-01-01

    This study assesses what role the CDM currently plays in relation to the transfer of GHG mitigation technologies from Annex 1 countries to non-Annex 1 countries. The study relies on multiple sources of qualitative data and is conducted as a case study of 13 CDM projects implemented in Malaysia...... it can be concluded that the CDM only plays a role in one out of the 13 projects examined. The study may contribute to provide a background for adopting future provisions concerning technology transfer in the CDM or other initiatives involving GHG mitigation activities in non-Annex 1 countries........ It focuses on the companies involved in the implementation of specific technologies in these projects and the channels that can facilitate the transfer process. In addition, the institutional CDM project approval process in Malaysia is taken into account. An analytical framework is put forward based on which...

  18. Joint source and relay optimization for interference MIMO relay networks

    Science.gov (United States)

    Khandaker, Muhammad R. A.; Wong, Kai-Kit

    2017-12-01

    This paper considers multiple-input multiple-output (MIMO) relay communication in multi-cellular (interference) systems in which MIMO source-destination pairs communicate simultaneously. It is assumed that due to severe attenuation and/or shadowing effects, communication links can be established only with the aid of a relay node. The aim is to minimize the maximal mean-square-error (MSE) among all the receiving nodes under constrained source and relay transmit powers. Both one- and two-way amplify-and-forward (AF) relaying mechanisms are considered. Since the exactly optimal solution for this practically appealing problem is intractable, we first propose optimizing the source, relay, and receiver matrices in an alternating fashion. Then we contrive a simplified semidefinite programming (SDP) solution based on the error covariance matrix decomposition technique, avoiding the high complexity of the iterative process. Numerical results reveal the effectiveness of the proposed schemes.

  19. MIMO Channel Capacity for Handsets in Data Mode Operation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Yanakiev, Boyan; Bonev, Ivan Bonev

    2010-01-01

    The current paper concerns realistic evaluation of the capacity of the MIMO channel between a BS and handheld device, such as a PDA or smart phone, held in front of the user’s body (data mode). The work is based on measurements of the MIMO channel between two widely separated BSs in a micro....... The random capacity of the channels are evaluated in terms of percentiles. For an SNR of 10 dB, median capacities in free space of about 4.4–4.7 bit/s/Hz for the low band and about 3.3– 3.8 bit/s/Hz for the high band were found. The mean decrease in capacity due to the user was found to be up to about 2...

  20. Greenhouse Environmental Control Using Optimized MIMO PID Technique

    Directory of Open Access Journals (Sweden)

    Fateh BOUNAAMA

    2011-10-01

    Full Text Available Climate control for protected crops brings the added dimension of a biological system into a physical system control situation. The thermally dynamic nature of a greenhouse suggests that disturbance attenuation (load control of external temperature, humidity, and sunlight is far more important than is the case for controlling other types of buildings. This paper investigates the application of multi-inputs multi-outputs (MIMO PID controller to a MIMO greenhouse environmental model with actuation constraints. This method is based on decoupling the system at low frequency point. The optimal tuning values are determined using genetic algorithms optimization (GA. The inside outsides climate model of the environmental greenhouse, and the automatically collected data sets of Avignon, France are used to simulate and test this technique. The control objective is to maintain a highly coupled inside air temperature and relative humidity of strongly perturbed greenhouse, at specified set-points, by the ventilation/cooling and moisturizing operations.

  1. Identification of MIMO systems with sparse transfer function coefficients

    Science.gov (United States)

    Qiu, Wanzhi; Saleem, Syed Khusro; Skafidas, Efstratios

    2012-12-01

    We study the problem of estimating transfer functions of multivariable (multiple-input multiple-output--MIMO) systems with sparse coefficients. We note that subspace identification methods are powerful and convenient tools in dealing with MIMO systems since they neither require nonlinear optimization nor impose any canonical form on the systems. However, subspace-based methods are inefficient for systems with sparse transfer function coefficients since they work on state space models. We propose a two-step algorithm where the first step identifies the system order using the subspace principle in a state space format, while the second step estimates coefficients of the transfer functions via L1-norm convex optimization. The proposed algorithm retains good features of subspace methods with improved noise-robustness for sparse systems.

  2. Efficient two-dimensional compressive sensing in MIMO radar

    Science.gov (United States)

    Shahbazi, Nafiseh; Abbasfar, Aliazam; Jabbarian-Jahromi, Mohammad

    2017-12-01

    Compressive sensing (CS) has been a way to lower sampling rate leading to data reduction for processing in multiple-input multiple-output (MIMO) radar systems. In this paper, we further reduce the computational complexity of a pulse-Doppler collocated MIMO radar by introducing a two-dimensional (2D) compressive sensing. To do so, we first introduce a new 2D formulation for the compressed received signals and then we propose a new measurement matrix design for our 2D compressive sensing model that is based on minimizing the coherence of sensing matrix using gradient descent algorithm. The simulation results show that our proposed 2D measurement matrix design using gradient decent algorithm (2D-MMDGD) has much lower computational complexity compared to one-dimensional (1D) methods while having better performance in comparison with conventional methods such as Gaussian random measurement matrix.

  3. Compressed Sensing in On-Grid MIMO Radar

    Directory of Open Access Journals (Sweden)

    Michael F. Minner

    2015-01-01

    Full Text Available The accurate detection of targets is a significant problem in multiple-input multiple-output (MIMO radar. Recent advances of Compressive Sensing offer a means of efficiently accomplishing this task. The sparsity constraints needed to apply the techniques of Compressive Sensing to problems in radar systems have led to discretizations of the target scene in various domains, such as azimuth, time delay, and Doppler. Building upon recent work, we investigate the feasibility of on-grid Compressive Sensing-based MIMO radar via a threefold azimuth-delay-Doppler discretization for target detection and parameter estimation. We utilize a colocated random sensor array and transmit distinct linear chirps to a small scene with few, slowly moving targets. Relying upon standard far-field and narrowband assumptions, we analyze the efficacy of various recovery algorithms in determining the parameters of the scene through numerical simulations, with particular focus on the l1-squared Nonnegative Regularization method.

  4. Asymptotic analysis of multicell massive MIMO over Rician fading channels

    KAUST Repository

    Sanguinetti, Luca

    2017-06-20

    This work considers the downlink of a multicell massive MIMO system in which L base stations (BSs) of N antennas each communicate with K single-antenna user equipments randomly positioned in the coverage area. Within this setting, we are interested in evaluating the sum rate of the system when MRT and RZF are employed under the assumption that each intracell link forms a MIMO Rician uncorrelated fading channel. The analysis is conducted assuming that N and K grow large with a non-trivial ratio N/K under the assumption that the data transmission in each cell is affected by channel estimation errors, pilot contamination, and an arbitrary large scale attenuation. Numerical results are used to validate the asymptotic analysis in the finite system regime and to evaluate the network performance under different settings. The asymptotic results are also instrumental to get insights into the interplay among system parameters.

  5. Compressed Sensing in On-Grid MIMO Radar.

    Science.gov (United States)

    Minner, Michael F

    2015-01-01

    The accurate detection of targets is a significant problem in multiple-input multiple-output (MIMO) radar. Recent advances of Compressive Sensing offer a means of efficiently accomplishing this task. The sparsity constraints needed to apply the techniques of Compressive Sensing to problems in radar systems have led to discretizations of the target scene in various domains, such as azimuth, time delay, and Doppler. Building upon recent work, we investigate the feasibility of on-grid Compressive Sensing-based MIMO radar via a threefold azimuth-delay-Doppler discretization for target detection and parameter estimation. We utilize a colocated random sensor array and transmit distinct linear chirps to a small scene with few, slowly moving targets. Relying upon standard far-field and narrowband assumptions, we analyze the efficacy of various recovery algorithms in determining the parameters of the scene through numerical simulations, with particular focus on the ℓ 1-squared Nonnegative Regularization method.

  6. Characteristic Equation of the Modified Smith predictor to MIMO Systems

    Directory of Open Access Journals (Sweden)

    Jorge A. Herrera-Cuartas

    2013-11-01

    Full Text Available The delay in control systems is a feature frequently in real systems due to the transport of objects or information, a series connection of multiple systems or own processing and sensors delay, among others. Recently there have been several studies to identify the external delay MIMO systems, these works are focused on identification and on-line control of MIMO systems and use a multimodel structure based on modified Smith predictor using different search method. It is clear that for the implementation of the algorithm, and to obtain the convergence and stability analysis, it is necessary to have closed-loop equations of modified Smith predictor. However, in these works is not presented the analytical procedure, not be the main object, displaying only the closed loop equations without the procedure for obtaining it. Therefore, to respond, in this paper, we present an analytical way to derive the closed-loop equations of a modified Smith predictor.  

  7. The Latin American Energy Organization and CDM

    Energy Technology Data Exchange (ETDEWEB)

    Poveda, M.

    2000-07-01

    OLADE (Latin American Energy Organization) is a consortium of 26 countries from Latin America and the Carribean. This paper describes the objectives of the organization, its programs (energy integration. capacity building and cooperation, energy studies and projects, energy information), the role played by private sector players such as privately owned utilities, industry organizations, private industries and state agencies, and OLADE's CDM-related projects in energy efficiency, information access and capacity building. The energy efficiency project is a joint venture with Quebec and is focused on hydroelectric power development and training; the other project is in co-operation with the University of Calgary and involves a Master's degree program in Energy and the Environment, and research projects in Latin American and Canadian environmental legislation. OLADE is also involved in incorporating sustainable development into energy policies. In this regard OLADE does situation analysis, prepares proposals, and develops indicators and guides for energy policy making. Details of the energy-economics information system, developed in cooperation with the University of Calgary, and energy efficiency activities related specifically to Carribean countries are also discussed.

  8. A Thresholding-Based Antenna Switching in SWIPT-Enabled MIMO Cognitive Radio Networks with Co-Channel Interference

    KAUST Repository

    Benkhelifa, Fatma

    2016-10-23

    In this paper, we consider the simultaneous wireless power and information transfer (SWIPT) for spectrum sharing (SS) in cognitive radio (CR) networks with a multiple antenna SWIPT-Enabled secondary receiver (SR). The SR harvests the energy from the signals sent from the secondary transmitter (ST) and the interfering signals sent from the primary transmitter (PT). Moreover, the ST uses the antenna switching (AS) technique which selects a subset of the antennas to decode the information and the rest to harvest the energy. The antenna selection is performed via a thresholding strategy inspired from the maximum ratio combining (MRC) technique with an output threshold (OT-MRC). The thresholding-based antenna selection strategy is proposed in two ways: one is prioritizing the information data and the other is prioritizing the harvested energy. For the two proposed selection schemes, we study the probability mass function of the selected antennas, the average harvested energy, and the data transmission outage probability. Through the analytic expressions and the simulation results, we show that there is a tradeoff between the outage probability and the harvested energy for both schemes. We see also that the preference of one scheme on the other is also affected by this energy-data trade off.

  9. A thresholding-based antenna switching in MIMO cognitive radio networks with SWIPT-enabled secondary receiver

    KAUST Repository

    Benkhelifa, Fatma

    2017-07-31

    Simultaneous wireless power and information transfer (SWIPT) in a cognitive radio (CR) network is considered where a multiple antenna energy harvesting (EH) secondary receiver (SR) harvests the energy using the antenna switching (AS) technique. In fact, the AS technique selects a subset of the SR antennas to decode the information (namely the information decoding (ID) antennas) and the rest to harvest the energy (namely the EH antennas). In this context, we propose a thresholding-based antenna selection strategy, termed as the prioritizing data selection (PDS) scheme, which selects the ID antennas such that the received power from the secondary transmitter (ST) at these antennas is above a certain threshold. For this scheme, we derive the analytic expressions of the probability mass function (PMF) of the selected ID antennas, the average harvested energy, and the outage probability. In the simulation results, we illustrate the performance of the PDS scheme and we compare it to the prioritizing energy selection (PES) scheme which selects the EH antennas such that the received power from ST at these antennas is above a certain threshold. For both schemes, we show that there is a tradeoff between the outage probability and the average harvested energy.

  10. Approximation-Based Adaptive Neural Tracking Control of Nonlinear MIMO Unknown Time-Varying Delay Systems With Full State Constraints.

    Science.gov (United States)

    Li, Da-Peng; Li, Dong-Juan; Liu, Yan-Jun; Tong, Shaocheng; Chen, C L Philip

    2017-10-01

    This paper deals with the tracking control problem for a class of nonlinear multiple input multiple output unknown time-varying delay systems with full state constraints. To overcome the challenges which cause by the appearances of the unknown time-varying delays and full-state constraints simultaneously in the systems, an adaptive control method is presented for such systems for the first time. The appropriate Lyapunov-Krasovskii functions and a separation technique are employed to eliminate the effect of unknown time-varying delays. The barrier Lyapunov functions are employed to prevent the violation of the full state constraints. The singular problems are dealt with by introducing the signal function. Finally, it is proven that the proposed method can both guarantee the good tracking performance of the systems output, all states are remained in the constrained interval and all the closed-loop signals are bounded in the design process based on choosing appropriate design parameters. The practicability of the proposed control technique is demonstrated by a simulation study in this paper.

  11. Downlink Training Techniques for FDD Massive MIMO Systems: Open-Loop and Closed-Loop Training with Memory

    OpenAIRE

    Choi, Junil; Love, David J.; Bidigare, Patrick

    2013-01-01

    The concept of deploying a large number of antennas at the base station, often called massive multiple-input multiple-output (MIMO), has drawn considerable interest because of its potential ability to revolutionize current wireless communication systems. Most literature on massive MIMO systems assumes time division duplexing (TDD), although frequency division duplexing (FDD) dominates current cellular systems. Due to the large number of transmit antennas at the base station, currently standar...

  12. Matching Parasitic Antenna for Single RF MIMO

    DEFF Research Database (Denmark)

    Han, Bo; Kalis, A; Nielsen, Rasmus Hjorth

    2012-01-01

    . In order to have such performance, an antenna with rich pattern modes is required by the system, thus the ESPAR antenna is investigated. The critical part on such antenna is parasitic element impedance matching. Unlike the conventional smith-chart matching method which assumes the minimal resistance......Single RF MIMO communication emerges a novel low cost communication method which does not consume as much power as the conventional MIMO. The implementation of such single RF MIMO system is done by mapping the weighting factors to the polarizations or the radiation patterns of the antennas...

  13. 3D Massive MIMO Systems: Modeling and Performance Analysis

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2015-07-30

    Multiple-input-multiple-output (MIMO) systems of current LTE releases are capable of adaptation in the azimuth only. Recently, the trend is to enhance system performance by exploiting the channel’s degrees of freedom in the elevation, which necessitates the characterization of 3D channels. We present an information-theoretic channel model for MIMO systems that supports the elevation dimension. The model is based on the principle of maximum entropy, which enables us to determine the distribution of the channel matrix consistent with the prior information on the angles. Based on this model, we provide analytical expression for the cumulative density function (CDF) of the mutual information (MI) for systems with a single receive and finite number of transmit antennas in the general signalto- interference-plus-noise-ratio (SINR) regime. The result is extended to systems with finite receive antennas in the low SINR regime. A Gaussian approximation to the asymptotic behavior of MI distribution is derived for the large number of transmit antennas and paths regime. We corroborate our analysis with simulations that study the performance gains realizable through meticulous selection of the transmit antenna downtilt angles, confirming the potential of elevation beamforming to enhance system performance. The results are directly applicable to the analysis of 5G 3D-Massive MIMO-systems.

  14. A Triply Selective MIMO Channel Simulator Using GPUs

    Directory of Open Access Journals (Sweden)

    R. Carrasco-Alvarez

    2018-01-01

    Full Text Available A methodology for implementing a triply selective multiple-input multiple-output (MIMO simulator based on graphics processing units (GPUs is presented. The resulting simulator is based on the implementation of multiple double-selective single-input single-output (SISO channel generators, where the multiple inputs and the multiple received signals have been transformed in order to supply the corresponding space correlation of the channel under consideration. A direct consequence of this approach is the flexibility provided, which allows different propagation statistics to each SISO channel to be specified and thus more complex environments to be replicated. It is shown that under some specific constraints, the statistics of the triply selective MIMO simulator are the same as those reported in the state of art. Simulation results show the computational time improvement achieved, up to 650-fold for an 8 × 8 MIMO channel simulator when compared with sequential implementations. In addition to the computational improvement, the proposed simulator offers flexibility for testing a variety of scenarios in vehicle-to-vehicle (V2V and vehicle-to-infrastructure (V2I systems.

  15. El mimo entre los griegos

    Directory of Open Access Journals (Sweden)

    Manuel Briceño Jauregui

    1969-05-01

    Full Text Available El instinto de imitación ha encontrado siempre su expresión en todos los pueblos. De todas las formas de entretenimiento, el mimo es a la vez la más primitiva y estable. En el mundo antiguo existen juglares, acróbatas, diversiones públicas de todas clases realizadas por hombres y mujeres, que prueban sus múltiples habilidades en las plazas de mercado, en las calles, con motivo de festividades públicas, o en los banquetes privados -como cuenta Jenofonte en el Simposio para entretención de los huéspedes a la mesa.

  16. CDM viability of CURB-AIR cases. Four Asian Projects Evaluated

    Energy Technology Data Exchange (ETDEWEB)

    Dass, A.; Bordoloi, A. [Winrock International India, Haryana (India); Bakker, S.J.A. [ECN Policy Studies, Petten (Netherlands)

    2008-01-15

    up as CDM projects with respect to the baseline in the cities. Section 4 details out the long term effects of the projects in meeting the national development goals; section 5 gives an overview of the air quality scenario of the four Asian cities before and after the implementation of the project. Finally, section 6 gives the overview on the CDM viability of the case projects in the four Asian cities based on the previous sections. Please see the CURB-AIR website (www.curb-air.org) for a more detailed discussion on the links and opportunities.

  17. Experiences of project developers around CDM projects in South Africa

    International Nuclear Information System (INIS)

    Thurner, Thomas W.; Varughese, Arun

    2013-01-01

    Project developers in South Africa are puzzled with the long process of evaluating and registering their CDM projects. In addition to other obstacles, we find that South African big businesses are rather reluctant to engage in any new business activities such as CDM projects and municipalities often lack the necessary flexibility. This offers opportunities for small-scale project developers who spot the opportunities and find creative solutions to overcome these difficulties. - Highlights: • First paper analysing the experience of small project developers in South Africa. • Project developers in South Africa are puzzled with the long process. • South African big businesses are reluctant to engage in CDM projects. • Small-scale project developers spot opportunities and find creative solutions to overcome difficulties. • Also, we saw learning processes of South African administration in support of CDM projects

  18. Direction Finding for Bistatic MIMO Radar with Uniform Circular Array

    Directory of Open Access Journals (Sweden)

    Cao Yunhe

    2013-01-01

    Full Text Available A method of direction of arrival (DOA and direction of departure (DOD angle estimation based on polynomial rooting for bistatic multiple-input multiple-output (MIMO radar with uniform circular array (UCA configuration is proposed in this paper. The steering vector of the UCA is firstly transformed into a steering vector with a Vandermonde structure by using the Jacobi-Anger expansion. Then the null-spectrum function of the MIMO radar can be written as an expression in which the transmit and receive steering vectors are decoupled. Finally, a two-step polynomial rooting is used to estimate DOA and DOD of targets instead of two-dimensional multiple signal classification (MUSIC search method for bistatic UCA MIMO radar. The angle estimation performance of the proposed method is similar to that of the MUSIC spectral search method, but the computation burden of the proposed polynomial rooting algorithm is much lower than that of the conventional MUSIC method. The simulation results of the proposed algorithm are presented and the performances are investigated and analyzed.

  19. Time-Domain Diversity in Ultra-Wideband MIMO Communications

    Directory of Open Access Journals (Sweden)

    Alain Sibille

    2005-03-01

    Full Text Available The development of ultra-wideband (UWB communications is impeded by the drastic transmitted power limitations imposed by regulation authorities due to the “polluting” character of these radio emissions with respect to existing services. Technical solutions must be researched in order either to limit the level of spectral pollution by UWB devices or to increase their reception sensitivity. In the present work, we consider pulse-based modulations and investigate time-domain multiple-input multiple-output (MIMO diversity as one such possible solution. The basic principles of time-domain diversity in the extreme (low multipath density or intermediate (dense multipath UWB regimes are addressed, which predict the possibility of a MIMO gain equal to the product Nt×Nr of the numbers of transmit/receive antenna elements when the channel is not too severe. This analysis is confirmed by simulations using a parametric empirical stochastic double-directional channel model. They confirm the potential interest of MIMO approaches solutions in order to bring a valuable performance gain in UWB communications.

  20. Analysis and Transceiver Design for the MIMO Broadcast Channel

    CERN Document Server

    Hunger, Raphael

    2013-01-01

    This book deals with the optimization-based joint design of the transmit and receive filters in   MIMO broadcast channel in which the user terminals may be equipped with several antenna elements. Furthermore, the maximum performance of the system in the high power regime as well as the set of all feasible quality-of-service requirements is analyzed. First, a fundamental duality is derived that holds between the MIMO broadcast channel and virtual MIMO multiple access channel. This duality construct allows for the efficient solution of problems originally posed in the broadcast channel in the dual domain where a possibly hidden convexity can often be revealed. On the basis of the established duality result, the gradient-projection algorithm is introduced as a tool to solve constrained optimization problems to global optimality under certain conditions. The gradient-projection tool is then applied to solving the weighted sum rate maximization problem which is a central optimization that arises in any network u...

  1. Smoothing techniques for decision-directed MIMO OFDM channel estimation

    Science.gov (United States)

    Beinschob, P.; Zölzer, U.

    2011-07-01

    With the purpose of supplying the demand of faster and more reliable communication, multiple-input multiple-output (MIMO) systems in conjunction with Orthogonal Frequency Division Multiplexing (OFDM) are subject of extensive research. Successful Decoding requires an accurate channel estimate at the receiver, which is gained either by evaluation of reference symbols which requires designated resources in the transmit signal or decision-directed approaches. The latter offers a convenient way to maximize bandwidth efficiency, but it suffers from error propagation due to the dependency between the decoding of the current data symbol and the calculation of the next channel estimate. In our contribution we consider linear smoothing techniques to mitigate error propagation by the introduction of backward dependencies in the decision-based channel estimation. Designed as a post-processing step, frame repeat requests can be lowered by applying this technique if the data is insensitive to latency. The problem of high memory requirements of FIR smoothing in the context of MIMO-OFDM is addressed with an recursive approach that acquires minimal resources with virtual no performance loss. Channel estimate normalized mean square error and bit error rate (BER) performance evaluations are presented. For reference, a median filtering technique is presented that operates on the MIMO time-frequency grids of channel coefficients to reduce the peak-like outliers produced by wrong decisions due to unsuccessful decoding. Performance in terms of Bit Error Rate is compared to the proposed smoothing techniques.

  2. A Portable MIMO Testbed and Selected Channel Measurements

    Directory of Open Access Journals (Sweden)

    Goud Jr Paul

    2006-01-01

    Full Text Available A portable multiple-input multiple-output (MIMO testbed that is based on field programmable gate arrays (FPGAs and which operates in the 902–928 MHz industrial, scientific, and medical (ISM band has been developed by the High Capacity Digital Communications (HCDC Laboratory at the University of Alberta. We present a description of the HCDC testbed along with MIMO channel capacities that were derived from measurements taken with the HCDC testbed for three special locations: a narrow corridor, an athletics field that is surrounded by a metal fence, and a parkade. These locations are special because the channel capacities are different from what is expected for a typical indoor or outdoor channel. For two of the cases, a ray-tracing analysis has been performed and the simulated channel capacity values closely match the values calculated from the measured data. A ray-tracing analysis, however, requires accurate geometrical measurements and sophisticated modeling for each specific location. A MIMO testbed is ideal for quickly obtaining accurate channel capacity information.

  3. MAX-SLNR Precoding Algorithm for Massive MIMO System

    Directory of Open Access Journals (Sweden)

    Jiang Jing

    2016-01-01

    Full Text Available Pilot Contamination obviously degrades the system performance of Massive MIMO systems. In this paper, a downlink precoding algorithm based on the Signal-to- Leakage-plus-Noise-Ratio (SLNR criterion is put forward. First, the impact of Pilot Contamination on SLNR is analyzed,then the precoding matrix is calculated with the eigenvalues decomposition of SLNR, which not only maximize the array gains of the target user, but also minimize the impact of Pilot Contamination and the leak to the users of other cells. Further, a simplified solution is derived, in which the impact of Pilot Contamination can be suppressed only with the large-scale fading coefficients. Simulation results reveal that: in the scenario of the serious pilot contamination, the proposed algorithm can avoid the performance loss caused by the pilot contamination compared with the conventional Massive MIMO precoding algorithm. Thus the proposed algorithm can acquire the perfect performance gains of Massive MIMO system and has better practical value since the large-scale fading coefficients are easy to measure and feedback.

  4. Analysis of registered CDM projects: potential removal of evidenced bottlenecks

    Energy Technology Data Exchange (ETDEWEB)

    Agosto, D.; Bombard, P.; Gostinelli, F.

    2007-07-01

    The Clean Development Mechanism (CDM) has developed during its first period of implementation, a distinctive set of patterns. The authors thought of concentrating on the CDM analysis in order to highlight potential remedies or reasons for given bottlenecks. In order to establish a sort of extensive SWOT analysis for CDMs, all the 356 projects actually (November 2006) registered at UNFCCC were examined, together with all the about 1000 PDDs presented to the UNFCCC but not registered yet. The CDM projects have been studied trying to cluster projects according to relevant characteristics, both from a technical and an economic point of view. Chosen indicators are meant to identify: more convenient/more diffused energy system for a CDM; reasons for a geographical distribution of different types of projects; potentials for a future exploitation of lower used technologies in CDM. Conclusions are drawn and appropriate tables and graphs presented. (1) the Baseline Emission Factor, combined to economic patterns, is the pivotal factor that characterizes both choices of host country and technology; (2) some technologies can exploit appropriately CDM scheme, whilst other technologies, are constrained by it. (3) there are still some important weak points: grouping of non Annex I countries; crediting period; criteria for the evaluation of sustainable development. (auth)

  5. Multiple Input - Multiple Output (MIMO) SAR

    Data.gov (United States)

    National Aeronautics and Space Administration — This effort will research and implement advanced Multiple-Input Multiple-Output (MIMO) Synthetic Aperture Radar (SAR) techniques which have the potential to improve...

  6. Adaptive neural network control for a class of MIMO nonlinear systems with disturbances in discrete-time.

    Science.gov (United States)

    Ge, Shuzhi Sam; Zhang, Jin; Lee, Tong Heng

    2004-08-01

    In this paper, adaptive neural network (NN) control is investigated for a class of multiinput and multioutput (MIMO) nonlinear systems with unknown bounded disturbances in discrete-time domain. The MIMO system under study consists of several subsystems with each subsystem in strict feedback form. The inputs of the MIMO system are in triangular form. First, through a coordinate transformation, the MIMO system is transformed into a sequential decrease cascade form (SDCF). Then, by using high-order neural networks (HONN) as emulators of the desired controls, an effective neural network control scheme with adaptation laws is developed. Through embedded backstepping, stability of the closed-loop system is proved based on Lyapunov synthesis. The output tracking errors are guaranteed to converge to a residue whose size is adjustable. Simulation results show the effectiveness of the proposed control scheme.

  7. Antenna Design for Diversity and MIMO Application

    DEFF Research Database (Denmark)

    Ying, Zhinong; Chiu, Chi-Yuk; Zhao, Kun

    2015-01-01

    Recently, multiple-input multiple-output (MIMO) technology and diversity have attracted much attention both in industry and academia due to high data rate and high spectrum efficiency. By increasing the number of antennas at the transmitter and/or the receiver side of the wireless link, the diver......Recently, multiple-input multiple-output (MIMO) technology and diversity have attracted much attention both in industry and academia due to high data rate and high spectrum efficiency. By increasing the number of antennas at the transmitter and/or the receiver side of the wireless link......, the diversity/MIMO techniques can increase wireless channel capacity without the need of additional power or spectrum in rich scattering environments. However, due to limited space of small mobile devices, the correlation coefficients between MIMO antenna elements are usually very high, and the total...... efficiencies of MIMO elements would be degraded severely due to mutual couplings. In addition, the human body causes high losses on electromagnetic waves. In real applications, the presence of users may result in significant reduction of total antenna efficiencies, and the correlations of MIMO antenna systems...

  8. Propagation Characterization and MIMO Channel-Modelling for 3G

    DEFF Research Database (Denmark)

    Schumacher, Laurent; Berger, Lars Torsten; Ramiro-Moreno, Juan

    2004-01-01

    This paper presents a survey of MIMO channel models, distinguishing between determinsistic and stochastic channel models.......This paper presents a survey of MIMO channel models, distinguishing between determinsistic and stochastic channel models....

  9. Issues related to a programme of activities under the CDM

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, J.

    2006-05-15

    Emissions of CO2 from the energy and land-use change and forestry sectors are responsible for the majority of emissions in non-Annex I Parties to the UNFCCC. Tackling greenhouse gas (GHG) emissions from these sectors is a key to slowing the growth in GHG emissions in non-Annex I countries. Implementing Clean Development Mechanism (CDM) projects can help achieve this aim, while also assisting non-Annex I countries to move towards sustainable development and Annex I countries achieve their emission commitments under the Kyoto Protocol. There has been rapid progress in the CDM over the last year - in terms of the number of projects in the pipeline and registered, and in terms of credits issued. However, some important sectors are notable by their small share in the CDM portfolio. Several countries have also called attention to the need to accelerate the process of approving CDM methodologies and projects. In order to improve the effectiveness of the CDM to achieve its dual objectives, the COP/MOP agreed a decision on 'further guidance relating to the clean development mechanism. This decision lays out guidance on how to improve the operation of the CDM, and includes provisions that allow: (1) Bundling of project activities; and (2) Project activities under a programme of activities, to be registered as a CDM project activity. At present, of the 172 currently registered CDM project activities, 27 involve programmes or bundles. These project activities can include more than one project type, be implemented in several locations, and/or occur in more than one sector. This paper assesses how project activities under a programme of activities under the CDM (referred to here as PCDM) could help to increase the effectiveness of the CDM by encouraging a wide spread of emission mitigation activities. This paper also explores the key issues that may need to be considered for the PCDM concept to be further implemented. The paper concludes that: (1) Key concepts and issues

  10. Preliminary assessment of potential CDM early start projects in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, S.; Sathaye, J.; Lehman, B.; Schumacher, K.; van Vliet, O.; Moreira, J.R.

    2000-11-01

    The Brazil/US Aspen Global Forum on Climate Change Policies and Programs has facilitated a dialogue between key Brazil and US public and private sector leaders on the subject of the Clean Development Mechanism (CDM). With support from the US government, a cooperative effort between Lawrence Berkeley National Laboratory and the University of Sao Paulo conducted an assessment of a number of projects put forth by Brazilian sponsors. Initially, we gathered information and conducted a screening assessment for ten projects in the energy sector and six projects in the forestry sector. Some of the projects appeared to offer greater potential to be attractive for CDM, or had better information available. We then conducted a more detailed assessment of 12 of these projects, and two other projects that were submitted after the initial screening. An important goal was to assess the potential impact of Certified Emission Reductions (CERs) on the financial performance of projects. With the exception of the two forestry-based fuel displacement projects, the impact of CERs on the internal rate of return (IRR) is fairly small. This is true for both the projects that displace grid electricity and those that displace local (diesel-based) electricity production. The relative effect of CERs is greater for projects whose IRR without CERs is low. CERs have a substantial effect on the IRR of the two short-rotation forestry energy substitution projects. One reason is that the biofuel displaces coke and oil, both of which are carbon-intensive. Another factor is that the product of these projects (charcoal and woodfuel, respectively) is relatively low value, so the revenue from carbon credits has a strong relative impact. CERs also have a substantial effect on the NPV of the carbon sequestration projects. Financial and other barriers pose a challenge for implementation of most of the projects. In most cases, the sponsor lacks sufficient capital, and loans are available only at high interest

  11. Estimation of MIMO channel capacity from phase-noise impaired measurements

    DEFF Research Database (Denmark)

    Pedersen, Troels; Yin, Xuefeng; Fleury, Bernard Henri

    2008-01-01

    that phase noise of the transmitter and receiver local oscillators, when it is assumed to be a white Gaussian random process, can cause large errors of the estimated channel capacity of a low-rank MIMO channel when the standard channel matrix estimator is used. Experimental evidence shows that consecutive...... phase noise samples affecting measurement samples collected with real TDMMIMO channel sounders are correlated. In this contribution a capacity estimator that accounts for the phase noise correlation is proposed. The estimator is based on a linear minimum mean square error estimate of the MIMO channel...... matrix. It is shown by means of Monte Carlo simulations assuming a measurementbased phase noise model, that the MIMO channel capacity can be estimated accurately for signal to noise ratios up to about 35 dB...

  12. A non-parametric consistency test of the ΛCDM model with Planck CMB data

    Energy Technology Data Exchange (ETDEWEB)

    Aghamousa, Amir; Shafieloo, Arman [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Hamann, Jan, E-mail: amir@aghamousa.com, E-mail: jan.hamann@unsw.edu.au, E-mail: shafieloo@kasi.re.kr [School of Physics, The University of New South Wales, Sydney NSW 2052 (Australia)

    2017-09-01

    Non-parametric reconstruction methods, such as Gaussian process (GP) regression, provide a model-independent way of estimating an underlying function and its uncertainty from noisy data. We demonstrate how GP-reconstruction can be used as a consistency test between a given data set and a specific model by looking for structures in the residuals of the data with respect to the model's best-fit. Applying this formalism to the Planck temperature and polarisation power spectrum measurements, we test their global consistency with the predictions of the base ΛCDM model. Our results do not show any serious inconsistencies, lending further support to the interpretation of the base ΛCDM model as cosmology's gold standard.

  13. Simplified Antenna Group Determination of RS Overhead Reduced Massive MIMO for Wireless Sensor Networks.

    Science.gov (United States)

    Lee, Byung Moo

    2017-12-29

    Massive multiple-input multiple-output (MIMO) systems can be applied to support numerous internet of things (IoT) devices using its excessive amount of transmitter (TX) antennas. However, one of the big obstacles for the realization of the massive MIMO system is the overhead of reference signal (RS), because the number of RS is proportional to the number of TX antennas and/or related user equipments (UEs). It has been already reported that antenna group-based RS overhead reduction can be very effective to the efficient operation of massive MIMO, but the method of deciding the number of antennas needed in each group is at question. In this paper, we propose a simplified determination scheme of the number of antennas needed in each group for RS overhead reduced massive MIMO to support many IoT devices. Supporting many distributed IoT devices is a framework to configure wireless sensor networks. Our contribution can be divided into two parts. First, we derive simple closed-form approximations of the achievable spectral efficiency (SE) by using zero-forcing (ZF) and matched filtering (MF) precoding for the RS overhead reduced massive MIMO systems with channel estimation error. The closed-form approximations include a channel error factor that can be adjusted according to the method of the channel estimation. Second, based on the closed-form approximation, we present an efficient algorithm determining the number of antennas needed in each group for the group-based RS overhead reduction scheme. The algorithm depends on the exact inverse functions of the derived closed-form approximations of SE. It is verified with theoretical analysis and simulation that the proposed algorithm works well, and thus can be used as an important tool for massive MIMO systems to support many distributed IoT devices.

  14. Simplified Antenna Group Determination of RS Overhead Reduced Massive MIMO for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Byung Moo Lee

    2017-12-01

    Full Text Available Massive multiple-input multiple-output (MIMO systems can be applied to support numerous internet of things (IoT devices using its excessive amount of transmitter (TX antennas. However, one of the big obstacles for the realization of the massive MIMO system is the overhead of reference signal (RS, because the number of RS is proportional to the number of TX antennas and/or related user equipments (UEs. It has been already reported that antenna group-based RS overhead reduction can be very effective to the efficient operation of massive MIMO, but the method of deciding the number of antennas needed in each group is at question. In this paper, we propose a simplified determination scheme of the number of antennas needed in each group for RS overhead reduced massive MIMO to support many IoT devices. Supporting many distributed IoT devices is a framework to configure wireless sensor networks. Our contribution can be divided into two parts. First, we derive simple closed-form approximations of the achievable spectral efficiency (SE by using zero-forcing (ZF and matched filtering (MF precoding for the RS overhead reduced massive MIMO systems with channel estimation error. The closed-form approximations include a channel error factor that can be adjusted according to the method of the channel estimation. Second, based on the closed-form approximation, we present an efficient algorithm determining the number of antennas needed in each group for the group-based RS overhead reduction scheme. The algorithm depends on the exact inverse functions of the derived closed-form approximations of SE. It is verified with theoretical analysis and simulation that the proposed algorithm works well, and thus can be used as an important tool for massive MIMO systems to support many distributed IoT devices.

  15. A Guide to Bundling Small-scale CDM Projects

    International Nuclear Information System (INIS)

    Mariyappan, J.; Bhardwaj, N.; De Coninck, H.; Van der Linden, N.

    2005-07-01

    Small-scale renewable energy and energy efficiency projects that fit the development needs of many developing countries, can potentially be supported via the Clean Development Mechanism (CDM), one of the Kyoto Protocol's flexible mechanisms for tackling climate change. However, there is concern that due to high transaction costs, as well as many existing barriers, very few investments will be made in small-scale projects, which are often the most suitable development option in countries such as India. In view of this, the 'bundling' together of appropriate small-scale projects on a regional basis has been proposed as a way in which funding can be leveraged from international sources and transaction costs reduced. IT Power, IT Power India and the Energy research Centre of the Netherlands (ECN) are carrying out a 2-year project to establish the capacity within India to enable individual small scale projects to be bundled as a single CDM project. Overall objectives are to develop the necessary institutional capabilities to formulate and implement small scale CDM projects in India; to provide a guide on how to bundle small scale projects under the CDM in developing countries; and to raise the awareness of the potential for investment in small scale energy projects which can gain funding through the CDM

  16. A correction in the CDM methodological tool for estimating methane emissions from solid waste disposal sites.

    Science.gov (United States)

    Santos, M M O; van Elk, A G P; Romanel, C

    2015-12-01

    Solid waste disposal sites (SWDS) - especially landfills - are a significant source of methane, a greenhouse gas. Although having the potential to be captured and used as a fuel, most of the methane formed in SWDS is emitted to the atmosphere, mainly in developing countries. Methane emissions have to be estimated in national inventories. To help this task the Intergovernmental Panel on Climate Change (IPCC) has published three sets of guidelines. In addition, the Kyoto Protocol established the Clean Development Mechanism (CDM) to assist the developed countries to offset their own greenhouse gas emissions by assisting other countries to achieve sustainable development while reducing emissions. Based on methodologies provided by the IPCC regarding SWDS, the CDM Executive Board has issued a tool to be used by project developers for estimating baseline methane emissions in their project activities - on burning biogas from landfills or on preventing biomass to be landfilled and so avoiding methane emissions. Some inconsistencies in the first two IPCC guidelines have already been pointed out in an Annex of IPCC latest edition, although with hidden details. The CDM tool uses a model for methane estimation that takes on board parameters, factors and assumptions provided in the latest IPCC guidelines, while using in its core equation the one of the second IPCC edition with its shortcoming as well as allowing a misunderstanding of the time variable. Consequences of wrong ex-ante estimation of baseline emissions regarding CDM project activities can be of economical or environmental type. Example of the first type is the overestimation of 18% in an actual project on biogas from landfill in Brazil that harms its developers; of the second type, the overestimation of 35% in a project preventing municipal solid waste from being landfilled in China, which harms the environment, not for the project per se but for the undue generated carbon credits. In a simulated landfill - the same

  17. Radar mutual information and communication channel capacity of integrated radar-communication system using MIMO

    Directory of Open Access Journals (Sweden)

    Renhui Xu

    2015-12-01

    Full Text Available Integrated radar-communication system based on multiple input and multiple output (MIMO shares the hardware resource and spectrum to fulfill radar and communication functions, simultaneously. The baseband signal models of the MIMO radar and the integrated radar-communication system are set up. Then, the radar mutual information and the communication channel capacity are derived accordingly. Radar mutual information is used to evaluate the radar performance; communication channel capacity is one of the methods used to measure the communication capability. The influences of signal-to-noise ratio and the number of antennas, on the mutual information and channel capacity are presented through simulations.

  18. Options for utilizing the CDM for global emission reductions

    Energy Technology Data Exchange (ETDEWEB)

    Butzengeiger-Geyer, Sonja; Castro, Paula; Harthan, Ralph O.; Hayashi, Daisuke; Healy, Sean; Maribu, Karl Magnus; Michaelowa, Axel; Okubo, Yuri; Schneider, Lambert; Storroe, Ingunn [Zuerich Univ. (Switzerland); Oeko-Institut e.V., Berlin (Germany); Perspectives GmbH, Hamburg (Germany); Point Carbon A/S, Oslo (Norway)

    2010-11-15

    The study describes and discusses in detail how four CDM reform alternatives, namely discounting of emission reductions, ambitious baselines, purchase and cancellation of CERs and reinvestment of CER levies, could be integrated in a Post-2012 climate regime. The study assesses these alternatives, according to their impacts on GHG emission reductions, contribution to sustainable development, cost-efficiency, technical feasibility, incentives and distributional effects as well as negotiability. The study shows that the introduction of discounting and ambitious baselines is technically feasible but politically a massive challenge. With the help of an economic model the study shows that the introduction of reform alternatives increases the amount of emission reductions but in comparison to the current CDM the impact is rather limited. But a CDM reform can in any case increase the credibility and improve the environmental integrity of the mechanism. (orig.)

  19. A Tale of Two Sites: Lessons on Leadership from the Implementation of a Long-term Care Delivery Model (CDM) in Western Canada

    OpenAIRE

    Denise Cloutier; Amy Cox; Ruth Kampen; Karen Kobayashi; Heather Cook; Deanne Taylor; Gina Gaspard

    2016-01-01

    Residential, long-term care serves vulnerable older adults in a facility-based environment. A new care delivery model (CDM) designed to promote more equitable care for residents was implemented in a health region in Western Canada. Leaders and managers faced challenges in implementing this model alongside other concurrent changes. This paper explores the question: How did leadership style influence team functioning with the implementation of the CDM? Qualitative data from interviews with lead...

  20. Application of MIMO Techniques in sky-surface wave hybrid networking sea-state radar system

    Science.gov (United States)

    Zhang, L.; Wu, X.; Yue, X.; Liu, J.; Li, C.

    2016-12-01

    The sky-surface wave hybrid networking sea-state radar system contains of the sky wave transmission stations at different sites and several surface wave radar stations. The subject comes from the national 863 High-tech Project of China. The hybrid sky-surface wave system and the HF surface wave system work simultaneously and the HF surface wave radar (HFSWR) can work in multi-static and surface-wave networking mode. Compared with the single mode radar system, this system has advantages of better detection performance at the far ranges in ocean dynamics parameters inversion. We have applied multiple-input multiple-output(MIMO) techniques in this sea-state radar system. Based on the multiple channel and non-causal transmit beam-forming techniques, the MIMO radar architecture can reduce the size of the receiving antennas and simplify antenna installation. Besides, by efficiently utilizing the system's available degrees of freedom, it can provide a feasible approach for mitigating multipath effect and Doppler-spread clutter in Over-the-horizon Radar. In this radar, slow-time phase-coded MIMO method is used. The transmitting waveforms are phase-coded in slow-time so as to be orthogonal after Doppler processing at the receiver. So the MIMO method can be easily implemented without the need to modify the receiver hardware. After the radar system design, the MIMO experiments of this system have been completed by Wuhan University during 2015 and 2016. The experiment used Wuhan multi-channel ionospheric sounding system(WMISS) as sky-wave transmitting source and three dual-frequency HFSWR developed by the Oceanography Laboratory of Wuhan University. The transmitter system located at Chongyang with five element linear equi-spaced antenna array and Wuhan with one log-periodic antenna. The RF signals are generated by synchronized, but independent digital waveform generators - providing complete flexibility in element phase and amplitude control, and waveform type and parameters

  1. 5G MIMO Conformal Microstrip Antenna Design

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2017-01-01

    Full Text Available With the development of wireless communication technology, 5G will develop into a new generation of wireless mobile communication systems. MIMO (multiple-input multiple-output technology is expected to be one of the key technologies in the field of 5G wireless communications. In this paper, 4 pairs of microstrip MIMO conformal antennas of 35 GHz have been designed. Eight-element microstrip Taylor antenna array with series-feeding not only achieves the deviation of the main lobe of the pattern but also increases the bandwidth of the antenna array and reduces sidelobe. MIMO antennas have been fabricated and measured. Measurement results match the simulation results well. The return loss of the antenna at 35 GHz is better than 20 dB, the first sidelobe level is −16 dB, and the angle between the main lobe and the plane of array is 60°.

  2. Scoping paper on new CDM baseline methodology for cross-border power trade

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Poeyry has been sub-contracted by Carbon Limits, under the African Development Bank CDM Support Programme, to prepare a new CDM baseline methodology for cross border trade, based on a transmission line from Ethiopia to Kenya. The first step in that process is to review the response of the UNFCCC, particularly the Methodologies Panel ('Meth Panel') of the CDM Executive Board, to the various proposals on cross-border trade and interconnection of grids. This report reviews the Methodology Panel and Executive Board decisions on 4 requests for revisions of ACM2 'Consolidated baseline methodology for grid-connected electricity generation from renewable sources', and 5 proposed new baseline methodologies (NM255, NM269, NM272, NM318, NM342), all of which were rejected. We analyse the reasons the methodologies were rejected, and whether the proposed draft Approved Methodology (AM) that the Methodology Panel created in response to NM269 and NM272 is a suitable basis for a new methodology proposal.(auth)

  3. Annual Report 2011 for the Swedish CDM and JI program; Aarsredovisning 2011 foer Sveriges CDM och JI-program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    The report is an annual report of the Swedish CDM [Clean Development Mechanism] and JI [Joint Implementation]program for 2011. The report shows aims and goals of the business and the work of individual CDM and JI projects and multilateral funds which have been performed over the entire duration of life and especially during 2011. The report presents volume orders, deliveries of emission reduction units as well as the volumes expected to be needed for the fulfillment of the national target by 2020. The report also includes information about the average price for the emission reductions as well as alternative costs.

  4. A new DOD and DOA estimation method for MIMO radar

    Science.gov (United States)

    Gong, Jian; Lou, Shuntian; Guo, Yiduo

    2018-04-01

    The battlefield electromagnetic environment is becoming more and more complex, and MIMO radar will inevitably be affected by coherent and non-stationary noise. To solve this problem, an angle estimation method based on oblique projection operator and Teoplitz matrix reconstruction is proposed. Through the reconstruction of Toeplitz, nonstationary noise is transformed into Gauss white noise, and then the oblique projection operator is used to separate independent and correlated sources. Finally, simulations are carried out to verify the performance of the proposed algorithm in terms of angle estimation performance and source overload.

  5. Emulating Dynamic Radio Channels for Radiated Testing of Massive MIMO Devices

    DEFF Research Database (Denmark)

    Kyösti, Pekka; Hentilä, Lassi; Kyröläinen, Jukka

    2018-01-01

    This paper discusses a multi-probe anechoic chamber based (MPAC) setup, capable of reconstructing non-stationary radio propagation environments for testing of mm-wave and massive MIMO devices. The test setup is aimed for evaluation of end to end performance of devices, including hybrid beamformin...

  6. 12 Mode, MIMO-Free OAM Transmission

    DEFF Research Database (Denmark)

    Ingerslev, Kasper; Gregg, Patrick; Galili, Michael

    2017-01-01

    Simultaneous MIMO-free transmission of a record number (12) of orbital angular momentum modes over 1.2 km is demonstrated. WDM compatibility of the system is shown by using 60 WDM channels with 25 GHz spacing and 10 GBaud QPSK.......Simultaneous MIMO-free transmission of a record number (12) of orbital angular momentum modes over 1.2 km is demonstrated. WDM compatibility of the system is shown by using 60 WDM channels with 25 GHz spacing and 10 GBaud QPSK....

  7. Small Terminal MIMO Channels with User Interaction

    DEFF Research Database (Denmark)

    Pedersen, Gert Frølund; Andersen, Jørgen Bach; Eggers, Patrick Claus F.

    2007-01-01

    This paper gives an overview of results obtained from measurements of different types of multiple-input multiple-output (MIMO) channels. For the indoor case measurements were made at 5.8 GHz from access points (APs) to mobile stations (MSs) at different places in a large open office type room...... were made in a cellular scenario in an urban environment with a phantom user holding a mobile device in browsing position. These measurements show that MIMO techniques are beneficial even for small handheld devices. Finally, vehicle to vehicle (VTV) highway measurements at 3.5 GHz allow...

  8. Wind farm investment risks under uncertain CDM benefit in China

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming [3E and T International, Luo-Ma-Shi Street, Xuan Wu District, Beijing 100052 (China); Nguyen, Francois; T' Serclaes, Philippine de; Buchner, Barbara [The International Energy Agency, 9 rue de la Federation, Paris 75015 (France)

    2010-03-15

    China has set an ambitious target to increase its wind power capacity by 35 GW from 2007 to 2020. The country's hunger for clean power provides great opportunities for wind energy investors. However, risks from China's uncertain electricity market regulation and an uncertain energy policy framework, mainly due to uncertain Clean Development Mechanism (CDM) benefits, prevent foreign investors from investing in China's wind energy. The objectives of this paper are to: (1) quantify wind energy investment risk premiums in an uncertain international energy policy context and (2) evaluate the impact of uncertain CDM benefits on the net present values of wind power projects. With four scenarios, this study simulates possible prices of certified emissions reductions (CERs) from wind power projects. Project net present values (NPVs) have been calculated. The project risk premiums are drawn from different and uncertain CER prices. Our key findings show that uncertain CDM benefits will significantly affect the project NPVs. This paper concludes that the Chinese government needs revising its tariff incentives, most likely by introducing fixed feed-in tariffs (FITs), and re-examining its CDM-granting policy and its wind project tax rates, to facilitate wind power development and enable China to achieve its wind energy target. (author)

  9. Wind farm investment risks under uncertain CDM benefit in China

    Energy Technology Data Exchange (ETDEWEB)

    Ming Yang, E-mail: ming.yang7@gmail.co [3E and T International, Suite 1506, Building No. 10, Luo-Ma-Shi Street, Xuan Wu District, Beijing 100052 (China); Nguyen, Francois; De T' Serclaes, Philippine; Buchner, Barbara [International Energy Agency, 9 rue de la Federation, Paris 75015 (France)

    2010-03-15

    China has set an ambitious target to increase its wind power capacity by 35 GW from 2007 to 2020. The country's hunger for clean power provides great opportunities for wind energy investors. However, risks from China's uncertain electricity market regulation and an uncertain energy policy framework, mainly due to uncertain Clean Development Mechanism (CDM) benefits, prevent foreign investors from investing in China's wind energy. The objectives of this paper are to: (1) quantify wind energy investment risk premiums in an uncertain international energy policy context and (2) evaluate the impact of uncertain CDM benefits on the net present values of wind power projects. With four scenarios, this study simulates possible prices of certified emissions reductions (CERs) from wind power projects. Project net present values (NPVs) have been calculated. The project risk premiums are drawn from different and uncertain CER prices. Our key findings show that uncertain CDM benefits will significantly affect the project NPVs. This paper concludes that the Chinese government needs revising its tariff incentives, most likely by introducing fixed feed-in tariffs (FITs), and re-examining its CDM-granting policy and its wind project tax rates, to facilitate wind power development and enable China to achieve its wind energy target.

  10. CDM: Teaching Discrete Mathematics to Computer Science Majors

    Science.gov (United States)

    Sutner, Klaus

    2005-01-01

    CDM, for computational discrete mathematics, is a course that attempts to teach a number of topics in discrete mathematics to computer science majors. The course abandons the classical definition-theorem-proof model, and instead relies heavily on computation as a source of motivation and also for experimentation and illustration. The emphasis on…

  11. A Reformed CDM - including new mechanisms for sustainable development

    Energy Technology Data Exchange (ETDEWEB)

    Holm Olsen, K.; Fenhann, J.

    2009-07-01

    The annual CD4CDM Perspectives Series features a topic of pivotal importance to the global carbon market. The series seeks to communicate the diverse insights and visions of leading actors in the carbon market to better inform the decisions of professionals and policymakers in developing countries. The second theme of the series focuses on how the CDM can be reformed in a post-2012 climate regime, including new mechanism for sustainable development. Seventeen contributors from the private sector, Designated National Authorities, the Executive Board, research, and development agencies present their perspective on meeting challenges such as the unequal regional distribution of CDM projects, concerns about environmental integrity and technology transfer, complex governance procedures, and questions about the CDM's contribution to sustainable development. The new ideas and solutions to these challenges proposed by the authors in this edition of Perspectives have been solicited to help professionals and policy makers make the best decisions in the lead-up to COP 15 in Copenhagen and beyond. (au)

  12. Wind farm investment risks under uncertain CDM benefit in China

    International Nuclear Information System (INIS)

    Ming Yang; Nguyen, Francois; De T'Serclaes, Philippine; Buchner, Barbara

    2010-01-01

    China has set an ambitious target to increase its wind power capacity by 35 GW from 2007 to 2020. The country's hunger for clean power provides great opportunities for wind energy investors. However, risks from China's uncertain electricity market regulation and an uncertain energy policy framework, mainly due to uncertain Clean Development Mechanism (CDM) benefits, prevent foreign investors from investing in China's wind energy. The objectives of this paper are to: (1) quantify wind energy investment risk premiums in an uncertain international energy policy context and (2) evaluate the impact of uncertain CDM benefits on the net present values of wind power projects. With four scenarios, this study simulates possible prices of certified emissions reductions (CERs) from wind power projects. Project net present values (NPVs) have been calculated. The project risk premiums are drawn from different and uncertain CER prices. Our key findings show that uncertain CDM benefits will significantly affect the project NPVs. This paper concludes that the Chinese government needs revising its tariff incentives, most likely by introducing fixed feed-in tariffs (FITs), and re-examining its CDM-granting policy and its wind project tax rates, to facilitate wind power development and enable China to achieve its wind energy target.

  13. Wind power projects in the CDM: Methodologies and tools for baselines, carbon financing and substainability analysis[CDM=Clean Development Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ringius, L.; Grohnheit, P.E.; Nielsen, L.H.; Olivier, A.L.; Painuly, J.; Villavicencio, A.

    2002-12-01

    The report is intended to be a guidance document for project developers, investors, lenders, and CDM host countries involved in wind power projects in the CDM. The report explores in particular those issues that are important in CDM project assessment and development - that is, baseline development, carbon financing, and environmental sustainability. It does not deal in detail with those issues that are routinely covered in a standard wind power project assessment. The report tests, compares, and recommends methodologies for and approaches to baseline development. To present the application and implications of the various methodologies and approaches in a concrete context, Africa's largest wind farm-namely the 60 MW wind farm located in Zafarana, Egypt- is examined as a hypothetical CDM wind power project The report shows that for the present case example there is a difference of about 25% between the lowest (0.5496 tCO2/MWh) and the highest emission rate (0.6868 tCO{sub 2}/MWh) estimated in accordance with these three standardized approaches to baseline development according to the Marrakesh Accord. This difference in emission factors comes about partly as a result of including hydroelectric power in the baseline scenario. Hydroelectric resources constitute around 21% of the generation capacity in Egypt, and, if excluding hydropower, the difference between the lowest and the highest baseline is reduced to 18%. Furthermore, since the two variations of the 'historical' baseline option examined result in the highest and the lowest baselines, by disregarding this baseline option altogether the difference between the lowest and the highest is reduced to 16%. The ES3-model, which the Systems Analysis Department at Risoe National Laboratory has developed, makes it possible for this report to explore the project-specific approach to baseline development in some detail. Based on quite disaggregated data on the Egyptian electricity system, including the wind

  14. Addressing the need for a Clean Development Mechanism (CDM) specific project management strategy

    CSIR Research Space (South Africa)

    Lotz, M

    2009-01-01

    Full Text Available Clean Development Mechanism (CDM) projects have additional technical, financial and regulatory requirements that are not fully addressed by classic project management approaches. Research has been done on individual novel concepts of the CDM, like...

  15. Crystallized Rate Regions for MIMO Transmission

    Directory of Open Access Journals (Sweden)

    Debbah Merouane

    2010-01-01

    Full Text Available When considering the multiuser SISO interference channel, the allowable rate region is not convex and the maximization of the aggregated rate of all the users by the means of transmission power control becomes inefficient. Hence, a concept of the crystallized rate regions has been proposed, where the time-sharing approach is considered to maximize the sumrate.In this paper, we extend the concept of crystallized rate regions from the simple SISO interference channel case to the MIMO/OFDM interference channel. As a first step, we extend the time-sharing convex hull from the SISO to the MIMO channel case. We provide a non-cooperative game-theoretical approach to study the achievable rate regions, and consider the Vickrey-Clarke-Groves (VCG mechanism design with a novel cost function. Within this analysis, we also investigate the case of OFDM channels, which can be treated as the special case of MIMO channels when the channel transfer matrices are diagonal. In the second step, we adopt the concept of correlated equilibrium into the case of two-user MIMO/OFDM, and we introduce a regret-matching learning algorithm for the system to converge to the equilibrium state. Moreover, we formulate the linear programming problem to find the aggregated rate of all users and solve it using the Simplex method. Finally, numerical results are provided to confirm our theoretical claims and show the improvement provided by this approach.

  16. A Design of Double Broadband MIMO Antenna

    Directory of Open Access Journals (Sweden)

    Yanfeng Geng

    2015-01-01

    Full Text Available The MIMO antenna applied to LTE mobile system should be miniaturization and can work in the current communication frequency band; isolation between each antenna unit also should be good so as to reduce loss of radio wave energy and improve the antenna performance of the MIMO system. This paper puts forward the design scheme of a broadband MIMO double antenna. And the design of antenna unit and debugging and related technical measures, such as bending antenna bracket, are both presented; the integration design of high isolation of ultra broadband MIMO antenna is realized on the plate with the volume of 100 × 52 × 0.8 mm3; antenna working bands are 698 MHz~960 MHz and 1710 MHz~2700 MHz; in the whole spectrum, the 10 dB of port isolation can be basically achieved; in low frequency band, the isolation degree of antenna port can reach 12 dB.

  17. Orthogonal antenna architecture for MIMO handsets

    DEFF Research Database (Denmark)

    Tatomirescu, Alexandru; Alrabadi, Osama; Pedersen, Gert Frølund

    2012-01-01

    The paper presents a method for decorrelating the antenna elements of a MIMO system in a compact handheld terminal at low bands. The architecture of the antenna system induces orthogonal currents over the closely spaced antennas resulting in a correlation free system. Nevertheless, due to the small...

  18. A Perspective on the MIMO Wiretap Channel

    KAUST Repository

    Oggier, Frederique

    2015-10-01

    A wiretap channel is a communication channel between a transmitter Alice and a legitimate receiver Bob, in the presence of an eavesdropper Eve. The goal of communication is to achieve reliability between Alice and Bob, but also confidentiality despite Eve’s presence. Wiretap channels are declined in all kinds of flavors, depending on the underlying channels used by the three players: discrete memoryless channels, additive Gaussian noise channels, or fading channels, to name a few. In this survey, we focus on the case where the three players use multiple-antenna channels with Gaussian noise to communicate. After summarizing known results for multiple-input–multiple-output (MIMO) channels, both in terms of achievable reliable data rate (capacity) and code design, we introduce the MIMO wiretap channel. We then state the MIMO wiretap capacity, summarize the idea of the proof(s) behind this result, and comment on the insights given by the proofs on the physical meaning of the secrecy capacity. We finally discuss design criteria for MIMO wiretap codes.

  19. Assessing Usefulness. Do Stakeholders Regard the CDM's SD Tool as Practicial?

    DEFF Research Database (Denmark)

    Olsen, Karen Holm; Fenhann, Jørgen Villy; Hinostroza, Miriam L.

    a tool for voluntary use in order to highlight the contribution of CDM to sustainability. As a result, in late 2012 The Sustainable Development Tool was developed and adopted. The fact that CDM projects should support sustainable development in the host countries is a key element of the CDM, which is why...

  20. CDM in sub-Saharan Africa and the prospects of the Nairobi Framework Initiative

    NARCIS (Netherlands)

    Byigero, Alfred D.; Clancy, Joy S.; Skutsch, Margaret

    2010-01-01

    To what extent can capacity-building activities under the Nairobi Framework (NF) Initiative overcome barriers to the Clean Development Mechanism (CDM) in sub-Saharan Africa and, in particular, the East African region? The level of CDM penetration into sub-Saharan Africa is compared with CDM market

  1. Iterative Sparse Channel Estimation and Decoding for Underwater MIMO-OFDM

    Directory of Open Access Journals (Sweden)

    Berger ChristianR

    2010-01-01

    Full Text Available We propose a block-by-block iterative receiver for underwater MIMO-OFDM that couples channel estimation with multiple-input multiple-output (MIMO detection and low-density parity-check (LDPC channel decoding. In particular, the channel estimator is based on a compressive sensing technique to exploit the channel sparsity, the MIMO detector consists of a hybrid use of successive interference cancellation and soft minimum mean-square error (MMSE equalization, and channel coding uses nonbinary LDPC codes. Various feedback strategies from the channel decoder to the channel estimator are studied, including full feedback of hard or soft symbol decisions, as well as their threshold-controlled versions. We study the receiver performance using numerical simulation and experimental data collected from the RACE08 and SPACE08 experiments. We find that iterative receiver processing including sparse channel estimation leads to impressive performance gains. These gains are more pronounced when the number of available pilots to estimate the channel is decreased, for example, when a fixed number of pilots is split between an increasing number of parallel data streams in MIMO transmission. For the various feedback strategies for iterative channel estimation, we observe that soft decision feedback slightly outperforms hard decision feedback.

  2. Effects of applying realistic channel conditions on performance prediction of UCA-VBLAST-MIMO systems

    Directory of Open Access Journals (Sweden)

    Mohab A. Mangoud

    2014-01-01

    Full Text Available Recently, many realistic spatially and temporally clustered channel models were developed to be applied in the simulations of multiple input multiple output (MIMO systems. IEEE 802.11n standard channel model includes spatio-temporal fading correlation effects and accounts for six various real propagation profiles. These profiles represent variety of propagation scenarios for indoor environments. This paper presents the impact of applying various channel model conditions on the link performance of Vertical Bell Laboratories Space-Time detection (VBLAST-MIMO systems that employ Uniform Circular array (UCA. Also, capacity and channel estimation accuracy for this system are investigated under different channel conditions. The effect of varying the SNR on the Channel State Information (CSI error and capacity for UCA-MIMO systems are included. Training based techniques such as Least Square (LS, scaled least square (SLS and minimum mean square error (MMSE methods and relaxed MMSE (RMMSE are considered for estimating channel properties. It is found that the presence of spatial correlation can help to improve the Channel estimation accuracy at low SNR for UCA-VBLAST-MIMO system under different spatial correlation conditions.

  3. Deep-subwavelength Decoupling for MIMO Antennas in Mobile Handsets with Singular Medium.

    Science.gov (United States)

    Xu, Su; Zhang, Ming; Wen, Huailin; Wang, Jun

    2017-09-22

    Decreasing the mutual coupling between Multi-input Multi-output (MIMO) antenna elements in a mobile handset and achieving a high data rate is a challenging topic as the 5 th -generation (5G) communication age is coming. Conventional decoupling components for MIMO antennas have to be re-designed when the geometries or frequencies of antennas have any adjustment. In this paper, we report a novel metamaterial-based decoupling strategy for MIMO antennas in mobile handsets with wide applicability. The decoupling component is made of subwavelength metal/air layers, which can be treated as singular medium over a broad frequency band. The flexible applicable property of the decoupling strategy is verified with different antennas over different frequency bands with the same metamaterial decoupling element. Finally, 1/100-wavelength 10-dB isolation is demonstrated for a 24-element MIMO antenna in mobile handsets over the frequency band from 4.55 to 4.75 GHz.

  4. Latin America-Alberta-Canada CDM Conference: Conference Summary

    International Nuclear Information System (INIS)

    Anon

    2000-01-01

    Proposals for joint initiatives put forward by participants at the Clean Development Mechanisms Conference included (1) the development of regional guidelines to assist governments in setting regulatory framework for projects to qualify as CDMs, (2) development of regional baselines and regional performance indicators for social benefit and sustainable development, (3) a specific project in Mexico to test the CDM framework and eligibility criteria, (4) development of bilateral agreements between governments, (5) staff exchanges between associations and governments, (6) government recognition for private sector actions such as a letter affirming that certified emission reductions would be accepted for commitments, (7) sharing of information on websites, and (8) capacity building, training programs and workshops. The Conference also identified common ground and shared interest in CDM initiatives among participants, and readiness to explore joint ventures and technology transfer opportunities. There is wide-spread agreement on the need to resolve uncertainties of CDM, such as baseline and additionality; monitoring, reporting, certification; buyer/seller liability; adaptation levy for international emissions trading, joint implementation and clean development mechanism transactions. Significant consensus exists regarding benefits of 'learning by doing' and the need for minimizing transaction costs and risks. Baseline and Additionality are recognized as the critical issues, with social benefits, sustainable development aspects of projects, and the critical nature of integrity, technical expertise, and track record of both partners as close seconds. The importance of framework arrangements, host country approval, clear designation of responsibility and authority to approve projects, the need for specific guidelines and specific approval procedures, country-to-country agreements and national crediting arrangement are recognized by all participants. With regard to issues

  5. Statistical Angular Resolution Limit for Ultrawideband MIMO Noise Radar

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhou

    2015-01-01

    Full Text Available The two-dimensional angular resolution limit (ARL of elevation and azimuth for MIMO radar with ultrawideband (UWB noise waveforms is investigated using statistical resolution theory. First, the signal model of monostatic UWB MIMO noise radar is established in a 3D reference frame. Then, the statistical angular resolution limits (SARLs of two closely spaced targets are derived using the detection-theoretic and estimation-theoretic approaches, respectively. The detection-theoretic approach is based on the generalized likelihood ratio test (GLRT with given probabilities of false alarm and detection, while the estimation-theoretic approach is based on Smith’s criterion which involves the Cramér-Rao lower bound (CRLB. Furthermore, the relationship between the two approaches is presented, and the factors affecting the SARL, that is, detection parameters, transmit waveforms, array geometry, signal-to-noise ratio (SNR, and parameters of target (i.e., radar cross section (RCS and direction, are analyzed. Compared with the conventional radar resolution theory defined by the ambiguity function, the SARL reflects the practical resolution ability of radar and can provide an optimization criterion for radar system design.

  6. Λ CDM is Consistent with SPARC Radial Acceleration Relation

    Energy Technology Data Exchange (ETDEWEB)

    Keller, B. W.; Wadsley, J. W., E-mail: kellerbw@mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)

    2017-01-20

    Recent analysis of the Spitzer Photometry and Accurate Rotation Curve (SPARC) galaxy sample found a surprisingly tight relation between the radial acceleration inferred from the rotation curves and the acceleration due to the baryonic components of the disk. It has been suggested that this relation may be evidence for new physics, beyond Λ CDM . In this Letter, we show that 32 galaxies from the MUGS2 match the SPARC acceleration relation. These cosmological simulations of star-forming, rotationally supported disks were simulated with a WMAP3 Λ CDM cosmology, and match the SPARC acceleration relation with less scatter than the observational data. These results show that this acceleration relation is a consequence of dissipative collapse of baryons, rather than being evidence for exotic dark-sector physics or new dynamical laws.

  7. Sustainable waste management in Africa through CDM projects.

    Science.gov (United States)

    Couth, R; Trois, C

    2012-11-01

    Only few Clean Development Mechanism (CDM) projects (traditionally focussed on landfill gas combustion) have been registered in Africa if compared to similar developing countries. The waste hierarchy adopted by many African countries clearly shows that waste recycling and composting projects are generally the most sustainable. This paper undertakes a sustainability assessment for practical waste treatment and disposal scenarios for Africa and makes recommendations for consideration. The appraisal in this paper demonstrates that mechanical biological treatment of waste becomes more financially attractive if established through the CDM process. Waste will continue to be dumped in Africa with increasing greenhouse gas emissions produced, unless industrialised countries (Annex 1) fund carbon emission reduction schemes through a replacement to the Kyoto Protocol. Such a replacement should calculate all of the direct and indirect carbon emission savings and seek to promote public-private partnerships through a concerted support of the informal sector. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Defining Investment Additionality for CDM projects - practical approaches

    International Nuclear Information System (INIS)

    Greiner, Sandra; Michaelowa, Axel

    2003-01-01

    The environmental integrity of the CDM under the Kyoto Protocol depends on the possibility to avoid giving emission credits to projects that would have happened anyway. Whether and how 'Investment Additionality' of CDM projects has to be determined is currently a part of climate negotiations. We discuss the rationale of companies to invest in projects and analyse possible criteria to determine Investment Additionality from a theoretical point of view. Differences in the type of investment call for the application of different criteria. Although some criteria are better than others, no single criterion can outweigh the others in all respects. We therefore suggest a scheme for additionality testing that aims at matching types of investment and criteria in a sensible way. Criteria are evaluated on the grounds of robustness to manipulation, degree of coverage and appropriateness for testing the investment decision under consideration

  9. Efficient SDM-MIMO Stokes-space equalization

    DEFF Research Database (Denmark)

    Caballero, F. J.Vaquero; Zanaty, A.; Pittala, F.

    2016-01-01

    We propose a novel frequency-domain 6x6 MIMO Stokes-space equalizer and compare its performance to a 6x6 MIMO LMS architecture. This method is suited to overcome DSP complexity and laser linewidth issues in SDM transmission systems.......We propose a novel frequency-domain 6x6 MIMO Stokes-space equalizer and compare its performance to a 6x6 MIMO LMS architecture. This method is suited to overcome DSP complexity and laser linewidth issues in SDM transmission systems....

  10. Technology transfer to Africa: constraints for CDM operations

    International Nuclear Information System (INIS)

    Karani, Patrick

    2002-01-01

    It is practically difficult to design, implement and manage Clean Development Mechanism (CDM) projects in Africa without a provision for capacity building that will enable the application of modern technologies and techniques. Existing institutions need strengthening, human capacity needs to be developed and new markets need to be promoted. The author outlines institutional and market constraints in relation to technology transfer (e.g renewable energy technologies) and development in Africa. (Author)

  11. Efficient coordinated recovery of sparse channels in massive MIMO

    KAUST Repository

    Masood, Mudassir

    2015-01-01

    This paper addresses the problem of estimating sparse channels in massive MIMO-OFDM systems. Most wireless channels are sparse in nature with large delay spread. In addition, these channels as observed by multiple antennas in a neighborhood have approximately common support. The sparsity and common support properties are attractive when it comes to the efficient estimation of large number of channels in massive MIMO systems. Moreover, to avoid pilot contamination and to achieve better spectral efficiency, it is important to use a small number of pilots. We present a novel channel estimation approach which utilizes the sparsity and common support properties to estimate sparse channels and requires a small number of pilots. Two algorithms based on this approach have been developed that perform Bayesian estimates of sparse channels even when the prior is non-Gaussian or unknown. Neighboring antennas share among each other their beliefs about the locations of active channel taps to perform estimation. The coordinated approach improves channel estimates and also reduces the required number of pilots. Further improvement is achieved by the data-aided version of the algorithm. Extensive simulation results are provided to demonstrate the performance of the proposed algorithms.

  12. Decision-Directed Recursive Least Squares MIMO Channels Tracking

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available A new approach for joint data estimation and channel tracking for multiple-input multiple-output (MIMO channels is proposed based on the decision-directed recursive least squares (DD-RLS algorithm. RLS algorithm is commonly used for equalization and its application in channel estimation is a novel idea. In this paper, after defining the weighted least squares cost function it is minimized and eventually the RLS MIMO channel estimation algorithm is derived. The proposed algorithm combined with the decision-directed algorithm (DDA is then extended for the blind mode operation. From the computational complexity point of view being O3 versus the number of transmitter and receiver antennas, the proposed algorithm is very efficient. Through various simulations, the mean square error (MSE of the tracking of the proposed algorithm for different joint detection algorithms is compared with Kalman filtering approach which is one of the most well-known channel tracking algorithms. It is shown that the performance of the proposed algorithm is very close to Kalman estimator and that in the blind mode operation it presents a better performance with much lower complexity irrespective of the need to know the channel model.

  13. Unified Theoretical Frame of a Joint Transmitter-Receiver Reduced Dimensional STAP Method for an Airborne MIMO Radar

    Directory of Open Access Journals (Sweden)

    Guo Yiduo

    2016-10-01

    Full Text Available The unified theoretical frame of a joint transmitter-receiver reduced dimensional Space-Time Adaptive Processing (STAP method is studied for an airborne Multiple-Input Multiple-Output (MIMO radar. First, based on the transmitted waveform diverse characteristics of the transmitted waveform of the airborne MIMO radar, a uniform theoretical frame structure for the reduced dimensional joint adaptive STAP is constructed. Based on it, three reduced dimensional STAP fixed structures are established. Finally, three reduced rank STAP algorithms, which are suitable for a MIMO system, are presented corresponding to the three reduced dimensional STAP fixed structures. The simulations indicate that the joint adaptive algorithms have preferable clutter suppression and anti-interference performance.

  14. 60-GHz optical/wireless MIMO system integrated with optical subcarrier multiplexing and 2x2 wireless communication.

    Science.gov (United States)

    Lin, Chi-Hsiang; Lin, Chun-Ting; Huang, Hou-Tzu; Zeng, Wei-Siang; Chiang, Shou-Chih; Chang, Hsi-Yu

    2015-05-04

    This paper proposes a 2x2 MIMO OFDM Radio-over-Fiber scheme based on optical subcarrier multiplexing and 60-GHz MIMO wireless transmission. We also schematically investigated the principle of optical subcarrier multiplexing, which is based on a dual-parallel Mach-Zehnder modulator (DP-MZM). In our simulation result, combining two MIMO OFDM signals to drive DP-MZM gives rise to the PAPR augmentation of less than 0.4 dB, which mitigates nonlinear distortion. Moreover, we applied a Levin-Campello bit-loading algorithm to compensate for the uneven frequency responses in the V-band. The resulting system achieves OFDM signal rates of 61.5-Gbits/s with BER of 10(-3) over 25-km SMF transmission followed by 3-m wireless transmission.

  15. Economic Impact of CDM Implementation through Alternate Energy Resource Substitution

    Directory of Open Access Journals (Sweden)

    K.J. Sreekanth

    2013-02-01

    Full Text Available Since the Kyoto protocol agreement, Clean Development Mechanism (CDM hasgarnered large emphasis in terms of certified emission reductions (CER not only amidst the globalcarbon market but also in India. This paper attempts to assess the impact of CDM towardssustainable development particularly in rural domestic utility sector that mainly includes lightingand cooking applications, with electricity as the source of energy. A detailed survey has undertakenin the state of Kerala, in southern part of India to study the rural domestic energy consumptionpattern. The data collected was analyzed that throws insight into the interrelationships of thevarious parameters that influence domestic utility sector pertaining to energy consumption byusing electricity as the source of energy. The interrelationships between the different parameterswere modeled that optimizes the contribution of electricity on domestic utility sector. The resultswere used to estimate the feasible extent of CO2 emission reduction through use of electricity as theenergy resources, vis-à-vis its economic viability through cost effectiveness. The analysis alsoprovides a platform for implementing CDM projects in the sector and related prospects withrespects to the Indian scenario.

  16. MIMoSA: An Automated Method for Intermodal Segmentation Analysis of Multiple Sclerosis Brain Lesions.

    Science.gov (United States)

    Valcarcel, Alessandra M; Linn, Kristin A; Vandekar, Simon N; Satterthwaite, Theodore D; Muschelli, John; Calabresi, Peter A; Pham, Dzung L; Martin, Melissa Lynne; Shinohara, Russell T

    2018-03-08

    Magnetic resonance imaging (MRI) is crucial for in vivo detection and characterization of white matter lesions (WMLs) in multiple sclerosis. While WMLs have been studied for over two decades using MRI, automated segmentation remains challenging. Although the majority of statistical techniques for the automated segmentation of WMLs are based on single imaging modalities, recent advances have used multimodal techniques for identifying WMLs. Complementary modalities emphasize different tissue properties, which help identify interrelated features of lesions. Method for Inter-Modal Segmentation Analysis (MIMoSA), a fully automatic lesion segmentation algorithm that utilizes novel covariance features from intermodal coupling regression in addition to mean structure to model the probability lesion is contained in each voxel, is proposed. MIMoSA was validated by comparison with both expert manual and other automated segmentation methods in two datasets. The first included 98 subjects imaged at Johns Hopkins Hospital in which bootstrap cross-validation was used to compare the performance of MIMoSA against OASIS and LesionTOADS, two popular automatic segmentation approaches. For a secondary validation, a publicly available data from a segmentation challenge were used for performance benchmarking. In the Johns Hopkins study, MIMoSA yielded average Sørensen-Dice coefficient (DSC) of .57 and partial AUC of .68 calculated with false positive rates up to 1%. This was superior to performance using OASIS and LesionTOADS. The proposed method also performed competitively in the segmentation challenge dataset. MIMoSA resulted in statistically significant improvements in lesion segmentation performance compared with LesionTOADS and OASIS, and performed competitively in an additional validation study. Copyright © 2018 by the American Society of Neuroimaging.

  17. The clean development mechanism (CDM) an international perspective and implications for the LAC region

    International Nuclear Information System (INIS)

    2004-08-01

    This paper addresses activity a) an analysis of international CDM experiences and its potential contribution to the LAC region. The paper begins with a section describing the basic principles of the CDM and retrieves the lessons learned from the first two years of the CDM operation. This is followed by a more detailed review in section 2 of the on-going baseline and monitoring methodology approval process. In section 3, the development value of the CDM is explored. Section 4 describes the current CDM markets, while section 5 reviews the response of host countries to the CDM outside the LAC region. Section 6 describes the various capacity building programs established by Annex 1 countries to support the CDM. In each of the first 6 sections, implications for the LAC region are identified. Section 7 brings these conclusions together into a concise summary. (The author)

  18. Addressing the need for a clean development mechanism (CDM specific project management strategy

    Directory of Open Access Journals (Sweden)

    Marco Lotz

    2011-08-01

    Full Text Available Clean Development Mechanism (CDM projects have additional technical, financial and regulatory requirements that are not fully addressed by classic project management approaches. Research has been done on individual novel concepts of the CDM, like additionality, but little has been achieved to address an overall CDM project management approach. CDM and project management literature was reviewed and the South African CDM Industry Association was used as a case study to gain insight into an appropriate CDM specific project management strategy. A stage-gate model was subsequently derived to align classic project management approaches with the additional requirements of CDM projects. Further research will, in time, determine the completeness and practicability of the proposed model.

  19. Why only few CDM projects? The case of reforestation projects and remote sensing

    DEFF Research Database (Denmark)

    Brandt, Urs Steiner; Svendsen, Gert Tinggaard

    2013-01-01

    CDM projects have large potentials but also face significant obstacles that have so far limited their applicability. Two serious problems that an effective contracting faces are the presence of private information and the lack of sufficiently precise output measures. In a principal-agent framework...... structure is feasible. In the case of reforestation projects, and with respect to both economic and sustainability criteria, our model point to that a differentiated payment structure based on output due to remote sensing is superior to a uniform contract....

  20. Investigation of Doppler Effects on high mobility OFDM-MIMO systems with the support of High Altitude Platforms (HAPs)

    International Nuclear Information System (INIS)

    Mohammed, H A; Sibley, M J N; Mather, P J

    2012-01-01

    The merging of Orthogonal Frequency Division Multiplexing (OFDM) with Multiple-input multiple-output (MIMO) is a promising mobile air interface solution for next generation wireless local area networks (WLANs) and 4G mobile cellular wireless systems. This paper details the design of a highly robust and efficient OFDM-MIMO system to support permanent accessibility and higher data rates to users moving at high speeds, such as users travelling on trains. It has high relevance for next generation wireless local area networks (WLANs) and 4G mobile cellular wireless systems. The paper begins with a comprehensive literature review focused on both technologies. This is followed by the modelling of the OFDM-MIMO physical layer based on Simulink/Matlab that takes into consideration high vehicular mobility. Then the entire system is simulated and analysed under different encoding and channel estimation algorithms. The use of High Altitude Platform system (HAPs) technology is considered and analysed.

  1. The Study of Indoor and Field Trials on 2×8 MIMO Architecture in TD-LTE Network

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2013-01-01

    the networks are based on frequency division duplexing (FDD. In this paper, measurement methods of four MIMO transmission modes (TMs in time division-LTE (TD-LTE are studied and analyzed. Link level simulation is carried out to evaluate the downlink throughput for different signal-to-noise ratios and parameter settings. Furthermore, indoor and field tests are also presented in the paper to investigate how real-world propagation affects the capacity and the error performance of MIMO transmission scheme. For the indoor test, radio channel emulators are applied to generate realistic wireless fading channel, while in the field trials, a live TD-LTE experiment cellular network is built, which contains several evolved nodeBs (eNBs and a precommercial user equipment (UE. It is shown from both simulation and tests results that MIMO deployment gives a substantial performance improvement compared with the third generation wireless networks.

  2. Massive-MIMO Sparse Uplink Channel Estimation Using Implicit Training and Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Babar Mansoor

    2017-01-01

    Full Text Available Massive multiple-input multiple-output (massive-MIMO is foreseen as a potential technology for future 5G cellular communication networks due to its substantial benefits in terms of increased spectral and energy efficiency. These advantages of massive-MIMO are a consequence of equipping the base station (BS with quite a large number of antenna elements, thus resulting in an aggressive spatial multiplexing. In order to effectively reap the benefits of massive-MIMO, an adequate estimate of the channel impulse response (CIR between each transmit–receive link is of utmost importance. It has been established in the literature that certain specific multipath propagation environments lead to a sparse structured CIR in spatial and/or delay domains. In this paper, implicit training and compressed sensing based CIR estimation techniques are proposed for the case of massive-MIMO sparse uplink channels. In the proposed superimposed training (SiT based techniques, a periodic and low power training sequence is superimposed (arithmetically added over the information sequence, thus avoiding any dedicated time/frequency slots for the training sequence. For the estimation of such massive-MIMO sparse uplink channels, two greedy pursuits based compressed sensing approaches are proposed, viz: SiT based stage-wise orthogonal matching pursuit (SiT-StOMP and gradient pursuit (SiT-GP. In order to demonstrate the validity of proposed techniques, a performance comparison in terms of normalized mean square error (NCMSE and bit error rate (BER is performed with a notable SiT based least squares (SiT-LS channel estimation technique. The effect of channels’ sparsity, training-to-information power ratio (TIR and signal-to-noise ratio (SNR on BER and NCMSE performance of proposed schemes is thoroughly studied. For a simulation scenario of: 4 × 64 massive-MIMO with a channel sparsity level of 80 % and signal-to-noise ratio (SNR of 10 dB , a performance gain of 18 dB and 13 d

  3. Indoor MIMO Channel Measurement and Modeling

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Andersen, Jørgen Bach

    2005-01-01

    Forming accurate models of the multiple input multiple output (MIMO) channel is essential both for simulation as well as understanding of the basic properties of the channel. This paper investigates different known models using measurements obtained with a 16x32 MIMO channel sounder for the 5.8GHz...... band. The measurements were carried out in various indoor scenarios including both temporal and spatial aspects of channel changes. The models considered include the so-called Kronecker model, a model proposed by Weichselberger et. al., and a model involving the full covariance matrix, the most...... accurate model for Gaussian channels. For each of the environments different sizes of both the transmitter and receiver antenna arrays are investigated, 2x2 up to 16x32. Generally it was found that in terms of capacity cumulative distribution functions (CDFs) all models fit well for small array sizes...

  4. Wind power projects in the CDM: Methodologies and tools for baselines, carbon financing and sustainability analysis

    International Nuclear Information System (INIS)

    Ringius, L.; Grohnheit, P.E.; Nielsen, L.H.; Olivier, A.L.; Painuly, J.; Villavicencio, A.

    2002-12-01

    The report is intended to be a guidance document for project developers, investors, lenders, and CDM host countries involved in wind power projects in the CDM. The report explores in particular those issues that are important in CDM project assessment and development - that is, baseline development, carbon financing, and environmental sustainability. It does not deal in detail with those issues that are routinely covered in a standard wind power project assessment. The report tests, compares, and recommends methodologies for and approaches to baseline development. To present the application and implications of the various methodologies and approaches in a concrete context, Africa's largest wind farm-namely the 60 MW wind farm located in Zafarana, Egypt- is examined as a hypothetical CDM wind power project The report shows that for the present case example there is a difference of about 25% between the lowest (0.5496 tCO2/MWh) and the highest emission rate (0.6868 tCO 2 /MWh) estimated in accordance with these three standardized approaches to baseline development according to the Marrakesh Accord. This difference in emission factors comes about partly as a result of including hydroelectric power in the baseline scenario. Hydroelectric resources constitute around 21% of the generation capacity in Egypt, and, if excluding hydropower, the difference between the lowest and the highest baseline is reduced to 18%. Furthermore, since the two variations of the 'historical' baseline option examined result in the highest and the lowest baselines, by disregarding this baseline option altogether the difference between the lowest and the highest is reduced to 16%. The ES3-model, which the Systems Analysis Department at Risoe National Laboratory has developed, makes it possible for this report to explore the project-specific approach to baseline development in some detail. Based on quite disaggregated data on the Egyptian electricity system, including the wind power production

  5. Gamma-ray bursts as cosmological probes: ΛCDM vs. conformal gravity

    Energy Technology Data Exchange (ETDEWEB)

    Diaferio, Antonaldo; Ostorero, Luisa [Dipartimento di Fisica Generale ' Amedeo Avogadro' , Università degli Studi di Torino, Via P. Giuria 1, I-10125, Torino (Italy); Cardone, Vincenzo, E-mail: diaferio@ph.unito.it, E-mail: ostorero@ph.unito.it, E-mail: winnyenodrac@gmail.com [INAF - Osservatorio Astronomico di Roma, via Frascati 33, 00040, Monte Porzio Catone, Roma (Italy)

    2011-10-01

    ΛCDM, for the currently preferred cosmological density Ω{sub 0} and cosmological constant Ω{sub Λ}, predicts that the Universe expansion decelerates from early times to redshift z ≈ 0.9 and accelerates at later times. On the contrary, the cosmological model based on conformal gravity predicts that the cosmic expansion has always been accelerating. To distinguish between these two very different cosmologies, we resort to gamma-ray bursts (GRBs), which have been suggested to probe the Universe expansion history at z > 1, where identified type Ia supernovae (SNe) are rare. We use the full Bayesian approach to infer the cosmological parameters and the additional parameters required to describe the GRB data available in the literature. For the first time, we use GRBs as cosmological probes without any prior information from other data. In addition, when we combine the GRB samples with SNe, our approach neatly avoids all the inconsistencies of most numerous previous methods that are plagued by the so-called circularity problem. In fact, when analyzed properly, current data are consistent with distance moduli of GRBs and SNe that can respectively be, in a variant of conformal gravity, ∼ 15 and ∼ 3 magnitudes fainter than in ΛCDM. Our results indicate that the currently available SN and GRB samples are accommodated equally well by both ΛCDM and conformal gravity and do not exclude a continuous accelerated expansion. We conclude that GRBs are currently far from being effective cosmological probes, as they are unable to distinguish between these two very different expansion histories.

  6. Soil carbon sequestration and the CDM. Opportunities and challenges for Africa

    Energy Technology Data Exchange (ETDEWEB)

    Ringius, Lasse

    1999-12-17

    The agriculture sector dominates the economies of most sub-Saharan countries, contributing about one-third of the region's GDP, accounting for forty percent of the export, and employing about two-thirds of the economically active population. Moreover, some soils in sub-Saharan Africa could, by providing sinks for carbon sequestration, play an important role in managing global climate change. Improvements in agricultural techniques and land use practices could lead to higher agricultural productivity and accumulate soil carbon. Hence, soil carbon sequestration could produce local economic income as well as social and other benefits in Africa. The Clean Development Mechanism (CDM) established in the 1997 Kyoto Protocol is designed to give developed countries with high domestic abatement cost access to low-cost greenhouse gas abatement projects in developing countries, and to benefit developing countries selling projects to investors in developed countries. It is presently unclear whether the CDM will provide credit for sink enhancement and permit broader sink activities. Unfortunately, few cost estimates of soil carbon sequestration strategies presently exist. While these costs are uncertain and all input costs have not been estimated, manure-based projects in small-holdings in Kenya could increase maize yield significantly and sequester one ton of soil carbon for a net cost of -US$806. Clearly, such projects would be very attractive economically. There is presently an urgent need to launch useful long-term (>10 years) field experiments and demonstration projects in Africa. Existing data are not readily comparable, it is uncertain how large amount of carbon could be sequestered, findings are site-specific, and it is unclear how well the sites represent wider areas. To develop CDM projects, it is important that experimental trials generate reliable and comparable data. Finally, it will be important to estimate local environmental effects and economic benefits

  7. Small Terminal MIMO Channels with User Interaction

    DEFF Research Database (Denmark)

    Pedersen, Gert Frølund; Andersen, Jørgen Bach; Eggers, Patrick Claus F.

    2007-01-01

    This paper gives an overview of results obtained from measurements of different types of multiple-input multiple-output (MIMO) channels. For the indoor case measurements were made at 5.8 GHz from access points (APs) to mobile stations (MSs) at different places in a large open office type room. Th...... an investigation of the potentials for communication between cars approaching as well as in convoy and from inside and outside the car....

  8. A Recognition Method for MIMO DUSTC Signals

    Directory of Open Access Journals (Sweden)

    Qian Bo

    2017-01-01

    Full Text Available For recognizing the MIMO DUSTC signals without a priori knowledge, a blind recognition method is presented. By estimating the number of transmitting antennas, separating the mixed signals, and recognizing modulation, the unitary matrices S is estimated by statistics and DUSTC signals are recognized. The simulation results showed that the method was effectively to recognize DUSTC signals with the SNR no less than 4dB.

  9. Extracting the resource rent from the CDM projects: Can the Chinese Government do better?

    International Nuclear Information System (INIS)

    Liu Xuemei

    2010-01-01

    The revenue generated from a CDM project in China will be shared by the government and the project owner, and is also subject to the corporate income tax. This paper studies the impacts of the revenue sharing policy and income tax on the CDM market. The economic model presented in this paper shows that higher-cost CDM projects will be more affected by the CDM policies than lower-cost projects. In addition, the majority of CERs will be generated from lower-cost projects. This kind of distribution of CERs across different types of CDM projects, which is in line with the current picture of the CDM market in China, is not consistent with the goal of sustainable development. A simulation shows that a type-by-type tax/fee scheme would be more effective in assisting sustainable development than the current CDM policies. The study also suggests the government use negative tax/fee with the type-by-type scheme to subsidize the CDM projects that generate large sustainability benefits but would otherwise not be developed due to high costs. If all of the revenue from the CDM is recycled, it is estimated that CERs generation will increase by 98.28 MtC, mainly from the CDM projects that have substantial sustainability benefits for the host country.

  10. Downlink SINR Distribution of Linearly Precoded Multiuser MIMO Systems

    DEFF Research Database (Denmark)

    Lin, Zihuai; Sørensen, Troels Bundgaard; Mogensen, Preben

    2007-01-01

    is confined to 3GPP downlink transmission in which we specifically investigate the Single User (SU) and Multi-user (MU) Spatial Divsion Multiplexing (SDM) MIMO schemes. From the analytical results we find that the outage probability for systems using the SU-MIMO scheme is larger than the one for the MU...

  11. Efficient SDM-MIMO Stokes-space equalization

    DEFF Research Database (Denmark)

    Caballero, F. J.Vaquero; Zanaty, A.; Pittala, F.

    2016-01-01

    We propose a novel frequency-domain 6x6 MIMO Stokes-space equalizer and compare its performance to a 6x6 MIMO LMS architecture. This method is suited to overcome DSP complexity and laser linewidth issues in SDM transmission systems....

  12. Design and Verification of MIMO 2x2 Reference Antennas

    DEFF Research Database (Denmark)

    Szini, Istvan Janos; Pedersen, Gert Frølund; Estrada, J.

    2012-01-01

    The development and initial discussion of a reference MIMO 2×2 antenna concept has been presented in [1]. The reference antenna concept has been created to eliminate the uncertainties linked to the unknown antenna performance of the few LTE MIMO 2×2 reference devices or golden standards currently...

  13. Array calibration technique for a coherent MIMO radar

    NARCIS (Netherlands)

    Belfiori, F.; Rossum, W. van; Hoogeboom, P.

    2012-01-01

    In this paper we present a technique to estimate the calibration coefficients of a coherent Multiple-Input Multiple-Output (MIMO) array radar built on a printed circuit board (PCB). Due to the integrated structure and the MIMO nature of the system, a direct measurement of each antenna element

  14. Double Ring Antenna Design for MIMO Application in Mobile Terminals

    DEFF Research Database (Denmark)

    Zhao, Kun; Zhang, Shuai; Ying, Zhinong

    2015-01-01

    In this paper, We present a MIMO bezel antenna design composed by a seamless double metal ring structure. The MIMO antenna mainly operates in the loop mode and can cover the majority of globe cellular bands. Good efficiencies (>-4dB) and a low envelope correlation coefficient (<0.5) are achieved,...

  15. Transmitter Layering for Multiuser MIMO Systems

    Directory of Open Access Journals (Sweden)

    Zachary Bagley

    2008-03-01

    Full Text Available A novel structure for multiple antenna transmissions utilizing space-time dispersion is proposed, where the original data stream is divided into K substreams which are modulated onto all available transmit antennas using stream-specific transmit signature sequences. In order to achieve this, the transmit antennas are partitioned into M groups of antennas, called partitions. The signals from the K data streams are independently interleaved by partition over the entire transmission frame. The interleaved partitions are then added over all K substreams prior to transmission over the MIMO channel. At the receiver, a low-complexity iterative detector adapted from recent CDMA multiuser detection research is used. It is shown that with careful substream power assignments this transmission methodology can efficiently utilize the capacity of rank-deficient channels as it can approach the capacity limits of the multiple antenna channel closely over the entire range of available signal-to-noise ratios and system sizes. This transmission methodology and receiver structure are then applied to multiuser MIMO systems where several multiple antenna terminals communicate concurrently to a joint receiver. It is shown that different received power levels from the different MIMO terminals can be beneficial and that higher spectral efficiencies can be achieved than in the single-terminal case.

  16. Transmitter Layering for Multiuser MIMO Systems

    Directory of Open Access Journals (Sweden)

    Schlegel Christian

    2008-01-01

    Full Text Available Abstract A novel structure for multiple antenna transmissions utilizing space-time dispersion is proposed, where the original data stream is divided into substreams which are modulated onto all available transmit antennas using stream-specific transmit signature sequences. In order to achieve this, the transmit antennas are partitioned into groups of antennas, called partitions. The signals from the data streams are independently interleaved by partition over the entire transmission frame. The interleaved partitions are then added over all substreams prior to transmission over the MIMO channel. At the receiver, a low-complexity iterative detector adapted from recent CDMA multiuser detection research is used. It is shown that with careful substream power assignments this transmission methodology can efficiently utilize the capacity of rank-deficient channels as it can approach the capacity limits of the multiple antenna channel closely over the entire range of available signal-to-noise ratios and system sizes. This transmission methodology and receiver structure are then applied to multiuser MIMO systems where several multiple antenna terminals communicate concurrently to a joint receiver. It is shown that different received power levels from the different MIMO terminals can be beneficial and that higher spectral efficiencies can be achieved than in the single-terminal case.

  17. Experimental Study of the Benefits of a Second Antenna at the User Side in a Massive MIMO System

    DEFF Research Database (Denmark)

    Martinez, Alex Oliveras; Popovski, Petar; Nielsen, Jesper Ødum

    2017-01-01

    Massive MIMO is commonly described as a large number of base station (BS) antennas serving a smaller number of single-antenna users. However, adding a second antenna to the user handset opens the possibility to exploit multiplexing techniques and obtain higher throughput. This paper is based...

  18. An improved MIMO-SAR simulator strategy with ray tracing

    Science.gov (United States)

    Xiang, Xingyu; Mo, Zijian; Wang, Zhonghai; Chen, Genshe; Pham, Khanh; Blasch, Erik

    2016-05-01

    High resolution and wide-swath imaging can be obtained by Multiple-Input Multiple-Output (MIMO) synthetic aperture radar (SAR) with the state of the art technologies. The time division multiple access (TDMA) MIMO SAR mimics the motion of the antenna of SAR systems by switching the array channels to transmit the radar signals at different time slots. In this paper, we develop a simulation tool with ray tracing techniques to retrieve high resolution and accurate SAR images for development of MIMO SAR imaging methods. Without loss of generality, in the proposed simulator, we apply a TDMA MIMO SAR system with 13 transmitting antennas and 8 receiving antennas, where all transmitting antennas share a single transmitter and the receiving antennas share a single receiver. By comparing with the normal simulation MIMO SAR strategies, the simulation image using ray tracing results validate that the proposed method provides more accurate and higher resolution SAR images.

  19. MIMO Intensity-Modulation Channels: Capacity Bounds and High SNR Characterization

    KAUST Repository

    Chaaban, Anas

    2016-10-01

    The capacity of MIMO intensity modulation channels is studied. The nonnegativity of the transmit signal (intensity) poses a challenge on the precoding of the transmit signal, which limits the applicability of classical schemes in this type of channels. To resolve this issue, capacity lower bounds are developed by using precoding-free schemes. This is achieved by channel inversion or QR decomposition to convert the MIMO channel to a set of parallel channels. The achievable rate of a DC-offset SVD based scheme is also derived as a benchmark. Then, a capacity upper bound is derived and is shown to coincide with the achievable rate of the QR decomposition based scheme at high SNR, consequently characterizing the high-SNR capacity of the channel. The high-SNR gap between capacity and the achievable rates of the channel inversion and the DC-offset SVD based schemes is also characterized. Finally, the ergodic capacity of the channel is also briefly discussed.

  20. Design and Experimental Validation of MIMO Multiuser Detection for Downlink Packet Data

    Directory of Open Access Journals (Sweden)

    Samardzija Dragan

    2005-01-01

    Full Text Available In single-user MIMO communication, the first-order throughput scaling is determined by the smallest of the number of transmit and receive antennas. This typically renders terminals the constraining bottleneck. In a multiuser downlink, this bottleneck can be bypassed by having the base station communicate with multiple terminals simultaneously, in which case the receive antennas at those terminals are effectively pooled in terms of the capacity scaling. This, however, requires that the base have instantaneous channel information. Without such information, the structure and statistics of the channel can be exploited to form multiple simultaneous beams towards the various users, but these beams are in general mutually interfering. This paper proposes the use of multiuser detection to discriminate the signals conveyed over interfering beams. This approach is formulated and experimentally evaluated on an HSDPA MIMO testbed that involves a commercial base station, multiantenna terminals, and custom ASICs.

  1. ΛCDM model with dissipative nonextensive viscous dark matter

    Science.gov (United States)

    Gimenes, H. S.; Viswanathan, G. M.; Silva, R.

    2018-03-01

    Many models in cosmology typically assume the standard bulk viscosity. We study an alternative interpretation for the origin of the bulk viscosity. Using nonadditive statistics proposed by Tsallis, we propose a bulk viscosity component that can only exist by a nonextensive effect through the nonextensive/dissipative correspondence (NexDC). In this paper, we consider a ΛCDM model for a flat universe with a dissipative nonextensive viscous dark matter component, following the Eckart theory of bulk viscosity, without any perturbative approach. In order to analyze cosmological constraints, we use one of the most recent observations of Type Ia Supernova, baryon acoustic oscillations and cosmic microwave background data.

  2. Gravitational wave memory in ΛCDM cosmology

    International Nuclear Information System (INIS)

    Bieri, Lydia; Garfinkle, David; Yunes, Nicolás

    2017-01-01

    We examine gravitational wave memory in the case where sources and detector are in a ΛCDM cosmology. We consider the case where the Universe can be highly inhomogeneous, but gravitational radiation is treated in the short wavelength approximation. We find results very similar to those of gravitational wave memory in an asymptotically flat spacetime; however, the overall magnitude of the memory effect is enhanced by a redshift-dependent factor. In addition, we find the memory can be affected by lensing. (paper)

  3. Linking renewable energy CDM projects and TGC schemes: An analysis of different options

    Energy Technology Data Exchange (ETDEWEB)

    Del Rio, Pablo [Department of Economics and Business, Facultad de Ciencias Juridicas y Sociales, Universidad de Castilla-La Mancha, C/ Cobertizo de S. Pedro Martir s/n., Toledo-45071 (Spain)]. E-mail: pablo.rio@uclm.es

    2006-11-15

    Renewable energy CDM (RE-CDM) projects encourage cost-effective GHG mitigation and enhanced sustainable development opportunities for the host countries. CERs from CDM projects include the value of the former benefits (i.e., 'climate change benefits'), whereas the second can be given value through the issuing and trading of tradable green certificates (TGCs). Countries could agree to trade these TGCs, leading to additional revenues for the investors in renewable energy projects and, therefore, further encouraging the deployment of CDM projects, currently facing significant barriers. However, the design of a combination of CDM projects and TGC schemes raises several conflicting issues and leads to trade-offs. This paper analyses these issues, identifies the alternatives that may exist to link TGC schemes with RE-CDM projects and analyses the impacts of those options on different variables and actors.

  4. A virtually blind spectrum efficient channel estimation technique for mimo-ofdm system

    International Nuclear Information System (INIS)

    Ullah, M.O.

    2015-01-01

    Multiple-Input Multiple-Output antennas in conjunction with Orthogonal Frequency-Division Multiplexing is a dominant air interface for 4G and 5G cellular communication systems. Additionally, MIMO- OFDM based air interface is the foundation for latest wireless Local Area Networks, wireless Personal Area Networks, and digital multimedia broadcasting. Whether it is a single antenna or a multi-antenna OFDM system, accurate channel estimation is required for coherent reception. Training-based channel estimation methods require multiple pilot symbols and therefore waste a significant portion of channel bandwidth. This paper describes a virtually blind spectrum efficient channel estimation scheme for MIMO-OFDM systems which operates well below the Nyquist criterion. (author)

  5. Joint Linear Filter Design in Multiuser Cooperative Nonregenerative MIMO Relay Systems

    Directory of Open Access Journals (Sweden)

    Gen Li

    2009-01-01

    Full Text Available This paper addresses the filter design issues for multiuser cooperative nonregenerative MIMO relay systems in both downlink and uplink scenarios. Based on the formulated signal model, the filter matrix optimization is first performed for direct path and relay path respectively, aiming to minimize the mean squared error (MSE. To be more specific, for the relay path, we derive the local optimal filter scheme at the base station and the relay station jointly in the downlink scenario along with a more practical suboptimal scheme, and then a closed-form joint local optimal solution in the uplink scenario is exploited. Furthermore, the optimal filter for the direct path is also presented by using the exiting results of conventional MIMO link. After that, several schemes are proposed for cooperative scenario to combine the signals from both paths. Numerical results show that the proposed schemes can reduce the bit error rate (BER significantly.

  6. Blind Identification of Convolutive MIMO Systems with 3 Sources and 2 Sensors

    Directory of Open Access Journals (Sweden)

    De Lathauwer Lieven

    2002-01-01

    Full Text Available We address the problem of blind identification of a convolutive Multiple-Input Multiple-Output (MIMO system with more inputs than outputs, and in particular, the 3-input 2-output case. We assume that the inputs are temporally white, non-Gaussian distributed, and spatially independent. Solutions for the scalar MIMO case, within scaling and permutation ambiguities, have been proposed in the past, based on the canonical decomposition of tensors constructed from higher-order cross-cumulants of the system output. In this paper, we look at the problem in the frequency domain, where, for each frequency we construct a number of tensors based on cross-polyspectra of the output. These tensors lead to the system frequency response within frequency dependent scaling and permutation ambiguities. We propose ways to resolve these ambiguities, and show that it is possible to obtain the system response within a scalar and a linear phase.

  7. Pilot Design for Sparse Channel Estimation in Large-Scale MIMO-OFDM System

    Directory of Open Access Journals (Sweden)

    Chao Xu

    2016-01-01

    Full Text Available The pilot design problem in large-scale multi-input-multioutput orthogonal frequency division multiplexing (MIMO-OFDM system is investigated from the perspective of compressed sensing (CS. According to the CS theory, the success probability of estimation is dependent on the mutual coherence of the reconstruction matrix. Specifically, the smaller the mutual coherence is, the higher the success probability is. Based on this conclusion, this paper proposes a pilot design algorithm based on alternating projection and obtains a nonorthogonal pilot pattern. Simulation results show that applying the proposed pattern gives the better performance compared to applying conventional orthogonal one in terms of normalized mean square error (NMSE of the channel estimate. Moreover, the bit error rate (BER performance of the large-scale MIMO-OFDM system is improved.

  8. Precoding Design for Single-RF Massive MIMO Systems: A Large System Analysis

    KAUST Repository

    Sifaou, Houssem

    2016-08-26

    This work revisits a recently proposed precoding design for massive multiple-input multiple output (MIMO) systems that is based on the use of an instantaneous total power constraint. The main advantages of this technique lie in its suitability to the recently proposed single radio frequency (RF) MIMO transmitter coupled with a very-high power efficiency. Such features have been proven using simulations for uncorrelated channels. Based on tools from random matrix theory, we propose in this work to analyze the performance of this precoder for more involved channels accounting for spatial correlation. The obtained expressions are then optimized in order to maximize the signalto- interference-plus-noise ratio (SINR). Simulation results are provided in order to illustrate the performance of the optimized precoder in terms of peak-to-average power ratio (PAPR) and signal-to-interference-plus-noise ratio (SINR). © 2012 IEEE.

  9. The economic potential of bagasse cogeneration as CDM projects in Indonesia

    International Nuclear Information System (INIS)

    Restuti, Dewi; Michaelowa, Axel

    2007-01-01

    Surplus bagasse in Indonesian sugar mills is potential for grid-connected electricity-generating projects under Clean Development Mechanism (CDM) scheme. In addition, it is further perceived to considerably support the efforts to address prevailing crises in domestic sugar industry and power generation sector. This paper aims at analyzing the economic potential of bagasse cogeneration as CDM projects in Indonesia with the main deliverables of total emission reductions per year and Certified Emission Reduction (CER) earnings. The analysis was made by following the applicable methodologies and based on publicly available data from official and other sources on the websites. The results show that with the electricity displacement potential at 260,253 MWh, Indonesia could generate Greenhouse Gas (GHG) emission reductions as much as 240,774 (large scale) or 198,177 tCO 2 (small scale) per annum from the recently-employed low efficiency cogeneration leading to the earnings of about US$1.36 or 1.12 million, respectively. Out of 6 regional grids where the electricity from the project activities can be grid-connected, the primary emission reductions potentials are encountered in Java-Bali and Southern Sumatera grids. Additionally, various barriers in technical, institutional, financial, and other aspects have been identified as the justifications to pass the additionality test

  10. Experimental demonstration of MIMO-OFDM underwater wireless optical communication

    Science.gov (United States)

    Song, Yuhang; Lu, Weichao; Sun, Bin; Hong, Yang; Qu, Fengzhong; Han, Jun; Zhang, Wei; Xu, Jing

    2017-11-01

    In this paper, we propose and experimentally demonstrate a multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) underwater wireless optical communication (UWOC) system, with a gross bit rate of 33.691 Mb/s over a 2-m water channel using low-cost blue light-emitting-diodes (LEDs) and 10-MHz PIN photodiodes. The system is capable of realizing robust data transmission within a relatively large reception area, leading to relaxed alignment requirement for UWOC. In addition, we have compared the system performance of repetition coding OFDM (RC-OFDM), Alamouti-OFDM and multiple-input single-output OFDM (MISO-OFDM) in turbid water. Results show that the Alamouti-OFDM UWOC is more resistant to delay than the RC-OFDM-based system.

  11. Optimized Data Sharing in Multicell MIMO With Finite Backhaul Capacity

    Science.gov (United States)

    Zakhour, Randa; Gesbert, David

    2011-12-01

    This paper addresses cooperation in a multicell environment where base stations (BSs) wish to jointly serve multiple users, under a constrained-capacity backhaul. We point out that for finite backhaul capacity a trade-off between sharing user data, which allows for full MIMO cooperation, and not doing so, which reduces the setup to an interference channel but also requires less overhead, emerges. We optimize this trade-off by formulating a rate splitting approach in which non-shared data (private to each transmitter) and shared data are superposed. We derive the corresponding achievable rate region and obtain the optimal beamforming design for both shared and private symbols. We show how the capacity of the backhaul can be used to determine how much of the user data is worth sharing across multiple BSs, particularly depending on how strong the interference is.

  12. Iterative Reconfigurable Tree Search Detection of MIMO Systems

    Directory of Open Access Journals (Sweden)

    Hanwen Luo

    2007-01-01

    Full Text Available This paper is concerned with reduced-complexity detection, referred to as iterative reconfigurable tree search (IRTS detection, with application in iterative receivers for multiple-input multiple-output (MIMO systems. Instead of the optimum maximum a posteriori probability detector, which performs brute force search over all possible transmitted symbol vectors, the new scheme evaluates only the symbol vectors that contribute significantly to the soft output of the detector. The IRTS algorithm is facilitated by carrying out the search on a reconfigurable tree, constructed by computing the reliabilities of symbols based on minimum mean-square error (MMSE criterion and reordering the symbols according to their reliabilities. Results from computer simulations are presented, which proves the good performance of IRTS algorithm over a quasistatic Rayleigh channel even for relatively small list sizes.

  13. Analysis and experimental study of MIMO control in refrigeration system

    International Nuclear Information System (INIS)

    Tian Jian; Feng Quanke; Zhu Ruiqi

    2008-01-01

    For various operating conditions and loads of refrigeration systems, converters are used to change the compressor's speed, and electronic expansion valves are adopted to regulate refrigerant flow rates. The refrigeration system, as a process under control, is a multi-input multi-output (MIMO) and nonlinear complex system. Based on the analysis of fuzzy and neural networks control, a self organized fuzzy neural network controller with the capacity of construction and parameter learning is proposed according to the simplified fuzzy control algorithm and the similarity between structure and function of a counter propagation network (CPN). This controller is easily structured with the feature of fuzzy control, and it also possesses the learning ability of neutral networks. The air cooled refrigeration experimental results show that the present controller can modulate the evaporation pressure and the superheating

  14. MIMO High Frequency Surface Wave Radar Using Sparse Frequency FMCW Signals

    Directory of Open Access Journals (Sweden)

    Mengguan Pan

    2017-01-01

    Full Text Available The heavily congested radio frequency environment severely limits the signal bandwidth of the high frequency surface wave radar (HFSWR. Based on the concept of multiple-input multiple-output (MIMO radar, we propose a MIMO sparse frequency HFSWR system to synthesize an equivalent large bandwidth waveform in the congested HF band. The utilized spectrum of the proposed system is discontinuous and irregularly distributed between different transmitting sensors. We investigate the sparse frequency modulated continuous wave (FMCW signal and the corresponding deramping based receiver and signal processor specially. A general processing framework is presented for the proposed system. The crucial step is the range-azimuth processing and the sparsity of the carrier frequency causes the two-dimensional periodogram to fail when applied here. Therefore, we introduce the iterative adaptive approach (IAA in the range-azimuth imaging. Based on the initial 1D IAA algorithm, we propose a modified 2D IAA which particularly fits the deramping processing based range-azimuth model. The proposed processing framework for MIMO sparse frequency FMCW HFSWR with the modified 2D IAA applied is shown to have a high resolution and be able to provide an accurate and clear range-azimuth image which benefits the following detection process.

  15. Carbon market risks and rewards: Firm perceptions of CDM investment decisions in Brazil and India

    International Nuclear Information System (INIS)

    Hultman, Nathan E.; Pulver, Simone; Guimarães, Leticia; Deshmukh, Ranjit; Kane, Jennifer

    2012-01-01

    The carbon market experiences of Brazil and India represent policy success stories under several criteria. A careful evaluation, however, reveals challenges to market development that should be addressed in order to make the rollout of a post-2012 CDM more effective. We conducted firm-level interviews covering 82 CDM plants in the sugar and cement sectors in Brazil and India, focusing on how individual managers understood the potential benefits and risks of undertaking clean development mechanism (CDM) investments. Our results indicate that the CDM operates in a far more complex way in practice than that of simply adding a marginal increment to a project's internal rate of return. Our results indicate the following: first, although anticipated revenue played a central role in most managers' decisions to pursue CDM investments, there was no standard practice to account for financial benefits of CDM investments; second, some managers identified non-financial reputational factors as their primary motivation for pursuing CDM projects; and third, under fluctuating regulatory regimes with real immediate costs and uncertain CDM revenue, managers favored projects that often did not require carbon revenue to be viable. The post-2012 CDM architecture can benefit from incorporating these insights, and in particular reassess goals for strict additionality and mechanisms for achieving it.

  16. Link adaptation performance evaluation for a MIMO-OFDM physical layer in a realistic outdoor environment

    OpenAIRE

    Han, C; Armour, SMD; Doufexi, A; Ng, KH; McGeehan, JP

    2006-01-01

    This paper presents a downlink performance analysis of a link adaptation (LA) algorithm applied to a MIMO-OFDM Physical Layer (PHY) which is a popular candidate for future generation cellular communication systems. The new LA algorithm attempts to maximize throughput and adaptation between various modulation and coding schemes in combination with both space-time block codes (STBC) and spatial multiplexing (SM) is based on knowledge of SNR and H matrix determinant; the parameters which are fou...

  17. Adaptive vector quantization in SVD MIMO system backward link with limited number of active sub channels

    Directory of Open Access Journals (Sweden)

    Ivaniš Predrag

    2004-01-01

    Full Text Available This paper presents combination of Channel Optimized Vector Quantization based on LBG algorithm and sub channel power allocation for MIMO systems with Singular Value Decomposition and limited number of active sub channels. Proposed algorithm is designed to enable maximal throughput with bit error rate bellow some tar- get level in case of backward channel capacity limitation. Presence of errors effect in backward channel is also considered.

  18. Multiple Subcarrier Indoor Geolocation System in MIMO-OFDM WLAN APs Structure

    OpenAIRE

    Abdul Hafiizh; Shigeki Obote; Kenichi Kagoshima

    2009-01-01

    This report aims to utilize existing and future Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing Wireless Local Area Network (MIMO-OFDM WLAN) systems characteristics–such as multiple subcarriers, multiple antennas, and channel estimation characteristics–for indoor location estimation systems based on the Direction of Arrival (DOA) and Radio Signal Strength Indication (RSSI) methods. Hybrid of DOA-RSSI methods also evaluated. In the experimental data result, we show th...

  19. 3D Massive MIMO Systems: Channel Modeling and Performance Analysis

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2015-03-01

    Multiple-input-multiple-output (MIMO) systems of current LTE releases are capable of adaptation in the azimuth only. More recently, the trend is to enhance the system performance by exploiting the channel\\'s degrees of freedom in the elevation through the dynamic adaptation of the vertical antenna beam pattern. This necessitates the derivation and characterization of three-dimensional (3D) channels. Over the years, channel models have evolved to address the challenges of wireless communication technologies. In parallel to theoretical studies on channel modeling, many standardized channel models like COST-based models, 3GPP SCM, WINNER, ITU have emerged that act as references for industries and telecommunication companies to assess system-level and link-level performances of advanced signal processing techniques over real-like channels. Given the existing channels are only two dimensional (2D) in nature; a large effort in channel modeling is needed to study the impact of the channel component in the elevation direction. The first part of this work sheds light on the current 3GPP activity around 3D channel modeling and beamforming, an aspect that to our knowledge has not been extensively covered by a research publication. The standardized MIMO channel model is presented, that incorporates both the propagation effects of the environment and the radio effects of the antennas. In order to facilitate future studies on the use of 3D beamforming, the main features of the proposed 3D channel model are discussed. A brief overview of the future 3GPP 3D channel model being outlined for the next generation of wireless networks is also provided. In the subsequent part of this work, we present an information-theoretic channel model for MIMO systems that supports the elevation dimension. The model is based on the principle of maximum entropy, which enables us to determine the distribution of the channel matrix consistent with the prior information on the angles of departure and

  20. Performance and Complexity Evaluation of Iterative Receiver for Coded MIMO-OFDM Systems

    Directory of Open Access Journals (Sweden)

    Rida El Chall

    2016-01-01

    Full Text Available Multiple-input multiple-output (MIMO technology in combination with channel coding technique is a promising solution for reliable high data rate transmission in future wireless communication systems. However, these technologies pose significant challenges for the design of an iterative receiver. In this paper, an efficient receiver combining soft-input soft-output (SISO detection based on low-complexity K-Best (LC-K-Best decoder with various forward error correction codes, namely, LTE turbo decoder and LDPC decoder, is investigated. We first investigate the convergence behaviors of the iterative MIMO receivers to determine the required inner and outer iterations. Consequently, the performance of LC-K-Best based receiver is evaluated in various LTE channel environments and compared with other MIMO detection schemes. Moreover, the computational complexity of the iterative receiver with different channel coding techniques is evaluated and compared with different modulation orders and coding rates. Simulation results show that LC-K-Best based receiver achieves satisfactory performance-complexity trade-offs.

  1. Spatial Correlation Characterization of a Full Dimension Massive MIMO System

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2017-02-07

    Elevation beamforming and Full Dimension MIMO (FD-MIMO) are currently active areas of research and standardization in 3GPP LTE-Advanced. FD-MIMO utilizes an active antenna array system (AAS), that provides the ability of adaptive electronic beam control over the elevation dimension, resulting in a better system performance as compared to the conventional 2D MIMO systems. FD-MIMO is more advantageous when amalgamated with massive MIMO systems, in that it exploits the additional degrees of freedom offered by a large number of antennas in the elevation. To facilitate the evaluation of these systems, a large effort in 3D channel modeling is needed. This paper aims at providing a summary of the recent 3GPP activity around 3D channel modeling. The 3GPP proposed approach to model antenna radiation pattern is compared with the ITU approach. A closed-form expression is then worked out for the spatial correlation function (SCF) for channels constituted by individual antenna elements in the array by exploiting results on spherical harmonics and Legendre polynomials. The proposed expression can be used to obtain correlation coefficients for any arbitrary 3D propagation environment. Simulation results corroborate and study the derived spatial correlation expression. The results are directly applicable to the analysis of future 5G 3D massive MIMO systems.

  2. Compressive MIMO Beamforming of Data Collected in a Refractive Environment

    Science.gov (United States)

    Wagner, Mark; Nannuru, Santosh; Gerstoft, Peter

    2017-12-01

    The phenomenon of ducting is caused by abnormal atmospheric refractivity patterns and is known to allow electromagnetic waves to propagate over the horizon with unusually low propagation loss. It is unknown what effect ducting has on multiple input multiple output (MIMO) channels, particularly its effect on multipath propagation in MIMO channels. A high-accuracy angle-of-arrival and angle-of-departure estimation technique for MIMO communications, which we will refer to as compressive MIMO beamforming, was tested on simulated data then applied to experimental data taken from an over the horizon MIMO test bed located in a known ducting hot spot in Southern California. The multipath channel was estimated from the receiver data recorded over a period of 18 days, and an analysis was performed on the recorded data. The goal is to observe the evolution of the MIMO multipath channel as atmospheric ducts form and dissipate to gain some understanding of the behavior of channels in a refractive environment. This work is motivated by the idea that some multipath characteristics of MIMO channels within atmospheric ducts could yield important information about the duct.

  3. User Influence on MIMO Channel Capacity for Handsets in Data Mode Operation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Yanakiev, Boyan Radkov; Bonev, Ivan Bonev

    2012-01-01

    The current paper concerns realistic evaluation of the capacity of the MIMO channel between a BS and handheld device, such as a PDA or smartphone, held in front of the user’s body (data mode). The work is based on measurements of the MIMO channel between two widely separated BSs in a micro...... hands. The random capacities of the channels are evaluated in terms of outage capacity. For an SNR of 10 dB, median capacities in free space of about 4.4–4.7 bit/s/Hz for the low band and about 3.3–3.8 bit/s/Hz for the high band were found. The mean decrease in outage capacity due to the user was found...

  4. On Antenna Design Objectives and the Channel Capacity of MIMO Handsets

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Yanakiev, Boyan; Barrio, Samantha Caporal Del

    2014-01-01

    environment in a setup with two different base stations (BSs) and with the users inside a single building. For each measurement combination, the mean capacity (MC) and associated values of BCC, BPR, and TMP are obtained. From the data it is found that the MC is only weakly correlated with both the BCC......The branch correlation coefficient (BCC), the branch power ratio (BPR), and the total mean power (TMP) are often used to characterize the mobile multiple-input multiple- output (MIMO) channel. This work investigates to which degree these parameters are useful for maximizing the channel capacity...... of MIMO handheld devices used in data mode. A statistical point of view is applied, using about 2,800 outdoor to indoor channel sounder measurements obtained with combinations of 10 different handsets, 4-8 test users and a variety of different use cases (UCs). All measurements were made in an urban...

  5. Real-Valued Covariance Vector Sparsity-Inducing DOA Estimation for Monostatic MIMO Radar.

    Science.gov (United States)

    Wang, Xianpeng; Wang, Wei; Li, Xin; Liu, Jing

    2015-11-10

    In this paper, a real-valued covariance vector sparsity-inducing method for direction of arrival (DOA) estimation is proposed in monostatic multiple-input multiple-output (MIMO) radar. Exploiting the special configuration of monostatic MIMO radar, low-dimensional real-valued received data can be obtained by using the reduced-dimensional transformation and unitary transformation technique. Then, based on the Khatri-Rao product, a real-valued sparse representation framework of the covariance vector is formulated to estimate DOA. Compared to the existing sparsity-inducing DOA estimation methods, the proposed method provides better angle estimation performance and lower computational complexity. Simulation results verify the effectiveness and advantage of the proposed method.

  6. Polarization-interleave-multiplexed discrete multi-tone modulation with direct detection utilizing MIMO equalization.

    Science.gov (United States)

    Zhou, Xian; Zhong, Kangping; Gao, Yuliang; Sui, Qi; Dong, Zhenghua; Yuan, Jinhui; Wang, Liang; Long, Keping; Lau, Alan Pak Tao; Lu, Chao

    2015-04-06

    Discrete multi-tone (DMT) modulation is an attractive modulation format for short-reach applications to achieve the best use of available channel bandwidth and signal noise ratio (SNR). In order to realize polarization-multiplexed DMT modulation with direct detection, we derive an analytical transmission model for dual polarizations with intensity modulation and direct diction (IM-DD) in this paper. Based on the model, we propose a novel polarization-interleave-multiplexed DMT modulation with direct diction (PIM-DMT-DD) transmission system, where the polarization de-multiplexing can be achieved by using a simple multiple-input-multiple-output (MIMO) equalizer and the transmission performance is optimized over two distinct received polarization states to eliminate the singularity issue of MIMO demultiplexing algorithms. The feasibility and effectiveness of the proposed PIM-DMT-DD system are investigated via theoretical analyses and simulation studies.

  7. MIMO Fading Emulator Development with FPGA and Its Application to Performance Evaluation of Mobile Radio Systems

    Directory of Open Access Journals (Sweden)

    Yoshio Karasawa

    2017-01-01

    Full Text Available We present four new developments for a multiple-input multiple-output (MIMO over-the-air measurement system based on our previous studies. The first two developments relate to the channel model for multipath environment generation. One is a further simplification of the circuit configuration without performance degradation by reducing the number of delay generation units, which dominate the performance limit when implementing the circuit on a field-programmable gate array (FPGA. The other is to realize spatial correlation characteristics among the input ports on the transmission side, whereas the previously proposed channel model did not consider this correlation. The third development involves the details of implementing the MIMO fading emulator on an FPGA as a two-stage scheme. The fourth is the demonstration of application examples of the developed system.

  8. Impact of Probe Placement Error on MIMO OTA Test Zone Performance

    DEFF Research Database (Denmark)

    Fan, Wei; Nielsen, Jesper Ødum; Carreño, Xavier

    2012-01-01

    Standardization work for MIMO OTA testing methods is currently ongoing, where a multi-probe anechoic chamber based solution is an important candidate. In this paper, the probes located on an OTA ring are used to synthesize a plane wave field in the center of the OTA ring, and the EM field for each...... probe is obtained using FDTD simulation. This paper investigates the extent to which we can control the field structure inside the test zone where the device under test is located. The focus is on performance deterioration introduced by probe placement error including OTA probe orientation error...... and location mismatch, which are general non-idealities in practical MIMO OTA test systems....

  9. Wideband MIMO Channel Capacity Analysis in Multiprobe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Kyosti, Pekka; Nielsen, Jesper Ødum

    2016-01-01

    This paper discusses over the air (OTA) testing for multiple input multiple output (MIMO) capable terminals with emphasis on wideband MIMO channel capacity analysis in a multi-probe anechoic chamber setup. In the literature, the spatial correlation simulation accuracy at the receiver (Rx) side has...... been used to determine the test area size for a limited number of probes. However, it is desirable that the test area size is defined in terms of data rate deviation of the simulated channel in the laboratory from that of the target channel model. This paper reports MIMO capacity analysis results...

  10. Performance of Spatial Division Multiplexing MIMO with Frequency Domain Packet Scheduling

    DEFF Research Database (Denmark)

    Wei, Na; Pokhariyal, Akhilesh; Sørensen, Troels Bundgaard

    2008-01-01

    This paper addresses the performance of Spatial Division Multiplexing (SDM) Multiple-input Multiple-output (MIMO) techniques together with Frequency Domain Packet Scheduling (FDPS) in both theory and practice. We start with a theoretical analysis under some ideal assumptions to derive the perform......This paper addresses the performance of Spatial Division Multiplexing (SDM) Multiple-input Multiple-output (MIMO) techniques together with Frequency Domain Packet Scheduling (FDPS) in both theory and practice. We start with a theoretical analysis under some ideal assumptions to derive...... the performance bounds of SDM-FDPS. To facilitate the analysis, a unified SINR concept is utilized to make a fair comparison of MIMO schemes with different number of spatial streams. The effect of packet scheduling is included in the post-scheduling SINR distribution using an analytical model. Based on that......, the performance bounds are obtained with a more realistic SINR to throughput mapping metric. The system-level performance of SDM-FDPS has been evaluated under practical constraints using detailed simulations based on the UTRAN Long Term Evolution (LTE) downlink cellular system framework. The purpose...

  11. A novel power and offset allocation method for spatial multiplexing MIMO Systems in optical wireless channels

    KAUST Repository

    Park, Kihong

    2011-12-01

    We consider optical wireless communication which can be utilized for illumination and communication by relying on lighting devices. Due to the limited bandwidth of optical sources, it is challenging to achieve high data rate in optical wireless systems. In order to obtain a multiplexing gain and high spectral efficiency, we design an optical multi-input multi-output (MIMO) system utilizing a singular value decomposition-based spatial multiplexing and adaptive modulation. We note that the conventional allocation method in radio frequency MIMO channels cannot be applied directly to the optical intensity channels. In this paper, we generalize the result of power allocation method in [1] for arbitrary number of transmit and receive antennas in optical wireless MIMO systems. Based on three constraints, namely, the nonnegativity, the aggregate optical power, and the bit error rate requirement, we propose a novel method to allocate the optical power, the offset value, and the modulation size for maximum sum rate. From some selected simulation results, we show that our proposed allocation method gives a better spectral efficiency than the method that allocates the optical power equally for each data stream. © 2011 IEEE.

  12. Efficient Near Maximum-Likelihood Detection for Underdetermined MIMO Antenna Systems Using a Geometrical Approach

    Directory of Open Access Journals (Sweden)

    Arogyaswami Paulraj

    2007-12-01

    Full Text Available Maximum-likelihood (ML detection is guaranteed to yield minimum probability of erroneous detection and is thus of great importance for both multiuser detection and space-time decoding. For multiple-input multiple-output (MIMO antenna systems where the number of receive antennas is at least the number of signals multiplexed in the spatial domain, ML detection can be done efficiently using sphere decoding. Suboptimal detectors are also well known to have reasonable performance at low complexity. It is, nevertheless, much less understood for obtaining good detection at affordable complexity if there are less receive antennas than transmitted signals (i.e., underdetermined MIMO systems. In this paper, our aim is to develop an effcient detection strategy that can achieve near ML performance for underdetermined MIMO systems. Our method is based on the geometrical understanding that the ML point happens to be a point that is “close” to the decoding hyperplane in all directions. The fact that such proximity-close points are much less is used to devise a decoding method that promises to greatly reduce the decoding complexity while achieving near ML performance. An average-case complexity analysis based on Gaussian approximation is also given.

  13. Efficient Near Maximum-Likelihood Detection for Underdetermined MIMO Antenna Systems Using a Geometrical Approach

    Directory of Open Access Journals (Sweden)

    Paulraj Arogyaswami

    2007-01-01

    Full Text Available Maximum-likelihood (ML detection is guaranteed to yield minimum probability of erroneous detection and is thus of great importance for both multiuser detection and space-time decoding. For multiple-input multiple-output (MIMO antenna systems where the number of receive antennas is at least the number of signals multiplexed in the spatial domain, ML detection can be done efficiently using sphere decoding. Suboptimal detectors are also well known to have reasonable performance at low complexity. It is, nevertheless, much less understood for obtaining good detection at affordable complexity if there are less receive antennas than transmitted signals (i.e., underdetermined MIMO systems. In this paper, our aim is to develop an effcient detection strategy that can achieve near ML performance for underdetermined MIMO systems. Our method is based on the geometrical understanding that the ML point happens to be a point that is "close" to the decoding hyperplane in all directions. The fact that such proximity-close points are much less is used to devise a decoding method that promises to greatly reduce the decoding complexity while achieving near ML performance. An average-case complexity analysis based on Gaussian approximation is also given.

  14. Parasitic antenna arrays for wireless MIMO systems

    CERN Document Server

    Kanatas, Athanasios; Papadias, Constantinos

    2014-01-01

    This  book covers a cross-section of two technologies: parasitic antenna arrays driven via analogue circuits; and MIMO technology for multi-antenna arrays.  The combination of these two technologies results in novel functionality. Relevant technical angles, ranging from theoretic to electromagnetic considerations; from analogue circuit to digital baseband control for signal generation; and from channel modeling to communication theoretic aspects are detailed by the contributors. Potential applications are considered in conjunction with current and upcoming wireless standards is provided.

  15. MIMO Communication Using Single Feed Antenna Arrays

    DEFF Research Database (Denmark)

    Alrabadi, Osama

    Multi-input-multi-output (MIMO) communication has emerged as a promis- ing technology for meeting the increasing demand on higher data rates. The technology exploits the spatial resource dimension by sending the datas- treams to different locations in the multi element array (MEA) domain while......, and is best suited for binary phase shift keying (BPSK) signal formats. The idea there is to encode the remaining datastreams to the active antenna index by moving the excitation point using an RF switch. In the second case, reactance-assisted antenna systems are found important for scaling the single...

  16. Sum-Rate Enhancement in Multiuser MIMO Decode-and-Forward Relay Broadcasting Channel with Energy Harvesting Relays

    KAUST Repository

    Benkhelifa, Fatma

    2016-09-20

    In this paper, we consider a multiuser multipleinput multiple-output (MIMO) decode-and-forward (DF) relay broadcasting channel (BC) with single source, multiple energy harvesting (EH) relays and multiple destinations. All the nodes are equipped with multiple antennas. The EH and information decoding (ID) tasks at the relays and destinations are separated over the time, which is termed as the time switching (TS) scheme. As optimal solutions for the sum-rate maximization problems of BC channels and the MIMO interference channels are hard to obtain, the end-to-end sum rate maximization problem of a multiuser MIMO DF relay BC channel is even harder. In this paper, we propose to tackle a simplified problem where we employ the block diagonalization (BD) procedure at the source, and we mitigate the interference between the relaydestination channels using an algorithm similar to the BD method. In order to show the relevance of our low complex proposed solution, we compare it to the minimum mean-square error (MMSE) solution that was shown in the literature to be equivalent to the solution of the sum-rate maximization in MIMO broadcasting interfering channels. We also investigate the time division multiple access (TDMA) solution which separates all the information transmissions from the source to the relays and from the relays to the destinations over time. We provide numerical results to show the relevance of our proposed solution, in comparison with the no co-channel interference (CCI) case, the TDMA based solution and the MMSE based solution.

  17. Cosmic constraint on massive neutrinos in viable f(R) gravity with producing ΛCDM background expansion

    International Nuclear Information System (INIS)

    Lu, Jianbo; Wu, Yabo; Wang, Yan; Yang, Weiqiang; Liu, Molin

    2016-01-01

    Tensions between several cosmic observations were found recently, such as the inconsistent values of H 0 (or σ 8 ) were indicated by the different cosmic observations. Introducing the massive neutrinos in ΛCDM could potentially solve the tensions. Viable f(R) gravity producing ΛCDM background expansion with massive neutrinos is investigated in this paper. We fit the current observational data: Planck-2015 CMB, RSD, BAO, and SNIa to constrain the mass of neutrinos in viable f(R) theory. The constraint results at 95% confidence level are: Σm ν < 0.202 eV for the active-neutrino case, m ν,sterile eff < 0.757 eV with N eff < 3.22 for the sterile neutrino case. For the effects due to the mass of the neutrinos, the constraint results on model parameter at 95% confidence level become f R0 x 10 -6 > -1.89 and f R0 x 10 -6 > -2.02 for two cases, respectively. It is also shown that the fitting values of several parameters much depend on the neutrino properties, such as the cold dark matter density, the cosmological quantities at matter-radiation equality, the neutrino density and the fraction of baryonic mass in helium. Finally, the constraint result shows that the tension between direct and CMB measurements of H 0 gets slightly weaker in the viable f(R) model than that in the base ΛCDM model. (orig.)

  18. Superheated Droplet Detectors as CDM Detectors The SIMPLE Experiment

    CERN Document Server

    Collar, J I; Limagne, D; Waysand, G

    1996-01-01

    Superheated Droplet Detectors (SDDs) are becoming commonplace in neutron personnel dosimetry. Their total insensitivity to minimum ionizing radiation (while responsive to nuclear recoils of energies ~ few keV), together with their low cost, ease of production, and operation at room temperature and 1 atm makes them ideal for Cold Dark Matter (CDM) searches. SDD's are optimal for the exploration of the spin-dependent neutralino coupling due to their high fluorine content. The status of SIMPLE (Superheated Instrument for Massive ParticLe Experiments) is presented. Under realistic background considerations, we expect an improvement in the present Cold Dark Matter sensitivity of 2-3 orders of magnitude after ~1 kg-y of data acquisition.

  19. Magnetized $\\Lambda$CDM inhomogeneities and the cosmic dark ages

    CERN Document Server

    Giovannini, Massimo

    2011-01-01

    Exact solutions of the perturbations equations in the magnetized LambdaCDM scenario are presented. They apply during the dark ages and, more specifically, after the baryons are freed from the drag of the photons. The magnetized growth rate of matter perturbations is compared with the growth index obtained in the concordance paradigm and under the assumption that dark energy does not cluster for a redshift window ranging from the epoch of reionization to the stage of dark-energy dominance. The constraints derived from this analysis are shown to be qualitatively complementary and quantitatively competitive with the bounds stemming from the analysis of the distortion patterns induced by the magnetized adiabatic mode on the temperature and polarization anisotropies of the Cosmic Microwave Background.

  20. Waste management CDM projects barriers NVivo 10® qualitative dataset.

    Science.gov (United States)

    Bufoni, André Luiz; de Sousa Ferreira, Aracéli Cristina; Oliveira, Luciano Basto

    2017-12-01

    This article contains one NVivo 10® file with the complete 432 projects design documents (PDD) of seven waste management sector industries registered as Clean Development Mechanism (CDM) under United Nations Framework Convention on Climate Change (UNFCCC) Kyoto Protocol Initiative from 2004 to 2014. All data analyses and sample statistics made during the research remain in the file. We coded PDDs in 890 fragments of text, classified in five categories of barriers (nodes): technological, financial, human resources, regulatory, socio-political. The data supports the findings of author thesis [1] and other two indexed publication in Waste Management Journal: "The financial attractiveness assessment of large waste management projects registered as clean development mechanism" and "The declared barriers of the large developing countries waste management projects: The STAR model" [2], [3]. The data allows any computer assisted qualitative content analysis (CAQCA) on the sector and it is available at Mendeley [4].

  1. A Novel Metamaterial MIMO Antenna with High Isolation for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Nguyen Khac Kiem

    2015-01-01

    Full Text Available A compact 2×2 metamaterial-MIMO antenna for WLAN applications is presented in this paper. The MIMO antenna is designed by placing side by side two single metamaterial antennas which are constructed based on the modified composite right/left-handed (CRLH model. By adding another left-handed inductor, the total left-handed inductor of the modified CRLH model is increased remarkably in comparison with that of conventional CRLH model. As a result, the proposed metamaterial antenna achieves 60% size reduction in comparison with the unloaded antenna. The MIMO antenna is electrically small (30 mm × 44 mm with an edge-to-edge separation between two antennas of 0.06λ0 at 2.4 GHz. In order to reduce the mutual coupling of the antenna, a defected ground structure (DGS is inserted to suppress the effect of surface current between elements of the proposed antenna. The final design of the MIMO antenna satisfies the return loss requirement of less than −10 dB in a bandwidth ranging from 2.38 GHz to 2.5 GHz, which entirely covers WLAN frequency band allocated from 2.4 GHz to 2.48 GHz. The antenna also shows a high isolation coefficient which is less than −35 dB over the operating frequency band. A good agreement between simulation and measurement is shown in this context.

  2. The implementation of clean development mechanism (CDM) in the construction and built environment industry

    International Nuclear Information System (INIS)

    Mok, Ken L.; Han, Seung H.; Choi, Seokjin

    2014-01-01

    Greenhouse gas emissions due to human activities are the main contributors to global climate change, a problem that should not be ignored. Through the clean development mechanism (CDM) introduced under the Kyoto Protocol, developing countries are able to earn certified emission reduction (CER) credits through a myriad of emission reduction projects. This study aims to explore the potential of implementing CDM projects in the construction and built environment (C and BE) industry, which has been criticized for not only consuming an enormous amount of resources, but also for contributing to adverse environmental health. In this research, we limit the boundary of the C and BE industry to include the planning, procurement, construction, occupation and refurbishment/demolition phases of a project's life cycle. Surveys and in-depth follow-up interviews with experts have generated useful insights pertaining to CDM potential and its adaptation into the C and BE industry. From this foundation, this paper evaluates the current obstacles to CDM and presents feasible suggestions to increase CDM projects related to the C and BE industry. - Highlights: • We review the development and limitation of CDM relates to the construction and built environment (C and BE) industry. • We obtain experts' opinions on the feasibility of CDM in the C and BE industry. • Validation, monitoring, verification and additionality of CDM projects are crucial. • Experts agreed that most of our suggestions are feasible in principle

  3. A data support infrastructure for CDM forestry implementation: an inventory perspective from Cameroon

    NARCIS (Netherlands)

    Minang, Peter A.; McCall, M.K.; Skutsch, Margaret; Verplanke, J.J.

    2007-01-01

    Clean Development Mechanism (CDM) forestry project development requires highly multi-disciplinary and multiple-source information that can be complex, cumbersome and costly to acquire. Yet developing countries in which CDM projects are created and implemented are often data poor environments and

  4. Power Allocation Optimization: Linear Precoding Adapted to NB-LDPC Coded MIMO Transmission

    Directory of Open Access Journals (Sweden)

    Tarek Chehade

    2015-01-01

    Full Text Available In multiple-input multiple-output (MIMO transmission systems, the channel state information (CSI at the transmitter can be used to add linear precoding to the transmitted signals in order to improve the performance and the reliability of the transmission system. This paper investigates how to properly join precoded closed-loop MIMO systems and nonbinary low density parity check (NB-LDPC. The q elements in the Galois field, GF(q, are directly mapped to q transmit symbol vectors. This allows NB-LDPC codes to perfectly fit with a MIMO precoding scheme, unlike binary LDPC codes. The new transmission model is detailed and studied for several linear precoders and various designed LDPC codes. We show that NB-LDPC codes are particularly well suited to be jointly used with precoding schemes based on the maximization of the minimum Euclidean distance (max-dmin criterion. These results are theoretically supported by extrinsic information transfer (EXIT analysis and are confirmed by numerical simulations.

  5. Efficient linear precoding for massive MIMO systems using truncated polynomial expansion

    KAUST Repository

    Müller, Axel

    2014-06-01

    Massive multiple-input multiple-output (MIMO) techniques have been proposed as a solution to satisfy many requirements of next generation cellular systems. One downside of massive MIMO is the increased complexity of computing the precoding, especially since the relatively \\'antenna-efficient\\' regularized zero-forcing (RZF) is preferred to simple maximum ratio transmission. We develop in this paper a new class of precoders for single-cell massive MIMO systems. It is based on truncated polynomial expansion (TPE) and mimics the advantages of RZF, while offering reduced and scalable computational complexity that can be implemented in a convenient parallel fashion. Using random matrix theory we provide a closed-form expression of the signal-to-interference-and-noise ratio under TPE precoding and compare it to previous works on RZF. Furthermore, the sum rate maximizing polynomial coefficients in TPE precoding are calculated. By simulation, we find that to maintain a fixed peruser rate loss as compared to RZF, the polynomial degree does not need to scale with the system, but it should be increased with the quality of the channel knowledge and signal-to-noise ratio. © 2014 IEEE.

  6. Optimal Multiuser Diversity in Multi-Cell MIMO Uplink Networks: User Scaling Law and Beamforming Design

    Directory of Open Access Journals (Sweden)

    Bang Chul Jung

    2017-07-01

    Full Text Available We introduce a distributed protocol to achieve multiuser diversity in a multicell multiple-input multiple-output (MIMO uplink network, referred to as a MIMO interfering multiple-access channel (IMAC. Assuming both no information exchange among base stations (BS and local channel state information at the transmitters for the MIMO IMAC, we propose a joint beamforming and user scheduling protocol, and then show that the proposed protocol can achieve the optimal multiuser diversity gain, i.e., KMlog(SNRlog N, as long as the number of mobile stations (MSs in a cell, N, scales faster than SNR K M − L 1 − ϵ for a small constant ϵ > 0, where M, L, K, and SNR denote the number of receive antennas at each BS, the number of transmit antennas at each MS, the number of cells, and the signal-to-noise ratio, respectively. Our result indicates that multiuser diversity can be achieved in the presence of intra-cell and inter-cell interference even in a distributed fashion. As a result, vital information on how to design distributed algorithms in interference-limited cellular environments is provided.

  7. A switched-beam millimeter-wave array with MIMO configuration for 5G applications

    KAUST Repository

    Ikram, Muhammad

    2018-03-08

    In this work, a switched-beam 2-element multiple-input multiple-output (MIMO) antenna system is proposed at mm-wave bands for 5G applications. The antenna system consists of a 4 × 4 connected slot antennas for each MIMO element forming the connected antenna array (CAA). A feed network based on a Butler matrix is used to excite the CAA, in addition to steer the beam at different locations which enhance the diversity performances. The mm-wave MIMO antenna system operates at 28 GHz with at least −10 dB measured bandwidth of 830 MHz (27.4 GHZ–28.23 GHz). It is fabricated on a commercially available RO3003 substrate with dielectric constant of 3.3 and height of 0.13 mm, respectively. The dimensions of the board are equal to 150 mm3 × 100 mm3 × 0.13 mm3. The proposed design is compact, low profile, and suitable for future 5G-enabled tablet PCs.

  8. On the Performance Evaluation of a MIMO-WCDMA Transmission Architecture for Building Management Systems.

    Science.gov (United States)

    Tsampasis, Eleftherios; Gkonis, Panagiotis K; Trakadas, Panagiotis; Zahariadis, Theodοre

    2018-01-08

    The goal of this study was to investigate the performance of a realistic wireless sensor nodes deployment in order to support modern building management systems (BMSs). A three-floor building orientation is taken into account, where each node is equipped with a multi-antenna system while a central base station (BS) collects and processes all received information. The BS is also equipped with multiple antennas; hence, a multiple input-multiple output (MIMO) system is formulated. Due to the multiple reflections during transmission in the inner of the building, a wideband code division multiple access (WCDMA) physical layer protocol has been considered, which has already been adopted for third-generation (3G) mobile networks. Results are presented for various MIMO orientations, where the mean transmission power per node is considered as an output metric for a specific signal-to-noise ratio (SNR) requirement and number of resolvable multipath components. In the first set of presented results, the effects of multiple access interference on overall transmission power are highlighted. As the number of mobile nodes per floor or the requested transmission rate increases, MIMO systems of a higher order should be deployed in order to maintain transmission power at adequate levels. In the second set of results, a comparison is performed among transmission in diversity combining and spatial multiplexing mode, which clearly indicate that the first case is the most appropriate solution for indoor communications.

  9. MIMO Channel Model with Propagation Mechanism and the Properties of Correlation and Eigenvalue in Mobile Environments

    Directory of Open Access Journals (Sweden)

    Yuuki Kanemiyo

    2012-01-01

    Full Text Available This paper described a spatial correlation and eigenvalue in a multiple-input multiple-output (MIMO channel. A MIMO channel model with a multipath propagation mechanism was proposed and showed the channel matrix. The spatial correlation coefficient formula −,′−′( between MIMO channel matrix elements was derived for the model and was expressed as a directive wave term added to the product of mobile site correlation −′( and base site correlation −′( without LOS path, which are calculated independently of each other. By using −,′−′(, it is possible to create the channel matrix element with a fixed correlation value estimated by −,′−′( for a given multipath condition and a given antenna configuration. Furthermore, the correlation and the channel matrix eigenvalue were simulated, and the simulated and theoretical correlation values agreed well. The simulated eigenvalue showed that the average of the first eigenvalue λ1 hardly depends on the correlation −,′−′(, but the others do depend on −,′−′( and approach 1 as −,′−′( decreases. Moreover, as the path moves into LOS, the 1 state with mobile movement becomes more stable than the 1 of NLOS path.

  10. A study on the achievable data rate in massive MIMO system

    Science.gov (United States)

    Salh, Adeeb; Audah, Lukman; Shah, Nor Shahida M.; Hamzah, Shipun A.

    2017-09-01

    The achievable high data rates depend on the ability of massive multi-input-multi-output (MIMO) for the fifth-generation (5G) cellular networks, where the massive MIMO systems can support very high energy and spectral efficiencies. A major challenge in mobile broadband networks is how to support the throughput in the future 5G, where the highlight of 5G expected to provide high speed internet for every user. The performance massive MIMO system increase with linear minimum mean square error (MMSE), zero forcing (ZF) and maximum ratio transmission (MRT) when the number of antennas increases to infinity, by deriving the closed-form approximation for achievable data rate expressions. Meanwhile, the high signal-to-noise ratio (SNR) can be mitigated by using MMSE, ZF and MRT, which are used to suppress the inter-cell interference signals between neighboring cells. The achievable sum rate for MMSE is improved based on the distributed users inside cell, mitigated the inter-cell interference caused when send the same signal by other cells. By contrast, MMSE is better than ZF in perfect channel state information (CSI) for approximately 20% of the achievable sum rate.

  11. Spatial-Temporal Correlation Properties of the 3GPP Spatial Channel Model and the Kronecker MIMO Channel Model

    Directory of Open Access Journals (Sweden)

    Cheng-Xiang Wang

    2007-02-01

    Full Text Available The performance of multiple-input multiple-output (MIMO systems is greatly influenced by the spatial-temporal correlation properties of the underlying MIMO channels. This paper investigates the spatial-temporal correlation characteristics of the spatial channel model (SCM in the Third Generation Partnership Project (3GPP and the Kronecker-based stochastic model (KBSM at three levels, namely, the cluster level, link level, and system level. The KBSM has both the spatial separability and spatial-temporal separability at all the three levels. The spatial-temporal separability is observed for the SCM only at the system level, but not at the cluster and link levels. The SCM shows the spatial separability at the link and system levels, but not at the cluster level since its spatial correlation is related to the joint distribution of the angle of arrival (AoA and angle of departure (AoD. The KBSM with the Gaussian-shaped power azimuth spectrum (PAS is found to fit best the 3GPP SCM in terms of the spatial correlations. Despite its simplicity and analytical tractability, the KBSM is restricted to model only the average spatial-temporal behavior of MIMO channels. The SCM provides more insights of the variations of different MIMO channel realizations, but the implementation complexity is relatively high.

  12. A Robust Pre-Filter and Power Loading Design for Time Reversal UWB Systems over Time-Correlated MIMO Channels

    Directory of Open Access Journals (Sweden)

    Sajjad Alizadeh

    2014-04-01

    Full Text Available Conventional Time Reversal (TR technique suffers from performance degradation in time varying Multiple-Input Multiple-Output Ultra-Wideband (MIMO-UWB systems due to outdating Channel State Information (CSI over time progressions. That is, the outdated CSI degrades the TR performance significantly in time varying channels. The correlation property of time correlated channels can improve the TR performance against other traditional TR designs. Based on this property, at first, we propose a robust TR-MIMO-UWB system design for a time-varying channel in which the CSI is updated only at the beginning of each block of data where the CSI is assumed to be known. As the channel varies over time, pre-processor blindly pre-equalizes the channel during the next symbol time by using the correlation property. Then, a novel recursive power allocation strategy is derived over time-correlated time-varying TR-MIMO-UWB channels. We show that the proposed power loading technique, considerably improves the BER performance of TR-MIMO-UWB system in imperfect CSI with robust pre-filter. The proposed algorithms lead to a cost-efficient CSI updating procedure for the TR optimization. Simulation results are provided to confirm the new design performance against traditional method.

  13. Performance of Overlaid MIMO Cellular Networks with TAS/MRC under Hybrid-Access Small Cells and Poisson Field Interference

    KAUST Repository

    AbdelNabi, Amr A.

    2018-02-12

    This paper presents new approaches to characterize the achieved performance of hybrid control-access small cells in the context of two-tier multi-input multi-output (MIMO) cellular networks with random interference distributions. The hybrid scheme at small cells (such as femtocells) allows for sharing radio resources between the two network tiers according to the densities of small cells and their associated users, as well as the observed interference power levels in the two network tiers. The analysis considers MIMO transceivers at all nodes, for which antenna arrays can be utilized to implement transmit antenna selection (TAS) and receive maximal ratio combining (MRC) under MIMO point-to-point channels. Moreover, it tar-gets network-level models of interference sources inside each tier and between the two tiers, which are assumed to follow Poisson field processes. To fully capture the occasions for Poisson field distribution on MIMO spatial domain. Two practical scenarios of interference sources are addressed including highly-correlated or uncorrelated transmit antenna arrays of the serving macrocell base station. The analysis presents new analytical approaches that can characterize the downlink outage probability performance in any tier. Furthermore, the outage performance in high signal-to-noise (SNR) regime is also obtained, which can be useful to deduce diversity and/or coding gains.

  14. EU-MENA energy technology transfer under the CDM: Israel as a frontrunner?

    International Nuclear Information System (INIS)

    Karakosta, Charikleia; Doukas, Haris; John, Psarras

    2010-01-01

    The majority of the Middle East and North Africa (MENA) countries possess substantial potential for the implementation of CDM projects. Abatement of Greenhouse Gas (GHG) emissions can mainly be achieved through utilizing the abundant Renewable Energy Sources (RES) in the region and the implementation of Energy Efficiency (ENEF) measures. However, most of the MENA countries have a limited track record as regards CDM projects in the pipeline comparing to the major CDM-players, like Asia-Pacific regions and Latin America. In the above framework, this paper investigates the current status of CDM in the MENA region and the related perspectives for further diffusion of the CDM though the elaboration of a Strengths-Weaknesses-Opportunities and Threats (SWOT) Analysis. Particular emphasis is laid on the case of Israel, which seems to make an exception to the rule, since it hosts most projects in the region and dominates among the MENA countries.

  15. A 2-order MIMO Full-Duplex Antenna System

    DEFF Research Database (Denmark)

    Tsakalaki, Elpiniki; Foroozanfard, Ehsan; De Carvalho, Elisabeth

    2014-01-01

    The paper presents an antenna system with combined full-duplex and 2-order multiple-input-multiple-output (MIMO) functionalities, i.e., a system capable of spatially multiplexing and spatially demultiplexing 2 datastreams in the same frequency and in the same time. By exploiting symmetries....... On the other hand, the 2 MIMO ports (either at the Tx or at the Rx) are sufficiently decoupled thanks to polarization diversity. The proposed antenna system exhibits a remarkable level of fullduplex isolation over a wide bandwidth while maintaining low coupling between its MIMO ports and can serve...... as a concrete implementation of an antenna system equipped with both MIMO as well as full-duplex capabilities....

  16. Low Complexity Receiver Design for MIMO-Radar

    KAUST Repository

    Ahmed, Sajid

    2012-09-08

    In this work, an algorithm for the multiple-input multiple-output (MIMO) radar is proposed. It has low computational complexity compared to the available schemes, and relatively low side-lobe-levels in the receive beampattern compared to the phased-array and MIMO-radar. In the proposed algorithm, the received signal vector of MIMO-radar is divided into sub-vectors, and each sub-vector is multiplied with the corresponding weight vector. The number of sub-vectors and weight vectors are optimally found to maximise the received signal power from the target of interest direction. The proposed scheme can be effectively applied in passive radars to minimise the side-lobe levels and place deep nulls for interferers in the receive beampattern. Simulation results show that the proposed scheme has relatively lower side lobe levels and better detection capabilities compared to MIMO-radar and phased-array.

  17. MIMO Technologies in 3GPP LTE and LTE-Advanced

    Directory of Open Access Journals (Sweden)

    Zhang Jianzhong(Charlie

    2009-01-01

    Full Text Available Abstract 3rd Generation Partnership Project (3GPP has recently completed the specification of the Long Term Evolution (LTE standard. Majority of the world's operators and vendors are already committed to LTE deployments and developments, making LTE the market leader in the upcoming evolution to 4G wireless communication systems. Multiple input multiple output (MIMO technologies introduced in LTE such as spatial multiplexing, transmit diversity, and beamforming are key components for providing higher peak rate at a better system efficiency, which are essential for supporting future broadband data service over wireless links. Further extension of LTE MIMO technologies is being studied under the 3GPP study item "LTE-Advanced" to meet the requirement of IMT-Advanced set by International Telecommunication Union Radiocommunication Sector (ITU-R. In this paper, we introduce various MIMO technologies employed in LTE and provide a brief overview on the MIMO technologies currently discussed in the LTE-Advanced forum.

  18. The ATLAS(3D) project : VIII. Modelling the formation and evolution of fast and slow rotator early-type galaxies within lambda CDM

    NARCIS (Netherlands)

    Khochfar, Sadegh; Emsellem, Eric; Serra, Paolo; Bois, Maxime; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bournaud, Frederic; Bureau, M.; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Krajnovic, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-01-01

    We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical Lambda cold dark matter (Lambda CDM) scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed

  19. The ATLAS3D project - VIII. Modelling the formation and evolution of fast and slow rotator early-type galaxies within ΛCDM

    NARCIS (Netherlands)

    Khochfar, Sadegh; Emsellem, Eric; Serra, Paolo; Bois, Maxime; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bournaud, Frédéric; Bureau, M.; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-01-01

    We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical Λcold dark matter (ΛCDM) scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed via λR. Within

  20. Over the Air Testing of MIMO Capable Terminals

    DEFF Research Database (Denmark)

    Fan, Wei

    This thesis focuses on multi-probe anechoic chamber testing, which is a promising over the air (OTA) testing method to evaluate multiple-input multiple-output (MIMO) capable terminals. With MIMO technology being adopted by new wireless technologies, mobile manufacturers and cellular operators nee...... selection method and a flexible probe configuration concept are proposed. Experimental verifications of the proposed algorithms and measurement uncertainties in practical setups are investigated and results are included in the thesis....

  1. The EU emissions trading scheme (ETS). How linked to JI/CDM?

    International Nuclear Information System (INIS)

    Jepma, C.J.

    2003-01-01

    The paper first argues that the Directive for EU-wide greenhouse gas emission trading still carries a number of weaknesses, such as: still no clear link with other climate policies in the Member States; the subsidiarity with regard to the allocation of allowances may distort intra-EU competition; and lack of clarity as to what the (future) scope and coverage of the scheme may look like. Then, it is argued that not convincingly linking the scheme to the flexibility instruments of the Kyoto Protocol, JI (Joint Implementation) and CDM (Clean Development Mechanism), or establishing such a link only later or based on some supplementarity rule, not only carries a number of risks, but may also be circumvented by the Member States using their freedom with regard to their national climate policy design

  2. Interference Cancellation Using Replica Signal for HTRCI-MIMO/OFDM in Time-Variant Large Delay Spread Longer Than Guard Interval

    Directory of Open Access Journals (Sweden)

    Yuta Ida

    2012-01-01

    Full Text Available Orthogonal frequency division multiplexing (OFDM and multiple-input multiple-output (MIMO are generally known as the effective techniques for high data rate services. In MIMO/OFDM systems, the channel estimation (CE is very important to obtain an accurate channel state information (CSI. However, since the orthogonal pilot-based CE requires the large number of pilot symbols, the total transmission rate is degraded. To mitigate this problem, a high time resolution carrier interferometry (HTRCI for MIMO/OFDM has been proposed. In wireless communication systems, if the maximum delay spread is longer than the guard interval (GI, the system performance is significantly degraded due to the intersymbol interference (ISI and intercarrier interference (ICI. However, the conventional HTRCI-MIMO/OFDM does not consider the case with the time-variant large delay spread longer than the GI. In this paper, we propose the ISI and ICI compensation methods for a HTRCI-MIMO/OFDM in the time-variant large delay spread longer than the GI.

  3. New Arenas of Engagement at the Water Governance-Climate Finance Nexus? An Analysis of the Boom and Bust of Hydropower CDM Projects in Vietnam

    Directory of Open Access Journals (Sweden)

    Mattijs Smits

    2014-10-01

    Full Text Available This article explores whether new arenas of engagement for water governance have been created and utilised following the implementation of the Clean Development Mechanism (CDM in large hydropower projects in Vietnam. Initial optimism for climate finance – in particular amongst Northern aid providers and private CDM consultants – resulted in a boom in registration of CDM hydropower projects in Vietnam. These plans, however, have since then busted. The article utilises a multi-scale and multi-place network governance analysis of the water governance-climate finance nexus, based on interviews with government officials, consultants, developers, NGOs, multilateral and international banks, and project-affected people at the Song Bung 2 and Song Bung 4 hydropower projects in Central Vietnam. Particular attention is paid to how the place-based nature of organisations shapes the ability of these actors to participate in decision-making. The article concludes that the CDM has had little impact on water governance in Vietnam at the project level in terms of carbon reduction (additionality or attaining sustainable development objectives. Furthermore, whilst climate finance has the potential to open new, more transparent and more accountable arenas of water governance, current arenas of the water governance-climate finance nexus are 'rendered technical', and therefore often underutilised and inaccessible to civil society and project-affected people.

  4. Channel Models for Capacity Evaluation of MIMO Handsets in Data Mode

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Yanakiev, Boyan; Barrio, Samantha Caporal Del

    2017-01-01

    This work investigates different correlation based models useful for evaluation of outage capacity (OC) of mobile multiple-input multiple-output (MIMO) handsets. The work is based on a large measurement campaign in a micro-cellular setup involving two dual-band base stations, 10 different handsets...... in an indoor environment for different use cases and test users. Several models are evaluated statistically, comparing the OC values estimated from the model and measurement data, respectively, for about 2,700 measurement routes. The models are based on either estimates of the full correlation matrices...

  5. The correlated factors of the uneven performances of the CDM host countries

    Science.gov (United States)

    Zhu, Jinshan

    2012-03-01

    The Kyoto Protocol’s Clean Development Mechanism (CDM) has experienced a rapid growth. Up to 2010, 2763 projects have been registered, standing for about 433 million ton CO2 equivalent (CO2-eq.) of annual carbon credits. However, the performances of CDM host countries are remarkably unbalanced. Previous literature suggested that economic and investment conditions, energy intensity, energy structure, the share of annual carbon credits from high global warming potential (GWP) green house gas (GHG), capacity and institutional buildings of domestic CDM governance can play important roles in promoting CDM. This quantitative analysis shows that domestic economic and investment conditions are the most decisive factors determining the performance of the CDM host countries. Additionally, the influence of carbon intensity of energy consumption is relatively modest, and energy intensity of GDP as well as the share of annual carbon credits from high GWP GHG is less significant. Moreover, several leading CDM countries are not as successful as they seem to be, when the influences of their vast territories, distinguished economic and investment conditions are excluded. Therefore, to simply transplant the CDM governances of these countries can hardly guarantee that other countries will boost their carbon credit outputs.

  6. Array Configuration and Channel Model of MIMO Sensor for Home Security

    OpenAIRE

    Yamada, Hiroyoshi; Tanaka, Kei; Yamaguchi, Yoshio

    2011-01-01

    This report discusses MIMO system as home security sensor. MIMO propagation channel is very sensitive to the environmental change. The proposed radio sensor called MIMO sensor utilizes this feature to detect events for home security. We report fundamental results for evaluation of array configuration and propagation channel.

  7. Distributed User Selection in Network MIMO Systems with Limited Feedback

    KAUST Repository

    Elkhalil, Khalil

    2015-09-06

    We propose a distributed user selection strategy in a network MIMO setting with M base stations serving K users. Each base station is equipped with L antennas, where LM ≪ K. The conventional selection strategy is based on a well known technique called semi-orthogonal user selection when the zero-forcing beamforming (ZFBF) is adopted. Such technique, however, requires perfect channel state information at the transmitter (CSIT), which might not be available or need large feedback overhead. This paper proposes an alternative distributed user selection technique where each user sets a timer that is inversely proportional to his channel quality indicator (CQI), as a means to reduce the feedback overhead. The proposed strategy allows only the user with the highest CQI to respond with a feedback. Such technique, however, remains collision free only if the transmission time is shorter than the difference between the strongest user timer and the second strongest user timer. To overcome the situation of longer transmission times, the paper proposes another feedback strategy that is based on the theory of compressive sensing, where collision is allowed and all users encode their feedback information and send it back to the base-stations simultaneously. The paper shows that the problem can be formulated as a block sparse recovery problem which is agnostic on the transmission time, which makes it a good alternative to the timer approach when collision is dominant.

  8. MIMO Four-Way Relaying

    DEFF Research Database (Denmark)

    Liu, Huaping; Sun, Fan; De Carvalho, Elisabeth

    2013-01-01

    the sum-rate of the new scheme for Decode-and-Forward (DF) operational model for the RS. We compare the performance with state-of-the-art reference schemes, based on two-way relaying with DF. The results indicate that the sum-rate of the two-phase four-way relaying scheme largely outperforms the four...

  9. SmartMIMO: An Energy-Aware Adaptive MIMO-OFDM Radio Link Control for Next-Generation Wireless Local Area Networks

    Directory of Open Access Journals (Sweden)

    Dehaene Wim

    2007-01-01

    Full Text Available Multiantenna systems and more particularly those operating on multiple input and multiple output (MIMO channels are currently a must to improve wireless links spectrum efficiency and/or robustness. There exists a fundamental tradeoff between potential spectrum efficiency and robustness increase. However, multiantenna techniques also come with an overhead in silicon implementation area and power consumption due, at least, to the duplication of part of the transmitter and receiver radio front-ends. Although the area overhead may be acceptable in view of the performance improvement, low power consumption must be preserved for integration in nomadic devices. In this case, it is the tradeoff between performance (e.g., the net throughput on top of the medium access control layer and average power consumption that really matters. It has been shown that adaptive schemes were mandatory to avoid that multiantenna techniques hamper this system tradeoff. In this paper, we derive smartMIMO: an adaptive multiantenna approach which, next to simply adapting the modulation and code rate as traditionally considered, decides packet-per-packet, depending on the MIMO channel state, to use either space-division multiplexing (increasing spectrum efficiency, space-time coding (increasing robustness, or to stick to single-antenna transmission. Contrarily to many of such adaptive schemes, the focus is set on using multiantenna transmission to improve the link energy efficiency in real operation conditions. Based on a model calibrated on an existing reconfigurable multiantenna transceiver setup, the link energy efficiency with the proposed scheme is shown to be improved by up to 30% when compared to nonadaptive schemes. The average throughput is, on the other hand, improved by up to 50% when compared to single-antenna transmission.

  10. SmartMIMO: An Energy-Aware Adaptive MIMO-OFDM Radio Link Control for Next-Generation Wireless Local Area Networks

    Directory of Open Access Journals (Sweden)

    Wim Dehaene

    2007-12-01

    Full Text Available Multiantenna systems and more particularly those operating on multiple input and multiple output (MIMO channels are currently a must to improve wireless links spectrum efficiency and/or robustness. There exists a fundamental tradeoff between potential spectrum efficiency and robustness increase. However, multiantenna techniques also come with an overhead in silicon implementation area and power consumption due, at least, to the duplication of part of the transmitter and receiver radio front-ends. Although the area overhead may be acceptable in view of the performance improvement, low power consumption must be preserved for integration in nomadic devices. In this case, it is the tradeoff between performance (e.g., the net throughput on top of the medium access control layer and average power consumption that really matters. It has been shown that adaptive schemes were mandatory to avoid that multiantenna techniques hamper this system tradeoff. In this paper, we derive smartMIMO: an adaptive multiantenna approach which, next to simply adapting the modulation and code rate as traditionally considered, decides packet-per-packet, depending on the MIMO channel state, to use either space-division multiplexing (increasing spectrum efficiency, space-time coding (increasing robustness, or to stick to single-antenna transmission. Contrarily to many of such adaptive schemes, the focus is set on using multiantenna transmission to improve the link energy efficiency in real operation conditions. Based on a model calibrated on an existing reconfigurable multiantenna transceiver setup, the link energy efficiency with the proposed scheme is shown to be improved by up to 30% when compared to nonadaptive schemes. The average throughput is, on the other hand, improved by up to 50% when compared to single-antenna transmission.

  11. Covariance Matrix Estimation for Massive MIMO

    Science.gov (United States)

    Upadhya, Karthik; Vorobyov, Sergiy A.

    2018-04-01

    We propose a novel pilot structure for covariance matrix estimation in massive multiple-input multiple-output (MIMO) systems in which each user transmits two pilot sequences, with the second pilot sequence multiplied by a random phase-shift. The covariance matrix of a particular user is obtained by computing the sample cross-correlation of the channel estimates obtained from the two pilot sequences. This approach relaxes the requirement that all the users transmit their uplink pilots over the same set of symbols. We derive expressions for the achievable rate and the mean-squared error of the covariance matrix estimate when the proposed method is used with staggered pilots. The performance of the proposed method is compared with existing methods through simulations.

  12. The gold standard: linking the CDM to development and poverty reduction

    Energy Technology Data Exchange (ETDEWEB)

    Schlup, M. [Hamburg Inst. of International Economics (HWWA), Hamburg (Germany)

    2005-07-01

    This paper introduces to the objectives, methodologies and procedures of the gold standard, a tool to generate high-quality emission reduction projects with a strong development component. It is discussed how this tool can be used to create sound synergies between climate policy, private sector and non-ODA government involvement in the CDM and development and poverty alleviation objectives. Recommendations are given to direct more CDM investments towards sustainable and additional projects. It is concluded that renewable energy and energy efficiency projects need to become more dominant under the current CDM regime and that both developing as well as industrialised country actors have different but common responsibilities to achieve this. (orig.)

  13. Fiscal 1998 research report. Research on the possibility of promoting CDM project through technology transfer with plant exports; 1998 nendo chosa hokokusho. Plant yushutsugata gijutsu iten wo tsujita CDM project suishin kanosei ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Study was made on promotion of CDM (clean development mechanism) project through technology transfer with plant exports. Although CDM system was provided in COP3 on climate change held in Kyoto in 1997, its detailed rules including project approval are yet undecided, and only the schedule to provide the detailed rules until COP6 in 2000 was decided in COP4 in 1998. The common recognition that the CDM project with plant exports produces various merits for both Japan and the partner country is increasing. However, from the viewpoint of forming concrete CDM projects, most Japanese enterprises are passive in approach to the CDM project because of no detailed design of CDM, uncertain profitability and procedures, and avoidance of additional burdens. Plant export is also difficult because of the fact that assessment of a new project is difficult. Enterprises' deeper recognition on the CDM project, and a governmental integrated support system are desirable. (NEDO)

  14. Bidirectional Fano Algorithm for Lattice Coded MIMO Channels

    KAUST Repository

    Al-Quwaiee, Hessa

    2013-05-08

    Recently, lattices - a mathematical representation of infinite discrete points in the Euclidean space, have become an effective way to describe and analyze communication systems especially system those that can be modeled as linear Gaussian vector channel model. Channel codes based on lattices are preferred due to three facts: lattice codes have simple structure, the code can achieve the limits of the channel, and they can be decoded efficiently using lattice decoders which can be considered as the Closest Lattice Point Search (CLPS). Since the time lattice codes were introduced to Multiple Input Multiple Output (MIMO) channel, Sphere Decoder (SD) has been an efficient way to implement lattice decoders. Sphere decoder offers the optimal performance at the expense of high decoding complexity especially for low signal-to-noise ratios (SNR) and for high- dimensional systems. On the other hand, linear and non-linear receivers, Minimum Mean Square Error (MMSE), and MMSE Decision-Feedback Equalization (DFE), provide the lowest decoding complexity but unfortunately with poor performance. Several studies works have been conducted in the last years to address the problem of designing low complexity decoders for the MIMO channel that can achieve near optimal performance. It was found that sequential decoders using backward tree 
search can bridge the gap between SD and MMSE. The sequential decoder provides an interesting performance-complexity trade-off using a bias term. Yet, the sequential decoder still suffers from high complexity for mid-to-high SNR values. In this work, we propose a new algorithm for Bidirectional Fano sequential Decoder (BFD) in order to reduce the mid-to-high SNR complexity. Our algorithm consists of first constructing a unidirectional Sequential Decoder based on forward search using the QL decomposition. After that, BFD incorporates two searches, forward and backward, to work simultaneously till they merge and find the closest lattice point to the

  15. Novel Adaptive Forward Neural MIMO NARX Model for the Identification of Industrial 3-DOF Robot Arm Kinematics

    OpenAIRE

    Ho Pham Huy Anh; Nguyen Thanh Nam

    2012-01-01

    In this paper, a novel forward adaptive neural MIMO NARX model is used for modelling and identifying the forward kinematics of an industrial 3‐DOF robot arm system. The nonlinear features of the forward kinematics of the industrial robot arm drive are thoroughly modelled based on the forward adaptive neural NARX model‐based identification process using experimental input‐output training data. This paper proposes a novel use of a back propagation (BP) algorithm to generate the forward neural M...

  16. Optimizing the wireless power transfer over MIMO Channels

    Directory of Open Access Journals (Sweden)

    K. Wiedmann

    2017-09-01

    Full Text Available In this paper, the optimization of the power transfer over wireless channels having multiple-inputs and multiple-outputs (MIMO is studied. Therefore, the transmitter, the receiver and the MIMO channel are modeled as multiports. The power transfer efficiency is described by a Rayleigh quotient, which is a function of the channel's scattering parameters and the incident waves from both transmitter and receiver side. This way, the power transfer efficiency can be maximized analytically by solving a generalized eigenvalue problem, which is deduced from the Rayleigh quotient. As a result, the maximum power transfer efficiency achievable over a given MIMO channel is obtained. This maximum can be used as a performance bound in order to benchmark wireless power transfer systems. Furthermore, the optimal operating point which achieves this maximum will be obtained. The optimal operating point will be described by the complex amplitudes of the optimal incident and reflected waves of the MIMO channel. This supports the design of the optimal transmitter and receiver multiports. The proposed method applies for arbitrary MIMO channels, taking transmitter-side and/or receiver-side cross-couplings in both near- and farfield scenarios into consideration. Special cases are briefly discussed in this paper in order to illustrate the method.

  17. Financing Structures for CDM Projects in India and Capacity Building Options for EU-Indo Collaboration

    OpenAIRE

    Krey, Matthias; Michaelowa, Axel; Deodhar, Vinay

    2003-01-01

    The Clean Development Mechanism (CDM) under the Kyoto Protocol to the UN Framework Convention on Climate Change (UNFCCC) enables industrialized countries to meet a part of their emission reduction requirements through purchase of emission reduction credits from projects in developing countries. Various studies have concluded that India is likely to be one of the major countries supplying such projects. However, in order that a large number of high-quality CDM projects is developed and result ...

  18. CDM criticisms: don't throw the baby out with the bathwater

    Energy Technology Data Exchange (ETDEWEB)

    Buen, Joerund

    2012-07-01

    CDM has delivered greater offset volumes than anticipated, mainly with money from the private sector in host countries (underlying project investment) and investor countries (carbon offset purchasing) and has built considerable institutional capacity. Criticisms have focused on high transaction costs and lack of scalability; additionality challenges and lack of net mitigation impact; preventing more ambitious targets and changes in emissions paths in developed and developing countries alike; excessive rents and perverse incentives; unbalanced regional distribution; low local sustainable development benefits; corruption and lack of transparency; and lack of technology transfer. While some of these criticisms are justified, others are outdated. Transaction costs have been drastically reduced. Excessive rents and perverse incentives in the CDM will be substantially reduced post-2012. Unbalanced regional distribution will be reduced by new rules; moreover, this is probably less of a problem than commonly thought. Some criticisms are erroneously founded. There is no evidence of CDM preventing more ambitious targets in developing countries while it could prevent changes in emissions paths in developed countries. Few CDM projects have serious known problems as regards sustainable development. Corruption and fraud seem limited; and technology transfer has never been a core CDM concern. Ironically, critics often neglect the elements that need to be improved. To ensure additionality, CDM rules must be tightened to exclude common practice projects and prevent host countries from changing their policies to cater for CDM projects. CDM's scalability and additionality challenges could be substantially reduced by discounting emission reductions. There could still be some non-additional projects, but the volume of the overall portfolio of projects would be additional.(Author)

  19. The First Generation of Stars in Lambda-CDM Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Liang; /Durham U. /Garching, Max Planck Inst.; Abel, T.; /KIPAC, Menlo Park; Frenk, C.S.; Jenkins, A.; /Durham U.; Springel, V.; /Garching, Max Planck Inst.; Yoshida,; /Nagoya U.

    2006-10-10

    We have performed a large set of high-resolution cosmological simulations using smoothed particle hydrodynamics (SPH) to study the formation of the first luminous objects in the {Lambda}CDM cosmology. We follow the collapse of primordial gas clouds in eight early structures and document the scatter in the properties of the first star-forming clouds. Our first objects span formation redshifts from z {approx} 10 to z {approx} 50 and cover an order of magnitude in halo mass. We find that the physical properties of the central star-forming clouds are very similar in all of the simulated objects despite significant differences in formation redshift and environment. This suggests that the formation path of the first stars is largely independent of the collapse redshift; the physical properties of the clouds have little correlation with spin, mass, or assembly history of the host halo. The collapse of proto-stellar objects at higher redshifts progresses much more rapidly due to the higher densities, which accelerates the formation of molecular hydrogen, enhances initial cooling and shortens the dynamical timescales. The mass of the star-forming clouds cover a broad range, from a few hundred to a few thousand solar masses, and exhibit various morphologies: some have disk-like structures which are nearly rotational supported; others form flattened spheroids; still others form bars. All of them develop a single protostellar ''seed'' which does not fragment into multiple objects up to the moment that the central gas becomes optically thick to H{sub 2} cooling lines. At this time, the instantaneous mass accretion rate onto the centre varies significantly from object to object, with disk-like structures having the smallest mass accretion rates. The formation epoch and properties of the star-forming clouds are sensitive to the values of cosmological parameters.

  20. Energy-Efficient Power Allocation for MIMO-SVD Systems

    KAUST Repository

    Sboui, Lokman

    2017-05-24

    In this paper, we address the problem of energyefficient power allocation in MIMO systems. In fact, the widely adopted water-filling power allocation does not ensure the maximization of the energy efficiency (EE). Since the EE maximization is a non-convex problem, numerical methods based on fractional programming were introduced to find the optimal power solutions. In this paper, we present a novel and simple power allocation scheme based on the explicit expressions of the optimal power. We also present a low-complexity algorithm that complements the proposed scheme for low circuit-power regime. Furthermore, we analyze power-constrained and rate-constrained systems and present the corresponding optimal power control. In the numerical results, we show that the presented analytical expressions are accurate and that the algorithm converges within two iterations. We also show that as the number of antenna increases, the system becomes more energy-efficient. Also, a saturation of the EE is observed at high power budget and low minimal rate regimes.

  1. Power efficient low complexity precoding for massive MIMO systems

    KAUST Repository

    Sifaou, Houssem

    2014-12-01

    This work aims at designing a low-complexity precoding technique in the downlink of a large-scale multiple-input multiple-output (MIMO) system in which the base station (BS) is equipped with M antennas to serve K single-antenna user equipments. This is motivated by the high computational complexity required by the widely used zero-forcing or regularized zero-forcing precoding techniques, especially when K grows large. To reduce the computational burden, we adopt a precoding technique based on truncated polynomial expansion (TPE) and make use of the asymptotic analysis to compute the deterministic equivalents of its corresponding signal-to-interference-plus-noise ratios (SINRs) and transmit power. The asymptotic analysis is conducted in the regime in which M and K tend to infinity with the same pace under the assumption that imperfect channel state information is available at the BS. The results are then used to compute the TPE weights that minimize the asymptotic transmit power while meeting a set of target SINR constraints. Numerical simulations are used to validate the theoretical analysis. © 2014 IEEE.

  2. Energy-Efficient Power Allocation for Cognitive MIMO Channels

    KAUST Repository

    Sboui, Lokman

    2017-03-20

    Due to the massive data traffic in wireless networks, energy consumption has become a crucial concern, especially with the limited power supply of the mobile terminals and the increasing CO2 emission of the cellular industry. In this context, we study the energy efficiency (EE) of MIMO spectrum sharing cognitive radio (CR) systems under power and interference constraints. We present an energy-efficient power allocation framework based on maximizing the average EE per parallel channel resulting from the singular value decomposition (SVD) eigenmode transmission. We also present a sub-optimal low-complexity power allocation scheme based on the water-filling power allocation. In the numerical results, we show that the sub-optimal power allocation achieves at least 95% of the optimal performance. In addition, we show that adopting more antennas is more energy efficient for a given power budget. Finally, we show that the interference threshold has a significant effect on both the EE and the spectral efficiency at high-power regime.

  3. A Hybrid Approach to Spatial Multiplexing in Multiuser MIMO Downlinks

    Directory of Open Access Journals (Sweden)

    Spencer Quentin H

    2004-01-01

    Full Text Available In the downlink of a multiuser multiple-input multiple-output (MIMO communication system, simultaneous transmission to several users requires joint optimization of the transmitted signals. Allowing all users to have multiple antennas adds an additional degree of complexity to the problem. In this paper, we examine the case where a single base station transmits to multiple users using linear processing (beamforming at each of the antenna arrays. We propose generalizations of several previous iterative algorithms for multiuser transmit beamforming that allow multiple antennas and multiple data streams for each user, and that take into account imperfect channel estimates at the transmitter. We then present a new hybrid algorithm that is based on coordinated transmit-receive beamforming, and combines the strengths of nonorthogonal iterative solutions with zero-forcing solutions. The problem of distributing power among the subchannels is solved by using standard bit-loading algorithms combined with the subchannel gains resulting from the zero-forcing solution. The result is a significant performance improvement over equal power distribution. At the same time, the number of iterations required to compute the final solution is reduced.

  4. Point Climat no. 20 'CDM Policy Dialogue: a traditional 'treatment' coupled with new 'prescriptions' '

    International Nuclear Information System (INIS)

    Shishlov, Igor; Bellassen, Valentin

    2012-01-01

    Among the publications of CDC Climat Research, 'Climate Briefs' presents, in a few pages, hot topics in climate change policy. This issue addresses the following points: As the Clean Development Mechanism (CDM) reached the milestone billionth CER issued and the secondary CER price tipped below 2 euros, the recommendations of the High Level Panel on the CDM Policy Dialogue published on 11 September 2012 could not be timelier. By focusing on the current supply-demand disequilibrium that threatens the very survival of the CDM, the Panel extended its recommendations beyond the traditional scope of CDM reform. The Panel's ambition to pro-actively engage with other climate initiatives such as the Green Fund and regional markets is also innovative. Indeed, the CDM toolbox enriched by 10-years of experience stands to apply to or be partly recycled through new mechanisms. Along the 51 recommendations from the Policy Dialogue, there are calls for further standardization and streamlining, together with both old and new ideas on governance and contribution of the CDM to sustainable development

  5. Derivative-Free Distributed Filtering for MIMO Robotic Systems under Delays and Packet Drops

    Directory of Open Access Journals (Sweden)

    Gerasimos G. Rigatos

    2013-02-01

    Full Text Available This paper presents an approach to distributed state estimation-based control of nonlinear MIMO systems, capable of incorporating delayed measurements in the estimation algorithm while also being robust to packet losses. First, the paper examines the problem of distributed nonlinear filtering over a communication/sensors network, and the use of the estimated state vector in a control loop. As a possible filtering approach, an extended information filter (EIF is proposed. The extended information filter requires the computation of Jacobians which in the case of high order nonlinear dynamical systems can be a cumbersome procedure, while it also introduces cumulative errors to the state estimation due to the approximative linearization performed in the Taylor series expansion of the system's nonlinear model. To overcome the aforementioned weaknesses of the extended information filter, a derivative-free approach to extended information filtering has been proposed. Distributed filtering is now based on a derivative-free implementation of Kalman filtering which is shown to be applicable to MIMO nonlinear dynamical systems. In the proposed derivative-free extended information filtering, the system is first subject to a linearization transformation that makes use of the differential flatness theory. It is shown how the proposed distributed filtering method can succeed in compensation of random delays and packet drops which may appear during the transmission of measurements and of state vector estimates, thus assuring a reliable performance of the distributed filtering-based control scheme. Evaluation tests are carried out on benchmark MIMO nonlinear systems, such as multi-DOF robotic manipulators.

  6. Novel Adaptive Forward Neural MIMO NARX Model for the Identification of Industrial 3-DOF Robot Arm Kinematics

    Directory of Open Access Journals (Sweden)

    Ho Pham Huy Anh

    2012-10-01

    Full Text Available In this paper, a novel forward adaptive neural MIMO NARX model is used for modelling and identifying the forward kinematics of an industrial 3-DOF robot arm system. The nonlinear features of the forward kinematics of the industrial robot arm drive are thoroughly modelled based on the forward adaptive neural NARX model-based identification process using experimental input-output training data. This paper proposes a novel use of a back propagation (BP algorithm to generate the forward neural MIMO NARX (FNMN model for the forward kinematics of the industrial 3-DOF robot arm. The results show that the proposed adaptive neural NARX model trained by a Back Propagation learning algorithm yields outstanding performance and perfect accuracy.

  7. A novel mirror diversity receiver for indoor MIMO visible light

    KAUST Repository

    Park, Ki-Hong

    2016-03-01

    In this paper, we propose and study a non-imaging receiver design reducing the correlation of channel matrix for indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. Contrary to previous works, our proposed mirror diversity receiver (MDR) not only blocks the reception of light on one specific direction but also improves the channel gain on the other direction by receiving the light reflected by a mirror deployed between the photodetectors. We analyze the channel capacity and optimal height of mirror in terms of maximum channel capacity for a 2 -by-2 MIMO-VLC system in a 2-dimensional geometric model.We prove that this constructive and destructive effects in channel matrix resulting from our proposed MDR are more beneficial to obtain well-conditioned channel matrix which is suitable for implementing spatial-multiplexing MIMO-VLC systems in order to support high data rate.

  8. Optimal beamforming in MIMO systems with HPA nonlinearity

    KAUST Repository

    Qi, Jian

    2010-09-01

    In this paper, multiple-input multiple-output (MIMO) transmit beamforming (TB) systems under the consideration of nonlinear high-power amplifiers (HPAs) are investigated. The optimal beamforming scheme, with the optimal beamforming weight vector and combining vector, is proposed for MIMO systems with HPA nonlinearity. The performance of the proposed MIMO beamforming scheme in the presence of HPA nonlinearity is evaluated in terms of average symbol error probability (SEP), outage probability and system capacity, considering transmission over uncorrelated quasi-static frequency-flat Rayleigh fading channels. Numerical results are provided and show the effects of several system parameters, namely, parameters of nonlinear HPA, numbers of transmit and receive antennas, and modulation order of phase-shift keying (PSK), on performance. ©2010 IEEE.

  9. Secret Sharing over Fast-Fading MIMO Wiretap Channels

    Directory of Open Access Journals (Sweden)

    Bloch Matthieu

    2009-01-01

    Full Text Available Secret sharing over the fast-fading MIMO wiretap channel is considered. A source and a destination try to share secret information over a fast-fading MIMO channel in the presence of an eavesdropper who also makes channel observations that are different from but correlated to those made by the destination. An interactive, authenticated public channel with unlimited capacity is available to the source and destination for the secret sharing process. This situation is a special case of the "channel model with wiretapper" considered by Ahlswede and Csiszár. An extension of their result to continuous channel alphabets is employed to evaluate the key capacity of the fast-fading MIMO wiretap channel. The effects of spatial dimensionality provided by the use of multiple antennas at the source, destination, and eavesdropper are then investigated.

  10. On the transfer matrix of a MIMO system

    DEFF Research Database (Denmark)

    Bentosela, Francois; Cornean, Horia; Fleury, Bernard Henri

    2011-01-01

    We develop a deterministic ab initio model for the input–output relationship of a multiple-input multiple-output (MIMO) wireless channel, starting from the Maxwell equations combined with Ohm's law. The main technical tools are scattering and geometric perturbation theories. The derived relations......We develop a deterministic ab initio model for the input–output relationship of a multiple-input multiple-output (MIMO) wireless channel, starting from the Maxwell equations combined with Ohm's law. The main technical tools are scattering and geometric perturbation theories. The derived...... relationship can lead us to a deep understanding of how the propagation conditions and the coupling effects between the elements of multiple-element arrays affect the properties of an MIMO channel, e.g. its capacity and its number of degrees of freedom....

  11. MIMO capacity for deterministic channel models: sublinear growth

    DEFF Research Database (Denmark)

    Bentosela, Francois; Cornean, Horia; Marchetti, Nicola

    2013-01-01

    This is the second paper by the authors in a series concerned with the development of a deterministic model for the transfer matrix of a MIMO system. In our previous paper, we started from the Maxwell equations and described the generic structure of such a deterministic transfer matrix. In the cu......This is the second paper by the authors in a series concerned with the development of a deterministic model for the transfer matrix of a MIMO system. In our previous paper, we started from the Maxwell equations and described the generic structure of such a deterministic transfer matrix....... In the current paper, we apply those results in order to study the (Shannon-Foschini) capacity behavior of a MIMO system as a function of the deterministic spread function of the environment and the number of transmitting and receiving antennas. The antennas are assumed to fill in a given fixed volume. Under...

  12. Modified Spatial Channel Model for MIMO Wireless Systems

    Directory of Open Access Journals (Sweden)

    Pekka Kyösti

    2007-12-01

    Full Text Available The third generation partnership Project's (3GPP spatial channel model (SCM is a stochastic channel model for MIMO systems. Due to fixed subpath power levels and angular directions, the SCM model does not show the degree of variation which is encountered in real channels. In this paper, we propose a modified SCM model which has random subpath powers and directions and still produces Laplace shape angular power spectrum. Simulation results on outage MIMO capacity with basic and modified SCM models show that the modified SCM model gives constantly smaller capacity values. Accordingly, it seems that the basic SCM gives too small correlation between MIMO antennas. Moreover, the variance in capacity values is larger using the proposed SCM model. Simulation results were supported by the outage capacity results from a measurement campaign conducted in the city centre of Oulu, Finland.

  13. Cosmic constraint on massive neutrinos in viable f(R) gravity with producing ΛCDM background expansion

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jianbo; Wu, Yabo; Wang, Yan; Yang, Weiqiang [Liaoning Normal University, Department of Physics, Dalian (China); Liu, Molin [Xinyang Normal University, Department of Physics, Xinyang (China)

    2016-12-15

    Tensions between several cosmic observations were found recently, such as the inconsistent values of H{sub 0} (or σ{sub 8}) were indicated by the different cosmic observations. Introducing the massive neutrinos in ΛCDM could potentially solve the tensions. Viable f(R) gravity producing ΛCDM background expansion with massive neutrinos is investigated in this paper. We fit the current observational data: Planck-2015 CMB, RSD, BAO, and SNIa to constrain the mass of neutrinos in viable f(R) theory. The constraint results at 95% confidence level are: Σm{sub ν} < 0.202 eV for the active-neutrino case, m{sub ν,sterile}{sup eff} < 0.757 eV with N{sub eff} < 3.22 for the sterile neutrino case. For the effects due to the mass of the neutrinos, the constraint results on model parameter at 95% confidence level become f{sub R0} x 10{sup -6} > -1.89 and f{sub R0} x 10{sup -6} > -2.02 for two cases, respectively. It is also shown that the fitting values of several parameters much depend on the neutrino properties, such as the cold dark matter density, the cosmological quantities at matter-radiation equality, the neutrino density and the fraction of baryonic mass in helium. Finally, the constraint result shows that the tension between direct and CMB measurements of H{sub 0} gets slightly weaker in the viable f(R) model than that in the base ΛCDM model. (orig.)

  14. Nonconcave Utility Maximisation in the MIMO Broadcast Channel

    Directory of Open Access Journals (Sweden)

    Wolfgang Utschick

    2008-09-01

    Full Text Available The problem of determining an optimal parameter setup at the physical layer in a multiuser, multiantenna downlink is considered. An aggregate utility, which is assumed to depend on the users' rates, is used as performance metric. It is not assumed that the utility function is concave, allowing for more realistic utility models of applications with limited scalability. Due to the structure of the underlying capacity region, a two step approach is necessary. First, an optimal rate vector is determined. Second, the optimal parameter setup is derived from the optimal rate vector. Two methods for computing an optimal rate vector are proposed. First, based on the differential manifold structure offered by the boundary of the MIMO BC capacity region, a gradient projection method on the boundary is developed. Being a local algorithm, the method converges to a rate vector which is not guaranteed to be a globally optimal solution. Second, the monotonic structure of the rate space problem is exploited to compute a globally optimal rate vector with an outer approximation algorithm. While the second method yields the global optimum, the first method is shown to provide an attractive tradeoff between utility performance and computational complexity.

  15. On Radiated Performance Evaluation of Massive MIMO Devices in Multi-Probe Anechoic Chamber OTA Setups

    DEFF Research Database (Denmark)

    Kyösti, Pekka; Hentilä, Lassi; Fan, Wei

    2018-01-01

    Radiated testing of massive multiple-input-multipleoutput (MIMO) devices in fading radio channel conditions is expected to be essential in development of the fifth generation (5G) base stations (BS) and user equipment (UE) operating at or close to the millimetre wave (mm-wave) frequencies. In thi...... setup and find key design parameters by simulations. The results with the utilized channel models indicate that at 28 GHz up to 1616 planar arrays can be tested with range length of one meter and with at minimum eight active dual polarized probes....

  16. Laguerre-Volterra model and architecture for MIMO system identification and output prediction.

    Science.gov (United States)

    Li, Will X Y; Xin, Yao; Chan, Rosa H M; Song, Dong; Berger, Theodore W; Cheung, Ray C C

    2014-01-01

    A generalized mathematical model is proposed for behaviors prediction of biological causal systems with multiple inputs and multiple outputs (MIMO). The system properties are represented by a set of model parameters, which can be derived with random input stimuli probing it. The system calculates predicted outputs based on the estimated parameters and its novel inputs. An efficient hardware architecture is established for this mathematical model and its circuitry has been implemented using the field-programmable gate arrays (FPGAs). This architecture is scalable and its functionality has been validated by using experimental data gathered from real-world measurement.

  17. Performance Characterization of a Real-Time Massive MIMO System with LOS Mobile Channels

    OpenAIRE

    Harris, Paul; Malkowsky, Steffen; Vieira, Joao; Hassan, Fredrik Tufvesson Wael Boukley; Liu, Liang; Beach, Mark; Armour, Simon; Edfors, Ove

    2017-01-01

    The first measured results for massive multiple input, multiple-output (MIMO) performance in a line-of-sight (LOS) scenario with moderate mobility are presented, with 8 users served in real-time using a 100 antenna base Station (BS) at 3.7 GHz. When such a large number of channels dynamically change, the inherent propagation and processing delay has a critical relationship with the rate of change, as the use of outdated channel information can result in severe detection and precoding inaccura...

  18. Low complexity symbol-wise beamforming for MIMO-OFDM systems

    KAUST Repository

    Lee, Hyun Ho

    2011-12-01

    In this paper, we consider a low complexity symbol-wise beamforming for MIMO-OFDM systems. We propose a non-iterative algorithm for the symbol-wise beamforming, which can provide the performance approaching that of the conventional symbol-wise beamforming based on the iterative algorithm. We demonstrate that our proposed scheme can reduce the computational complexity significantly. From our simulation results, it is evident that our proposed scheme leads to a negligible performance loss compared to the conventional symbol-wise beamforming regardless of spatial correlation or presence of co-channel interference. © 2011 IEEE.

  19. A universal encoding scheme for MIMO transmission using a single active element for PSK modulation schemes

    DEFF Research Database (Denmark)

    Alrabadi, Osama; Papadias, C.B.; Kalis, A.

    2009-01-01

    A universal scheme for encoding multiple symbol streams using a single driven element (and consequently a single radio frequency (RF) frontend) surrounded by parasitic elements (PE) loaded with variable reactive loads, is proposed in this paper. The proposed scheme is based on creating a MIMO...... systems. The array can spatially multiplex the input streams by creating all the desired linear combinations (for a given modulation scheme) of the basis functions. The desired combinations are obtained by projecting the ratio of the symbols to be spatially multiplexed on the ratio of the basis functions...

  20. Implementations of FFT and STBD for MIMO-OFDM on a Reconfigurable Baseband Platform

    Science.gov (United States)

    Zhao, Shuang; Lu, Wenqing; Zhou, Xiaofang; Zhou, Dian; Sobelman, Gerald E.

    MIMO-OFDM systems aim to improve transmission quality and/or throughput but require significant signal processing capability and flexibility at reasonable cost. This paper proposes a reconfigurable architecture and associated algorithm optimizations for these types of systems based on the IEEE 802.11n and IEEE 802.16e standards. In particular, we describe the implementation of two key computations onto this architecture, namely Fast Fourier Transform (FFT) and Space-Time Block Decoding (STBD). The design is post-layout using a UMC 0.18micron technology at a clock rate of 100MHz. Performance comparisons with other optimization methods and hardware implementations are given.

  1. Improved Detection Technique for the Uncoded MIMO Systems Using an Efficient K-best Algorithm.

    OpenAIRE

    Hellassa Wassim; Boukari Karima

    2015-01-01

    This paper presents a new algorithm for spatially multiplexed MIMO detection that exploits the resources available in the search procedure to enhance the error performance of the K-best approach of search. The proposed algorithm exploits the heuristics of the nodes and it is referred as the Heuristic K-best algorithm (HK-best). Unlike the conventional K-best algorithm, the HK-best algorithm sort the visited nodes in each layer based on the path metric and the heuristic. Simulation results sho...

  2. The application of LDPC code in MIMO-OFDM system

    Science.gov (United States)

    Liu, Ruian; Zeng, Beibei; Chen, Tingting; Liu, Nan; Yin, Ninghao

    2018-03-01

    The combination of MIMO and OFDM technology has become one of the key technologies of the fourth generation mobile communication., which can overcome the frequency selective fading of wireless channel, increase the system capacity and improve the frequency utilization. Error correcting coding introduced into the system can further improve its performance. LDPC (low density parity check) code is a kind of error correcting code which can improve system reliability and anti-interference ability, and the decoding is simple and easy to operate. This paper mainly discusses the application of LDPC code in MIMO-OFDM system.

  3. An agile and efficient MIMO system for small terminals

    DEFF Research Database (Denmark)

    Alrabadi, Osama; Tsakalaki, Elpiniki; Pelosi, Mauro

    2013-01-01

    A novel multiple-input-multiple-output (MIMO) system for the high LTE bands is proposed. The system is comprised of four small loop antennas, each having one communication and one control port. The antennas exhibit impressive frequency agility and a good level of inherent isolation over the diffe......A novel multiple-input-multiple-output (MIMO) system for the high LTE bands is proposed. The system is comprised of four small loop antennas, each having one communication and one control port. The antennas exhibit impressive frequency agility and a good level of inherent isolation over...

  4. Joint compensation of multiple RF impairments in MIMO STBC systems

    KAUST Repository

    Qi, Jian

    2011-09-01

    In this paper, we propose a compensation method for the joint effect of high-power amplifier (HPA) nonlinearity, in-phase/quadrature-phase (I/Q) imbalance and crosstalk in multiple-input multiple-output (MIMO) orthogonal space-time block coding (OSTBC) systems. The performance of the MIMO OSTBC equipped with the proposed compensation mechanism is evaluated in terms of average symbol error probability and system capacity, in Rayleigh fading channels. Numerical results are provided and show the effects on performance of several system parameters, namely, the HPA parameters, image-leakage ratio, crosstalk, numbers of antennas, and phase-shift keying modulation order. © 2011 IEEE.

  5. Capacity and Performance of MIMO systems for Wireless Communications

    Directory of Open Access Journals (Sweden)

    E. Ghayoula

    2014-08-01

    Full Text Available This paper presents the capacity performance of multiple antennas for wireless communication systems. Multiple antennas structures can be classified into single-input multiple-outputs (SIMO, multiple-inputs single output (MISO, and multiple-inputs multiple-outputs (MIMO systems. Assuming that the channel is unknown at receiver, capacity expressions are provided for each structure. Our results also show that increasing the number of transmitting and receiving antennas for a wireless MIMO channel does indeed improve the channel capacity that can be obtained.

  6. Performance Evaluation Of Modified V-Blast In Mimo System

    Science.gov (United States)

    Suneetha, Ch.; Harathi, N.; Sudha, K.

    2012-03-01

    The MIMO system (multiple Antennas at the transmitter and receiver)is a capable of very high theoretical capacities, the most popular architecture is so called vertical VBLAST. VBLAST is an effective detection method for MIMO communication system, but has large computational complexity due its successive iteration . In this paper we used modified VBLAST to lessen its computational complexity reducing the number of successive iterations. As a result of this simplification, the computational complexity of the detection is lowered significantly. Simulation results show that the proposed V-BLAST reduces calculation complexity by about 30% while achieving a very close BER performance s the original one.

  7. On the power and offset allocation for rate adaptation of spatial multiplexing in optical wireless MIMO channels

    KAUST Repository

    Park, Kihong

    2013-04-01

    In this paper, we consider resource allocation method in the visible light communication. It is challenging to achieve high data rate due to the limited bandwidth of the optical sources. In order to increase the spectral efficiency, we design a suitable multiple-input multiple-output (MIMO) system utilizing spatial multiplexing based on singular value decomposition and adaptive modulation. More specifically, after explaining why the conventional allocation method in radio frequency MIMO channels cannot be applied directly to the optical intensity channels, we theoretically derive a power allocation method for an arbitrary number of transmit and receive antennas for optical wireless MIMO systems. Based on three key constraints: the nonnegativity of the intensity-modulated signal, the aggregate optical power budget, and the bit error rate requirement, we propose a novel method to allocate the optical power, the offset value, and the modulation size. Based on some selected simulation results, we show that our proposed allocation method gives a better spectral efficiency at the expense of an increased computational complexity in comparison to a simple method that allocates the optical power equally among all the data streams. © 2013 IEEE.

  8. Channel Characteristics and Performance of MIMO E-SDM Systems in an Indoor Time-Varying Fading Environment

    Directory of Open Access Journals (Sweden)

    Huu Phu Bui

    2010-01-01

    Full Text Available Multiple-input multiple-output (MIMO systems employ advanced signal processing techniques. However, the performance is affected by propagation environments and antenna characteristics. The main contributions of the paper are to investigate Doppler spectrum based on measured data in a typical meeting room and to evaluate the performance of MIMO systems based on an eigenbeam-space division multiplexing (E-SDM technique in an indoor time-varying fading environment, which has various distributions of scatterers, line-of-sight wave existence, and mutual coupling effect among antennas. We confirm that due to the mutual coupling among antennas, patterns of antenna elements are changed and different from an omnidirectional one of a single antenna. Results based on the measured channel data in our measurement campaigns show that received power, channel autocorrelation, and Doppler spectrum are dependent not only on the direction of terminal motion but also on the antenna configuration. Even in the obstructed-line-of-sight environment, observed Doppler spectrum is quite different from the theoretical U-shaped Jakes one. In addition, it has been also shown that a channel change during the time interval between the transmit weight matrix determination and the actual data transmission can degrade the performance of MIMO E-SDM systems.

  9. Experimental study on the statistic characteristics of a 3x3 RF MIMO channel over a single conventional multimode fiber.

    Science.gov (United States)

    Lei, Yi; Li, Jianqiang; Wu, Rui; Fan, Yuting; Fu, Songnian; Yin, Feifei; Dai, Yitang; Xu, Kun

    2017-06-01

    Based on the observed random fluctuation phenomenon of speckle pattern across multimode fiber (MMF) facet and received optical power distribution across three output ports, we experimentally investigate the statistic characteristics of a 3×3 radio frequency multiple-input multiple-output (MIMO) channel enabled by mode division multiplexing in a conventional 50 µm MMF using non-mode-selective three-dimensional waveguide photonic lanterns as mode multiplexer and demultiplexer. The impacts of mode coupling on the MIMO channel coefficients, channel matrix, and channel capacity have been analyzed over different fiber lengths. The results indicate that spatial multiplexing benefits from the greater fiber length with stronger mode coupling, despite a higher optical loss.

  10. Constrained Optimization of MIMO Training Sequences

    Directory of Open Access Journals (Sweden)

    Coon Justin P

    2007-01-01

    Full Text Available Multiple-input multiple-output (MIMO systems have shown a huge potential for increased spectral efficiency and throughput. With an increasing number of transmitting antennas comes the burden of providing training for channel estimation for coherent detection. In some special cases optimal, in the sense of mean-squared error (MSE, training sequences have been designed. However, in many practical systems it is not feasible to analytically find optimal solutions and numerical techniques must be used. In this paper, two systems (unique word (UW single carrier and OFDM with nulled subcarriers are considered and a method of designing near-optimal training sequences using nonlinear optimization techniques is proposed. In particular, interior-point (IP algorithms such as the barrier method are discussed. Although the two systems seem unrelated, the cost function, which is the MSE of the channel estimate, is shown to be effectively the same for each scenario. Also, additional constraints, such as peak-to-average power ratio (PAPR, are considered and shown to be easily included in the optimization process. Numerical examples illustrate the effectiveness of the designed training sequences, both in terms of MSE and bit-error rate (BER.

  11. Experimental Verification of Multiple-input Multiple Output (MIMO) Beamforming Capabilities Using a Time-division Coherent MIMO Radar

    Science.gov (United States)

    2015-04-01

    à 8 canaux et à répartition dans le temps sont discutés. Des données de radar à réseau à éléments en phase, obtenus avec une ap- proche mixte...obtenus avec un radar MIMO de bande X à 8 canaux et à répartition dans le temps, clarifient l’exacti- tude de l’estimation de l’angle des radars MIMO...However, where further distribution (beyond the audience specified in (11)) is possible, a wider announcement audience may be selected.) Unlimited 13

  12. Moving from the CDM to 'various approaches'

    International Nuclear Information System (INIS)

    Shishlov, Igor; Bellassen, Valentin

    2014-03-01

    The Clean Development Mechanism (CDM) facilitated the emergence and deployment of low-cost greenhouse gas (GHG) abatement technologies such as destruction of industrial gases and capturing methane from landfills and coal mines. Some of these technologies are now ripe to 'graduate' from the CDM into other, more mainstream, economic tools. The first such step was taken in September 2013 when the G20 leaders agreed to phase out HFCs - highly potent greenhouse gases - including HFC-23 that was the focus of 19 CDM projects. A potential HFC-23 abatement fund under the Montreal Protocol could reduce up to 1.8 Gt CO 2 e by 2020 at a cost of under US$0.2 per ton of CO 2 e, i.e. much cheaper than the price paid to CDM projects through carbon crediting. The next potential candidate technology to 'graduate' from the CDM is the abatement of nitrous oxide (N 2 O) emissions in the chemical industry, which have already been placed on the agenda of the Montreal Protocol. (authors)

  13. PIPELINE PROGRAM CDM DI INDONESIA: SEBUAH PELUANG DAN TANTANGAN UNTUK INDUSTRI PERTAMBANGAN

    Directory of Open Access Journals (Sweden)

    Joni Safaat Adiansyah

    2011-12-01

    Full Text Available Climate change is one of the world’s problems that must be dealt; the failure in tackling climate change will impact on increasing the earth temperature and endanger the archipelago countries including Indonesia. Clean Development Mechanism (CDM is one of the Kyoto Protocol mechanisms designed to mitigate climate change. Indonesia is one of the countries that meets the requirement as the host of CDM program and has set up the target to reduce GHG emissions as much as 26 percent in year 2020. The industrial sector has opportunities to engage actively in reducing GHG emission including mining industry.  The objectives of this research are to find out the potency of mining company’s involvement in climate change mitigation efforts particularly through CDM. In addition, the research of method that is chosen is literature study including reviewing data relating to CDM and with qualitative approached. The result shows that mining industry has a potency to involve actively in CDM program, among others, through energy efficiency, fuel substitution, renewable energy, Coal Bed Methane and the handling of critical lands through afforestation and reforestation scheme. Furthermore, by using Business as Usual assumption, the linier  regression that is produced y=27.255.x + 12.711 therefore  It is estimated that about 15 Mt CO2-e (assuming 4 percent reduction needs to be derived from the energy sector in 2020 that can be taken as an opportunity for the mining industry as well.

  14. Trends in renewable energy strategy development and the role of CDM in Bangladesh

    International Nuclear Information System (INIS)

    Noim Uddin, Sk; Taplin, Ros

    2009-01-01

    This article analyses and discusses trends in renewable energy strategy development in Bangladesh and the prospective role of the clean development mechanism (CDM) under the Kyoto Protocol. Use of renewables for electricity generation results in less greenhouse gas emissions compared with fossil fuel energy systems and often offers additional synergistic benefits. Despite the large potential for development of renewable energy sources in Bangladesh, currently their contribution to electricity generation remains insignificant. Existing policies and programs on renewable energy in Bangladesh are reviewed in relation to the specific requirements needed for CDM. A number of barriers are identified that impede the implementation of the CDM mechanism. Overall, it is recommended that more appropriate energy strategies, including a new national renewable energy strategy, need to be formulated and implemented and more suitable institutional settings need to be provided to promote energy sustainability for Bangladesh. Also, the suggestion is made that incorporation of objectives for CDM promotion in the new national renewable energy strategy to tie in with Bangladesh's CDM strategy should assist in advancement of renewables

  15. Time-Varying FIR Equalization for MIMO Transmission over Doubly Selective Channels

    Science.gov (United States)

    Barhumi, Imad; Moonen, Marc

    2010-12-01

    We propose time-varying FIR equalization techniques for spatial multiplexing-based multiple-input multiple-output (MIMO) transmission over doubly selective channels. The doubly selective channel is approximated using the basis expansion model (BEM), and equalized by means of time-varying FIR filters designed according to the BEM. By doing so, the time-varying deconvolution problem is converted into a two-dimensional time-invariant deconvolution problem in the time-invariant coefficients of the channel BEM and the time-invariant coefficients of the equalizer BEM. The timevarying FIR equalizers are derived based on either the matched filtering criterion, or the linear minimum mean-square error (MMSE) or the zero-forcing (ZF) criteria. In addition to the linear equalizers, the decision feedback equalizer (DFE) is proposed. The DFE can be designed according to two different scenarios. In the first scenario, the DFE is based on feeding back previously estimated symbols from one particular antenna at a time. Whereas, in the second scenario, the previously estimated symbols from all transmit antennas are fed back together. The performance of the proposed equalizers in the context of MIMO transmission is analyzed in terms of numerical simulations.

  16. Time-Varying FIR Equalization for MIMO Transmission over Doubly Selective Channels

    Directory of Open Access Journals (Sweden)

    Marc Moonen

    2010-01-01

    Full Text Available We propose time-varying FIR equalization techniques for spatial multiplexing-based multiple-input multiple-output (MIMO transmission over doubly selective channels. The doubly selective channel is approximated using the basis expansion model (BEM, and equalized by means of time-varying FIR filters designed according to the BEM. By doing so, the time-varying deconvolution problem is converted into a two-dimensional time-invariant deconvolution problem in the time-invariant coefficients of the channel BEM and the time-invariant coefficients of the equalizer BEM. The timevarying FIR equalizers are derived based on either the matched filtering criterion, or the linear minimum mean-square error (MMSE or the zero-forcing (ZF criteria. In addition to the linear equalizers, the decision feedback equalizer (DFE is proposed. The DFE can be designed according to two different scenarios. In the first scenario, the DFE is based on feeding back previously estimated symbols from one particular antenna at a time. Whereas, in the second scenario, the previously estimated symbols from all transmit antennas are fed back together. The performance of the proposed equalizers in the context of MIMO transmission is analyzed in terms of numerical simulations.

  17. Interference Alignment in Multi-user MIMO Systems

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2015-06-01

    Full Text Available Interference alignment (IA has been studied extensively as an advanced technology to obtain the maximum degree of freedom (DoF of multi-user wireless communication systems. This letter provides a brief review of recent works on IA. The most effective approach of IA is to deploy optimal linear transceivers by exploiting spatial characteristics of wireless channels. It is evaluated in measured multi-input multi-output (MIMO interference channels. The implementation of IA depends on the characteristics of channel state information (CSI feedback to the transmitters, such as imperfect, noisy, localized, delayed nature, and so on. In this work, we present a review of existing techniques for IA in typical multi-user MIMO systems. Moreover, we also consider some future research issues related to implementation. The study covers IA's feasibility conditions, solution algorithms in MIMO interference channel and MIMO multi-cell networks, with emphasis on the CSI feedback technology which remains as the major challenge of IA.

  18. MIMO Self-Tuning Control of Chemical Process Operation

    OpenAIRE

    Hallager, L.; Jørgensen, S. B.; Goldschmidt, L.

    1984-01-01

    The problem of selecting a feasible model structure for a MIMO self-tuning controller (MIMOSC) is addressed. The dependency of the necessary structure complexity in relation to the specific process operating point is investigated. Experimental results from a fixed-bed chemical reactor are used to illustrate the points.

  19. MIMO Device Performance Testing with the Wireless Cable Method

    DEFF Research Database (Denmark)

    Fan, Wei; Kyösti, Pekka; Hentilä, Lassi

    2018-01-01

    Conducted cable testing has been dominantly utilized in the industry to evaluate multiple-input multiple-output (MIMO) capable mobile terminals. Desired testing signals can be guided directly to the antenna ports on the mobile terminal by radio frequency (RF) coaxial cables in the conducted cable...

  20. Performance Comparisons of MIMO Techniques with Application to WCDMA Systems

    Directory of Open Access Journals (Sweden)

    Li Chuxiang

    2004-01-01

    Full Text Available Multiple-input multiple-output (MIMO communication techniques have received great attention and gained significant development in recent years. In this paper, we analyze and compare the performances of different MIMO techniques. In particular, we compare the performance of three MIMO methods, namely, BLAST, STBC, and linear precoding/decoding. We provide both an analytical performance analysis in terms of the average receiver and simulation results in terms of the BER. Moreover, the applications of MIMO techniques in WCDMA systems are also considered in this study. Specifically, a subspace tracking algorithm and a quantized feedback scheme are introduced into the system to simplify implementation of the beamforming scheme. It is seen that the BLAST scheme can achieve the best performance in the high data rate transmission scenario; the beamforming scheme has better performance than the STBC strategies in the diversity transmission scenario; and the beamforming scheme can be effectively realized in WCDMA systems employing the subspace tracking and the quantized feedback approach.

  1. On Small Antenna Measurements in a Realistic MIMO Scenario

    DEFF Research Database (Denmark)

    Yanakiev, Boyan; Nielsen, Jesper Ødum; Pedersen, Gert Frølund

    2010-01-01

    This paper deals with the challenges related to evaluating the performance of multiple, small terminal antennas within a natural MIMO environment. The focus is on the antenna measurement accuracy. First a method is presented for measuring small phone mock-ups, with the use of optical fibers...

  2. Coherent MIMO Array Design With Periodical Physical Element Structures

    NARCIS (Netherlands)

    Belfiori, F.; Rossum, W.L. van; Peter Hoogeboom, P.

    2011-01-01

    Multiple-input-multiple-output (MIMO) processing is a consolidated technique in communication systems thanks to the benefits that it offers in multipath fading environments. In recent years, studies have shown how the performances of conventional phased-array radar can be improved by using the same

  3. Precoder and decoder prediction in time-varying MIMO channel

    DEFF Research Database (Denmark)

    Nguyen, Tuan Hung; Leus, Geert; Khaled, Nadia

    2005-01-01

    the performance of a prediction scheme for multiple input multiple output (MIMO) systems that apply spatial multiplexing. We aim at predicting the future precoder/decoder directly without going through the prediction of the channel matrix. The results show that in a slowly time varying channel an increase...

  4. MIMO Self-Tuning Control of Chemical Process Operation

    DEFF Research Database (Denmark)

    Hallager, L.; Jørgensen, S. B.; Goldschmidt, L.

    1984-01-01

    The problem of selecting a feasible model structure for a MIMO self-tuning controller (MIMOSC) is addressed. The dependency of the necessary structure complexity in relation to the specific process operating point is investigated. Experimental results from a fixed-bed chemical reactor are used...

  5. Evaluation of Reflections in a MIMO OTA Test Setup

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Franek, Ondrej; Krenz, Gunter

    2014-01-01

    With the commercialization of MIMO devices, accurate over-the-air testing has become a major research area in mobile communications. Several test methods are investigated in the related work. This paper discusses the anechoic chamber method and specifically deals with reflections between probes...

  6. Frequency Dependence of Measured Massive MIMO Channel Properties

    DEFF Research Database (Denmark)

    Oliveras Martínez, Àlex; Carvalho, Elisabeth De; Nielsen, Jesper Ødum

    2016-01-01

    A multi-user massive MIMO measurement campaign is conducted to study the channel propagation characteristics (e.g. user correlation, sum of eigenvalues and condition number), focusing on the stability over frequencies and the impact of the array aperture. We use 3 arrays with 64 antennas (6m linear...

  7. Fast Estimation of Outage Probabilities in MIMO Channels

    NARCIS (Netherlands)

    Srinivasan, R.; Tiba, G.

    2004-01-01

    Fast estimation methods for small outage probabilities of signaling in fading multiple-input multiple-output (MIMO) channels are developed. Communication over such channels is of much current interest, and quick and accurate methods for estimating outage capacities are needed. The methods described

  8. MIMO Terminal Performance Evaluation with a Novel Wireless Cable Method

    DEFF Research Database (Denmark)

    Fan, Wei; Kyösti, Pekka; Hentilä, Lassi

    2017-01-01

    Conventional conductive method, where antennas on the device under test (DUT) are disconnected from antenna ports and replaced with radio frequency (RF) coaxial cables, has been dominantly utilized in industry to evaluate multiple-input multiple-output (MIMO) capable terminals. However, direct RF...

  9. Performance Analysis of a Two-Hop MIMO Mobile-to-Mobile via Stratospheric-Relay Link Employing Hierarchical Modulation

    Directory of Open Access Journals (Sweden)

    Nikolaos Nomikos

    2013-01-01

    Full Text Available Next generation wireless communication networks intend to take advantage of the integration of terrestrial and aerospace infrastructures. Besides, multiple-input multiple-output (MIMO architecture is the key technology, which has brought the wireless gigabit vision closer to reality. In this direction, high-altitude platforms (HAPs could act as relay stations in the stratosphere transferring information from an uplink to a downlink MIMO channel. This paper investigates the performance of a novel transmission scheme for the delivery of mobile-to-mobile (M-to-M services via a stratospheric relay. It is assumed that the source, relay, and destination nodes are equipped with multiple antennas and that amplify-and-forward (AF relaying is adopted. The performance is analyzed through rigorous simulations in terms of the bit-error rate (BER by using a recently proposed 3D geometry-based reference model in spatially correlated flat-fading MIMO channels, employing a hierarchical broadcast technique and minimum mean square error (MMSE receivers.

  10. A Novel Mirror-Aided Non-imaging Receiver for Indoor 2x2 MIMO Visible Light Communication Systems

    KAUST Repository

    Park, Kihong

    2017-06-07

    Indoor visible light communication (VLC) systems are now possible because of advances in light emitting diode and laser diode technologies. These lighting technologies provide the foundation for multiple-input multiple-output (MIMO) data transmission through visible light. However, the channel matrix can be strongly correlated in indoor MIMO-VLC systems, preventing parallel data streams from being decoded. Here, in $2\\\\times 2$ MIMO-VLC systems, we describe a mirror diversity receiver (MDR) design that reduces the channel correlation by both blocking the reception of light from one specific direction and improving the channel gain from light from another direction by utilizing a double-sided mirror deployed between the receiver\\'s photodetectors. We report on the channel capacity of the MDR system and the optimal height of its mirrors in terms of maximum channel capacity. We also derived analytic results on the effect of rotation on MDR\\'s performance. Based on numerical and experimental results, we show that the double-sided mirror has both constructive and destructive effects on the channel matrix. Our design can be used with previously described non-imaging systems to improve the performance of indoor VLC systems.

  11. Experimental demonstration of high spectral efficient 4 × 4 MIMO SCMA-OFDM/OQAM radio over multi-core fiber system.

    Science.gov (United States)

    Liu, Chang; Deng, Lei; He, Jiale; Li, Di; Fu, Songnian; Tang, Ming; Cheng, Mengfan; Liu, Deming

    2017-07-24

    In this paper, 4 × 4 multiple-input multiple-output (MIMO) radio over 7-core fiber system based on sparse code multiple access (SCMA) and OFDM/OQAM techniques is proposed. No cyclic prefix (CP) is required by properly designing the prototype filters in OFDM/OQAM modulator, and non-orthogonally overlaid codewords by using SCMA is help to serve more users simultaneously under the condition of using equal number of time and frequency resources compared with OFDMA, resulting in the increase of spectral efficiency (SE) and system capacity. In our experiment, 11.04 Gb/s 4 × 4 MIMO SCMA-OFDM/OQAM signal is successfully transmitted over 20 km 7-core fiber and 0.4 m air distance in both uplink and downlink. As a comparison, 6.681 Gb/s traditional MIMO-OFDM signal with the same occupied bandwidth has been evaluated for both uplink and downlink transmission. The experimental results show that SE could be increased by 65.2% with no bit error rate (BER) performance degradation compared with the traditional MIMO-OFDM technique.

  12. Hierarchical scheme for detecting the rotating MIMO transmission of the in-door RGB-LED visible light wireless communications using mobile-phone camera

    Science.gov (United States)

    Chen, Shih-Hao; Chow, Chi-Wai

    2015-01-01

    Multiple-input and multiple-output (MIMO) scheme can extend the transmission capacity for the light-emitting-diode (LED) based visible light communication (VLC) systems. The MIMO VLC system that uses the mobile-phone camera as the optical receiver (Rx) to receive MIMO signal from the n×n Red-Green-Blue (RGB) LED array is desirable. The key step of decoding this signal is to detect the signal direction. If the LED transmitter (Tx) is rotated, the Rx may not realize the rotation and transmission error can occur. In this work, we propose and demonstrate a novel hierarchical transmission scheme which can reduce the computation complexity of rotation detection in LED array VLC system. We use the n×n RGB LED array as the MIMO Tx. In our study, a novel two dimensional Hadamard coding scheme is proposed. Using the different LED color layers to indicate the rotation, a low complexity rotation detection method can be used for improving the quality of received signal. The detection correction rate is above 95% in the indoor usage distance. Experimental results confirm the feasibility of the proposed scheme.

  13. Compact MIMO Microstrip Antennas for USB Dongle Operating in 2.5–2.7 GHz Frequency Band

    Directory of Open Access Journals (Sweden)

    Vladimir Ssorin

    2012-01-01

    Full Text Available This paper considers design of microstrip MIMO antennas for an LTE/WiMAX USB dongle operating in the 2.5–2.7 GHz frequency band. The MIMO system includes two antenna elements with an additional requirement of high isolation between them that is especially difficult to realize due to size limitations of a USB dongle. Three approaches to achieve the needed system characteristics using microstrip PCB antennas are proposed. For the first design, high port-to-port isolation is achieved by using a decoupling techniques based on a direct connection of the antenna elements. For the second approach, high port-to-port isolation of the MIMO antenna system is realized by a lumped decorrelation capacitance between antenna elements feeding points. The third proposed antenna system does not use any special techniques, and high port-to-port isolation is achieved by using only the properties of a developed printed inverted-F antenna element. The designed MIMO antenna systems have the return loss S11 and the insertion loss S21 bandwidths of more than 200 MHz at the −8 dB level with the correlation coefficient lower than 0.1 and exhibit pattern diversity when different antenna elements are excited. Experimental measurements of the fabricated antenna systems proved the characteristics obtained from electromagnetic simulation.

  14. Stochastic backgrounds of relic gravitons, T$\\Lambda$CDM paradigm and the stiff ages

    CERN Document Server

    Giovannini, Massimo

    2008-01-01

    Absent any indirect tests on the thermal history of the Universe prior to the formation of light nuclear elements, it is legitimate to investigate situations where, before nucleosyntheis, the sound speed of the plasma was larger than $c/\\sqrt{3}$, at most equalling the speed of light $c$. In this plausible extension of the current cosmological paradigm, hereby dubbed Tensor-$\\Lambda$CDM (i.e. T$\\Lambda$CDM) scenario, high-frequency gravitons are copiously produced. Without conflicting with the bounds on the tensor to scalar ratio stemming from the combined analysis of the three standard cosmological data sets (i.e. cosmic microwave background anisotropies, large-scale structure and supenovae), the spectral energy density of the relic gravitons in the T$\\Lambda$CDM scenario can be potentially observable by wide-band interferometers (in their advanced version) operating in a frequency window which ranges between few Hz and few kHz.

  15. Optimal Superimposed Training Sequences for Channel Estimation in MIMO-OFDM Systems

    Directory of Open Access Journals (Sweden)

    Ratnam V. Raja Kumar

    2010-01-01

    Full Text Available In this work an iterative time domain Least Squares (LS based channel estimation method using superimposed training (ST for a Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM system over time varying frequency selective fading channels is proposed. The performance of the channel estimator is analyzed in terms of the Mean Square Estimation Error (MSEE and its impact on the uncoded Bit Error Rate (BER of the MIMO-OFDM system is studied. A new selection criterion for the training sequences that jointly optimizes the MSEE and the BER of the OFDM system is proposed. Chirp based sequences are proposed and shown to satisfy the same. These are compared with the other sequences proposed in the literature and are found to yield a superior performance. The sequences, one for each transmitting antenna, offers fairness through providing equal interference in all the data carriers unlike earlier proposals. The effectiveness of the mathematical analysis presented is demonstrated through a comparison with the simulation studies. Experimental studies are carried out to study and validate the improved performance of the proposed scheme. The scheme is applied to the IEEE 802.16e OFDM standard and a case is made with the required design of the sequence.

  16. Modeling and Simulation of MIMO Mobile-to-Mobile Wireless Fading Channels

    Directory of Open Access Journals (Sweden)

    Gholamreza Bakhshi

    2012-01-01

    Full Text Available Analysis and design of multielement antenna systems in mobile fading channels require a model for the space-time cross-correlation among the links of the underlying multipleinput multiple-output (MIMO Mobile-to-Mobile (M-to-M communication channels. In this paper, we propose the modified geometrical two-ring model, a MIMO channel reference model for M-to-M communication systems. This model is based on the extension of single-bounce two-ring scattering model for flat fading channel under the assumption that the transmitter and the receiver are moving. Assuming single-bounce scattering model in both isotropic and nonisotropic environment, a closed-form expression for the space-time cross-correlation function (CCF between any two subchannels is derived. The proposed model provides an important framework in M-to-M system design, where includes many existing correlation models as special cases. Also, two realizable statistical simulation models are proposed for simulating both isotropic and nonisotropic reference model. The realizable simulation models are based on Sum-of-Sinusoids (SoS simulation model. Finally, the correctness of the proposed simulation models is shown via different simulation scenarios.

  17. A real-time Grad-Shafranov PDE solver and MIMO controller

    Energy Technology Data Exchange (ETDEWEB)

    Barp, A.; Cerna, M.; Concezzi, S. [National Instruments, Austin, TX 78759-3504 (United States); Giannone, L. [Max-Planck-Institute for Plasma Physics, EURATOM-IPP Association, D-85748 Garching (Germany); Morrow, G. [National Instruments, Austin, TX 78759-3504 (United States); Ruan, Q., E-mail: qing.ruan@ni.com [National Instruments, Austin, TX 78759-3504 (United States); Veeramani, A.; Wenzel, L. [National Instruments, Austin, TX 78759-3504 (United States)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Introduce a spectral algorithm based Grad-Shafranov equation solver. Black-Right-Pointing-Pointer Implement the solver using LabVIEW with cycle time less than 1 ms. Black-Right-Pointing-Pointer Benchmark the redesign of a MIMO controller. - Abstract: Plasma control experiments require enormous computational power to solve large problems with critical time constraints. For tokamak control, the non-linear and constrained Grad-Shafranov equation needs to be solved in real-time with a cycle time of less than 1 ms. A new algorithm for the solution of this equation based on discrete sine transforms and a tridiagonal solver rather than the commonly used cyclic reduction algorithm is presented. Input signals from magnetic probes and flux loops are the constraints for the equation that must be continuously solved to calculate the magnetic equilibrium. A number of novel mathematical ideas were introduced and several generally applicable numerical strategies were developed using LabVIEW graphical dataflow programming to meet the critical timing goals. Benchmarks on CPUs are reported. Furthermore, the design of a MIMO (multiple input and output) controller to demonstrate the possibilities of tokamak position and shape control using graphical dataflow programming is discussed.

  18. Antenna allocation in MIMO radar with widely separated antennas for multi-target detection.

    Science.gov (United States)

    Gao, Hao; Wang, Jian; Jiang, Chunxiao; Zhang, Xudong

    2014-10-27

    In this paper, we explore a new resource called multi-target diversity to optimize the performance of multiple input multiple output (MIMO) radar with widely separated antennas for detecting multiple targets. In particular, we allocate antennas of the MIMO radar to probe different targets simultaneously in a flexible manner based on the performance metric of relative entropy. Two antenna allocation schemes are proposed. In the first scheme, each antenna is allocated to illuminate a proper target over the entire illumination time, so that the detection performance of each target is guaranteed. The problem is formulated as a minimum makespan scheduling problem in the combinatorial optimization framework. Antenna allocation is implemented through a branch-and-bound algorithm and an enhanced factor 2 algorithm. In the second scheme, called antenna-time allocation, each antenna is allocated to illuminate different targets with different illumination time. Both antenna allocation and time allocation are optimized based on illumination probabilities. Over a large range of transmitted power, target fluctuations and target numbers, both of the proposed antenna allocation schemes outperform the scheme without antenna allocation. Moreover, the antenna-time allocation scheme achieves a more robust detection performance than branch-and-bound algorithm and the enhanced factor 2 algorithm when the target number changes.

  19. Unified tractable model for downlink MIMO cellular networks using stochastic geometry

    KAUST Repository

    Afify, Laila H.

    2016-07-26

    Several research efforts are invested to develop stochastic geometry models for cellular networks with multiple antenna transmission and reception (MIMO). On one hand, there are models that target abstract outage probability and ergodic rate for simplicity. On the other hand, there are models that sacrifice simplicity to target more tangible performance metrics such as the error probability. Both types of models are completely disjoint in terms of the analytic steps to obtain the performance measures, which makes it challenging to conduct studies that account for different performance metrics. This paper unifies both techniques and proposes a unified stochastic-geometry based mathematical paradigm to account for error probability, outage probability, and ergodic rates in MIMO cellular networks. The proposed model is also unified in terms of the antenna configurations and leads to simpler error probability analysis compared to existing state-of-the-art models. The core part of the analysis is based on abstracting unnecessary information conveyed within the interfering signals by assuming Gaussian signaling. To this end, the accuracy of the proposed framework is verified against state-of-the-art models as well as system level simulations. We provide via this unified study insights on network design by reflecting system parameters effect on different performance metrics. © 2016 IEEE.

  20. Public policy and regulatory strategies in the global climate change context: opportunities and limitations of programmatic CDM; Politicas publicas e estrategias regulatorias no contexto das mudancas climaticas globais: oportunidades e limitacoes do MDL programatico

    Energy Technology Data Exchange (ETDEWEB)

    Romeiro, Viviane; Simoes, Andre Felipe; Januzzi, Gilberto M. [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Planejamento de Sistemas Energeticos

    2008-07-01

    Carbon Market and its implications to reduce green house effect has been broadly discussed in the context of global climate change. This paper intends to analyze the new regulation of global climate change since Programmatic CDM was created, describing the proceeds to its implementation and discussing limitations and opportunities analyzes of this mechanism as a tool to obtain alternative energy source. It is discussed the challenges and opportunities about CDM programs in the international legal system in which Kyoto Protocol is based, as well as its contribution to attain benefits to global climate system and quality of social life. (author)

  1. Galaxy clustering, CMB and supernova data constraints on ϕCDM model with massive neutrinos

    Directory of Open Access Journals (Sweden)

    Yun Chen

    2016-01-01

    Full Text Available We investigate a scalar field dark energy model (i.e., ϕCDM model with massive neutrinos, where the scalar field possesses an inverse power-law potential, i.e., V(ϕ∝ϕ−α (α>0. We find that the sum of neutrino masses Σmν has significant impacts on the CMB temperature power spectrum and on the matter power spectrum. In addition, the parameter α also has slight impacts on the spectra. A joint sample, including CMB data from Planck 2013 and WMAP9, galaxy clustering data from WiggleZ and BOSS DR11, and JLA compilation of Type Ia supernova observations, is adopted to confine the parameters. Within the context of the ϕCDM model under consideration, the joint sample determines the cosmological parameters to high precision: the angular size of the sound horizon at recombination, the Thomson scattering optical depth due to reionization, the physical densities of baryons and cold dark matter, and the scalar spectral index are estimated to be θ⁎=(1.0415−0.0011+0.0012×10−2, τ=0.0914−0.0242+0.0266, Ωbh2=0.0222±0.0005, Ωch2=0.1177±0.0036, and ns=0.9644−0.0119+0.0118, respectively, at 95% confidence level (CL. It turns out that α<4.995 at 95% CL for the ϕCDM model. And yet, the ΛCDM scenario corresponding to α=0 is not ruled out at 95% CL. Moreover, we get Σmν<0.262 eV at 95% CL for the ϕCDM model, while the corresponding one for the ΛCDM model is Σmν<0.293 eV. The allowed scale of Σmν in the ϕCDM model is a bit smaller than that in the ΛCDM model. It is consistent with the qualitative analysis, which reveals that the increases of α and Σmν both can result in the suppression of the matter power spectrum. As a consequence, when α is larger, in order to avoid suppressing the matter power spectrum too much, the value of Σmν should be smaller.

  2. Downlink Performance of a Multi-Carrier MIMO System in a Bursty Traffic Cellular Network

    DEFF Research Database (Denmark)

    Nguyen, Hung Tuan; Kovacs, Istvan; Wang, Yuanye

    2011-01-01

    In this paper we analyse the downlink performance of a rank adaptive multiple input multiple output (MIMO) system in a busty traffic cellular network. A LTE-Advanced system with multiple component carriers was selected as a study case. To highlight the advantage of using MIMO techniques, we used...... a single input multiple output (SIMO) system as a baseline for performance comparison. The gain mechanisms of the MIMO system over the SIMO system are investigated and their characteristic at different traffic load conditions are highlighted. The simulation results are used to verified our proposed model...... to predict the performance of the SIMO and MIMO systems in a bursty traffic network....

  3. Body Loss Study of Beamforming Mode in LTE MIMO Mobile Terminals

    DEFF Research Database (Denmark)

    Zhang, Shuai; Zhao, Kun; Ying, Zhinong

    2015-01-01

    This paper mainly focuses on the investigation of the body loss of beamforming mode in LTE MIMO mobile terminals with CTIA user effects. The research of the body loss and radiation efficiency is carried out over different phase differences between two ports of each MIMO antenna. During studies......, four kinds of typical LTE MIMO antennas are used, namely, collocated ground free (GF), parallel GF, parallel on ground (OG) and orthogonal OG MIMO antennas, under four mobile terminal lengths at low and high frequencies. Two kinds of CTIA user effects are included in the research. From the studies...

  4. Mutual Coupling Reduction for UWB MIMO Antennas with a Wideband Neutralization Line

    DEFF Research Database (Denmark)

    Zhang, Shuai; Pedersen, Gert F.

    2016-01-01

    A wideband neutralization line is proposed to reduce the mutual coupling of a compact ultrawideband (UWB) MIMO antenna. With the introduced decoupling method, the designed UWB MIMO antenna covers the band of 3.1-5 GHz with an isolation of higher than 22 dB. The proposed wideband neutralization line...... is not necessarily placed in the clearance area between two MIMO elements and can be put above the copper ground. A small clearance (antenna area) of 35 mm × 16 mm is achieved. The designed UWB MIMO antenna is fabricated. S parameters, radiation patterns, total efficiency and realized gain of the prototype...

  5. VLSI architecture of a K-best detector for MIMO-OFDM wireless communication systems

    International Nuclear Information System (INIS)

    Jian Haifang; Shi Yin

    2009-01-01

    The K-best detector is considered as a promising technique in the MIMO-OFDM detection because of its good performance and low complexity. In this paper, a new K-best VLSI architecture is presented. In the proposed architecture, the metric computation units (MCUs) expand each surviving path only to its partial branches, based on the novel expansion scheme, which can predetermine the branches' ascending order by their local distances. Then a distributed sorter sorts out the new K surviving paths from the expanded branches in pipelines. Compared to the conventional K-best scheme, the proposed architecture can approximately reduce fundamental operations by 50% and 75% for the 16-QAM and the 64-QAM cases, respectively, and, consequently, lower the demand on the hardware resource significantly. Simulation results prove that the proposed architecture can achieve a performance very similar to conventional K-best detectors. Hence, it is an efficient solution to the K-best detector's VLSI implementation for high-throughput MIMO-OFDM systems.

  6. VLSI architecture of a K-best detector for MIMO-OFDM wireless communication systems

    Energy Technology Data Exchange (ETDEWEB)

    Jian Haifang; Shi Yin, E-mail: jhf@semi.ac.c [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2009-07-15

    The K-best detector is considered as a promising technique in the MIMO-OFDM detection because of its good performance and low complexity. In this paper, a new K-best VLSI architecture is presented. In the proposed architecture, the metric computation units (MCUs) expand each surviving path only to its partial branches, based on the novel expansion scheme, which can predetermine the branches' ascending order by their local distances. Then a distributed sorter sorts out the new K surviving paths from the expanded branches in pipelines. Compared to the conventional K-best scheme, the proposed architecture can approximately reduce fundamental operations by 50% and 75% for the 16-QAM and the 64-QAM cases, respectively, and, consequently, lower the demand on the hardware resource significantly. Simulation results prove that the proposed architecture can achieve a performance very similar to conventional K-best detectors. Hence, it is an efficient solution to the K-best detector's VLSI implementation for high-throughput MIMO-OFDM systems.

  7. On Secure Underlay MIMO Cognitive Radio Networks with Energy Harvesting and Transmit Antenna Selection

    KAUST Repository

    Lei, Hongjiang

    2017-03-20

    In this paper, we consider an underlay multipleinput- multiple-output (MIMO) cognitive radio network (CRN) including a pair of primary nodes, a couple of secondary nodes, and an eavesdropper, where the secondary transmitter is powered by the renewable energy harvested from the primary transmitter in order to improve both energy efficiency and spectral efficiency. Based on whether the channel state information (CSI) of wiretap links are available or not, the secrecy outage performance of the optimal antenna selection (OAS) scheme and suboptimal antenna selection (SAS) scheme for underlay MIMO CRN with energy harvesting are investigated and compared with traditional space-time transmission scheme. The closed-form expressions for exact and asymptotic secrecy outage probability are derived. Monte-Carlo simulations are conducted to testify the accuracy of the analytical results. The analysis illustrates that OAS scheme outperforms SAS scheme. Furthermore, the asymptotic result shows that no matter which scheme is considered, the OAS and SAS schemes can achieve the same secrecy diversity order.

  8. Multidimensional Taylor Network Optimal Control of MIMO Nonlinear Systems without Models for Tracking by Output Feedback

    Directory of Open Access Journals (Sweden)

    Qi-Ming Sun

    2017-01-01

    Full Text Available The actual controlled objects are generally multi-input and multioutput (MIMO nonlinear systems with imprecise models or even without models, so it is one of the hot topics in the control theory. Due to the complex internal structure, the general control methods without models tend to be based on neural networks. However, the neuron of neural networks includes the exponential function, which contributes to the complexity of calculation, making the neural network control unable to meet the real-time requirements. The newly developed multidimensional Taylor network (MTN requires only addition and multiplication, so it is easy to realize real-time control. In the present study, the MTN approach is extended to MIMO nonlinear systems without models to realize adaptive output feedback control. The MTN controller is proposed to guarantee the stability of the closed-loop system. Our experimental results show that the output signals of the system are bounded and the tracking error goes nearly to zero. The MTN optimal controller is proven to promise far better real-time dynamic performance and robustness than the BP neural network self-adaption reconstitution controller.

  9. A Blind Antenna Selection Scheme for Single-Cell Uplink Massive MIMO

    KAUST Repository

    Elkhalil, Khalil

    2017-02-09

    This paper considers the uplink of a single-cell large-scale multiple-input multiple output (MIMO) system in which m mono-antenna users communicate with a base station (BS) outfitted by n antennas. We assume that the number of antennas at the BS and that of users take large values, as envisioned by large-scale MIMO systems. This allows for high spectral efficiency gains but obviously comes at the cost of higher complexity, a fact that becomes all the more critical as the number of antennas grows large. To solve this issue is to choose a subset of the available n antennas. The subset must be carefully chosen to achieve the best performance. However, finding the optimal subset of antennas is usually a difficult task, requiring one to solve a high dimensional combinatorial optimization problem. In this paper, we approach this problem in two ways. The first one consists in solving a convex relaxation of the problem using standard convex optimization tools. The second technique solves the problem using a greedy approach. The main advantages of the greedy approach lies in its wider scope, in that, unlike the first approach, it can be applied irrespective of the considered performance criterion. As an outcome of this feature, we show that the greedy approach can be applied even when only the channel statistics are available at the BS, which provides blind way to perform antenna selection.

  10. Spatial correlation characterization of a uniform circular array in 3D MIMO systems

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2016-08-11

    In this paper, we consider a uniform circular array (UCA) of directional antennas at the base station (BS) and the mobile station (MS) and derive an exact closed-form expression for the spatial correlation present in the 3D multiple-input multiple-output (MIMO) channel constituted by these arrays. The underlying method leverages the mathematical convenience of the spherical harmonic expansion (SHE) of plane waves and the trigonometric expansion of Legendre and associated Legendre polynomials. In contrast to the existing results, this generalized closed-form expression is independent of the form of the underlying angular distributions and antenna patterns. Moreover, the incorporation of the elevation dimension into the antenna pattern and channel model renders the proposed expression extremely useful for the performance evaluation of 3D MIMO systems in the future. Verification is achieved with the help of simulation results, which highlight the dependence of the spatial correlation on channel and array parameters. An interesting interplay between the mean angle of departure (AoD), angular spread and the positioning of antennas in the array is demonstrated. © 2016 IEEE.

  11. Spreading Code Assignment Strategies for MIMO-CDMA Systems Operating in Frequency-Selective Channels

    Directory of Open Access Journals (Sweden)

    Dahmane AdelOmar

    2009-01-01

    Full Text Available Abstract Code Division Multiple Access (CDMA and multiple input multiple output- (MIMO- CDMA systems suffer from multiple access interference (MAI which limits the spectral efficiency of these systems. By making these systems more power efficient, we can increase the overall spectral efficiency. This can be achieved through the use of improved modulation and coding techniques. Conventional MIMO-CDMA systems use fixed spreading code assignments. By strategically selecting the spreading codes as a function of the data to be transmitted, we can achieve coding gain and introduce additional degrees of freedom in the decision variables at the output of the matched filters. In this paper, we examine the bit error rate performance of parity bit-selected spreading and permutation spreading under different wireless channel conditions. A suboptimal detection technique based on maximum likelihood detection is proposed for these systems operating in frequency selective channels. Simulation results demonstrate that these code assignment techniques provide an improvement in performance in terms of bit error rate (BER while providing increased spectral efficiency compared to the conventional system. Moreover, the proposed strategies are more robust to channel estimation errors as well as spatial correlation.

  12. Equivalent ZF precoding scheme for downlink indoor MU-MIMO VLC systems

    Science.gov (United States)

    Fan, YangYu; Zhao, Qiong; Kang, BoChao; Deng, LiJun

    2018-01-01

    In indoor visible light communication (VLC) systems, the channels of photo detectors (PDs) at one user are highly correlated, which determines the choice of spatial diversity model for individual users. In a spatial diversity model, the signals received by PDs belonging to one user carry the same information, and can be combined directly. Based on the above, we propose an equivalent zero-forcing (ZF) precoding scheme for multiple-user multiple-input single-output (MU-MIMO) VLC systems by transforming an indoor MU-MIMO VLC system into an indoor multiple-user multiple-input single-output (MU-MISO) VLC system through simply processing. The power constraints of light emitting diodes (LEDs) are also taken into account. Comprehensive computer simulations in three scenarios indicate that our scheme can not only reduce the computational complexity, but also guarantee the system performance. Furthermore, the proposed scheme does not require noise information in the calculating of the precoding weights, and has no restrictions on the numbers of APs and PDs.

  13. MIMO signal progressing with RLSCMA algorithm for multi-mode multi-core optical transmission system

    Science.gov (United States)

    Bi, Yuan; Liu, Bo; Zhang, Li-jia; Xin, Xiang-jun; Zhang, Qi; Wang, Yong-jun; Tian, Qing-hua; Tian, Feng; Mao, Ya-ya

    2018-01-01

    In the process of transmitting signals of multi-mode multi-core fiber, there will be mode coupling between modes. The mode dispersion will also occur because each mode has different transmission speed in the link. Mode coupling and mode dispersion will cause damage to the useful signal in the transmission link, so the receiver needs to deal received signal with digital signal processing, and compensate the damage in the link. We first analyzes the influence of mode coupling and mode dispersion in the process of transmitting signals of multi-mode multi-core fiber, then presents the relationship between the coupling coefficient and dispersion coefficient. Then we carry out adaptive signal processing with MIMO equalizers based on recursive least squares constant modulus algorithm (RLSCMA). The MIMO equalization algorithm offers adaptive equalization taps according to the degree of crosstalk in cores or modes, which eliminates the interference among different modes and cores in space division multiplexing(SDM) transmission system. The simulation results show that the distorted signals are restored efficiently with fast convergence speed.

  14. Adaptive NN controller design for a class of nonlinear MIMO discrete-time systems.

    Science.gov (United States)

    Liu, Yan-Jun; Tang, Li; Tong, Shaocheng; Chen, C L Philip

    2015-05-01

    An adaptive neural network tracking control is studied for a class of multiple-input multiple-output (MIMO) nonlinear systems. The studied systems are in discrete-time form and the discretized dead-zone inputs are considered. In addition, the studied MIMO systems are composed of N subsystems, and each subsystem contains unknown functions and external disturbance. Due to the complicated framework of the discrete-time systems, the existence of the dead zone and the noncausal problem in discrete-time, it brings about difficulties for controlling such a class of systems. To overcome the noncausal problem, by defining the coordinate transformations, the studied systems are transformed into a special form, which is suitable for the backstepping design. The radial basis functions NNs are utilized to approximate the unknown functions of the systems. The adaptation laws and the controllers are designed based on the transformed systems. By using the Lyapunov method, it is proved that the closed-loop system is stable in the sense that the semiglobally uniformly ultimately bounded of all the signals and the tracking errors converge to a bounded compact set. The simulation examples and the comparisons with previous approaches are provided to illustrate the effectiveness of the proposed control algorithm.

  15. Cyclic Communication and the Inseparability of MIMO Multi-way Relay Channels

    KAUST Repository

    Chaaban, Anas

    2015-10-27

    The K-user MIMO multi-way relay channel (Ychannel) consisting of K users with M antennas each and a common relay node with N antennas is studied in this paper. Each user wants to exchange messages with all the other users via the relay. A transmission strategy is proposed for this channel. The proposed strategy is based on two steps: channel diagonalization and cyclic communication. The channel diagonalization is applied by using zero-forcing beam-forming. After channel diagonalization, the channel is decomposed into parallel sub-channels. Cyclic communication is then applied, where signal-space alignment for network-coding is used over each sub-channel. The proposed strategy achieves the optimal DoF region of the channel if N M. To prove this, a new degrees-of-freedom outer bound is derived. As a by-product, we conclude that the MIMO Y-channel is not separable, i.e., independent coding on separate sub-channels is not enough, and one has to code jointly over several sub-channels.

  16. Iterative Multiuser Equalization for Subconnected Hybrid mmWave Massive MIMO Architecture

    Directory of Open Access Journals (Sweden)

    R. Magueta

    2017-01-01

    Full Text Available Millimeter waves and massive MIMO are a promising combination to achieve the multi-Gb/s required by future 5G wireless systems. However, fully digital architectures are not feasible due to hardware limitations, which means that there is a need to design signal processing techniques for hybrid analog-digital architectures. In this manuscript, we propose a hybrid iterative block multiuser equalizer for subconnected millimeter wave massive MIMO systems. The low complexity user-terminals employ pure-analog random precoders, each with a single RF chain. For the base station, a subconnected hybrid analog-digital equalizer is designed to remove multiuser interference. The hybrid equalizer is optimized using the average bit-error-rate as a metric. Due to the coupling between the RF chains in the optimization problem, the computation of the optimal solutions is too complex. To address this problem, we compute the analog part of the equalizer sequentially over the RF chains using a dictionary built from the array response vectors. The proposed subconnected hybrid iterative multiuser equalizer is compared with a recently proposed fully connected approach. The results show that the performance of the proposed scheme is close to the fully connected hybrid approach counterpart after just a few iterations.

  17. A Tale of Two Sites: Lessons on Leadership from the Implementation of a Long-term Care Delivery Model (CDM in Western Canada

    Directory of Open Access Journals (Sweden)

    Denise Cloutier

    2016-01-01

    Full Text Available Residential, long-term care serves vulnerable older adults in a facility-based environment. A new care delivery model (CDM designed to promote more equitable care for residents was implemented in a health region in Western Canada. Leaders and managers faced challenges in implementing this model alongside other concurrent changes. This paper explores the question: How did leadership style influence team functioning with the implementation of the CDM? Qualitative data from interviews with leadership personnel (directors and managers, residential care coordinators and clinical nurse educators, and direct care staff (registered nurses, licensed practical nurses, health care aides, and allied health therapists, working in two different facilities comprise the main sources of data for this study. The findings reveal that leaders with a servant leadership style were better able to create and sustain the conditions to support successful model implementation and higher team functioning, compared to a facility in which the leadership style was less inclusive and proactive, and more resistant to the change. Consequently, staff at the second facility experienced a greater sense of overload with the implementation of the CDM. This study concludes that strong leadership is key to facilitating team work and job satisfaction in a context of change.

  18. A Tale of Two Sites: Lessons on Leadership from the Implementation of a Long-term Care Delivery Model (CDM) in Western Canada.

    Science.gov (United States)

    Cloutier, Denise; Cox, Amy; Kampen, Ruth; Kobayashi, Karen; Cook, Heather; Taylor, Deanne; Gaspard, Gina

    2016-01-04

    Residential, long-term care serves vulnerable older adults in a facility-based environment. A new care delivery model (CDM) designed to promote more equitable care for residents was implemented in a health region in Western Canada. Leaders and managers faced challenges in implementing this model alongside other concurrent changes. This paper explores the question: How did leadership style influence team functioning with the implementation of the CDM? Qualitative data from interviews with leadership personnel (directors and managers, residential care coordinators and clinical nurse educators), and direct care staff (registered nurses, licensed practical nurses, health care aides, and allied health therapists), working in two different facilities comprise the main sources of data for this study. The findings reveal that leaders with a servant leadership style were better able to create and sustain the conditions to support successful model implementation and higher team functioning, compared to a facility in which the leadership style was less inclusive and proactive, and more resistant to the change. Consequently, staff at the second facility experienced a greater sense of overload with the implementation of the CDM. This study concludes that strong leadership is key to facilitating team work and job satisfaction in a context of change.

  19. Reheating via Gravitational Particle Production in Simple Models of Quintessence or ΛCDM Inflation

    Directory of Open Access Journals (Sweden)

    Jaume de Haro

    2017-11-01

    Full Text Available We have tested some simple Λ CDM (the same test is also valid for quintessence inflation models, imposing that they match with the recent observational data provided by the BICEP and Planck’s team and leading to a reheating temperature, which is obtained via gravitational particle production after inflation, supporting the nucleosynthesis success.

  20. Reheating via Gravitational Particle Production in Simple Models of Quintessence or ΛCDM Inflation

    Science.gov (United States)

    de Haro, Jaume; Aresté Saló, Llibert

    2017-11-01

    We have tested some simple $Lambda$CDM (the same test is also valid for quintessence) inflation models, imposing that they match with the recent observational data provided by the BICEP and Planck's team and leading to a reheating temperature, which is obtained via gravitational particle production after inflation, supporting the nucleosynthesis success.

  1. Transaction costs of unilateral CDM projects in India-results from an empirical survey

    International Nuclear Information System (INIS)

    Krey, Matthias

    2005-01-01

    Recently, transaction costs in the context of the Clean Development Mechanism (CDM) gained considerable attention as they were generally perceived to be significantly higher than for the other Kyoto Mechanisms. However, empirical evidence on the amount of transaction costs of CDM projects is very scarce. This paper presents the results from an empirical survey designed to quantify transaction costs of potential non-sink CDM projects in India. The definition of transaction costs of CDM projects was derived from recent literature and observations made in the current market for Certified Emission Reductions (CERs). During the survey, parts of transaction costs of 15 projects were quantified. An assessment of the results showed that specific transaction costs depend, to a large extent, on economies of scale in terms of total amount of CERs generated over the crediting period. Total transaction costs were quantified for seven projects. The costs range from 0.07 to 0.47 dollar/t CO 2 . As the projects have an emission reduction between 0.24 Mt CO 2 and 5.00 Mt CO 2 over the crediting period, the results support the assumption of Michaelowa et al. (Climate Policy 3 (2003) 273) that projects with emission reductions smaller than 0.20 Mt CO 2 are not economically viable at current CER prices

  2. Assessing measurement errors in the CDM research–innovation–productivity relationships

    NARCIS (Netherlands)

    Mairesse, J.; Robin, S.

    2017-01-01

    The Crépon-Duguet-Mairesse 1998 article, known as CDM, initiated a structural econometric framework to analyze the relationships among research, innovation and productivity, which has been estimated most generally on the basis of cross-sectional innovation survey-type data. Some econometric

  3. Comparison between the Logotropic and ΛCDM models at the cosmological scale

    Science.gov (United States)

    Chavanis, Pierre-Henri; Kumar, Suresh

    2017-05-01

    We perform a detailed comparison between the Logotropic model [P.H. Chavanis, Eur. Phys. J. Plus, 130 (2015)] and the ΛCDM model. These two models behave similarly at large (cosmological) scales up to the present. Differences will appear only in the far future, in about 25 Gyrs, when the Logotropic Universe becomes phantom while the ΛCDM Universe enters in the de Sitter era. However, the Logotropic model differs from the ΛCDM model at small (galactic) scales, where the latter encounters serious problems. Having a nonvanishing pressure, the Logotropic model can solve the cusp problem and the missing satellite problem of the ΛCDM model. In addition, it leads to dark matter halos with a constant surface density Σ0=ρ0 rh, and can explain its observed value Σ0=141 Msolar/pc2 without adjustable parameter. This makes the logotropic model rather unique among all the models attempting to unify dark matter and dark energy. In this paper, we compare the Logotropic and ΛCDM models at the cosmological scale where they are very close to each other in order to determine quantitatively how much they differ. This comparison is facilitated by the fact that these models depend on only two parameters, the Hubble constant H0 and the present fraction of dark matter Ωm0. Using the latest observational data from Planck 2015+Lensing+BAO+JLA+HST, we find that the best fit values of H0 and Ωm0 are H0=68.30 km s-1 Mpc-1 and Ωm0=0.3014 for the Logotropic model, and H0=68.02 km s-1 Mpc-1 and Ωm0=0.3049 for the ΛCDM model. The difference between the two models is at the percent level. As a result, the Logotropic model competes with the ΛCDM model at large scales and solves its problems at small scales. It may therefore represent a viable alternative to the ΛCDM model. Our study provides an explicit example of a theoretically motivated model that is almost indistinguishable from the ΛCDM model at the present time while having a completely different (phantom) evolution in the

  4. Low profile frequency agile MIMO slot antenna with TCM characterization

    KAUST Repository

    Ghalib, Asim

    2017-06-07

    In this paper, a frequency reconfigurable multiple-input-multiple-output (MIMO) slot antenna is presented. The proposed design is low profile and compact with wide tunability range, covering several well-known frequency bands from 1800 MHz to 2450 MHz. The frequency reconfigurability is achieved by loading the annular slot with varactor diodes. The antenna system is also analyzed for MIMO performance metrics. Moreover, the effect of circular slot antenna on the chassis modes is also investigated using the theory of characteristic modes (TCM). The physical principle behind frequency reconfigurability is also investigated using TCM analysis. An interesting finding is observed using varactor diodes for frequency reconfigurability, that is the reactive impedance loading does not alter the modal significance (MS) plots but only aid in the input impedance matching at different frequency bands.

  5. Design and optimization of LTE 1800 MIMO antenna.

    Science.gov (United States)

    Wong, Huey Shin; Islam, Mohammad Tariqul; Kibria, Salehin

    2014-01-01

    A multiple input and multiple output (MIMO) antenna that comprises a printed microstrip antenna and a printed double-L sleeve monopole antenna for LTE 1800 wireless application is presented. The printed double-L sleeve monopole antenna is fed by a 50 ohm coplanar waveguide (CPW). A novel T-shaped microstrip feedline printed on the other side of the PCB is used to excite the waveguide's outer shell. Isolation characteristics better than -15 dB can be obtained for the proposed MIMO antenna. The proposed antenna can operate in LTE 1800 (1710 MHz-1880 MHz). This antenna exhibits omnidirectional characteristics. The efficiency of the antenna is greater than 70% and has high gain of 2.18 dBi.

  6. Separate DOD and DOA Estimation for Bistatic MIMO Radar

    Directory of Open Access Journals (Sweden)

    Lin Li

    2016-01-01

    Full Text Available A novel MUSIC-type algorithm is derived in this paper for the direction of departure (DOD and direction of arrival (DOA estimation in a bistatic MIMO radar. Through rearranging the received signal matrix, we illustrate that the DOD and the DOA can be separately estimated. Compared with conventional MUSIC-type algorithms, the proposed separate MUSIC algorithm can avoid the interference between DOD and DOA estimations effectively. Therefore, it is expected to give a better angle estimation performance and have a much lower computational complexity. Meanwhile, we demonstrate that our method is also effective for coherent targets in MIMO radar. Simulation results verify the efficiency of the proposed method, particularly when the signal-to-noise ratio (SNR is low and/or the number of snapshots is small.

  7. Design and Optimization of LTE 1800 MIMO Antenna

    Science.gov (United States)

    Wong, Huey Shin; Islam, Mohammad Tariqul

    2014-01-01

    A multiple input and multiple output (MIMO) antenna that comprises a printed microstrip antenna and a printed double-L sleeve monopole antenna for LTE 1800 wireless application is presented. The printed double-L sleeve monopole antenna is fed by a 50 ohm coplanar waveguide (CPW). A novel T-shaped microstrip feedline printed on the other side of the PCB is used to excite the waveguide's outer shell. Isolation characteristics better than −15 dB can be obtained for the proposed MIMO antenna. The proposed antenna can operate in LTE 1800 (1710 MHz–1880 MHz). This antenna exhibits omnidirectional characteristics. The efficiency of the antenna is greater than 70% and has high gain of 2.18 dBi. PMID:24967440

  8. Efficient collaborative sparse channel estimation in massive MIMO

    KAUST Repository

    Masood, Mudassir

    2015-08-12

    We propose a method for estimation of sparse frequency selective channels within MIMO-OFDM systems. These channels are independently sparse and share a common support. The method estimates the impulse response for each channel observed by the antennas at the receiver. Estimation is performed in a coordinated manner by sharing minimal information among neighboring antennas to achieve results better than many contemporary methods. Simulations demonstrate the superior performance of the proposed method.

  9. Coding for MIMO-OFDM in future wireless systems

    CERN Document Server

    Ahmed, Bannour

    2015-01-01

    This book introduces the reader to the MIMO-OFDM system, in Rayleigh frequency selective-channels. Orthogonal frequency division multiplexing (OFDM) has been adopted in the wireless local-area network standards IEEE 802.11a due to its high spectral efficiency and ability to deal with frequency selective fading. The combination of OFDM with spectral efficient multiple antenna techniques makes the OFDM a good candidate to overcome the frequency selective problems.

  10. Analytical Computation of Information Rate for MIMO Channels

    Directory of Open Access Journals (Sweden)

    Jinbao Zhang

    2017-01-01

    Full Text Available Information rate for discrete signaling constellations is significant. However, the computational complexity makes information rate rather difficult to analyze for arbitrary fading multiple-input multiple-output (MIMO channels. An analytical method is proposed to compute information rate, which is characterized by considerable accuracy, reasonable complexity, and concise representation. These features will improve accuracy for performance analysis with criterion of information rate.

  11. Zero-Forcing Pre-coding for MIMO WiMAX Transceivers

    DEFF Research Database (Denmark)

    Cattoni, Andrea Fabio; Le Moullec, Yannick; Sacchi, Claudio

    2013-01-01

    Next generation wireless communication networks are expected to achieve ever increasing data rates. Multi-User Multiple-Input-Multiple-Output (MU-MIMO) is a key technique to obtain the expected performance, because such a technique combines the high capacity achievable using MIMO channel with the...

  12. MIMO-OFDM WDM PON with DM-VCSEL for femtocells application

    DEFF Research Database (Denmark)

    Binti Othman, Maisara; Deng, Lei; Pang, Xiaodan

    2011-01-01

    We report on experimental demonstration of 2x2 MIMO-OFDM 5.6-GHz radio over fiber signaling over 20 km WDM-PON with directly modulated (DM) VCSELs for femtocells application. MIMO-OFDM algorithms effectively compensate for impairments in the wireless link. Error-free signal demodulation of 64...

  13. Throughput Modeling and Validations for MIMO-OTA Testing with Arbitrary Multipath

    DEFF Research Database (Denmark)

    Chen, Xiaoming; Fan, Wei; Hentilä, Lassi

    2018-01-01

    A simple throughput model for multiple-input multiple-output (MIMO) systems has been proposed in the literature. The model takes the MIMO antenna effects into account and shows good agreement with measured throughputs in a reverberation chamber (RC). The RC emulates a multipath environment with i...

  14. Investigation of Diagonal Antenna-Chassis Mode in Mobile Terminal LTE MIMO Antennas for Bandwidth Enhancement

    DEFF Research Database (Denmark)

    Zhang, Shuai; Zhao, Kun; Ying, Zhinong

    2015-01-01

    A diagonal antenna-chassis mode is investigated in long-term evolution multiple-input-multiple-output (LTE MIMO) antennas. The MIMO bandwidth is defined in this paper as the overlap range of the low-envelope correlation coefficient, high total efficiency, and -6-dB impedance matching bandwidths...

  15. Frequency-domain 2×2 MIMO equalizer with stokes space updating algorithm

    DEFF Research Database (Denmark)

    Vaquero Caballero, F. J.; Zanaty, A.; Pittalà, Fabio

    2016-01-01

    We propose a novel frequency-domain Stokes space algorithm. Its low implementation complexity architecture allows merging static and dynamic 2×2 MIMO equalization in a single stage.......We propose a novel frequency-domain Stokes space algorithm. Its low implementation complexity architecture allows merging static and dynamic 2×2 MIMO equalization in a single stage....

  16. MIMO channel capacity versus mutual coupling in multi antenna element system

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2004-01-01

    In this paper the influence of mutual coupling on the capacity of a multiple-input multiple-output (MIMO) antenna system is demonstrated. No direct relation between the envelope correlation and the actual location and orientation of the antennas is found. Even though being essential for high MIMO...

  17. Student insight into the MIMO project's process, outcomes and feedback in Estonia / Ebe Link, Liis Luumberg

    Index Scriptorium Estoniae

    Link, Ebe

    2013-01-01

    MIMO projekt 2010-2013: 2011. ja 2012. a. Eesti linnades toimunud rahvusvahelise muusikaloome alase koolitus- ja noorteprojekti MIMO (Moving in! Moving on!) raames toimunust. Viljandi Kultuuriakadeemia tudengite töötubadest Eesti väikelinnade koolides ja noortekeskustes. Noorte poolt antud tagasisidest töötubadele

  18. Resource allocation and MIMO for 4G and beyond

    CERN Document Server

    2014-01-01

    This book presents the underlying technological breakthroughs that allowed the current state of wireless technology development to evolve. The book focuses on the two lower layers of the ISO/OSI layered model, specifically the physical and data link layers including the media access control sub-layer. These two layers are of particular importance to wireless systems due to the spectrum shortage, the broadcast nature of interference, and time variability in the wireless channel. Topics covered in this book include: radio resource allocation (RRA) for emerging architectures such as Coordinated Multipoint (CoMP) and Device-to-Device communications (D2D); RRA for quality of service control; propagation and transceiver aspects of MIMO systems; and the design and selection of MIMO multiuser precoders. The proposed approaches for RRA and MIMO are applicable to mobile communication standards such as 3GPP’s LTE and LTE-Advanced, but also apply further to the continuously evolving wireless access technologies lan...

  19. Subcarrier intensity modulation for MIMO visible light communications

    Science.gov (United States)

    Celik, Yasin; Akan, Aydin

    2018-04-01

    In this paper, subcarrier intensity modulation (SIM) is investigated for multiple-input multiple-output (MIMO) visible light communication (VLC) systems. A new modulation scheme called DC-aid SIM (DCA-SIM) is proposed for the spatial modulation (SM) transmission plan. Then, DCA-SIM is extended for multiple subcarrier case which is called DC-aid Multiple Subcarrier Modulation (DCA-MSM). Bit error rate (BER) performances of the considered system are analyzed for different MIMO schemes. The power efficiencies of DCA-SIM and DCA-MSM are shown in correlated MIMO VLC channels. The upper bound BER performances of the proposed models are obtained analytically for PSK and QAM modulation types in order to validate the simulation results. Additionally, the effect of power imbalance method on the performance of SIM is studied and remarkable power gains are obtained compared to the non-power imbalanced cases. In this work, Pulse amplitude modulation (PAM) and MSM-Index are used as benchmarks for single carrier and multiple carrier cases, respectively. And the results show that the proposed schemes outperform PAM and MSM-Index for considered single carrier and multiple carrier communication scenarios.

  20. Energy-Efficient Channel Estimation in MIMO Systems

    Directory of Open Access Journals (Sweden)

    Graff Charles J

    2006-01-01

    Full Text Available The emergence of MIMO communications systems as practical high-data-rate wireless communications systems has created several technical challenges to be met. On the one hand, there is potential for enhancing system performance in terms of capacity and diversity. On the other hand, the presence of multiple transceivers at both ends has created additional cost in terms of hardware and energy consumption. For coherent detection as well as to do optimization such as water filling and beamforming, it is essential that the MIMO channel is known. However, due to the presence of multiple transceivers at both the transmitter and receiver, the channel estimation problem is more complicated and costly compared to a SISO system. Several solutions have been proposed to minimize the computational cost, and hence the energy spent in channel estimation of MIMO systems. We present a novel method of minimizing the overall energy consumption. Unlike existing methods, we consider the energy spent during the channel estimation phase which includes transmission of training symbols, storage of those symbols at the receiver, and also channel estimation at the receiver. We develop a model that is independent of the hardware or software used for channel estimation, and use a divide-and-conquer strategy to minimize the overall energy consumption.