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Sample records for cdm based mimo

  1. Design of Transmitter for CDM Based 2×2 Multiple Input Multiple Output Channel Sounder for Multipath Delay Measurement

    Directory of Open Access Journals (Sweden)

    M. H. Ullah

    2012-01-01

    Full Text Available Problem statement: Multiple Input Multiple Output (MIMO wireless communication system is an innovative solution to improve the bandwidth efficiency by exploiting multipath-richness of the propagation environment. The degree of multipath-richness of the channel will determine the capacity gain attainable by MIMO deployment. Approach: Therefore, it is very important to have accurate knowledge of the propagation environment/radio channel before MIMO implement. The radio channel behavior can be anticipated by channel measurement or channel sounding. Code Division Multiplexing (CDM is one of the channel sounding techniques that allow accurate measurement at the cost of hardware complexity. CDM based channel sounder, requires code with excellent auto-correlation and cross-correlation properties which generally difficult to be achieved simultaneously. Results: In this study, an efficient transmitter for CDM-based 2×2 MIMO channel sounding technique with Loosely Synchronous (LS codes is designed. Simulation results shows that the channel sounding scheme using LS codes gives very good performance for measuring 2×2 MIMO channel behavior. The BPSK transmitter is designed using MATLAB, Verilog and Xilinx system generator blocks. Conclusion: The whole design is simulated as a single ISE project by using ModelSim simulation tool and compiled using ISE 9.2. However the proposed design of transmitter using LS code of length 8190 bits can measure multipath delay of minimum 0.13 μs and maximum 520 μs.

  2. Semiparametric theory based MIMO model and performance analysis

    Institute of Scientific and Technical Information of China (English)

    XU Fang-min; XU Xiao-dong; ZHANG Ping

    2007-01-01

    In this article, a new approach for modeling multi- input multi-output (MIMO) systems with unknown nonlinear interference is introduced. The semiparametric theory based MIMO model is established, and Kernel estimation is applied to combat the nonlinear interference. Furthermore, we derive MIMO capacity for these systems and explore the asymptotic properties of the new channel matrix via theoretical analysis. The simulation results show that the semiparametric theory based modeling and kernel estimation are valid to combat this kind of interference.

  3. Cooperative MIMO Transmissions in WSN Using Threshold Based MAC Protocol

    Directory of Open Access Journals (Sweden)

    J. Vidhya

    2010-08-01

    Full Text Available Sensor networks require robust and efficient communication protocols to maximise the network lifetime.Radio irregularity, channel fading and interference results in larger energy consumption and latency forpacket transmission over wireless channel. Cooperative multi-input multi-output (MIMO schemes whenincorporated in wireless senor network (WSN can significantly improve the communicationperformance. An inefficiently designed medium access control (MAC protocol however, may diminishthe performance gains of MIMO operation. Hence, this paper proposes a distributed threshold basedMAC protocol for cooperative MIMO transmissions using space time block codes (STBC. The protocoluses a thresholding scheme that is updated dynamically based on the queue length at the sending node toachieve lesser energy consumption and minimise latency ensuring the stability of transmission queues atthe nodes. STBC and code combining techniques are applied to utilise the inherent spatial diversity inwireless cooperative MIMO systems. Simulation results are provided to evaluate the performance of theproposed protocol and are compared with fixed group size cooperative MIMO MAC protocols with andwithout STBC coding. Results show that the proposed protocol outperforms point to point communicationas well as cooperative MIMO MAC protocols that use fixed group sizes. STBC technique for the proposedMAC protocol provides significant energy savings and minimises the packet delay by leveraging MIMOdiversity gains.

  4. CSSF MIMO RADAR: Low-Complexity Compressive Sensing Based MIMO Radar That Uses Step Frequency

    CERN Document Server

    Yu, Yao; Poor, H Vincent

    2011-01-01

    A new approach is proposed, namely CSSF MIMO radar, which applies the technique of step frequency (SF) to compressive sensing (CS) based multi-input multi-output (MIMO) radar. The proposed approach enables high resolution range, angle and Doppler estimation, while transmitting narrowband pulses. The problem of joint angle-Doppler-range estimation is first formulated to fit the CS framework, i.e., as an L1 optimization problem. Direct solution of this problem entails high complexity as it employs a basis matrix whose construction requires discretization of the angle-Doppler-range space. Since high resolution requires fine space discretization, the complexity of joint range, angle and Doppler estimation can be prohibitively high. For the case of slowly moving targets, a technique is proposed that achieves significant complexity reduction by successively estimating angle-range and Doppler in a decoupled fashion and by employing initial estimates obtained via matched filtering to further reduce the space that nee...

  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. Subspace- Based Blind Channel Estimation Method for MIMO- OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    HOU Yong-min; RONG Meng-tian

    2005-01-01

    A subspace-based blind channel estimation algorithm for MIMO-OFDM systems is proposed. This algorithm exploits the cyclostationarity introduced by cyclic prefix of OFDM to estimate the channel parameters. The proposed new algorithm is found to be outperforming the other algorithm with respect to convergence rate and achievable mean square error and robustness to channel order over determination.

  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. Optimum Co-Design for Spectrum Sharing between Matrix Completion Based MIMO Radars and a MIMO Communication System

    Science.gov (United States)

    Li, Bo; Petropulu, Athina P.; Trappe, Wade

    2016-09-01

    Recently proposed multiple input multiple output radars based on matrix completion (MIMO-MC) employ sparse sampling to reduce the amount of data that need to be forwarded to the radar fusion center, and as such enable savings in communication power and bandwidth. This paper proposes designs that optimize the sharing of spectrum between a MIMO-MC radar and a communication system, so that the latter interferes minimally with the former. First, the communication system transmit covariance matrix is designed to minimize the effective interference power (EIP) to the radar receiver, while maintaining certain average capacity and transmit power for the communication system. Two approaches are proposed, namely a noncooperative and a cooperative approach, with the latter being applicable when the radar sampling scheme is known at the communication system. Second, a joint design of the communication transmit covariance matrix and the MIMO-MC radar sampling scheme is proposed, which achieves even further EIP reduction.

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

    OpenAIRE

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

    2016-01-01

    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 w...

  10. 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.

  11. Iterative Soft Decision Based Complex K-best MIMO Decoder

    Directory of Open Access Journals (Sweden)

    Mehnaz Rahman

    2015-11-01

    Full Text Available This paper presents an iterative soft decision based complex multiple input multiple output (MIMO decoding algorithm, which reduces the complexity of Maximum Likelihood (ML detector. We develop a novel iterative complex K-best decoder exploiting the techniques of lattice reduction for 8×8 MIMO. Besides list size, a new adjustable variable has been introduced in order to control the on-demand child expansion. Following this method, we obtain 6.9 to 8.0 dB improvement over real domain K-best decoder and 1.4 to 2.5 dB better performance compared to iterative conventional complex decoder for 4th iteration and 64-QAM modulation scheme. We also demonstrate the significance of new parameter on bit error rate. The proposed decoder not only increases the performance, but also reduces the computational complexity to a certain level.

  12. Belief Propagation based MIMO Detection Operating on Quantized Channel Output

    CERN Document Server

    Mezghani, Amine

    2010-01-01

    In multiple-antenna communications, as bandwidth and modulation order increase, system components must work with demanding tolerances. In particular, high resolution and high sampling rate analog-to-digital converters (ADCs) are often prohibitively challenging to design. Therefore ADCs for such applications should be low-resolution. This paper provides new insights into the problem of optimal signal detection based on quantized received signals for multiple-input multiple-output (MIMO) channels. It capitalizes on previous works which extensively analyzed the unquantized linear vector channel using graphical inference methods. In particular, a "loopy" belief propagation-like (BP) MIMO detection algorithm, operating on quantized data with low complexity, is proposed. In addition, we study the impact of finite receiver resolution in fading channels in the large-system limit by means of a state evolution analysis of the BP algorithm, which refers to the limit where the number of transmit and receive antennas go t...

  13. Measurement Matrix Design for Compressive Sensing Based MIMO Radar

    CERN Document Server

    Yu, Y; Poor, H V

    2011-01-01

    In colocated multiple-input multiple-output (MIMO) radar using compressive sensing (CS), a receive node compresses its received signal via a linear transformation, referred to as measurement matrix. The samples are subsequently forwarded to a fusion center, where an L1-optimization problem is formulated and solved for target information. CS-based MIMO radar exploits the target sparsity in the angle-Doppler-range space and thus achieves the high localization performance of traditional MIMO radar but with many fewer measurements. The measurement matrix is vital for CS recovery performance. This paper considers the design of measurement matrices that achieve an optimality criterion that depends on the coherence of the sensing matrix (CSM) and/or signal-to-interference ratio (SIR). The first approach minimizes a performance penalty that is a linear combination of CSM and the inverse SIR. The second one imposes a structure on the measurement matrix and determines the parameters involved so that the SIR is enhanced...

  14. Massive MIMO Systems with Hardware-Constrained Base Stations

    OpenAIRE

    Bjornson, Emil; Matthaiou, Michail; Debbah, Merouane

    2014-01-01

    Massive multiple-input multiple-output (MIMO) systems are cellu-lar networks where the base stations (BSs) are equipped with un-conventionally many antennas. Such large antenna arrays offer huge spatial degrees-of-freedom for transmission optimization; in partic-ular, great signal gains, resilience to imperfect channel knowledge, and small inter-user interference are all achievable without exten-sive inter-cell coordination. The key to cost-efficient deployment of large arrays is the use of h...

  15. Performance Analysis of 3D Massive MIMO Cellular Systems with Collaborative Base Station

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    Xingwang Li

    2014-01-01

    Full Text Available Massive MIMO have drawn considerable attention as they enable significant capacity and coverage improvement in wireless cellular network. However, pilot contamination is a great challenge in massive MIMO systems. Under this circumstance, cooperation and three-dimensional (3D MIMO are emerging technologies to eliminate the pilot contamination and to enhance the performance relative to the traditional interference-limited implementations. Motivated by this, we investigate the achievable sum rate performance of MIMO systems in the uplink employing cooperative base station (BS and 3D MIMO systems. In our model, we consider the effects of both large-scale and small-scale fading, as well as the spatial correlation and indoor-to-outdoor high-rise propagation environment. In particular, we investigate the cooperative communication model based on 3D MIMO and propose a closed-form lower bound on the sum rate. Utilizing this bound, we pursue a “large-system” analysis and provide the asymptotic expression when the number of antennas at the BS grows large, and when the numbers of antennas at transceiver grow large with a fixed ratio. We demonstrate that the lower bound is very tight and becomes exact in the massive MIMO system limits. Finally, under the sum rate maximization condition, we derive the optimal number of UTs to be served.

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

    OpenAIRE

    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 numb...

  17. Stiefel Manifold and TCQ based on Unit Memory Coding for MIMO System

    Directory of Open Access Journals (Sweden)

    Vijey Thayananthan

    2014-02-01

    Full Text Available The Multi Input and Multi Output (MIMO systems have been analyzed with a number of quantization techniques. In this short communication, few problems like performance and accuracy are investigated through a quantization technique based on Stiefel Manifold (SM. In order to improve these problems, suitable Trellis Coded Quantization (TCQ based on Unit Memory (UM coding is studied and applied to SM of MIMO components as a novel approach. Anticipated results are the bit error performance which is an overall improvement of feedback connected between transmitter and receiver of MIMO. As a conclusion, this research not only reduces the quantization problems on SM but also improve the performance and accuracy of limited-rate feedback used in MIMO system.

  18. 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. PMID:27135805

  19. 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.

  20. 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.

  1. EVALUATION OF BER FOR VARIOUS FADING CHANNEL IN DWT BASED MIMO-OFDM SYSTEM

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    D. Meenakshi

    2013-04-01

    Full Text Available MIMO communication is mainly use in the OFDM to improve the communication performance and capacity. DWT based MIMO-OFDM is used in this paper. Compare to the FFT based MIMO-OFDM it has lot advantages. There is no need for cyclic prefix, flexibility and optimal resolution. Ripple(Wavelet concept has developed as a fresh scientific implement with the aim of preserve be functional in several applications such as processing of image, biomedical manufacturing, radar, physics, organize systems also message systems. The essential region of purpose of ripples in communication system: numerous accesses. A fresh modulation/multiplexing scheme consuming ripple transform remained planned for (3rd production organization project 3GPP systems. This fresh modulation system implemented in (orthogonal frequency division multiplexing OFDM scheme in addition to conventional based(FFT transform blocks is replaced by wavelet transform blocks. There are many multiplicity of ripple transforms are offered, out of which four were chosen. They are Haar, Daubechies, Bi-orthogonal and reverse Bi-orthogonal transforms. Haar wavelet is best one of among all types of wavelet. The performance of DWT based MIMO-OFDM is calculated by bit error rate (BER in various channel that is AWGN channel and Rayleigh channel. Using MATLAB-Simulation which channel is best for the DWT based MIMO-OFDM.

  2. 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.

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

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    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.

  4. Performance of Adaptive Subchannel Assignment-Based MIMO/OFDM Systems over Multipath Fading Channels

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Adaptive antenna arrays at both the base and mobile stations can further increase system capacity and improve the quality of service of conventional orthogonal frequency division multiplexing (OFDM) systems. Conventional adaptive antenna array-based multiple-input multiple-output (MIMO)/OFDM systems use the sub-carriers characterized by the largest eigenvalue to transmit the OFDM symbols. This paper describes the performance of adaptive subchannel assignment-based MIMO/OFDM systems over multipath fading channels. The system adaptively selects the eigenvectors associated with the relatively large subchannel eigenvalues to generate the antenna array weights at the base and mobile stations and then adaptively assigns the corresponding best subchannels to transmit the OFDM symbols. Simulation results show that the proposed system can achieve better performance than the conventional adaptive antenna array-based MIMO/OFDM system over multipath fading channels.

  5. Optimal Power Allocation for GSVD-Based Beamforming in the MIMO Wiretap Channel

    CERN Document Server

    Fakoorian, S Ali A

    2010-01-01

    This paper considers a multiple-input multiple-output (MIMO) Gaussian wiretap channel model, where there exists a transmitter, a legitimate receiver and an eavesdropper, each equipped with multiple antennas. Perfect secrecy is achieved when the transmitter and the legitimate receiver can communicate at some positive rate, while ensuring that the eavesdropper gets zero bits of information. In this paper, the perfect secrecy capacity of the multiple antenna MIMO wiretap channel is found for aribtrary numbers of antennas under the assumption that the transmitter performs beamforming based on the generalized singular value decomposition (GSVD). More precisely, the optimal allocation of power for the GSVD-based precoder that achieves the secrecy capacity is derived. This solution is shown to have several advantages over prior work that considered secrecy capacity for the general MIMO Gaussian wiretap channel under a high SNR assumption. Numerical results are presented to illustrate the proposed theoretical finding...

  6. 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.

  7. MIMO-DFE BASED SPACE-TIME RECEIVER OVER FREQUENCY SELECTIVE CHANNELS WITH LIMITED ERROR PROPAGATION

    Institute of Scientific and Technical Information of China (English)

    Shen Liyun; Hu Bo

    2005-01-01

    MIMO-DFE(Multiple-Input-Multiple-Output Decision Feedback Equalizer) based receiver architectures are researched recently to detect signals in BLAST(Bell laboratories LAyered Space-Time) over frequency-selective channels. Due to their recursive structure, these receivers may suffer from error propagation which results in an overall mean square error degradation. An MIMO-DFE based BLAST receiver with limited error propagation to combat frequencyselective channel is proposed, which employs both norm constraint on feedback filter taps and soft decision device. Simulation results show that the proposed receiver outperforms conventional ones in various frequency selective channels.

  8. Cooperative MIMO Transmissions in WSN Using Threshold Based MAC Protocol

    OpenAIRE

    Vidhya, J.; Dananjayan, P.

    2010-01-01

    Sensor networks require robust and efficient communication protocols to maximise the network lifetime.Radio irregularity, channel fading and interference results in larger energy consumption and latency forpacket transmission over wireless channel. Cooperative multi-input multi-output (MIMO) schemes whenincorporated in wireless senor network (WSN) can significantly improve the communicationperformance. An inefficiently designed medium access control (MAC) protocol however, may diminishthe per...

  9. On the Optimal Number of Cooperative Base Stations in Network MIMO

    CERN Document Server

    Hoydis, Jakob; Debbah, Merouane

    2009-01-01

    We consider the multi-cell uplink (network MIMO) where M base-stations (BSs) communicate simultaneously with M user terminals (UTs). Although the potential benefit of multi-cell cooperation increases with M, the overhead for the BSs to learn the uplink channels will rapidly dominate the uplink resource. In other words, there exists a non-trivial tradeoff between the performance gains of network MIMO and the related overhead in channel estimation for a finite coherence time. We use a close approximation of the ergodic capacity to study this tradeoff by taking some realistic aspects into account such as unreliable backhaul links and different path losses between the BSs and UTs. Our results provide some insight into practical limitations as well as realistic dimensions of network MIMO systems.

  10. A Fractional Lower Order Statistics-Based MIMO Detection Method in Impulse Noise for Power Line Channel

    Directory of Open Access Journals (Sweden)

    CHEN, Z.

    2014-11-01

    Full Text Available Impulse noise in power line communication (PLC channel seriously degrades the performance of Multiple-Input Multiple-Output (MIMO system. To remedy this problem, a MIMO detection method based on fractional lower order statistics (FLOS for PLC channel with impulse noise is proposed in this paper. The alpha stable distribution is used to model impulse noise, and FLOS is applied to construct the criteria of MIMO detection. Then the optimal detection solution is obtained by recursive least squares algorithm. Finally, the transmitted signals in PLC MIMO system are restored with the obtained detection matrix. The proposed method does not require channel estimation and has low computational complexity. The simulation results show that the proposed method has a better PLC MIMO detection performance than the existing ones under impulsive noise environment.

  11. A HOS-based Blind Signal Extraction Method for Chaotic MIMO Systems

    Institute of Scientific and Technical Information of China (English)

    GONG Yun-rui; HE Di; HE Chen; JIANG Ling-ge

    2008-01-01

    A novel method to extract multiple input and multiple output (MIMO) chaotic signals was pro-posed using the blind neural algorithm after transmitting in nonideal channel. The MIMO scheme with different chaotic signal generators was presented. In order to separate the chaotic source signals only by using the sensor signals at receivers, a blind neural extraction algorithm based on higher-order statistic (HOS) technique was used to recover the primary chaotic signals. Simulation results show that the proposed approach has good performance in separating the primary chaotic signals even under nonideal channel.

  12. A Simulation Study on Channel Estimation for MIMO-OFDM Based Beyond 3G Mobile Systems

    Institute of Scientific and Technical Information of China (English)

    YIN Chang-chuan; ZHAO Xue-yuan; HOU Xiao-lin; YUE Guang-xin

    2005-01-01

    Multi-Input Multi-Output antennas based Orthogonal Frequency-Division Multiplexing (MIMO-OFDM) has been chosen as the air interface technology for China's beyond 3G Time-Division Duplex (TDD) mobile system in the FuTURE research project. Channel estimation plays a key role on the performance of the MIMO-OFDM receiver. In this paper, we present five channel estimation algorithms and study their performance in a simulated beyond 3G TDD mobile system. Simulation results show that the adaptive 2D-LMS algorithm we proposed recently has the best performance when the signal to noise ratio is lower than 8 dB.

  13. 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...

  14. THE HIGH RESOLUTION MIMO RADAR SYSTEM BASED ON MINIMIZING THE STATISTICAL COHERENCE OF COMPRESSED SENSING MATRIX

    Institute of Scientific and Technical Information of China (English)

    Zhu Yanping; Song Yaoliang; Chen Jinli; Zhao Delin

    2012-01-01

    Compressed Sensing (CS) theory is a great breakthrough of the traditional Nyquist sampling theory.It can accomplish compressive sampling and signal recovery based on the sparsity of interested signal,the randomness of measurement matrix and nonlinear optimization method of signal recovery.Firstly,the CS principle is reviewed.Then the ambiguity function of Multiple-Input Multiple-Output (MIMO) radar is deduced.After that,combined with CS theory,the ambiguity function of MIMO radar is analyzed and simulated in detail.At last,the resolutions of coherent and non-coherent MIMO radars on the CS theory are discussed.Simulation results show that the coherent MIMO radar has better resolution performance than the non-coherent.But the coherent ambiguity function has higher side lobes,which caused a deterioration in radar target detection performances.The stochastic embattling method of sparse array based on minimizing the statistical coherence of sensing matrix is proposed.And simulation results show that it could effectively suppress side lobes of the ambiguity function and improve the capability of weak target detection.

  15. Hybrid Genetic Crossover Based Swarm Intelligence Optimization for Efficient Resource Allocation in MIMO OFDM Systems

    Directory of Open Access Journals (Sweden)

    B. Sathish Kumar

    2015-07-01

    Full Text Available Rapid development of wireless services, leads to ubiquitous personal connectivity in the world. The demand for multimedia interactivity is higher in the world which leads to the requirement of high data transmission rate. Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM is a future wireless service which is used to overcome the existing service problems such as development of subscriber pool and higher throughput per user. Although it overcomes the problems in existing services, resource allocation becomes one of the major issues in the MIMO-OFDM systems. Resource allocation in MIMO-OFDM is the optimization of subcarrier and power allocation for the user. The overall performance of the system can be improved only with the efficient resource allocation approach. The user data rate is increased by efficient allocation of the subcarrier and power allocation for each user at the base station, which is subject to constraints on total power and bit error rate. In this study, the problem of resource allocation in MIMO-OFDM system is tackled using hybrid artificial bee colony optimization algorithm based on a crossover operation along with Poisson-Jensen in equation. The experimental results show that the proposed methodology is better than the existing techniques.

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

    International Nuclear Information System (INIS)

    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. 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.

  18. A novel MMSE based codebook construction for MIMO precoded spatial multiplexing with limited feedback

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with the design and performance analysis of the transmission precoder optimization for multiple-input multiple-output (MIMO) systems with limited feedback of channel state information (CSI). We assume that the receiver can get perfect channel knowledge by channel estimation while the transmitter only has partial channel knowledge from limited feedback. We present a minimum mean square error (MMSE) criterion based codebook construction algorithm for MIMO precoded spatial multiplexing systems under a specific average power constraint. The optimal transmitter structure is employed in this paper. Simulation results show that the MMSE criteria based codebook construction algorithm with hybrid design of power allocation and precoding can achieve better performance than that of equal power allocation based codebook of previous research.

  19. Performance Analysis of Precoding Based on Massive MIMO System

    Directory of Open Access Journals (Sweden)

    Li Yi

    2015-01-01

    Full Text Available In order to improve the system performance, the authors consider a single-cell multiuser Massive MIMO downlink time-division duplex (TDD system for the imperfect channel state information (CSI. For the zero-forcing (ZF and the matched filtering (MF precoding scheme, the authors propose a normalization algorithm: the vector normalization. Assume that the channel estimation is used to acquire CSI by using the uplink pilot sequence, and utilize the proposed algorithm to normalize the precoding matrix in the downlink; we derive the achievable sum rate of ZF and MF. Through the analysis and comparison of two precoding schemes’ performance, the authors conclude that ZF is better than MF with vector normalization algorithm in the high SNR region; and MF is better than ZF in the low SNR region. Simulation results confirm the above conclusion.

  20. 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.

  1. Finite time control for MIMO nonlinear system based on higher-order sliding mode.

    Science.gov (United States)

    Liu, Xiangjie; Han, Yaozhen

    2014-11-01

    Considering a class of MIMO uncertain nonlinear system, a novel finite time stable control algorithm is proposed based on higher-order sliding mode concept. The higher-order sliding mode control problem of MIMO nonlinear system is firstly transformed into finite time stability problem of multivariable system. Then continuous control law, which can guarantee finite time stabilization of nominal integral chain system, is employed. The second-order sliding mode is used to overcome the system uncertainties. High frequency chattering phenomenon of sliding mode is greatly weakened, and the arbitrarily fast convergence is reached. The finite time stability is proved based on the quadratic form Lyapunov function. Examples concerning the triple integral chain system with uncertainty and the hovercraft trajectory tracking are simulated respectively to verify the effectiveness and the robustness of the proposed algorithm. PMID:25277626

  2. 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.

  3. 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......) performance of the proposed design is verified by simulations to have nearly no loss compared to the conventional MMSE approach....

  4. MIMO Detection for High-Order QAM Based on a Gaussian Tree Approximation

    OpenAIRE

    Goldberger, Jacobb; Leshem, Amir

    2010-01-01

    This paper proposes a new detection algorithm for MIMO communication systems employing high order QAM constellations. The factor graph that corresponds to this problem is very loopy; in fact, it is a complete graph. Hence, a straightforward application of the Belief Propagation (BP) algorithm yields very poor results. Our algorithm is based on an optimal tree approximation of the Gaussian density of the unconstrained linear system. The finite-set constraint is then applied to obtain a loop-fr...

  5. DOA estimation for monostatic MIMO radar based on unitary root-MUSIC

    Science.gov (United States)

    Wang, Wei; Wang, Xianpeng; Li, Xin; Song, Hongru

    2013-11-01

    Direction of arrival (DOA) estimation is an important issue for monostatic MIMO radar. A DOA estimation method for monostatic MIMO radar based on unitary root-MUSIC is presented in this article. In the presented method, a reduced-dimension matrix is first utilised to transform the high dimension of received signal data into low dimension one. Then, a low-dimension real-value covariance matrix is obtained by forward-backward (FB) averaging and unitary transformation. The DOA of targets can be achieved by unitary root-MUSIC. Due to the FB averaging of received signal data and the eigendecomposition of the real-valued matrix covariance, the proposed method owns better angle estimation performance and lower computational complexity. The simulation results of the proposed method are presented and the performances are investigated and discussed.

  6. Analysis of MIMO antenna array based on electromagnetic vector sensor%基于电磁矢量传感器的 MIMO 天线阵列系统研究

    Institute of Scientific and Technical Information of China (English)

    周杰; 邱琳; 菊池久和

    2013-01-01

    EVS(electromagnetic vetor sensor) signal processing method was combined with traditional MIMO signal processing method and three-dimensional channel model of multi-antenna array was set up. The algorithm of multiple signal classification (MUSIC) was adopted to make spatial spectrum estimation for direction of arrival (DOA) signal, analytical expressions of three-dimensional spatial channel was derived base on EVS for MIMO receiver system and the relationship between EVS signal processing and MIMO multipath channel correlation was clarified. To compare with tra-ditional MIMO antenna array, EVS array possesses abilities of obtaining multidimensional polarization information, processing spatial and polarization domain for arrival signal and degrading effects of spatial factors on MIMO channel capacity. Theoretical analysis and simulation results indicate that EVS array provide more advantages than traditional scalar sensor array on enhancing MIMO system performance.%  将电磁矢量传感器(EVS, electromagnetic vetor sensor)信号处理法与传统 MIMO 信号处理有机地结合,建立了基于 EVS 的多天线三维信道模型。采用多重信号分类(MUSIC, multiple signal classification)算法对 MIMO 的达波信号方向(DOA, direction of arrival)进行空间谱估计,导出基于 EVS 的三维空间信道解析式,阐明了 EVS 信号处理与 MIMO 多径信道相关性的关系。与传统标量传感器阵列(SSA, scalar sensor array)MIMO 天线阵列比较, EVS 阵列能获取达波信号的多维极化信息,同时具有空间域和极化信号处理能力。因此可缓解空间多径信道相关性,使空间极化分量的相关性趋于零值,而且使 MIMO 系统性能受空间结构的影响较小。理论分析和仿真结果表明在提高 MIMO 天线系统性能上,基于 EVS 阵列的系统比 SSA 系统具有更高的优越性。

  7. 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.

  8. 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.

  9. A New MIMO-OFDM System

    Institute of Scientific and Technical Information of China (English)

    XIAO Zheng-rong; ZHAO Shao-gang; WU Wei-ling

    2004-01-01

    Discrete Fourier Transform (DFT) based multiple-input multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is the focus of wireless communication, which uses cyclic prefixes to reduce the ISI. To improve the spectrum efficiency and system performance, Complex Wavelet Packet Transform (CWPT) based OFDM is used to realize the MIMO-OFDM system. For the good property of complex wavelet packet function, the CWPT based MIMO-OFDM system is better than the DFT based MIMO-OFDM system, but the CWPT based MIMO-OFDM scheme has some additional complexity, and simulation results show that the new system can improve the system performance.

  10. 基于GAIC的MIMO-OFDM信道估计%GAIC Based Approach for Channel Estimation in MIMO-OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    赵俊义; 贾世楼; 孟维晓

    2008-01-01

    对于多径稀疏的多输入多输出正交频分复用(Multiple-input and muItipIe-output orthogonal frequency division multiplexing,MIMO-OFDM)信道,提出了基于广义Akaike信息论准则(Generalized Akaike information criterion,GAIC)的MIMO-OFDM系统实用的信道估计算法,该算法能够估计出信道的长度和每径信道的时延,降低加性白噪声对信道估计的影响,提高信道估计的精度.通过仿真,与最小二来(Least squares,LS)算法和离散傅里叶变换(Discrete Fourier transform,DFT)算法相比较,大大地降低了信道的估计误差,提高了系统性能,且信道稀疏性越强,性能改善越好.

  11. Detection of weak target for MIMO radar based on Hough transform

    Institute of Scientific and Technical Information of China (English)

    Zeng Jiankui; He Zishu

    2009-01-01

    An effective method of multiple input multiple output (MIMO) radar weak target detection is proposed based on the Hough transform. The detection time duration is divided into multiple coherent processing intervals (CPIs). Within each CPI, conventional methods such as fast Fourier transform (FFT) is exploit to coherent inte-grating in same range cell. Furthermore, noncoherent integration through several range cells can be implemented by Hough transform among all CPIs. Thus, higher integration gain can be obtained. Simulation results are also given to demonstrate that the detection performance of weak moving target can be dramatically improved.

  12. SUBSPACE-BASED NOISE VARIANCE AND SNR ESTIMATION FOR MIMO OFDM SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper proposes a subspace-based noise variance and Signal-to-Noise Ratio (SNR) estimation algorithm for Multi-Input Multi-Output (MIMO) wireless Orthogonal Frequency Division Multiplexing (OFDM) systems. The special training sequences with the property of orthogonality and phase shift orthogonality are used in pilot tones to obtain the estimated channel correlation matrix. Partitioning the observation space into a delay subspace and a noise subspace, we achieve the measurement of noise variance and SNR.Simulation results show that the proposed estimator can obtain accurate and real-time measurements of the noise variance and SNR for various multipath fading channels, demonstrating its strong robustness against different channels.

  13. 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...

  14. Verification of Emulated Channels in Multi-Probe Based MIMO OTA Testing Setup

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  15. Spatially Common Sparsity Based Adaptive Channel Estimation and Feedback for FDD Massive MIMO

    Science.gov (United States)

    Gao, Zhen; Dai, Linglong; Wang, Zhaocheng; Chen, Sheng

    2015-12-01

    This paper proposes a spatially common sparsity based adaptive channel estimation and feedback scheme for frequency division duplex based massive multi-input multi-output (MIMO) systems, which adapts training overhead and pilot design to reliably estimate and feed back the downlink channel state information (CSI) with significantly reduced overhead. Specifically, a non-orthogonal downlink pilot design is first proposed, which is very different from standard orthogonal pilots. By exploiting the spatially common sparsity of massive MIMO channels, a compressive sensing (CS) based adaptive CSI acquisition scheme is proposed, where the consumed time slot overhead only adaptively depends on the sparsity level of the channels. Additionally, a distributed sparsity adaptive matching pursuit algorithm is proposed to jointly estimate the channels of multiple subcarriers. Furthermore, by exploiting the temporal channel correlation, a closed-loop channel tracking scheme is provided, which adaptively designs the non-orthogonal pilot according to the previous channel estimation to achieve an enhanced CSI acquisition. Finally, we generalize the results of the multiple-measurement-vectors case in CS and derive the Cramer-Rao lower bound of the proposed scheme, which enlightens us to design the non-orthogonal pilot signals for the improved performance. Simulation results demonstrate that the proposed scheme outperforms its counterparts, and it is capable of approaching the performance bound.

  16. Symbol Estimation Algorithm for MIMO Underwater Acoustic Communication System Based on Multiplicative Noise Model

    Directory of Open Access Journals (Sweden)

    Ling Zhang

    2015-01-01

    Full Text Available The stochastic and time-varying underwater acoustic (UWA channels are usually affected by serious multipath delays, energy loss and distortion factors, thus making the modeling and estimation of the UWA channel challenging problems in the research community. Based on the analysis of the UWA channel, the system with multiplicative noise (SMN model is established to characterize the complicated factors such as random time-variation, nonlinearity, and energy attenuation. As to the multiple-input multiple-output (MIMO UWA communication, the complicated SMN model is established for MIMO UWA channels; based on which, the transmitted symbols are estimated according to the optimal recursive filtering algorithm. The algorithm is derived based on the projection theorem, which is optimal in the sense of linear minimum variance, and can overcome the intersymbol interference and noise pollution efficiently. The optimal algorithm is computed recursively, which has the advantage of computation-efficiency and can track the random variation of the fast time-varying channel gain dynamically. Simulation results have validated the effectiveness of the algorithm. The model and the algorithm can be extended flexibly to certain practical problems, such as the joint channel and symbol estimation in underwater acoustic communication systems.

  17. 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.

  18. Improved Successive Interference Cancellation for MIMO/UWB-Based Wireless Body Area Network

    Directory of Open Access Journals (Sweden)

    M. Jayasheela

    2012-01-01

    Full Text Available In body area networks, various sensors are attached to clothing or on the body or even implanted under the skin. The sensors measure such as heart beat, the record of prolonged electrocardiogram, blood pressure, and so on. In this paper, an improved Successive interference cancellation (SIC scheme based on zero correlation zone sequences is proposed. Here ZCZ is used as a random code for TH PPM UWB system. Nodes in a WBAN are connected through wireless communication channel within a very close range. The decrease in internode distance leads to interference between devices. To reduce this interference, an enhanced successive interference cancellation scheme based on ZCZ with optimal ordering is adopted. Because of zero correlation property of ZCZ, the performance of TH PPM UWB system through WBAN channel with ZCZ sequences outperforms performance of existing zero correlation duration code. In this paper, performance of UWB system for various modulation schemes are compared. Performance of UWB/MIMO (2×2 system employing SIC with optimal ordering using ZCZ codes also compared with pseudorandom (PN and ZCD codes. Simulation results are obtained using sample biological functions as input to the proposed TH PPM UWB/MIMO (2×2 system with m-ZCZ codes in WBAN environment with multiple devices.

  19. A 3D Geometry-based Stochastic Model for 5G Massive MIMO Channels

    Directory of Open Access Journals (Sweden)

    Yi Xie

    2015-09-01

    Full Text Available Massive MIMO is one of the most promising technologies for the fifth generation (5G mobile communication systems. In order to better assess the system performance, it is essential to build a corresponding channel model accurately. In this paper, a three-dimension (3D two-cylinder regular-shaped geometry-based stochastic model (GBSM for non-isotropic scattering massive MIMO channels is proposed. Based on geometric method, all the scatters are distributed on the surface of a cylinder as equivalent scatters. Non-stationary property is that one antenna has its own visible area of scatters by using a virtual sphere. The proposed channel model is evaluated by comparing with the 3GPP 3D channel model [1]. The statistical properties are investigated. Simulation results show that close agreements are achieved between the characteristics of the proposed channel model and those of the 3GPP channel model, which justify the correctness of the proposed model. The model has advantages such as good applicability.

  20. Anti Deceptive Jamming for MIMO Radar Based on Data Fusion and Notch Filtering (in English

    Directory of Open Access Journals (Sweden)

    Li Wei

    2013-08-01

    Full Text Available Deceptive jamming can get vivid jamming effect on Multiple-Input Multiple-Output (MIMO radar with very low power. In order to remove those deceptive targets, one method based on signal jittering, data fusion and fake target notch filtering is proposed in this paper. Multiple orthogonal binary phase codes are used as transmitted signals, before each time of transmission each transmitter will choose one signal from all the orthogonal codes, images of echoes of all kinds of codes are detected with constant false alarm rate. Targets detected in images of echoes of all different signals are fused to determine to be real or not, fake targets will be nulled by notch filtering in the image, therefore, weak real targets can be detected in the next round of detection, in this way fusion and notch filtering are implemented again and again until no fake targets exist. The effect of deceptive jamming on radar will be removed completely. Simulation result testifies that the method based on signal jittering, data fusion and notch filtering can help MIMO radar remove deceptive jamming completely.

  1. A WiMAX-based implementation of network MIMO for indoor wireless systems

    OpenAIRE

    Sivarama Venkatesan; Howard Huang; Angel Lozano; Reinaldo Valenzuela

    2009-01-01

    It is well known that multiple-input multiple-output (MIMO) techniques can bring numerous benefits, such as higher spectral efficiency, to point-to-point wireless links. More recently, there has been interest in extending MIMO concepts to multiuser wireless systems. Our focus in this paper is on network MIMO, a family of techniques whereby each end user in a wireless access network is served through several access points within its range of influence. By tightly coordinating the transmission ...

  2. 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.

  3. Performance analysis of distributed cluster-based MAC protocol for multiuser MIMO wireless networks

    Directory of Open Access Journals (Sweden)

    Ettefagh Azadeh

    2011-01-01

    Full Text Available Abstract It is known that multiuser multiple-input multiple-output (MIMO communication can enhance the performance of wireless networks. It can substantially increase the spectral efficiency of wireless networks by utilising multiuser interference rather than avoiding it. This paradigm shift has most impact on the medium access control (MAC protocol because most existing MAC protocols are designed to reduce the interference. In this article, we propose a novel cluster-based carrier sense multiple access with collision avoidance (CB-CSMA/CA scheme. The proposed scheme enables multiuser MIMO transmissions in wireless local area networks (WLANs by utilising the multiuser interference cancellation capability of the physical layer. In this article we focus on the performance analysis of CB-CSMA/CA. We investigate saturation throughput applying optimum backoff parameters and in the presence of synchronisation errors. Furthermore, we study the impact of different clustering methods on non-saturation throughput. We show that CB-CSMA/CA improves throughput significantly compared to the CSMA/CA scheme used in the IEEE 802.11 system. It is a promising approach for a variety of network configurations including typical infrastructure WLANs as well as many other wireless cooperative networks.

  4. Interference Mitigation for Cognitive Radio MIMO Systems Based on Practical Precoding

    CERN Document Server

    Chen, Zengmao; Hong, Xuemin; Thompson, John; Vorobyov, Sergiy A; Zhao, Feng; Xiao, Hailin; Ge, Xiaohu

    2011-01-01

    In this paper, we propose two subspace-projection-based precoding schemes, namely, full-projection (FP)- and partial-projection (PP)-based precoding, for a cognitive radio multiple-input multiple-output (CR-MIMO) network to mitigate its interference to a primary time-division-duplexing (TDD) system. The proposed precoding schemes are capable of estimating interference channels between CR and primary networks, and incorporating the interference from the primary to the CR system into CR precoding via a novel sensing approach. Then, the CR performance and resulting interference of the proposed precoding schemes are analyzed and evaluated. By fully projecting the CR transmission onto a null space of the interference channels, the FP-based precoding scheme can effectively avoid interfering the primary system with boosted CR throughput. While, the PP-based scheme is able to further improve the CR throughput by partially projecting its transmission onto the null space.

  5. Radio frequency electromagnetic field compliance assessment of multi-band and MIMO equipped radio base stations.

    Science.gov (United States)

    Thors, Björn; Thielens, Arno; Fridén, Jonas; Colombi, Davide; Törnevik, Christer; Vermeeren, Günter; Martens, Luc; Joseph, Wout

    2014-05-01

    In this paper, different methods for practical numerical radio frequency exposure compliance assessments of radio base station products were investigated. Both multi-band base station antennas and antennas designed for multiple input multiple output (MIMO) transmission schemes were considered. For the multi-band case, various standardized assessment methods were evaluated in terms of resulting compliance distance with respect to the reference levels and basic restrictions of the International Commission on Non-Ionizing Radiation Protection. Both single frequency and multiple frequency (cumulative) compliance distances were determined using numerical simulations for a mobile communication base station antenna transmitting in four frequency bands between 800 and 2600 MHz. The assessments were conducted in terms of root-mean-squared electromagnetic fields, whole-body averaged specific absorption rate (SAR) and peak 10 g averaged SAR. In general, assessments based on peak field strengths were found to be less computationally intensive, but lead to larger compliance distances than spatial averaging of electromagnetic fields used in combination with localized SAR assessments. For adult exposure, the results indicated that even shorter compliance distances were obtained by using assessments based on localized and whole-body SAR. Numerical simulations, using base station products employing MIMO transmission schemes, were performed as well and were in agreement with reference measurements. The applicability of various field combination methods for correlated exposure was investigated, and best estimate methods were proposed. Our results showed that field combining methods generally considered as conservative could be used to efficiently assess compliance boundary dimensions of single- and dual-polarized multicolumn base station antennas with only minor increases in compliance distances.

  6. Design and Implementation of Digital Down-conversion Based on MIMO-OFDM Digital Receiver%基于MIMO-OFDM接收机的数字下变频设计与实现

    Institute of Scientific and Technical Information of China (English)

    廖海黔; 吴皓威; 杨力生

    2013-01-01

    In order to meet the specific requirements for digital down-conversion of MIMO-OFDM receiver,the program of digital down-conversion is designed and implemented based on ASIC.GC5016 chip and A/D sampler chip are configured and controlled by FPGA.Meanwhile the digital down-conversion schematic block diagram of MIMO-OFDM receiver,the implementation scheme of MIMO-OFDM receiver,the signal processing flowchart in the GC5016 and the block diagram of FPGA functional module are presented.The experiment result shows that this scheme has not only good performance but good programmable ability in digital down-conversion.%为了满足MIMO-OFDM接收机的数字下变频设计要求,设计并实现了基于专业芯片的数字下变频方案,主要使用FPGA对GC5016芯片、A/D采样芯片进行配置和控制.同时,给出了MIMO-OFDM接收机的数字下变频原理框图、MIMO-OFDM接收机实现方案框图、GC5016内部信号处理流程图以及FPGA功能模块框图.实验结果表明,本设计方案不仅具有优良的数字下变频性能,而且具有良好的可编程能力.

  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....... The numerical assessment of our solutions, based on Monte Carlo simulations, corroborates the high performance of the proposed algorithms and their superiority to heuristic approaches....... 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...

  8. Robotic Mobile System's Performance-Based MIMO-OFDM Technology

    Directory of Open Access Journals (Sweden)

    Omar Alani

    2009-10-01

    Full Text Available In this paper, a predistortion neural network (PDNN architecture has been imposed to the Sniffer Mobile Robot (SNFRbot that is based on spatial multiplexed wireless Orthogonal Frequency Division Multiplexing (OFDM transmission technology. This proposal is used to improve the system performance by combating one of the main drawbacks that is encountered by OFDM technology; Peak-to-Average Power Ratio (PAPR. Simulation results show that using PDNN resulted in better PAPR performance than the previously published work that is based on linear coding, such as Low Density Parity Check (LDPC codes and turbo encoding whether using flat fading channel or a Doppler spread channel.

  9. 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.

  10. A HIGH RESOLUTION WIDE SWATH SAR METHOD BASED ON INTRA-PULSE NULL STEERING AND MIMO

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    High Resolution Wide Swath(HRWS)Synthetic Aperture Radar(SAR)often Sufiers from low Signal-to-Noise Ratio(SNR)due to small transmitting antenna,especially in phased array antenna systems.Digital Beam Forming(DBF)based on Single Input and Multiple Output(SIMO)achieves receiving array gain at the cost of increasing data rate.This letter proposes a new HRWS SAR method, which employs intra-pulse null steering to get receiving gain in elevation and decrease the data rate,and Multiple Input and Multiple Output(MIMO)using Space-Time Block Coding(STBC)in azimuth to get transmitting gain and receiving array gain simultaneously.The feasibility is verified by deduction and simulations.

  11. Pilot Signal Design for Massive MIMO Systems: A Received Signal-To-Noise-Ratio-Based Approach

    Science.gov (United States)

    So, Jungho; Kim, Donggun; Lee, Yuni; Sung, Youngchul

    2015-05-01

    In this paper, the pilot signal design for massive MIMO systems to maximize the training-based received signal-to-noise ratio (SNR) is considered under two channel models: block Gauss-Markov and block independent and identically distributed (i.i.d.) channel models. First, it is shown that under the block Gauss-Markov channel model, the optimal pilot design problem reduces to a semi-definite programming (SDP) problem, which can be solved numerically by a standard convex optimization tool. Second, under the block i.i.d. channel model, an optimal solution is obtained in closed form. Numerical results show that the proposed method yields noticeably better performance than other existing pilot design methods in terms of received SNR.

  12. Dual Turbo MIMO-OFDM Channel Estimation Based on Puncher Technique via UWA Channels

    Directory of Open Access Journals (Sweden)

    Gang Qiao

    2013-02-01

    Full Text Available In this study, various techniques of UWA (Underwater Acoustic, UWA channel estimation for underwater MIMO-OFDM system are studied. Dual turbo channel estimation algorithm based on channel puncture technique is proposed. In order to judge the criteria of channel compensation, difference between the raw received signal and the re-coded information signal is carried out. The uncertain sub-channels are punched by using channel puncture technique and replaced by the responses estimated by MMSE (Minimum Mean Square Error, MMSE or OMP (Orthogonal Matching Pursuit, OMP algorithms. Compared with the conventional existing algorithms, the proposed algorithm can effectively reduce the occupancy of pilots, offer confined error propagation and significantly increase the stability of the system with Monte Caro simulation. The results of in-tank-experiment further indorse the reliable performance with improved efficiency of 1.51 bits/s/Hz.

  13. 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...... (DoA) estimation algorithm as well as multi-user MIMO sum-rate capacity are investigated to determine the range of the test setup. It was found that the link budget doesn’t support for the measurement distances claimed by the Fraunhofer distance. Most of the utilized metrics, especially the sum rate...... capacity, indicate that smaller setup sizes can still yield reasonable measurement accuracy. Simulations were performed at 2.6, 3.5, and 28 GHz frequencies....

  14. Low-Complexity Geometry-Based MIMO Channel Simulation

    Directory of Open Access Journals (Sweden)

    Christoph W. Ueberhuber

    2007-01-01

    Full Text Available The simulation of electromagnetic wave propagation in time-variant wideband multiple-input multiple-output mobile radio channels using a geometry-based channel model (GCM is computationally expensive. Due to multipath propagation, a large number of complex exponentials must be evaluated and summed up. We present a low-complexity algorithm for the implementation of a GCM on a hardware channel simulator. Our algorithm takes advantage of the limited numerical precision of the channel simulator by using a truncated subspace representation of the channel transfer function based on multidimensional discrete prolate spheroidal (DPS sequences. The DPS subspace representation offers two advantages. Firstly, only a small subspace dimension is required to achieve the numerical accuracy of the hardware channel simulator. Secondly, the computational complexity of the subspace representation is independent of the number of multipath components (MPCs. Moreover, we present an algorithm for the projection of each MPC onto the DPS subspace in 𝒪(1 operations. Thus the computational complexity of the DPS subspace algorithm compared to a conventional implementation is reduced by more than one order of magnitude on a hardware channel simulator with 14-bit precision.

  15. 使用复小波包的MIMO-OFDM无线系统%Complex wavelet packet based MIMO-OFDM wireless system

    Institute of Scientific and Technical Information of China (English)

    肖征荣; 余智; 赵绍刚; 吴伟陵

    2004-01-01

    为了在频率选择性信道中提供高速数据业务,提出了一种新的多入多出-正交频分复用系统MIMO-OFDM(Multi-Input Multi-Output-Orthogonal Frequency Division Multiplexing).该系统使用复小波包变换CWPT(Complex Wavelet Packet Transform)来实现OFDM,而不是使用传统的快速傅立叶变换FFT(Fast Fourier Transform).由于复小波包函数具有很好的特性,通过对有2个用户的MIMO-OFDM系统进行仿真的结果表明,基于CWPT的MIMO-OFDM系统性能要比使用传统的FFT的MIMO-OFDM 系统好,但是复杂度略高.

  16. 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.

  17. 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)

  18. 基于 MIMO 技术和“双环”技术的 Ad Hoc 网络路由协议%Ad Hoc network routing protocol based on MIMO technology and double loop technology

    Institute of Scientific and Technical Information of China (English)

    李艳霞

    2014-01-01

    According to the drawbacks of previous Ad Hoc network , this paper puts forward Ad Hoc network routing protocol based on MIMO technology and double loop technology .Under the support of MIMO technology and double loop technology , the new Ad Hoc net-work routing protocol adopts diversity link and reuse link to give play to the advantage of DZR protocol and ZRP protocol .With OPNET simulation as the platform, it is optimized.%针对以往的 Ad Hoc 网络的缺陷,提出了一种基于 MIMO 技术和“双环”技术的 Ad Hoc 网络路由协议方案。在MIMO 技术、“双环”技术的支持下,新的 Ad Hoc 网络路由协议中采用了分集链路与复用链路,发挥了 DZR 协议与 ZRP协议的优势,以 OPNET 仿真工具为平台,从而实现了新 Ad Hoc 网络路由协议的最优化。

  19. Performance comparison of wavelet denoising based fast DOA estimation of MIMO OFDM system over Rayleigh Fading Channel

    Directory of Open Access Journals (Sweden)

    A.V.Meenakshi

    2012-09-01

    Full Text Available This paper presents a tool for the analysis, and simulation of direction-of-arrival estimation for MIMO OFDM signal over the Rayleigh fading channel. The performance of the proposed technique is tested for wavelet denoising based CYCLIC MUSIC algorithm. Simulation results demonstrate that the proposed system not only has good ability of suppressing interference, but also significantly improves the DOA estimation of the system. In this paper, it is proposed to find DOA of the received MIMO OFDM signal, and the performances are analyzed using matlab simulation by the Monte Carlo computer iteration. This paper provides a fairly complete image of the performance and statistical efficiency with QPSK signal model for coherent system at a lower SNR(18dB and interference environment.

  20. A WiMAX-Based Implementation of Network MIMO for Indoor Wireless Systems

    Science.gov (United States)

    Venkatesan, Sivarama; Huang, Howard; Lozano, Angel; Valenzuela, Reinaldo

    2009-12-01

    It is well known that multiple-input multiple-output (MIMO) techniques can bring numerous benefits, such as higher spectral efficiency, to point-to-point wireless links. More recently, there has been interest in extending MIMO concepts to multiuser wireless systems. Our focus in this paper is on network MIMO, a family of techniques whereby each end user in a wireless access network is served through several access points within its range of influence. By tightly coordinating the transmission and reception of signals at multiple access points, network MIMO can transcend the limits on spectral efficiency imposed by cochannel interference. Taking prior information-theoretic analyses of network MIMO to the next level, we quantify the spectral efficiency gains obtainable under realistic propagation and operational conditions in a typical indoor deployment. Our study relies on detailed simulations and, for specificity, is conducted largely within the physical-layer framework of the IEEE 802.16e Mobile WiMAX system. Furthermore, to facilitate the coordination between access points, we assume that a high-capacity local area network, such as Gigabit Ethernet, connects all the access points. Our results confirm that network MIMO stands to provide a multiple-fold increase in spectral efficiency under these conditions.

  1. A WiMAX-Based Implementation of Network MIMO for Indoor Wireless Systems

    Directory of Open Access Journals (Sweden)

    Sivarama Venkatesan

    2009-01-01

    Full Text Available It is well known that multiple-input multiple-output (MIMO techniques can bring numerous benefits, such as higher spectral efficiency, to point-to-point wireless links. More recently, there has been interest in extending MIMO concepts to multiuser wireless systems. Our focus in this paper is on network MIMO, a family of techniques whereby each end user in a wireless access network is served through several access points within its range of influence. By tightly coordinating the transmission and reception of signals at multiple access points, network MIMO can transcend the limits on spectral efficiency imposed by cochannel interference. Taking prior information-theoretic analyses of network MIMO to the next level, we quantify the spectral efficiency gains obtainable under realistic propagation and operational conditions in a typical indoor deployment. Our study relies on detailed simulations and, for specificity, is conducted largely within the physical-layer framework of the IEEE 802.16e Mobile WiMAX system. Furthermore, to facilitate the coordination between access points, we assume that a high-capacity local area network, such as Gigabit Ethernet, connects all the access points. Our results confirm that network MIMO stands to provide a multiple-fold increase in spectral efficiency under these conditions.

  2. Eigen-Direction Alignment Based Physical-Layer Network Coding for MIMO Two-Way Relay Channels

    CERN Document Server

    Yang, Tao; Ping, Li; Collings, Iain B; Yuan, Jinhong

    2012-01-01

    In this paper, we propose a novel communication strategy which incorporates physical-layer network coding (PNC) into multiple-input multiple output (MIMO) two-way relay channels (TWRCs). At the heart of the proposed scheme lies a new key technique referred to as eigen-direction alignment (EDA) precoding. The EDA precoding efficiently aligns the two-user's eigen-modes into the same directions. Based on that, we carry out multi-stream PNC over the aligned eigen-modes. We derive an achievable rate of the proposed EDA-PNC scheme, based on nested lattice codes, over a MIMO TWRC. Asymptotic analysis shows that the proposed EDA-PNC scheme approaches the capacity upper bound as the number of user antennas increases towards infinity. For a finite number of user antennas, we formulate the design criterion of the optimal EDA precoder and present solutions. Numerical results show that there is only a marginal gap between the achievable rate of the proposed EDA-PNC scheme and the capacity upper bound of the MIMO TWRC, in ...

  3. CDM Country Guide for Cambodia

    International Nuclear Information System (INIS)

    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 Cambodia

  4. CDM Country Guides

    International Nuclear Information System (INIS)

    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

  5. CDM Country Guides

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    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

  6. 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...

  7. Cholesky Factorization-Based Adaptive BLAST DFE for Wideband MIMO Channels

    Directory of Open Access Journals (Sweden)

    Kostas Berberidis

    2007-01-01

    Full Text Available Adaptive equalization of wireless systems operating over time-varying and frequency-selective multiple-input multiple-output (MIMO channels is considered. A novel equalization structure is proposed, which comprises a cascade of decision feedback equalizer (DFE stages, each one detecting a single stream. The equalizer filters, as well as the ordering by which the streams are extracted, are updated based on the minimization of a set of least squares (LS cost functions in a BLAST-like fashion. To ensure numerically robust performance of the proposed algorithm, Cholesky factorization of the equalizer input autocorrelation matrix is applied. Moreover, after showing that the equalization problem possesses an order recursive structure, a computationally efficient scheme is developed. A variation of the method is also described, which is appropriate for slow time-varying conditions. Theoretical analysis of the equalization problem reveals an inherent numerical deficiency, thus justifying our choice of employing a numerically robust algebraic transformation. The performance of the proposed method in terms of convergence, tracking, and bit error rate (BER is evaluated through extensive computer simulations for time-varying and wideband channels.

  8. A Utility-Based Scheduling Scheme for MIMO-OFDMA Downlink Systems

    Institute of Scientific and Technical Information of China (English)

    Zhuang Liu; Xi Li; Hong Ji

    2014-01-01

    In this paper, a utility-based feedback delay-aware and buffer status-aware ( FABA ) scheduling scheme is proposed for downlink multiuser multiple-input multiple-output orthogonal frequency-division multiple-access ( MIMO-OFDMA ) systems. The FABA scheme allocates subcarriers to multiusers with an objective of not only maximizing the total system capacity but reducing the system packet loss rate as well. We design a utility function which consists of a feedback estimate module, a proportional fairness module and a buffer monitoring module. The feedback estimate module is used to improve the system throughput by utilizing the Automatic Repeat-reQuest ( ARQ) feedback information to combat the fast time-varying fading condition. The proportional fairness module can guarantee the scheduling fairness among users, and the buffer monitoring module can utilize the transmitting buffer status information to avoid high packet loss rate of the system caused by the system congestion. The FABA scheme then formulates the scheduling problem into a problem of overall system utility maximization. We solve the problem by using a heuristic algorithm with low computational complexity. The simulation results show that the proposed FABA scheme outperforms the existing algorithms in terms of the system throughput and the packet loss rate and can also guarantee the fairness demand among users.

  9. ISI Cancellation Using Blind Equalizer Based on DBC Model for MIMO-RFID Reader Reception

    Directory of Open Access Journals (Sweden)

    S. Duangsuwan

    2015-04-01

    Full Text Available Under the dyadic backscatter channel (DBC model, a conventional zero forcing (ZF and minimum mean square error (MMSE method for MIMO-RFID reader reception are not able to be rapidly cancelled inter-symbol interference (ISI because of the error of postpreamble transmission. In order to achieve the ISI cancellation, the conventional method of ZF and MMSE are proposed to resolve a convergence rate without postpreamble by using a constant modulus algorithm (CMA. Depending on the cost function, the CMA is used which based on second order statistics to estimate the channel statement of channel transfer function. Furthermore, the multiple-tag detection is also considered under the assumption of the maximum likelihood estimation. The comparison of the conventional method and the proposed method is analyzed by using computer simulation and experimental data. We can see that the proposed method is better than the conventional method with a faster ISI cancelling and a lower bit error rate (BER improving as up to 12 tags.

  10. A PARAFAC-based algorithm for multidimensional parameter estimation in polarimetric bistatic MIMO radar

    Science.gov (United States)

    Jiang, Hong; Zhang, Yu; Li, Jia; Cui, Haijing

    2013-12-01

    In this article, we investigate the problem of applying the parallel factor quadrilinear decomposition technique to multidimensional target parameter estimation in a polarimetric bistatic multiple-input multiple-output (MIMO) radar system with a uniform rectangular array at the transmitter and a cross-dipole-based uniform rectangular array at the receiver. The signal model is developed, and a novel algorithm is proposed exploiting the quadrilinear alternating least squares to jointly estimate the two-dimensional direction of departure (2D-DOD), two-dimensional direction of arrival (2D-DOA), polarization parameters and Doppler frequency. Multidimensional parameters can be automatically paired by this algorithm to avoid the performance degradation resulting from wrong pairing. The developed algorithm requires neither multidimensional spectral peak searching nor covariance matrix estimation and several eigen-value decompositions that may bring error accumulation. Furthermore, multiple targets having close 2D-DODs and close 2D-DOAs or even the same 2D-DOD or 2D-DOA are distinguishable by means of polarization diversity. The algorithm improves the performance of multi-target identification and three-dimensional localization. Numerical simulations demonstrate the effectiveness of the proposed algorithm.

  11. Protocol for the application of cooperative MIMO based on clustering in sparse wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-hua; QU Yu-gui; LIN Zhi-ting; BAI Rong-gang; ZHAO Bao-hua; PAN Quan-ke

    2007-01-01

    Wireless sensor networks (WSN) using cooperative multiple-input multiple-output (MIMO) communication are effective tools to collect data in several environments. However, how to apply cooperative MIMO in WSN remains a critical challenge, especially in sparse WSN. In this article, a novel clustering scheme is proposed for the application of cooperative MIMO in sparse WSN by extending the traditional low-energy adaptive clustering hierarchy (LEACH) protocol. This clustering scheme solves the problem that the cluster heads (CH) cannot find enough secondary cluster heads (SCH), which are used to cooperate and inform multiple-antenna transmitters with CHs. On the basis of this protocol, the overall energy consumption of the networks model is developed, and the optimal number of CHs is obtained. The simulation results show that this protocol is feasible for the sparse WSN. The simulation results also illustrate that this protocol provides significant energy efficiencies, even after allowing for additional overheads.

  12. 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......-SM-MRT). When the DFT-SM scheme alone is used, the data streams are either mapped onto different angles of departures in the case of aligned linear arrays, or mapped onto different orbital angular momentums in the case of aligned circular arrays. Maximum ratio transmission pre-equalizes the channel...

  13. Signal Detection for MIMO-OFDM Based on Compound Taguchi-GA%基于混合Taguchi-GA算法的MIMO-OFDM信号检测

    Institute of Scientific and Technical Information of China (English)

    吴静松; 冯慧玲

    2015-01-01

    为了避免传统MIMO-OFDM信号检测方法具有的计算量过大而导致的算法复杂度高的问题,设计了一种基于混合Taguchi方法和GA算法的MIMO-OFDM信号检测方法,首先建立了MIMO-OFDM信号检测的模型,然后依据信号检测模型建立目标函数,将目标函数作为混合Taguchi-GA算法的适应度函数,通过个体在信号检测问题的解空间中进行不断地选择、交叉和变异等操作来求解全局最优解,为了进一步增加算法的全局寻优能力,通过Taguchi方法进一步在交叉和变异之间产生新个体;最后,定义和描述了基于混合Taguchi和GA算法的MIMO-OFDM信号检测算法,仿真实验表明,文中方法能有效进行信号检测,与其他方法相比,在BPSK调制和16QAM调制情况下,均具有较小的BER均方误差.

  14. 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 b

  15. 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.

  16. 基于MIMO-OFDM技术的对流层散射通信系统研究%Tropospheric Scatter Communication System Based on MIMO-OFDM Technology

    Institute of Scientific and Technical Information of China (English)

    谢红; 谭泽富

    2010-01-01

    对流层散射通信是一种典型的随参信道,多径衰落十分突出,所以要实现高速大容量散射通信是非常困难的.为了抵抗由于多径衰落所带来的散射通信性能恶化,提出了基于MIMO-OFDM结构的的新一代对流层散射通信系统框架.通过分析散射信道中的MIMO-OFDM结构,讨论MIMO-OFDM技术应用的主要问题,发现运用该技术可以有效提高散射通信的可靠度,克服高速数据在散射信道下的多径衰落,实现散射的大容量、远距离通信.

  17. Compressive Sensing for MIMO Radar

    CERN Document Server

    Yu, Yao; Poor, H Vincent

    2009-01-01

    Multiple-input multiple-output (MIMO) radar systems have been shown to achieve superior resolution as compared to traditional radar systems with the same number of transmit and receive antennas. This paper considers a distributed MIMO radar scenario, in which each transmit element is a node in a wireless network, and investigates the use of compressive sampling for direction-of-arrival (DOA) estimation. According to the theory of compressive sampling, a signal that is sparse in some domain can be recovered based on far fewer samples than required by the Nyquist sampling theorem. The DOA of targets form a sparse vector in the angle space, and therefore, compressive sampling can be applied for DOA estimation. The proposed approach achieves the superior resolution of MIMO radar with far fewer samples than other approaches. This is particularly useful in a distributed scenario, in which the results at each receive node need to be transmitted to a fusion center for further processing.

  18. 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.

  19. 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.

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

    OpenAIRE

    Mueller, Axel; Kammoun, Abla; Björnson, Emil; Debbah, Merouane

    2016-01-01

    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-opt...

  1. 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...

  2. 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.

  3. An ESPRIT-Based Approach for 2-D Localization of Incoherently Distributed Sources in Massive MIMO Systems

    Science.gov (United States)

    Hu, Anzhong; Lv, Tiejun; Gao, Hui; Zhang, Zhang; Yang, Shaoshi

    2014-10-01

    In this paper, an approach of estimating signal parameters via rotational invariance technique (ESPRIT) is proposed for two-dimensional (2-D) localization of incoherently distributed (ID) sources in large-scale/massive multiple-input multiple-output (MIMO) systems. The traditional ESPRIT-based methods are valid only for one-dimensional (1-D) localization of the ID sources. By contrast, in the proposed approach the signal subspace is constructed for estimating the nominal azimuth and elevation direction-of-arrivals and the angular spreads. The proposed estimator enjoys closed-form expressions and hence it bypasses the searching over the entire feasible field. Therefore, it imposes significantly lower computational complexity than the conventional 2-D estimation approaches. Our analysis shows that the estimation performance of the proposed approach improves when the large-scale/massive MIMO systems are employed. The approximate Cram\\'{e}r-Rao bound of the proposed estimator for the 2-D localization is also derived. Numerical results demonstrate that albeit the proposed estimation method is comparable with the traditional 2-D estimators in terms of performance, it benefits from a remarkably lower computational complexity.

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

    Science.gov (United States)

    Jia, Yong; Zhong, Xiaoling; Liu, Jiangang; Guo, Yong

    2016-01-01

    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. PMID:27618039

  5. 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...... to find out the SINR statistics of different combinations of desired and interfering links. We have studied linear combining receivers for all the link combinations. Based on the current analysis, it is found that Space-Time Block Code (STBC) is a severe interferer compared to others, and specific...

  6. 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 of...... radio-frequency signals, an optical transmitter in the form of an electro-optic conversion unit for each of said plurality of antenna units, each electro-optic conversion unit adapted for converting an RF signal into an optical signal, a plurality of a single core optical fibers for guiding the optical...

  7. Cross-Layer Approach using k-NN Based Adaptive Modulation Coding (AMC and Incremental Redundancy Hybrid Automatic Repeat Request (IR-HARQ for MIMO

    Directory of Open Access Journals (Sweden)

    J. Sofia Priya Dharshini

    2014-09-01

    Full Text Available In MIMO Technology, a cross layer design enhances the spectral efficiency, reliability and throughput of the network. In this paper, a cross-layer approach using k-NN based Adaptive Modulation Coding (AMC and Incremental Redundancy Hybrid Automatic Repeat Request (IR-HARQ is proposed for MIMO Systems. The proposed cross layer approach connects physical layer and data link layer to enhance the performance of MIMO network. By means of MIMO fading channels, the coded symbols are forwarded in the physical layer on a frame by frame fashion subsequently using Space Time Block Coding (STBC. The receiver computes the signal to noise ratio (SNR and forwards back to the AMC controller. The controller selects a suitable MCS for the next transmission through k-NN classifier supervised learning algorithm. IR-HARQ is utilized at the data link layer to regulate packet retransmissions. The obtained results prove that the proposed technique has better performance in terms of throughput, BER and spectral efficiency

  8. BLIND EQUALIZATION OF MIMO SYSTEMS BASED ON ORTHOGONAL CONSTANT MODULUS ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper investigates adaptive blind source separation and equalization for Multiple Input Mul-tiple Output (MIMO) systems. To effectively recover input signals, remove Inter-Symbol Interference (ISI)and suppress Inter-User Interference (IUI), the array input is first transformed into the signal subspace, thenwith the derived orthogonality between weight vectors of different input signals, a new orthogonal ConstantModulus Algorithm (CMA) is proposed. Computer simulation results illustrate the promising performance ofthe proposed method. Without channel identification, the proposed method can recover all the system inputssimultaneously and can be adaptive to channel changes without prior knowledge about signals.

  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. Cognitive radar MIMO-STAP based on joint transmit and receive weight optimization%基于联合收发权值优化的认知雷达MIMO-STAP

    Institute of Scientific and Technical Information of China (English)

    张鑫; 崔琛; 王兴

    2012-01-01

    This paper studied the problem of joint transmit and receive weight optimization for cognitive radar MIMO-STAP. It proposed a method of joint space-time adaptive processing (JSTAP) both transmitter and receiver. It maximized the signal-to-interference-and-noise ratio ( SINR) by optimizing the weights of transmitter and receiver jointly. It analyzed the structure of the clutter covariance affected by the weithts of transmitter, and built the iterative updating structure of weights of MIMO-STAP. The process was as follows: the first step was to find the weight of receiver by solving the optimizing model when the weight of transmitter was considered to be constant. The second step was to find the weight of transmitter based on the characteristics of the clutter covariance matrix when the weight of receiver was considered to be constant. Then the next step was to go back to the first step, and the cycle would not stop until the optimum weight was solved. The experiment results show that JSTAP technology improves the SINR performance contrasting with the conventional STAP technology when the velocity of target is slow.%研究了认知雷达中多收多发空时自适应处理(MIMO-STAP)联合收发权值优化问题.提出了一种在收发两端联合空时自适应处理(JSTAP)的方法,该方法通过对收发权值联合寻优以获得最优的信干噪比.分析了受发射权值影响的杂波协方差矩阵结构,并基于此建立了MIMO-STAP的权值迭代更新结构.其权值迭代更新步骤为:固定发射权值,求解优化模型得到接收权值;然后固定接收权值,根据杂波协方差矩阵与发射权值的关系,得到发射权值;返回接收权值优化步骤,循环迭代以获得最优收发权值.仿真实验结果表明在慢速目标环境中,联合空时处理与常规空时处理相比,有效提高了接收端的信干噪比.

  11. 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...

  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. 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.

  14. Low complexity MIMO method based on matrix transformation for few-mode multi-core optical transmission system

    Science.gov (United States)

    Pan, Xiaolong; Liu, Bo; Li, Li; Tian, Qinghua

    2016-07-01

    This paper proposes and demonstrates a low complexity multiple-input multiple-output (MIMO) equalization digital signal processing (DSP) method for the few mode multi-core (FMMC) fiber optical transmission system. 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. Compared with traditional MIMO method, the proposed scheme has increased the convergence rate by 4 times and reduced the number of finite impulse response (FIR) filters by 55% when the numbers of mode and core are three.

  15. REVIEW OF THE PILOT CONTAMINATION PROBLEM FOR MASSIVE MIMO AND POSSIBLE SOLUTION

    OpenAIRE

    Atul Kumar Mishra*, Prof. Saurabh Gaur

    2016-01-01

    With the increasing demands of data communication speed for different type of data transmission, many revolutions occur with time in wireless communication system. The use of MIMO for wireless data transmission has proven itself for enhancing the capacity of data transmission. The mobile network based on the cell structure also uses the MIMO techniques. Further research in the field of massive MIMO has started for faithful data transmission. The enhancement by massive MIMO encounters many pro...

  16. A Novel Iterative Receiver Based on Extrinsic Information Update for MIMO Systems

    Institute of Scientific and Technical Information of China (English)

    LIN Wen-feng; HE Chen

    2007-01-01

    A novel iterative receiver for multiple input multiple output (MIMO) systems was introduced.Its basis concept is that the reliability of extrinsic information will be strengthened with continuous iterations.Extrinsic information of present iteration is added with prior information of last iteration to obtain performance gain.The simulation results show that the improved iterative receiver can approach the 5th iteration performance of conventional soft interference cancellation (SIC)-minimum mean square error (MMSE) iterative receiver after the 2nd iteration with less computational complexity.Compared with conventional iterative receiver, the improved iterative receiver has 1dB performance gain at bit error rate (BER) of 10-5, with four transmit antennas and four receive antennas system.

  17. SAGE based iterative receiver for joint synchronization and channel estimation in uplink MIMO-OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    JIANG Zheng; QIN Xiao-fang; ZHANG Xin; CHANG Yong-yu

    2008-01-01

    A new Turbo iterative receiver structure is proposed for the uplink multiple-input multiple-output orthogonal frequency division multiple access (MIMO-OFDMA) systems. The space-alternating generalized expectation-maximization (SAGE) algorithm is naturally embedded in the framework of iterative receiver to perform synchronization and detection using the Turbo detector outputs. In each iteration, the expectation step intends to remove the multiple access interference (MAI) caused by other asynchronous users, and the maximization step is utilized to estimate the required parameters (i.e., timing offset, carrier frequency offset, channel state information, etc.) sequentially for each user. Simulation results show that the proposed algorithm can approach the performance of ideal receiver closely, while the processing complexity is rather lower than the conventional detectors.

  18. 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...... 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...... 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....

  19. 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.

  20. 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....

  1. 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.

  2. 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,...

  3. 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...

  4. 基于CDM-CZM的复合材料补片补强参数分析%Parameter Analysis of Composite Laminates with Patched Reinforcement Based on CDM-CZM

    Institute of Scientific and Technical Information of China (English)

    姚辽军; 赵美英; 万小朋

    2012-01-01

    It is of engineering significance to determine the parameters of reinforcement design of notched composite laminates. In order to understand the influence of these parameters on the structure strength and damage propagation, a three-dimension anisotropic continuum damage model CCDM) is developed to describe the onset and damage evolution in a notched composite laminate under tensile loading condition. A cohesive zone model (CZM) Is used to simulate the damage evolution of an adhesive material between the notched composite laminate and the patched reinforcement structure. Good agreement is obtained between the numerical and the experimental results. Based on the validated model, three main parameters for reinforcement design are discussed, i.e., the lay-up configuration, patch thickness and radius of patch reinforcement. Furthermore, the delamination of the adhesive layer between the laminate and the patch is found to be the primary reason for the final failure of the reinforced structure.%复合材料开口补强设计参数的确定对于结构设计具有重要的意义.针对复合材料层合板开口区补片补强结构,采用各向异性材料连续介质损伤力学模型(CDM)对复合材料层合板的损伤演化进行描述,采用粘聚区模型(CZM)对补片与母板间界面材料的分层损伤进行模拟,建立了复合材料开口区补片补强结构三维非线性渐进损伤模型,模型可预测补强结构强度和损伤演化过程.应用本文模型分析了补片铺层方式、补片厚度和补片半径3个主要设计参数对补强效果的影响,明确了补片与母板间界面材料分层损伤破坏是导致补强结构最终失效的主要原因.

  5. 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.

  6. 基于SM调制的Massive MIMO信号检测算法%Research of SM-modulation Based Signal Detection Algorithm for Massive MIMO

    Institute of Scientific and Technical Information of China (English)

    杨大江; 钟子发; 宋常建; 朱然刚

    2015-01-01

    In recent years,large-scale multiple-input multiple-output (Multi-Input Multi-Output, MIMO)signal detection problem has attracted much attention,this paper studies the belief propagation (Belief Propagation,BP)-based algorithm on the proposed (Message Passing Detection for Spatial Modulation,MPD-SM) detection algorithm based Massive MIMO information transfer process. A new spatial modulation under the simulation comparison chart under two different modulation patterns,the results show that,under different circumstances modulation order,the performance of the proposed algorithm is superior to the traditional detection algorithm under the M-MIMO. And to some extent,the complexity of large-scale multi-user MIMO detection is reduced and the detection efficiency is improved.%近几年来,大规模多输入多输出(Multi-Input Multi-Output,MIMO)的信号检测问题已经引起了人们的关注,在研究了置信度传播(Belief Propagation,BP)算法的基础上,提出了一种新的空间调制下的基于信息传递过程的Massive MIMO(Message Passing Detection for Spatial Modulation,MPD-SM)检测算法,给出了两种不同用户天线数下的仿真对比图,结果表明,在这两种仿真下,所提算法性能要优于M-MIMO下传统的检测算法,且在一定程度上降低了大规模MIMO多用户检测的复杂度,提高了检测效率。

  7. Direction synthesis in DOA estimation for monostatic multiple input multiple output (MIMO) radar based on synthetic impulse and aperture radar (SIAR) and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new direction synthetic method for monostatic multiple input multiple output (MIMO) radar is presented based on synthetic impulse and aperture radar (SIAR) system. Concerned with the monostatic MIMO radar which simultaneously emits orthogonal signals with multi-carrier-frequency and possesses sparsely distributed transmitting and receiving arrays with respective location, as well as the situation for the presence of multipath propagation in the low flying target’s echo, the method integrates the aperture of the transmitting arrays with the receiving arrays to form the digital beam-forming (DBF) in azimuth and elevation dimensions. And a study has been made of planar general MUSIC algorithm based on decorrelating the multipath signals of multi-carrier-frequency MIMO radar. Through compensat-ing the phase delay of both the transmitting and the receiving arrays and synthe-sizing the transmitting beam in two dimensions at the receiver, the angular resolu-tion and measurement accuracy are improved and the computational complexity is reduced after transforming the three-dimensional (3D) parameter estimation prob-lem into a two-dimensional (2D) one. Finally, the Cramer-Rao Bounds (CRBs) of DOA estimation for azimuth and elevation is put forward with the exsiting multipath propagation. Results of computer simulation demonstrate the validity of the new method.

  8. Direction synthesis in DOA estimation for monostatic multiple input multiple output(MIMO) radar based on synthetic impulse and aperture radar (SIAR) and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO GuangHui; CHEN BaiXiao; ZHU ShouPing

    2008-01-01

    A new direction synthetic method for monostatic multiple input multiple output (MIMO) radar is presented based on synthetic impulse and aperture radar (SIAR) system. Concerned with the monostatic MIMO radar which simultaneously emits orthogonal signals with multi-carrier-frequency and possesses sparsely distributed transmitting and receiving arrays with respective location, as well as the situation for the presence of multipath propagation in the low flying target's echo, the method integrates the aperture of the transmitting arrays with the receiving arrays to form the digital beam-forming (DBF) in azimuth and elevation dimensions. And a study has been made of planar general MUSIC algorithm based on decorrelating the multipath signals of multi-carrier-frequency MIMO radar. Through compensat-ing the phase delay of both the transmitting and the receiving arrays and synthe-sizing the transmitting beam in two dimensions at the receiver, the angular resolu-tion and measurement accuracy are improved and the computational complexity is reduced after transforming the three-dimensional (3D) parameter estimation prob-lem into a two-dimensional (2D) one. Finally, the Cramer-Rao Bounds (CRBs) of DOA estimation for azimuth and elevation is put forward with the exsitJng multipath propagation. Results of computer simulation demonstrate the validity of the new method.

  9. CDM Country Guide for The Philippines

    International Nuclear Information System (INIS)

    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 The Philippines

  10. 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-cellular...

  11. MIMO Radar Using Compressive Sampling

    CERN Document Server

    Yu, Yao; Poor, H Vincent

    2009-01-01

    A MIMO radar system is proposed for obtaining angle and Doppler information on potential targets. Transmitters and receivers are nodes of a small scale wireless network and are assumed to be randomly scattered on a disk. The transmit nodes transmit uncorrelated waveforms. Each receive node applies compressive sampling to the received signal to obtain a small number of samples, which the node subsequently forwards to a fusion center. Assuming that the targets are sparsely located in the angle- Doppler space, based on the samples forwarded by the receive nodes the fusion center formulates an l1-optimization problem, the solution of which yields target angle and Doppler information. The proposed approach achieves the superior resolution of MIMO radar with far fewer samples than required by other approaches. This implies power savings during the communication phase between the receive nodes and the fusion center. Performance in the presence of a jammer is analyzed for the case of slowly moving targets. Issues rel...

  12. 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%.

  13. PMI-based MIMO OFDM PHY Integrated Key Exchange (P-MOPI) Scheme

    CERN Document Server

    Lan, Pang-Chang; Lee, Chia-Han; Yeh, Ping-Cheng; Cheng, Chen-Mou

    2011-01-01

    In the literature, J.-P. Cheng et al. have proposed the MIMO-OFDM PHY integrated (MOPI) scheme for achieving physical-layer security in practice without using any cryptographic ciphers. The MOPI scheme uses channel sounding and physical-layer network coding (PNC) to prevent eavesdroppers from learning the channel state information (CSI). Nevertheless, due to the use of multiple antennas for PNC at transmitter and beamforming at receiver, it is not possible to have spatial multiplexing nor use space-time codes in our previous MOPI scheme. In this paper, we propose a variant of the MOPI scheme, called P-MOPI, that works with a cryptographic cipher and utilizes precoding matrix index (PMI) as an efficient key-exchange mechanism. With channel sounding, the PMI is only known between the transmitter and the legal receiver. The shared key can then be used, e.g., as the seed to generate pseudo random bit sequences for securing subsequent transmissions using a stream cipher. By applying the same techniques at independ...

  14. NOVEL DECODING OF SQUARE QAM MODULATED MIMO SYSTEMS BASED ON TURBO MULTIUSER DETECTION

    Institute of Scientific and Technical Information of China (English)

    Zheng Jianping; Bai Baoming; Wang Xinmei

    2008-01-01

    By introducing the bit-level multi-stream coded Layered Space-Time (LST) transmitter along with a novel iterative MultiStage Decoding (MSD) at the receiver, the paper shows how to achieve the near-capacity performance of the Multiple-Input Multiple-Output (MIMO) systems with square Quadrature Amplitude Modulation (QAM). In the proposed iterative MSD scheme, the detection at each stage is equivalent to multiuser detection of synchronous Code Division Multiple Access (CDMA) multiuser systems with the aid of the binary representation of the transmitted symbols. Therefore, the optimal Soft-Input Soft-Output (SISO) multiuser detection and low-complexity SISO multiuser detection can be utilized herein. And the proposed scheme with low-complexity SISO multiuser detection has polynomial complexity in the number of transmit antennas M, the number of receive antennas N, and the number of bits per constellation point Mc. Simulation results demonstrate that the proposed scheme has similar Bit Error Rate (BER) performance to that of the known Iterative Tree Search (ITS) detection.

  15. 基于空频相关性的大规模MIMO-OFDM信道压缩反馈算法%Compressed Channel Feedback Based on Spatial-frequency Correlation for Massive MIMO-OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    李晓辉; 王维猛; 黑永强

    2014-01-01

    In Massive MIMO-OFDM systems, the channel shows strong correlations in both spatial and frequency domain. Aiming at the problem that only spatial or frequency domain correlation is considered in most of the existing compressed feedback algorithms, a joint spatial-frequency compression algorithm is proposed. First, a two dimensional sparsity of channel in spatial-frequency domain is analyzed according to the compressed sensing theory. Then, a joint sparse matrix of channel is derived. Based on the joint sparse matrix, the joint spatial-frequency compression algorithm is presented. Simulation results and analysis show that, the proposed algorithm can significantly reduce the feedback load with acceptable accuracy.%大规模MIMO-OFDM系统中,信道常常存在较强的空间和频域相关性。针对多数信道压缩反馈算法仅考虑空间或频域相关性的问题,该文提出一种空频联合压缩反馈算法。首先,根据压缩感知理论进行了信道空频2维稀疏度分析;然后,推导了信道矩阵在空间和频域2维相关性下的联合稀疏基;最后,利用该联合稀疏基给出了空频联合压缩算法。仿真结果与分析表明,该算法在保证信道反馈精度的同时,可显著降低反馈量。

  16. Adaptive channel estimation based on pilot signals and transform-domain processing in SISO/MIMO OFDM systems%基于导频和变换域的SISO/MIMO OFDM系统自适应信道估计

    Institute of Scientific and Technical Information of China (English)

    宋铁成; 尤肖虎; 沈连丰; 宋晓晋

    2005-01-01

    Based on the transform-domain characteristics of pilot signals,a band suppression filter is used as a transform-domain filter to restrain the interference of noise in channel estimation.The performance effect on channel estimation for an orthogonal frequency division multiplex (OFDM) system by different energy coefficients in the transform domain and the energy coefficient under the different signal-to-noise ratios (SNR) are also analyzed.A new energy coefficient expression is deduced.It is theoretically proven that dynamically selecting an energy coefficient can significantly improve the performance of channel estimation.Simulation results show that the proposed algorithm can achieve better performance close to the theoretic bounds of perfect channel estimation. The algorithm is adapted to single-input single-output (SISO) OFDM and multi-input multi-output (MIMO) OFDM systems.%根据导频信号在变换域中的频响特性,将系统的变换域滤波器设计成具有更好滤波效果的"带阻滤波器";在小信噪比和大信噪比条件下,分析了变换域能量参数对系统信道估计性能的影响,推导了新的能量参数表达式,理论证明了根据接收端检测到的信噪比自适应选择能量参数可以显著改善信道估计的性能.仿真结果表明,提出的信道估计算法具有较好的性能,在一定程度上可以接近于理想信道估计的性能,适用于SISO OFDM系统和MIMO OFDM系统.

  17. On detection performance and system configuration of MIMO radar

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; WU Yong; PENG YingNing; WANG XiuTan

    2009-01-01

    Multiple-input multiple-output (MIMO) radar is a new concept with some new characteristics, such as multiple orthogonal waveforms and omnidirectional coverage. Based on Stein's lemma, we use relative entropy as a precise and general measure of error exponent to study detection performance for both MIMO radar and phased array radar. And based on derived analytical results, we further study the system configuration problem of Bistatic MIMO radar systems, where transmitters and receivers are located in different positions. Some interesting results are presented. For phased array radar, when the total numbers of transmitters and receivers are fixed, we should always make the number of transmitters equal to the number of receivers. For MIMO radar, we should use a small number of transmitters in low signal noise ratio (SNR) region, and make the number of transmitters equal to the number of receivers in high SNR region. These results are instructive for deployment of bistatic MIMO radar systems in the future.

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

    International Nuclear Information System (INIS)

    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

  19. Free vibration analysis of DWCNTs using CDM and Rayleigh-Schmidt based on Nonlocal Euler-Bernoulli beam theory.

    Science.gov (United States)

    De Rosa, Maria Anna; Lippiello, Maria

    2014-01-01

    The free vibration response of double-walled carbon nanotubes (DWCNTs) is investigated. The DWCNTs are modelled as two beams, interacting between them through the van der Waals forces, and the nonlocal Euler-Bernoulli beam theory is used. The governing equations of motion are derived using a variational approach and the free frequencies of vibrations are obtained employing two different approaches. In the first method, the two double-walled carbon nanotubes are discretized by means of the so-called "cell discretization method" (CDM) in which each nanotube is reduced to a set of rigid bars linked together by elastic cells. The resulting discrete system takes into account nonlocal effects, constraint elasticities, and the van der Waals forces. The second proposed approach, belonging to the semianalytical methods, is an optimized version of the classical Rayleigh quotient, as proposed originally by Schmidt. The resulting conditions are solved numerically. Numerical examples end the paper, in which the two approaches give lower-upper bounds to the true values, and some comparisons with existing results are offered. Comparisons of the present numerical results with those from the open literature show an excellent agreement.

  20. 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.

  1. Noncircular Sources-Based Sparse Representation Algorithm for Direction of Arrival Estimation in MIMO Radar with Mutual Coupling

    Directory of Open Access Journals (Sweden)

    Weidong Zhou

    2016-09-01

    Full Text Available In this paper, a reweighted sparse representation algorithm based on noncircular sources is proposed, and the problem of the direction of arrival (DOA estimation for multiple-input multiple-output (MIMO radar with mutual coupling is addressed. Making full use of the special structure of banded symmetric Toeplitz mutual coupling matrices (MCM, the proposed algorithm firstly eliminates the effect of mutual coupling by linear transformation. Then, a reduced dimensional transformation is exploited to reduce the computational complexity of the proposed algorithm. Furthermore, by utilizing the noncircular feature of signals, the new extended received data matrix is formulated to enlarge the array aperture. Finally, based on the new received data, a reweighted matrix is constructed, and the proposed method further designs the joint reweighted sparse representation scheme to achieve the DOA estimation by solving the l 1 -norm constraint minimization problem. The proposed method enlarges the array aperture due to the application of signal noncircularity, and in the presence of mutual coupling, the proposed algorithm provides higher resolution and better angle estimation performance than ESPRIT-like, l 1 -SVD and l 1 -SRDML (sparse representation deterministic maximum likelihood algorithms. Numerical experiment results verify the effectiveness and advantages of the proposed method.

  2. 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

  3. 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…

  4. Supporting Open Access to European Academic Courses: The ASK-CDM-ECTS Tool

    Science.gov (United States)

    Sampson, Demetrios G.; Zervas, Panagiotis

    2013-01-01

    Purpose: This paper aims to present and evaluate a web-based tool, namely ASK-CDM-ECTS, which facilitates authoring and publishing on the web descriptions of (open) academic courses in machine-readable format using an application profile of the Course Description Metadata (CDM) specification, namely CDM-ECTS. Design/methodology/approach: The paper…

  5. 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.

  6. Programmable MIMO detectors

    OpenAIRE

    Janhunen, J. (Janne)

    2011-01-01

    Abstract The multiple-input multiple-output (MIMO) technique combined with an orthogonal frequency division multiplexing (MIMO--OFDM) has been introduced as a promising approach for the ever increasing capacity and quality of service (QoS) requirements for wireless communication systems. An efficient radio spectrum utilization expects a flexible transceiver solution, which has been the reason for the development of the software defined radio (SDR) technologies which in their turn are expe...

  7. Ultra Low Complexity Soft Output Detector for Non-Binary LDPC Coded Large MIMO Systems

    CERN Document Server

    Suthisopapan, Puripong; Kasai, Kenta; Imtawil, Virasit

    2012-01-01

    The theoretic results of MIMO capacity tell us that the higher the number of antennas are employed, the higher the transmission rate is. This makes MIMO systems with hundreds of antennas very attractive but one of the major problems that obstructs such large dimensional MIMO systems from the practical realization is a high complexity of the MIMO detector. We present in this paper the new soft output MIMO detector based on matched filtering that can be applied to the large MIMO systems which are coded by the powerful non-binary LDPC codes. The per-bit complexity of the proposed detector is just 0.28% to that of low complexity soft output MMSE detector and scales only linearly with a number of antennas. Furthermore, the coded performances with small information length 800 bits are within 4.2 dB from the associated MIMO capacity.

  8. Limited Feedback Precoding for Massive MIMO

    Directory of Open Access Journals (Sweden)

    Xin Su

    2013-01-01

    Full Text Available The large-scale array antenna system with numerous low-power antennas deployed at the base station, also known as massive multiple-input multiple-output (MIMO, can provide a plethora of advantages over the classical array antenna system. Precoding is important to exploit massive MIMO performance, and codebook design is crucial due to the limited feedback channel. In this paper, we propose a new avenue of codebook design based on a Kronecker-type approximation of the array correlation structure for the uniform rectangular antenna array, which is preferable for the antenna deployment of massive MIMO. Although the feedback overhead is quite limited, the codebook design can provide an effective solution to support multiple users in different scenarios. Simulation results demonstrate that our proposed codebook outperforms the previously known codebooks remarkably.

  9. A NOVEL INDOOR GEO-LOCATION METHOD USING MIMO ARRAY

    Institute of Scientific and Technical Information of China (English)

    Sun Guolin; Guo Wei

    2006-01-01

    In a Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) based Wireless Local Area Network (WLAN) system, both Access Points (Aps) and Mobile Terminals (MTs) are configured with multiple antennas, to make novel indoor geo-location method possible. In this paper, we presented a novel Least Square Support Vector Machine (LS-SVM) based data fusion algorithm to fuse signal strength measurements for indoor geo-location using only a single AP with MIMO arrays. We evaluate our proposed algorithms under indoor environments by MATLAB simulations. Simulation results show that our MIMO-based algorithm is superior to conventional least square algorithm.

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

    Science.gov (United States)

    Li, Jiehui; Xu, Yinfan; Shi, Jianyang; Wang, Yuanquan; Ji, Xinming; Ou, Haiyan; Chi, Nan

    2016-05-01

    In this paper, we proposed a 2×2 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. The proposed imaging system not only overcomes the limitation of bandwidth existing in LEDs, but also can reject the second-order nonlinearity distortion. It turned out to be very promising to use integrated antennas in the VLC system in the future.

  11. 基于QRM-MLD的MIMO检测算法研究%QRM-MLD-based MIMO Detection Algorithm

    Institute of Scientific and Technical Information of China (English)

    张朝霞; 王琼; 刘佳

    2013-01-01

    在多输入多输出( MIMO)通信系统中,MIMO检测是发送端MIMO编码的逆过程,是根据接收到的信号及接收信号质量、信道状态信息等获得发送端发送比特的概率信息过程。通信信道矩阵的QR分解( QRD)是几种MIMO信号检测方案的基本先决条件。首先针对QRD方案进行研究,详细介绍了QRM-MLD的算法实现并进行了优化。最后对复杂度进行了统计并对仿真结果进行了分析,证明此方案可以作为MIMO检测的优选方案。%In MIMO ( multi-input multi-output ) communication system, MIMO detection is the reverse process of MIMO coding, and from the received signal and its quality and channel status information it ob-tains the bits probability information of the transmitter. The QRD( QR decomposition) of communication channel matrices is a fundamental prerequisite for several detection schemes. Firstly, the QRD methods are studied. Then the realization procedure and optimization of QRM-MLD are described in detail. Finally, the statistics of the complexity are presented, the simulation results are analyzed. It is verified that this so-lution can be used as a preferred scheme of MIMO detection.

  12. A novel differential multiuser detection algorithm for multiuser MIMO-OFDM systems

    Institute of Scientific and Technical Information of China (English)

    Zheng-min KONG; Guang-xi ZHU; Qiao-ling TONG; Yan-chun LI

    2010-01-01

    We propose an efficient low bit error rate(BER)and low complexity multiple-input multiple-output(MIMO)multiuser detection(MUD)method for use with multiuser MIMO orthogonal frequency division multiplexing(OFDM)systems.It is a hybrid method combining a multiuser-interference-cancellation-based decision feedback equalizer using error feedback filter(MIMO MIC DFE-EFF)and a differential algorithm.The proposed method,termed 'MIMO MIC DFE-EFF with a differential algorithm' for short,has a multiuser feedback structure.We describe the schemes of MIMO MIC DFE-EFF and MIMO MIC DFE-EFF with a differential algorithm,and compare their minimum mean square error(MMSE)performance and computational complexity.Simulation results show that a significant performance gain can be achieved by employing the MIMO MIC DFE-EFF detection algorithm in the context of a multiuser MIMO-OFDM system over frequency selective Rayleigh channel.MIMO MIC DFE-EFF with the differential algorithm improves both computational efficiency and BEg performance in a multistage structure relative to conventional DFE-EFF,though there is a small reduction in system performance compared with MIMO MIC DFE-EFF without the differential algorithm.

  13. MIMO/SA Multi-antenna Space-time Channel Modeling%MIMO/SA多天线空时信道建模

    Institute of Scientific and Technical Information of China (English)

    吕郡陵; 郭爱煌

    2012-01-01

    Based on correlation matrix method. Multiple-input and Multiple-output(MIMO) channel coefficient matrix can be obtained by calculating the correlation coefficient between two antennas and MIMO correlation matrix. The steering vector and beam-forming vector of Smart Antenna(SA) are added to the MIMO channel coefficient matrix to form MIMO/SA channel matrix, so that MIMO/SA multi-antenna space-time channel is modeled. A channel simulation platform is established to simulate and analyze MIMO/SA channel in time domain, frequency domain and space domain. Simulation results show that the model has a good channel directivity gain and the channel properties in space, time and frequency meet the demands of 3GPP TR 25.996, and it is useful for designing and optimizing MIMO/SA multi-antenna system and the analysis of channel capacity.%运用相关矩阵法,通过计算2根天线之间的相关系数、多输入多输出(MIMO)的相关矩阵,得到MIMO信道系数矩阵,在其中加入智能天线(SA)的导向向量和赋形向量,得到MIMO/SA矩阵,由此实现对MIMO/SA多天线空时信道的建模.利用Matlab搭建一个仿真平台,从空间、时间、频率3个方面分析MIMO/SA多天线信道模型,结果表明,该模型具有较好的信道方向性增益,信道的空时频特性符合3GPP 25.996的要求,可用于MIMO/SA多天线的设计、优化和信道容量分析.

  14. 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

  15. A Cluster-based Virtual MIMO Protocol for Wireless Sensor Networks%基于分簇的传感网虚拟MIMO协议

    Institute of Scientific and Technical Information of China (English)

    宋世玮; 仇建

    2015-01-01

    提出一种应用于无线传感网的新型分簇式虚拟MIMO协议。协议基于簇头轮换,避免大量重新分簇带来的拓扑维护开销,从而提高网络能量效率。在簇间路由中,提出一种新型的“跨跳”操作,以平衡网络中不同节点与簇的能耗和生命周期。仿真实验结果表明,该协议较现有的的虚拟MIMO在能耗总量和均衡上均具有更好的效果。%This paper proposes a novel cluster-based virtual MIMO protocol for wireless sensor networks .The protocol adopts cluster-head rotation to avoid massive re-clustering energy waste as well as improving energy efficiency of the entire network.In the inter-cluster routing, a new operation named “over-jump” is introduced to make energy consumption and lifetime balance among different nodes .The simulation results show that the proposed protocol is more effectively in energy saving and balance, compared with traditional cluster-based virtual MIMO systems.

  16. Mac-Phy Cross-Layer analysis and design of Mimo-Ofdm Wlans based on fast link adaptation

    OpenAIRE

    Martorell Lliteras, Gabriel

    2013-01-01

    The latestWLAN standard, known as IEEE 802.11n, has notably increased the network capacity with respect to its predecessors thanks to the incorporation of the multipleinput multiple-output (MIMO) technology. Nonetheless, the new amendment, as its previous ones, does not specify how crucial configuration mechanisms, most notably the adaptive modulation and coding (AMC) algorithm should be implemented. The AMC process has proved essential to fully exploit the system resources in ...

  17. Cognitive MIMO Frequency Diverse Array Radar with High LPI Performance

    OpenAIRE

    Ling Huang; Kuandong Gao; Zhiming He; Jingye Cai

    2016-01-01

    Frequency diverse array (FDA) has its unique advantage in realizing low probability of intercept (LPI) technology for its dependent beam pattern. In this paper, we proposed a cognitive radar based on the frequency diverse array multiple-input multiple-output (MIMO). To implement LPI of FDA MIMO transmit signals, a scheme for array weighting design is proposed, which is to minimize the energy of the target location and maximize the energy of the receiver. This is based on the range dependent c...

  18. 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...

  19. Antenna Subset Selection for Cyclic Prefix Assisted MIMO Wireless Communications over Frequency Selective Channels

    Directory of Open Access Journals (Sweden)

    T. Kaiser

    2008-04-01

    Full Text Available Antenna (subset selection techniques are feasible to reduce the hardware complexity of multiple-input multiple-output (MIMO systems, while keeping the benefits of higher-order MIMO systems. Many studies of antenna selection schemes are based on frequency-flat channel models, which are inconsistent to broadband MIMO systems employing spatial-multiplexing. In broadband MIMO systems aiming to provide high-data-rate links, the employed signal bandwidth is typically larger than the coherence bandwidth of the channel so that the channel will be of frequency selective nature. Within this contribution we provide an overview on joint transmitter- and receiver-side antenna subset selection methods for frequency selective channels and deploy them in MIMO orthogonal frequency division multiplexing (OFDM systems and MIMO single-carrier (SC systems employing frequency domain equalization (FDE.

  20. On Issues about the Application of MIMO in Mobile Cellular Communications

    Institute of Scientific and Technical Information of China (English)

    REN Li-gang; SONG Mei; SONG Jun-de

    2004-01-01

    The convenience of mobile communications and the increasing demand for higher data transmitting rate have motivated people to explore more efficient methods of signal transmission because of the limited spectral resource. Multiple-Input and Multiple-Output (MIMO) is a high spectral efficient method and the theoretical capacity of a MIMO channel increases linearly with the number of transmitting/receiving antennas under the ideal conditions. We can adopt MIMO technology in the new generation of mobile cellular communication systems, which is IP based and requires high data rate to support multimedia services. Although much progress has been made in MIMO area recently, there are some problems in its practical application, especially in cellular application. In this paper we will analyze the channel model, the capacity and the technology of MIMO, and then we will focus on the issues of MIMO application in mobile cellular system by the Monte Carlo simulation and give the available solution schemes for the issues.

  1. Energy Efficiency of Massive MIMO: Coping with Daily Load Variation

    OpenAIRE

    Hossain, M. M. Aftab; Cavdar, Cicek; Björnson, Emil; Jäntti, Riku

    2015-01-01

    Massive MIMO is a promising technique to meet the exponential growth of mobile traffic demand. However, contrary to the current systems, energy consumption of next generation networks is required to be load adaptive as the network load varies significantly throughout the day. In this paper, we propose a load adaptive multi-cell massive MIMO system where each base station (BS) adapts the number of antennas to the daily load profile (DLP) in order to maximize the downlink energy efficiency (EE)...

  2. A Variational Approach to the Modeling of MIMO Systems

    Directory of Open Access Journals (Sweden)

    Jraifi A

    2007-01-01

    Full Text Available Motivated by the study of the optimization of the quality of service for multiple input multiple output (MIMO systems in 3G (third generation, we develop a method for modeling MIMO channel . This method, which uses a statistical approach, is based on a variational form of the usual channel equation. The proposed equation is given by with scalar variable . Minimum distance of received vectors is used as the random variable to model MIMO channel. This variable is of crucial importance for the performance of the transmission system as it captures the degree of interference between neighbors vectors. Then, we use this approach to compute numerically the total probability of errors with respect to signal-to-noise ratio (SNR and then predict the numbers of antennas. By fixing SNR variable to a specific value, we extract informations on the optimal numbers of MIMO antennas.

  3. On detection performance of MIMO radar for Rician target

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; WU Yong; PENG YingNing; WANG XiuTan

    2009-01-01

    By using spatial dlversity, multiple-input-multiple-output (MIMO) radar can improve detection performance for fluctuating targets. In this paper, we propose a spatial fluctuation target model for MIMO radar, where targets are classified as non-fluctuating target, Rayleigh target and Rician target. Based on Stein's lemma, we use relative entropy to study detection performance of optimum detector for Riclan target. It is found that in low signal noise ratio (SNR) region, the performance improvement of MIMO radar for detecting Rician target depends on array gain, which is related to the number of receivers. In high SNR region, the improvement of performance depends on diversity gain, which is related to the product of the number of receivers and the number of transmitters. The conclusions of this paper are Important for designing MIMO radar system.

  4. The CDM-Net Project: The Development, Implementation and Evaluation of a Broadband-Based Network for Managing Chronic Disease

    OpenAIRE

    Kay Jones; Trisha Dunning; Beth Costa; Kristine Fitzgerald; Akuh Adaji; Colin Chapman; Leon Piterman; Moira Paterson; Peter Schattner; John Catford

    2012-01-01

    Background. In Australia most chronic disease management is funded by Medicare Australia through General Practitioner Management Plans (GPMPs) and Team Care Arrangements (TCAs). Identified barriers may be reduced effectively using a broadband-based network known as the Chronic Disease Management Service (CDMS). Aims. To measure the uptake and adherence to CDMS, test CDMS, and assess the adherence of health providers and patients to GPMPs and TCAs generated through CDMS. Methods. A single coho...

  5. The CDM-Net Project: The Development, Implementation and Evaluation of a Broadband-Based Network for Managing Chronic Disease.

    Science.gov (United States)

    Jones, Kay; Dunning, Trisha; Costa, Beth; Fitzgerald, Kristine; Adaji, Akuh; Chapman, Colin; Piterman, Leon; Paterson, Moira; Schattner, Peter; Catford, John

    2012-01-01

    Background. In Australia most chronic disease management is funded by Medicare Australia through General Practitioner Management Plans (GPMPs) and Team Care Arrangements (TCAs). Identified barriers may be reduced effectively using a broadband-based network known as the Chronic Disease Management Service (CDMS). Aims. To measure the uptake and adherence to CDMS, test CDMS, and assess the adherence of health providers and patients to GPMPs and TCAs generated through CDMS. Methods. A single cohort before and after study. Results. GPMPs and TCAs increased. There was no change to prescribed medicines or psychological quality of life. Attendance at allied health professionals increased, but decreased at pharmacies. Overall satisfaction with CDMS was high among GPs, allied health professionals, and patients. Conclusion. This study demonstrates proof of concept, but replication or continuation of the study is desirable to enable the impact of CDMS on diabetes outcomes to be determined.

  6. The CDM-Net Project: The Development, Implementation and Evaluation of a Broadband-Based Network for Managing Chronic Disease

    Directory of Open Access Journals (Sweden)

    Kay Jones

    2012-01-01

    Full Text Available Background. In Australia most chronic disease management is funded by Medicare Australia through General Practitioner Management Plans (GPMPs and Team Care Arrangements (TCAs. Identified barriers may be reduced effectively using a broadband-based network known as the Chronic Disease Management Service (CDMS. Aims. To measure the uptake and adherence to CDMS, test CDMS, and assess the adherence of health providers and patients to GPMPs and TCAs generated through CDMS. Methods. A single cohort before and after study. Results. GPMPs and TCAs increased. There was no change to prescribed medicines or psychological quality of life. Attendance at allied health professionals increased, but decreased at pharmacies. Overall satisfaction with CDMS was high among GPs, allied health professionals, and patients. Conclusion. This study demonstrates proof of concept, but replication or continuation of the study is desirable to enable the impact of CDMS on diabetes outcomes to be determined.

  7. The CDM-Net Project: The Development, Implementation and Evaluation of a Broadband-Based Network for Managing Chronic Disease.

    Science.gov (United States)

    Jones, Kay; Dunning, Trisha; Costa, Beth; Fitzgerald, Kristine; Adaji, Akuh; Chapman, Colin; Piterman, Leon; Paterson, Moira; Schattner, Peter; Catford, John

    2012-01-01

    Background. In Australia most chronic disease management is funded by Medicare Australia through General Practitioner Management Plans (GPMPs) and Team Care Arrangements (TCAs). Identified barriers may be reduced effectively using a broadband-based network known as the Chronic Disease Management Service (CDMS). Aims. To measure the uptake and adherence to CDMS, test CDMS, and assess the adherence of health providers and patients to GPMPs and TCAs generated through CDMS. Methods. A single cohort before and after study. Results. GPMPs and TCAs increased. There was no change to prescribed medicines or psychological quality of life. Attendance at allied health professionals increased, but decreased at pharmacies. Overall satisfaction with CDMS was high among GPs, allied health professionals, and patients. Conclusion. This study demonstrates proof of concept, but replication or continuation of the study is desirable to enable the impact of CDMS on diabetes outcomes to be determined. PMID:22518307

  8. 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.

  9. 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.

  10. Improved Iterative Coordinated Beamforming Based on Singular Value Decomposition for Multiuser Mimo Systems With Limited Feedforward

    Directory of Open Access Journals (Sweden)

    L. Soriano-Equigua

    2011-12-01

    Full Text Available Coordinated beamforming based on singular value decomposition is an iterative method to jointly optimize thetransmit beamformers and receive combiners, to achieve high levels of sum rates in the downlink of multiusersystems, by exploiting the multi-dimensional wireless channel created by multiple transmit and receive antennas. The optimization is done at the base station and the quantized beamformers are sent to the users through a low rate link.In this work, we propose to optimize this algorithm by reducing the number of iterations and improving its uncoded bit error rate performance. Simulation results show that our proposal achieves a better bit error rate with a lower number of iterations than the original algorithm.

  11. A Novel Multiuser Detection Algorithm for CDMA-Based MIMO-OFDM System

    Institute of Scientific and Technical Information of China (English)

    LIU Jun-shi; TANG Bi-hua; WANG Ya-chen; LIU Yua-nan

    2006-01-01

    This paper investigates QR matrix decomposition based successive interference cancellation multiuser detection algorithms in synchronous uplink for code division multiple access based multiple input multiple output orthogonal frequency division multiplexing system. The Symbol Error Rate(SER) performance of the optimal order and the suboptimal order QR-SIC MUD algorithms are compared with conventional zero forcing and minimum mean square error multiuser detection algorithms by Monte Carlo simulations. Complexity analysis is presented at the end of the paper. Both our simulation results and complexity analysis show that SER performance of QR-Successive Interference Cancellation (QR-SIC) algorithms is superior to those of zero forcing(ZF) and minimum mean square error algorithms, and the suboptimal order QR-SIC algorithm has a good trade-off between SER performance and computation complexity.

  12. Improved Successive Interference Cancellation for MIMO/UWB-Based Wireless Body Area Network

    OpenAIRE

    M. Jayasheela; A. Rajeswari

    2012-01-01

    In body area networks, various sensors are attached to clothing or on the body or even implanted under the skin. The sensors measure such as heart beat, the record of prolonged electrocardiogram, blood pressure, and so on. In this paper, an improved Successive interference cancellation (SIC) scheme based on zero correlation zone sequences is proposed. Here ZCZ is used as a random code for TH PPM UWB system. Nodes in a WBAN are connected through wireless communication channel within a very clo...

  13. 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.

  14. 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.

  15. A Linear Precoding Scheme for Massive MIMO Systems Based on SSOR Method%一种基于SSOR的大规模MIMO线性预编码方案

    Institute of Scientific and Technical Information of China (English)

    龙恳; 卿瑞强; 涂斯宇

    2016-01-01

    大规模多输入多输出系统(Massive MIMO)由于天线数和用户数太大,导致预编码矩阵在求逆是复杂度过高。为了降低复杂度,本文提出了一种基于对称逐步超松弛(SSOR)的线性预编码方案,相比传统的规则化迫零(RZF)预编码方案,本文所提的方案在没有任何性能损失的情况下可以降低一个量级的运算复杂度,为了保证所提SSOR预编码方案的性能,提出一种仅依靠天线配置的简单的量化松弛参数。%Massive multiple-input multiple-output(MIMO) has a large number of attennas and users, which leads to high computational complexity in precoding matrix.To solve this problem,this paper proposed a linear precoding scheme based on symmetric successive overrelaxation(SSOR). Compared to conventional RZF scheme,it can reduce one order of magnitude with negligible performace loss. To guarantee the performance of SSOR-based precoding, we also proposed a simple quantiifed relaxation parameter for SSOR-based scheme, which only depends on the MIMO systemconifguration.

  16. 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...

  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. Performance of MIMO systems

    OpenAIRE

    Grande González, Patricia; Gros Vidal, Thomas

    2008-01-01

    Demand in high data rate communications, driven by internet and cellular mobile, have increased, specially in wireless local area networks, emerging home audio visual networks and multimedia services in general. The limitation of the available radio spectrum makes it impossible for the data rate needs to be accomplished by an increase in the bandwidth. The deployment of multiple antennas in the transmitter and the receiver, multiple input multiple output (MIMO), a cost effective technology, m...

  20. 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.

  1. Design MIMO Switch Architecture Based IEC 61850 Standard of Substation Automation Systems

    Directory of Open Access Journals (Sweden)

    Kutaiba Sabah Nimma

    2015-06-01

    Full Text Available Recently, there has been a tremendous change in the development of many protocols in electrical substation automation such as robust communication among control centers (GOOSE. It is a challenge to implement critical time operation such as tripping based on GOOSE protocol when the protocol is not tested in a wide area multi-substations environment. Another reason is the function of the packet forwarder may fail under a very high traffic condition with the constant generation of GOOSE packets due to multiple events. This study investigates the performance of packet forwarder in terms of packet loss under different models configurations. The investigations carried out on various switch configurations and architectures to reduce the number of dropped packets. The results showed that the architecture of two-switch system is the best performance in which the packet loss can be reduced by 2.9% in comparison with two buffer switches and 11.8% in comparison with the to original standard.

  2. 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...

  3. A Novel Diversity-Multiplexing Tradeoff Scheme in Cooperative MIMO Based on Distributed Space-Time Coding%一种基于分布式空时码的协作MIMO分集复用折衷新方案

    Institute of Scientific and Technical Information of China (English)

    许晓荣; 章坚武; 郑宝玉

    2011-01-01

    Cooperative MIMO which is composed of multiple single antenna nodes by cooperative communication could construct multipte virtual transmit antennas. Spatial diversity gain could be obtained from this virtual MIMO multiple antenna arrays. Considered the specific features of cooperative MIMO, code cooperation strategy with distributed space-time coding is implemented in the network. An enhanced divemity-multiplexing tradeoff (DMT) scheme based on distributed space-time ceding (DSTC) in cooperative MIMO is studied. The expression of outage probability and diversity gain of two DSTC strategies are derived in detail. Based on the two DMT schemes of DSTC, the optimal DMT and outage performance of the enhanced DMT strategy could be obtained through altering the threshold of multiplexing gain adaptively. Numerical results indicate that, the proposed DMT scheme could be asymptotical to DMT upper bound in cooperative MIMO, and the corresponding outage performance is also inferior to that of upper bound. Hence, cooperative diversity gain and optimum outage behavior could be achieved simultaneously by the proposed DMT scheme for DSTC code cooperation in multi-node cooperative MIMO scenario.%协作MIMO通过多个单天线节点的相互协作构造多发射天线,以此形成一种虚拟MIMO多天线阵列获得空间分集增益.考虑到协作MIMO特点,天线间采用分布式空时编码进行编码协作.文章研究了协作MIMO中基于分布式空时码(DSTC)的分集复用折衷(DMT)新方案,该方案通过推导两种DSTC的中断概率与分集增益表达式,结合两类DSYC的DMT策略,根据改变复用增益阈值自适应获得最佳DMT与中断性能.数值仿真表明,所提的DMT策略可以逼近协作MIMO的DMT上限,协作节点采用该策略的中断性能仅次于上限的中断性能.在多节点构成协作MIMO网络分布式空时编码协作中,提出的DMT新方案可使系统高效地获得协作分集增益与中断性能.

  4. 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.

  5. 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.

  6. 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.

  7. Distributed MIMO radar using compressive sampling

    CERN Document Server

    Petropulu, Athina P; Poor, H Vincent

    2009-01-01

    A distributed MIMO radar is considered, in which the transmit and receive antennas belong to nodes of a small scale wireless network. The transmit waveforms could be uncorrelated, or correlated in order to achieve a desirable beampattern. The concept of compressive sampling is employed at the receive nodes in order to perform direction of arrival (DOA) estimation. According to the theory of compressive sampling, a signal that is sparse in some domain can be recovered based on far fewer samples than required by the Nyquist sampling theorem. The DOAs of targets form a sparse vector in the angle space, and therefore, compressive sampling can be applied for DOA estimation. The proposed approach achieves the superior resolution of MIMO radar with far fewer samples than other approaches. This is particularly useful in a distributed scenario, in which the results at each receive node need to be transmitted to a fusion center.

  8. Grand Banquet of CDM for Power Enterprises

    Institute of Scientific and Technical Information of China (English)

    Peng Yuanchang; Jin Wen

    2007-01-01

    @@ The Kyoto Protocol was taken into effect on Feb. 16, 2005. It requires developed countries to reduce their greenhouse gas emissions, but it doesn't set binding limits on developing countries, such as China. The developed countries found that it is more cost-effective to reduce the emissions in developing countries than in their own. Therefore, the CDM emerged as the times require. Due to unfamiliarity and complicatedness, Chinese enterprises had been hesitating and taking wait-and-see attitude toward CDM, but they couldn't resist the attraction of free dinner of CDM, more and more enterprises started to attend the grand banquet of CDM since 2006.

  9. 10 lessons from 10 years of the CDM

    OpenAIRE

    Shishlov, Igor; Bellassen, Valentin

    2012-01-01

    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 r...

  10. 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

  11. 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)

  12. 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.

  13. Power amplifier linearization technique with IQ imbalance and crosstalk compensation for broadband MIMO-OFDM transmitters

    Directory of Open Access Journals (Sweden)

    Werner Stefan

    2011-01-01

    Full Text Available Abstract The design of predistortion techniques for broadband multiple input multiple output-OFDM (MIMO-OFDM systems raises several implementation challenges. First, the large bandwidth of the OFDM signal requires the introduction of memory effects in the PD model. In addition, it is usual to consider an imbalanced in-phase and quadrature (IQ modulator to translate the predistorted baseband signal to RF. Furthermore, the coupling effects, which occur when the MIMO paths are implemented in the same reduced size chipset, cannot be avoided in MIMO transceivers structures. This study proposes a MIMO-PD system that linearizes the power amplifier response and compensates nonlinear crosstalk and IQ imbalance effects for each branch of the multiantenna system. Efficient recursive algorithms are presented to estimate the complete MIMO-PD coefficients. The algorithms avoid the high computational complexity in previous solutions based on least squares estimation. The performance of the proposed MIMO-PD structure is validated by simulations using a two-transmitter antenna MIMO system. Error vector magnitude and adjacent channel power ratio are evaluated showing significant improvement compared with conventional MIMO-PD systems.

  14. Design of the Picking Robot Based on the Model of OFDM-MIMO High Speed Mobile Communication System%基于 OFDM-MIMO 移动通信模型的采摘机器人设计

    Institute of Scientific and Technical Information of China (English)

    高伟; 曹昕燕; 张万里; 吉淑娇

    2017-01-01

    In order to improve the fruit picking robot and automation level, improve the robot's real-time communication and online control ability, remote control of robot operation process, has brought the OFDM-MIMO model in communica-tion system of the picking robot, and mobile 4G technology applied to the design of the robot, breaking the robot control distance constraints, the realization of the robot cross regional wireless communication. The robot uses the vision sensor and 4G network to collect and transmit the image, and the image data can be displayed on the remote browser side in real time, so it is easy to grasp the robot operation information. When a signal when the robot collision sensor, you can use the OFDM-MIMO channel model for image, transmission, and collected by the vision sensor image information is trans-mitted to the remote control end, picking errors when can timely adjust the robot state, to achieve control of the fruit picking online. Finally design the experimental prototype robot, and the robot's fruit localization ability and communica-tion ability is studied by experiment and simulation. From the experiment and the simulation results show that, the robot can effectively identify the common fruit and bagging fruit and communication test, simulation and measurement test re-sults are in good agreement, thus validating the reliability results, verify the OFDM-MIMO model in picking robot com-munication system the feasibility.%为了提高果树采摘机器人的智能化和自动化水平,提高机器人的实时通信和在线控制能力,实现机器人作业过程的远程控制,在采摘机器人通信系统中引入了 OFDM-MIMO 模型,并将移动4 G 技术应用到了机器人的设计中,突破了机器人控制距离限制,实现了机器人的跨区域无线通信。机器人采用视觉传感器和4G 网络采集并传输图像,图像数据可以在远程浏览器端实时显示,便于掌握机器人作业信息。当机

  15. Integrating ecological restoration into CDM forestry projects

    International Nuclear Information System (INIS)

    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

  16. Investigating the Impact of Hybrid/SPREAD MIMO-OFDM System for Spectral-Efficient Wireless Networks

    Directory of Open Access Journals (Sweden)

    Nirmalendu Bikas Sinha

    2010-05-01

    Full Text Available This research proposes a novel signal scheme called Hybrid spread MIMO-OFDM system which interface OFDM with CDMA and integrate this CDMA-OFDM to MIMO to generate a system functionally superior to MIMO-OFDM systems are considered as candidates for future broadband wireless service. OFDM may be combined with antenna arrays at the transmitter and receiver to increase the diversity gain and/or to enhance the system capacity on time-variant and frequency-selective channels, resulting in a Multiple-Input Multiple-Output (MIMO configuration. The multiplexing technique proposed here is the Code Division Multiple Accesses (CDMA scheme which is considered the solution for eliminating the distortion caused by fast fading and provides the inherent advantage of DS-CDMA systems incorporating a spreading signal based on PN code sequence, by providing user discrimination based on coding at the same carrier frequency and simultaneously. The OFDM component provides resistance to multipath effects making it unnecessary to use RAKE receivers for CDMA and thus avoid hardware complexity. In order to compare their performances, the effects of multipath signal propagation on the capacity, under both single and multi user channel, are examined. The Inter Symbol Interference (ISI is used as a suitable measure of multipath effect. The obtained results show that the multipath has more influence on the capacity of MIMO than MIMO-OFDM and spread MIMO-OFDM. In addition, spread MIMO-OFDM offers more average capacity than MIMO under both single and multi user channel. In comparison with MIMO-OFDM, the capacity of spread MIMO-OFDM is higher under the condition of the multi user channel scenario. MIMO-OFDM spread system is being implemented using AWG and VSA. Thus making it possible to implement 4G using hardware and MATLAB/SIMULINK.

  17. Energy Efficiency of MIMO-OFDM Communication System

    Directory of Open Access Journals (Sweden)

    K.Swathi

    2014-09-01

    Full Text Available With the ever increasing number of subscribers and their seemingly “greedy” demands for high-data-rate services, the next generation networks will have to provide global connectivity to ensure success. So the combination of multiple-input multiple-output (MIMO signal processing with orthogonal frequency division multiplexing (OFDM is regarded as a promising solution for enhancing the data rates of next-generation wireless communication systems operating in frequency-selective fading environments. Therefore hybrid architecture between terrestrial and satellite networks based on MIMO-OFDM with frequency reuse is employed here. However, this frequency reuse introduces severe co-channel interference (CCI at the satellite end. To mitigate CCI, we propose an OFDM based adaptive beamformer implemented on-board the satellite with pilot reallocation at the transmitter side. The system performance is simulated by using the software MATLAB, the experimental result shows that the MIMO-OFDM communication system has better performance when compared.

  18. Diversity of MMSE MIMO Receivers

    CERN Document Server

    Mehana, Ahmed Hesham

    2011-01-01

    In most MIMO systems, the family of waterfall error curves, calculated at different spectral efficiencies, are asymptotically parallel at high SNR. In other words, most MIMO systems exhibit a single diversity value for all {\\em fixed} rates. The MIMO MMSE receiver does not follow this pattern and exhibits a varying diversity in its family of error curves. This effect cannot be captured by DMT analysis, due to the fact that all fixed rates correspond to the same multiplexing gain, thus they cannot be differentiated within DMT analysis. This work analyzes this interesting behavior of the MMSE MIMO receiver and produces the MMSE MIMO diversity at each rate. The diversity of the quasi-static flat-fading MIMO channel consisting of any arbitrary number of transmit and receive antennas is fully characterized, showing that full spatial diversity is possible for all antenna configurations if and only if the rate is within a certain bound which is a function of the number of antennas. For other rate brackets, the avail...

  19. A study of regional CDM projects distribution in China

    Institute of Scientific and Technical Information of China (English)

    Liu Xutong; Liu Qingqian; Gu A'lun

    2009-01-01

    sector development, CDM market and information circulation aspects, suggestions are given to support CDM development in western areas by the "sector development guidance + CDM capability construction + market support" mode in this paper.

  20. Energy Efficient Iterative Waterfilling for the MIMO Broadcasting Channels

    CERN Document Server

    Xu, Jie; Zhang, Shunqing

    2012-01-01

    Optimizing energy efficiency (EE) for the MIMO broadcasting channels (BC) is considered in this paper, where a practical power model is taken into account. Although the EE of the MIMO BC is non-concave, we reformulate it as a quasiconcave function based on the uplink-downlink duality. After that, an energy efficient iterative waterfilling scheme is proposed based on the block-coordinate ascent algorithm to obtain the optimal transmission policy efficiently, and the solution is proved to be convergent. Through simulations, we validate the efficiency of the proposed scheme and discuss the system parameters' effect on the EE.

  1. Gravitational Lensing by CDM Halos: Singular versus Nonsingular Profiles

    CERN Document Server

    Martel, H; Martel, Hugo; Shapiro, Paul R.

    2003-01-01

    The gravitational lensing properties of cosmological halos depend upon the mass distribution within each halo. The description of halos as nonsingular, truncated isothermal spheres, a particular solution of the isothermal Lane-Emden equation (suitably modified for Lambda nonzero), has proved to be a useful approximation for the halos which form from realistic initial conditions in a CDM universe. The nonsingular TIS model reproduces many of the quantitative features of the N-body results for CDM halos, except in the very center, where CDM N-body halos show density profiles which vary as rho ~ r^(-alpha), alpha>1, instead of a small flat core. Possible discrepancies between these cuspy halo predictions of the CDM N-body simulations and observations of the inner mass profiles of dwarf and LSB disk galaxies based upon their rotation curves and of clusters based upon strong lensing measurements have led to a search for other diagnostics. A description of the lensing by TIS halos would be useful in this regard, as...

  2. 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.

  3. 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.

  4. 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...

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

    International Nuclear Information System (INIS)

    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.

  6. Caracterización MIMO de una esquina mediante medidas

    OpenAIRE

    Ibernón Fernández, Rubén; Molina García-Pardo, José María; Juan Llacer, Leandro

    2006-01-01

    This paper presents results on capacity, correlation and K-factor for a 4x4 MIMO system in a microcellular environment. A MIMO channel sounder based on a multiport network analyzer and a fast switch controlled by a laptop has been used. LoS and NLoS situations are distinguished for three antenna elements separation of the arrays each. It has been appreciated a low capacity in some positions of the NLoS situation in spite of a not very high correlation. Los autores e...

  7. Joint detection and combining schemes in MIMO-HARQ systems

    Institute of Scientific and Technical Information of China (English)

    XIE Gang; XIONG Fang; ZHAO Yi; LIU Yuan-an

    2007-01-01

    This article mainly investigates the combining schemes for hybrid automatic retransmission request (HARQ) protocols in multiple-input multiple-output (MIMO) wireless communication systems. A novel scheme, which joins MIMO detection and HARQ combining, called mid-combining, is presented in this article. Based on the position of HARQ combining, we classify the HARQ combining schemes into three types, named pre-combining, mid-combining, and post-combining. The simulation results show that mid- combining can increase the system throughput for all SNRs.

  8. 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.

  9. Unitary space vector quantization codebook design for spatial correlated limited feedback MIMO system

    Institute of Scientific and Technical Information of China (English)

    WU Ping; LI Li-hua

    2008-01-01

    In the transmitting, beamforming, and receivingcombing (TBRC) MIMO system, a codebook based feedbackstrategy is usually used to provide the transmitter with thebeamforming vector. The adopted codebook affects the systemperformance considerably. Therefore, the codebook design is akey technology in the TBRC MIMO system. In this article, theunitary space vector quantization (USVQ) codebook designcriterion is proposed to design optimal codebooks for variousspatial correlated MIMO channels. And the unitary spaceK-mean (USK) codebook generating algorithm is provided togenerate the USVQ codebooks. Simulations show that thecapacities of the feedback based TBRC systems using USVQcodebooks are very close to those of the ideal cases.

  10. Antenna Design for Diversity and MIMO Application

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... are also highly affected. In this chapter, the performance of some basic MIMO antennas as well as recent technologies toimprove MIMO antenna performance of portable devices and mobile terminals are reviewed. The interactions between MIMO antennas and human body are also addressed particularly in...

  11. Cold Fronts in CDM clusters

    CERN Document Server

    Nagai, D; Nagai, Daisuke; Kravtsov, Andrey V.

    2003-01-01

    Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters (Vikhlinin et. al., 2001). These features, called ``cold fronts'', are characterized by an increase in surface brightness by a factor >2 over 10-50 kpc, accompanied by a drop in temperature of a similar magnitude. The existence of such sharp gradients can be used to put interesting constraints on the physics of the intracluster medium (ICM), if their mechanism and longevity are well understood. Here, we present results of a search for cold fronts in high-resolution simulations of galaxy clusters in cold dark matter (CDM) models. We show that sharp gradients with properties similar to those of observed cold fronts naturally arise in cluster mergers when the shocks heat gas surrounding the merging sub-cluster, while its dense core remains relatively cold. The compression induced by supersonic motions and shock heating during the merger enhance the ...

  12. The structure of CDM halos

    CERN Document Server

    Navarro, J F

    1995-01-01

    High resolution N-body simulations show that the density profiles of dark matter halos formed in the standard CDM cosmogony can be fit accurately by scaling a simple ``universal'' profile. Regardless of their mass, halos are nearly isothermal over a large range in radius, but significantly shallower than r^{-2} near the center and steeper than r^{-2} in the outer regions. The characteristic overdensity of a halo correlates strongly with halo mass in a manner consistent with the mass dependence of the epoch of halo formation. Matching the shape of the rotation curves of disk galaxies with this halo structure requires (i) disk mass-to-light ratios to increase systematically with luminosity, (ii) halo circular velocities to be systematically lower than the disk rotation speed, and (iii) that the masses of halos surrounding bright galaxies depend only weakly on galaxy luminosity. This offers an attractive explanation for the puzzling lack of correlation between luminosity and dynamics in observed samples of binar...

  13. China's CDM Policies and Their Development Implications: Major Concerns for CDM Implementation

    Institute of Scientific and Technical Information of China (English)

    Zhu Xianli; Pan Jiahua

    2006-01-01

    Most CDM (Clean Development Mechanism)opportunities exist in some large industrializing developing countries. For instance, China is estimated to take 48% of the world potential for CDM project activities. In reality, however, the share by China over the CDM projects registered and CDM projects in the pipeline is less than 10% as of Auguest 2005. This paper will examine the reasons behind, as reflected in China's CDM policies. Further investigation will be made into the use of these policies to boost the country's sustainable development, the sustainable development implications and effects of these policies. In addition, it is noted that incompatibility of some other Chinese laws and policies can be responsible for the low level and slow pace of CDM implementation in China and some suggestions are offered for promoting CDM project activities in China. There also exist barriers at the international level that impedes implementation of CDM project activities. A conclusion is drawn that CDM policies in a developing country like China aim mainly at promotion of sustainable development and to a lesser extent the generation of CERs.

  14. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    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......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...

  15. Full chip modelling of ICs under CDM stress

    NARCIS (Netherlands)

    Sowariraj, Mary Sheela Bobby

    2005-01-01

    In this thesis, CDM ESD stress on the Integrated Circuits (IC) and the various factors which affect the robustness of an IC design against CDM stress is investigated. One of the main reasons for CDM failure are the voltage gradients set across the circuit during CDM stress. The IC being also the sou

  16. MIMO-OFDM performance in relation to wideband channel properties

    NARCIS (Netherlands)

    Li, P.; Zhang, H.; Oostveen, J.; Fledderus, E.

    2010-01-01

    In this paper, the sensitivity of the error rate performance of MIMO-OFDM-based practical systems (WiMAX and LTE) to wide band channel properties is investigated. The behavior of the wideband channel is characterized in terms of delay spread (DS) and angular spread (AS). The impacts of DS and AS on

  17. Policy actions on post-Kyoto protocol framework. Nuclear power generation still doesn't match CDM?

    International Nuclear Information System (INIS)

    Five authors described their views titled as 'Present status of post-Kyoto protocol framework settlement', 'State of nuclear energy in Kyoto-protocol', 'To include nuclear energy into Clean Development Mechanism (CDM)-based on Marrakesh accords', 'Asian development and trend of nuclear power introduction - significance of joint communique of the Forum for Nuclear Cooperation in Asia (FNCA) ministerial level meeting' and 'Process and issues of establishment of CDM project of nuclear power - assumed case of China of rapid increase of energy demand'. Informal discussion titled 'What needs to include nuclear power generation into CDM?' was recorded. Nuclear power's eligibility requirements for CDM were argued. (T. Tanaka)

  18. Broadbeam for Massive MIMO Systems

    Science.gov (United States)

    Qiao, Deli; Qian, Haifeng; Li, Geoffrey Ye

    2016-05-01

    Massive MIMO has been identified as one of the promising disruptive air interface techniques to address the huge capacity requirement demanded by 5G wireless communications. For practical deployment of such systems, the control message need to be broadcast to all users reliably in the cell using broadbeam. A broadbeam is expected to have the same radiated power in all directions to cover users in any place in a cell. In this paper, we will show that there is no perfect broadbeam. Therefore, we develop a method for generating broadbeam that can allow tiny fluctuations in radiated power. Overall, this can serve as an ingredient for practical deployment of the massive MIMO systems.

  19. 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

  20. Peak-to-Average Power Ratio Reduction in MIMO-OFDM Systems Based on Decomposed Selected Mapping%基于分解选择映射的MIMO-OFDM系统峰均比降低算法

    Institute of Scientific and Technical Information of China (English)

    高静; 汪晋宽; 解志斌

    2009-01-01

    针对多输入多输出正交频分复用(MIMO-OFDM)系统中的高峰均功率比(PAPR)问题,提出了一种新的基于选择映射(SLM)的分解算法.所提算法将每根天线上OFDM 符号的实部和虚部进行分解,然后分别进行相位映射,从而增加了待选信号的数量.利用实序列固有的共轭对称特性,在不增加算法复杂度的前提下,显著提高了算法的峰均比降低性能.同时提出了一种基于并行选择映射的分解算法,进一步减少了边带信息的传输量,提高了系统的频带利用率.仿真实验结果证明,所提算法在保持计算复杂度不变的同时,可以有效的提高峰均比性能.

  1. Clutter Modeling of Airborne MIMO Radar Based on CUDA%基于CUDA的机载MIMO雷达杂波建模

    Institute of Scientific and Technical Information of China (English)

    王占广; 罗忠涛; 李军; 孙颖

    2011-01-01

    针对机载MIMO雷达杂波模型运算量大的问题,建立了基于CUDA的模型,利用图形处理器的并行运算能力来加速运算。为了符合CUDA的通用计算架构特性,该模型在算法上优先设计并行运算,在编程上尽量引入并行线程,实现图形处理器的浮点运算、存储器以及带宽资源的有效利用。最后测试了加速效果与模型结构、数据规模的关系。实验结果表明,与CPUInteli5750比较。图形处理器Grrx465的建模运算结果准确.效率提升教十倍.能麦特委大的运算号.%Considering big operand problem of clutter model for airborne MIMO radar, a clutter based on Compute Unified Device Architecture (CUDA) is established and operation is speeded up by using parallel operational capa- bility of Graphic Processing Unit(GPU). In order to accord with general computation architecture characteristic of CUPD, the new model prefers designing parallel computing in algorithm and introducing parallel threads in programming to implement effective usage of floating point operation, storage and wideband resources of GPU. And finally, relation between the speedup effect and model architecture and data size is tested. The tested results prove that modeling computation result of GPU based on GTX 465 is accurate in computing result, and efficiency is increased by tens of times and bigger operand can be supported comparing with CPUIntel i5 750.

  2. Precoding design for single-RF massive MIMO systems: A large system analysis

    OpenAIRE

    Sifaou, Houssem; Kammoun, Abla; Alouini, Mohamed-Slim

    2016-01-01

    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 single RF MIMO systems 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 precode...

  3. Multiuser MIMO Channel Estimation

    Directory of Open Access Journals (Sweden)

    G.Indumathi

    2016-05-01

    Full Text Available In this paper, three beamforming design are considered for multi user MIMO system. First, transmit beamformers are fixed and the receive (RX beamformers are calculated. Transmit beamformer (TX-BFis projectedas a null space of appropriate channels. It reduces the interference for each user. Then the receiver beamformer is determined which maximize the SNR. This beamforming design provides less computation time. The second case is joint TX and RX beamformer for SNR maximization. In this transmitter and receiver beamformer are calculated using extended alternating optimization (EAO algorithm. The third one is joint transmitter and receiver beamforming for SNR and SINR maximization using EAO algorithm. This algorithm provides better error performance and sum rate performance. All the design cases are simulated by using standard multipath channel model. Our simulation results illustrate that compared to the least square design and zero forcing design, the joint TX and RX beamforming design using EAO algorithm provides faster beamforming and improved error performance and sum rate.

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

    Energy Technology Data Exchange (ETDEWEB)

    Coninck, Heleen de [Unit Policy Studies, Energy Research Centre of the Netherlands (ECN), P.O. Box 56890, 1040 AW Amsterdam (Netherlands); Institute for Environmental Studies, VU University of Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam (Netherlands)

    2008-03-15

    The discussion around allowing CO{sub 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. (author)

  5. 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.)

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

    Directory of Open Access Journals (Sweden)

    H. Ndoumbè Mbonjo Mbonjo

    2005-01-01

    Full Text Available 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.

  7. Project Boundary Setting and Leakage Treatment in CDM Project

    Institute of Scientific and Technical Information of China (English)

    ZOU Chen; WANG Shujuan; DUAN Maosheng; CHEN Changhe

    2005-01-01

    Project boundary setting and leakage treatment are two important issues to be considered when a clean development mechanism (CDM) project is being designed. There are still many uncertainties concerning these two issues. This paper reviews the concepts of project boundary setting and leakage in CDM projects, cites the types and sources of leakage, discusses the principles for determining leakage, and gives some proposed methods for dealing with leakage. A case study, using several steps to solve the boundary and leakage problems,shows how the analyzed principles and treatments can be implemented in a real project. Based on the result of the case study, the methods discussed are shown to be appropriate for settling leakage issues.

  8. 基于小波子空间法的MIMO系统辨识研究%Identification of MIMO System Based on Subspace Method in Wavelet Domain

    Institute of Scientific and Technical Information of China (English)

    李振强

    2013-01-01

    For the LTI multi-input multi-output (MIMO) system with the noise corrupted output data,an identification method of MIMO system was proposed by using the input-output data in wavelet domain directly.The subspace state space system identification method is a main method for MIMO system in time domain.Through the projection of data matrices,we took the QR decomposition and singular value decomposition of data matrices,and identified the order of the MIMO system,then obtained the estimated system matrices of the state equation.By means of wavelet transform,the signal was become a signal in wavelet domain.The MIMO system was identified by the wavelet subspace state space system identifcation method.Compared with the subspace state space system identification method in time domain,the proposed method is feasible and effective by the simulation.%针对线性时不变多输人多输出(MIMO)系统的输出存在随机噪声情况下,提出直接利用小波域的输入输出数据,辨识MIMO系统的方法.子空间状态空间法是时域辨识MIMO系统的主要方法,通过数据矩阵投影,对数据矩阵进行QR分解和奇异值分解,辨识出系统的阶数和系统的状态方程矩阵.运用小波变换,将时域信号转换为小波域的信号,利用小波子空间状态空间辨识算法对MIMO系统辨识,通过仿真,得到辨识的结果与时域子空间状态空间法相比较,证明提出方法是有效的.

  9. 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...... to be up to about 2.2 bit/s/Hz, depending on the band and handset. More results are presented in the paper....

  10. Multiuser MIMO Channel Measurements and Performance in a Large Office Environment

    DEFF Research Database (Denmark)

    Bauch, Gerhard; Andersen, Jørgen Bach; Guthy, Christian;

    2007-01-01

    We consider a multiuser MIMO-OFDMA scheme which exploits multiuser diversity in all dimensions: time, frequency and space. The main contribution of this paper is the evaluation and explanation of multiuser MIMO in a real world scenario, i.e. a large office room, based on measured channels. We rep......S constraints. It is shown that the theoretical limits can be approximately achieved provided that the users which compete for the spatial resources are carefully chosen....

  11. MIMO Networks: the Effects of Interference

    CERN Document Server

    Chiani, Marco; Shin, Hyundong

    2008-01-01

    Multiple-input/multiple-output (MIMO) systems promise enormous capacity increase and are being considered as one of the key technologies for future wireless networks. However, the decrease in capacity due to the presence of interferers in MIMO networks is not well understood. In this paper, we develop an analytical framework to characterize the capacity of MIMO communication systems in the presence of multiple MIMO co-channel interferers and noise. We consider the situation in which transmitters have no information about the channel and all links undergo Rayleigh fading. We first generalize the known determinant representation of hypergeometric functions with matrix arguments to the case when the argument matrices have eigenvalues of arbitrary multiplicity. This enables the derivation of the ergodic capacity expressions for MIMO systems in the presence of multiple MIMO interferers. Our analysis is valid for any number of interferers, each with arbitrary number of antennas having possibly unequal power levels....

  12. Accounting methods for carbon credits: Impacts on the minimum area of CDM forestry projects

    OpenAIRE

    Locatelli, Bruno; Pedroni, Lucio

    2004-01-01

    International audience The Ninth Conference of the Parties (COP-9) decided to adopt an accounting system based on expiring carbon credits to address the problem of non-permanent carbon storage in forests established under the Clean Development Mechanism (CDM). This article reviews and discusses carbon accounting methods that were under consideration before COP-9 and presents a model which calculates the minimum area that forest plantation projects should reach to be able to compensate CDM ...

  13. Massive MIMO-OFDM indoor visible light communication system downlink architecture design

    Science.gov (United States)

    Lang, Tian; Li, Zening; Chen, Gang

    2014-10-01

    Multiple-input multiple-output (MIMO) technique is now used in most new broadband communication system, and orthogonal frequency division multiplexing (OFDM) is also utilized within current 4th generation (4G) of mobile telecommunication technology. With MIMO and OFDM combined, visible light communication (VLC) system's diversity gain is increase, yet system capacity for dispersive channels is also enhanced. Moreover, with the emerging massive MIMO-OFDM VLC system, there are significant advantages than smaller systems' such as channel hardening, further increasing of energy efficiency (EE) and spectral efficiency (SE) based on law of large number. This paper addresses one of the major technological challenges, system architecture design, which was solved by semispherical beehive structure (SBS) receiver and so that diversity gain can be identified and applied in Massive MIMO VLC system. Simulation results shows that the proposed design clearly presents a spatial diversity over conventional VLC systems.

  14. A Noise-Correlated Cancellation Transmission Scheme for Cooperative MIMO Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Wanni Liu

    2014-04-01

    Full Text Available A new transmission scheme based on noise-correlated cancellation (NCC is proposed, which absorbs the advantages of phase-inversion symmetric method and cooperative MIMO technology and makes full use of the correlation of noise in the adjacent channels to reduce channel noise. This paper firstly presents the implementation process of NCC transmission scheme in detail. Further, through theoretical analysis, it is showed that the signal-to-noise ratio gain which the proposed NCC transmission scheme gets is at least 4 times greater than the signal-to-noise ratio gain which the traditional cooperative MIMO transmission scheme gets. Finally, simulation experiment results also verify that the proposed NCC transmission scheme can make the channel capacity per bandwidth of cooperative MIMO Ad Hoc networks improve significantly and bit error rate (BER of the network reduce greatly, which will help to expand application scopes of cooperative MIMO Ad Hoc networks.

  15. Multimedia over massive MIMO wireless systems

    OpenAIRE

    Wang, Haichao; Ge, Xiaohu; Zi, Ran; Zhang, Jing; Ni, Qiang

    2015-01-01

    To satisfy the massive wireless traffic transmission generated by multimedia applications, the massive multi-input-multi-output (MIMO) wireless system has emerged as a possible solution for future 5G wireless communication systems. However, the mutual coupling effect of massive MIMO systems has a negative effect potential on the wireless capacity. In this paper, the receive diversity gain is first defined and analyzed for massive MIMO wireless systems. Furthermore, we propose an effective cap...

  16. 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.

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

    International Nuclear Information System (INIS)

    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

  18. Hidden photon CDM search at Tokyo

    CERN Document Server

    Suzuki, Jun'ya; Horie, Tomoki; Minowa, Makoto

    2015-01-01

    We report on a search for hidden photon cold dark matter (HP CDM) using a novel technique with a dish antenna. We constructed two independent apparatus: one is aiming at the detection of the HP with a mass of $\\sim\\,\\rm{eV}$ which employs optical instruments, and the other is for a mass of $\\sim5\\times10^{-5}\\, \\rm{eV}$ utilizing a commercially available parabolic antenna facing on a plane reflector. From the result of the measurements, we found no evidence for the existence of HP CDM and set upper limits on the photon-HP mixing parameter $\\chi$.

  19. Running vacuum versus the $\\Lambda$CDM

    CERN Document Server

    Gómez-Valent, Adrià; Pérez, Javier de Cruz

    2016-01-01

    It is well-known that a constant $\\Lambda$-term is a traditional building block of the concordance $\\Lambda$CDM model. We show that this assumption is not necessarily the optimal one from the phenomenological point of view. The class of running vacuum models, with a possible running of the gravitational coupling G, are capable to fit the overall cosmological data SNIa+BAO+H(z)+LSS+BBN+CMB better than the $\\Lambda$CDM, namely at a level of $\\sim 3\\sigma$ and with Akaike and Bayesian information criteria supporting a strong level of statistical evidence on this fact. Here we report on the results of such analysis.

  20. CAPACITY AND WEIGHT COEFFICIENTS IN MIMO WIRELESS COMMUNICATION CHANNELS BASED ON ADAPTIVE MULTI-BEAM ANTENNAS IN URBAN ENVIRONMENT WITH FADING

    OpenAIRE

    Blaunstein, N.; Cristodoulou, Ch; Sergeev, M.

    2014-01-01

    Purpose: Long-Term Evolution (LTE) system has had as many as 12 implementations, the later ones using multi-beam adaptive antennas. LTE development and usage have demonstrated that such systems cannot be adapted to environmental changes, to different locations of every subscriber in the service areas, either open or close for connection, or to the acknowledgement from every wireless channel of a Multiple Input Multiple Output (MIMO) system which goes through an environment with different fadi...

  1. Massive MIMO Codebook Design Based on BD-DFT Extension%基于BD-DFT扩展的大规模MIMO码本设计

    Institute of Scientific and Technical Information of China (English)

    李小兵; 吴学文; 景小荣

    2015-01-01

    考虑到大规模多输入多输出(Multiple Input Multiple Output,MIMO)阵列尺寸及外形等因素的限制,提出了一种适用于基站,采用交叉极化天线面阵的大规模MIMO(Massive MIMO)码本设计方法.该方法综合考虑交叉极化信道的对角化特点和相邻天线之间的相关性,首先设计出与采用交叉极化线阵匹配的码本,进而利用垂直维度天线间的相关性对其进行扩展,最终生成与交叉极化面阵相匹配的码本.仿真结果表明,该码本设计方法可使大规模MIMO系统的传输速率和误码率性能得到明显地提升.

  2. Achieving "Massive MIMO" Spectral Efficiency with a Not-so-Large Number of Antennas

    CERN Document Server

    Huh, Hoon; Papadopoulos, Haralabos C; Ramprashad, Sean A

    2011-01-01

    The main focus and contribution of this paper is a novel network-MIMO TDD architecture that achieves spectral efficiencies comparable with "Massive MIMO", with one order of magnitude fewer antennas per active user per cell. The proposed architecture is based on a family of network-MIMO schemes defined by small clusters of cooperating base stations, zero-forcing multiuser MIMO precoding with suitable inter-cluster interference constraints, uplink pilot signals reuse across cells, and frequency reuse. The key idea consists of partitioning the users population into geographically determined "bins", such that all users in the same bin are statistically equivalent, and use the optimal network-MIMO architecture in the family for each bin. A scheduler takes care of serving the different bins on the time-frequency slots, in order to maximize a desired network utility function that captures some desired notion of fairness. This results in a mixed-mode network-MIMO architecture, where different schemes, each of which i...

  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. An Algebraic Approach for the MIMO Control of Small Scale Helicopter

    CERN Document Server

    Budiyono, A

    2008-01-01

    The control of small-scale helicopter is a MIMO problem. To use of classical control approach to formally solve a MIMO problem, one needs to come up with multidimensional Root Locus diagram to tune the control parameters. The problem with the required dimension of the RL diagram for MIMO design has forced the design procedure of classical approach to be conducted in cascaded multi-loop SISO system starting from the innermost loop outward. To implement this control approach for a helicopter, a pitch and roll attitude control system is often subordinated to a, respectively, longitudinal and lateral velocity control system in a nested architecture. The requirement for this technique to work is that the inner attitude control loop must have a higher bandwidth than the outer velocity control loop which is not the case for high performance mini helicopter. To address the above problems, an algebraic design approach is proposed in this work. The designed control using s-CDM approach is demonstrated for hovering cont...

  5. MIMO Detection Algorithms for High Data Rate Wireless Transmission

    CERN Document Server

    Sinha, Nirmalendu Bikas; Mitra, M

    2010-01-01

    Motivated by MIMO broad-band fading channel model, in this section a comparative study is presented regarding various uncoded adaptive and non-adaptive MIMO detection algorithms with respect to BER/PER performance, and hardware complexity. All the simulations are conducted within MIMO-OFDM framework and with a packet structure similar to that of IEEE 802.11a/g standard. As the comparison results show, the RLS algorithm appears to be an affordable solution for wideband MIMO system targeting at Giga-bit wireless transmission. So MIMO can overcome huge processing power required for MIMO detection by using optimizing channel coding and MIMO detection.

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

    DEFF Research Database (Denmark)

    Dong, Yan; Olsen, Karen Holm

    2015-01-01

    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...... 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...... 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...

  7. Beamforming for multiuser MIMO systems

    OpenAIRE

    Toutounchian, Milad Amir

    2014-01-01

    Wireless communications systems use a multiple user scheme such as time- or frequency-division,but these do not allow truly simultaneous use of the spectrum. By deploying multiple antennas andbeamforming, it is possible, in principle, for users to share the spectrum simultaneously, and thisscenario is called the multiuser MIMO interference channel. This thesis presents new beamfomingdesign methods for this channel, derived from the convergence criteria for multi-objective optimization.Beamfor...

  8. 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 det

  9. 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)

  10. Analytical Expression for the MIMO Channel Capacity

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yifei; ZHAO Ming; XIAO Limin; WANG Jing

    2006-01-01

    This paper presents analytical expressions for the multiple-input multiple-output (MIMO) channel capacity in frequency-flat Rayleigh fading environments. An exact analytical expression is given for the ergodic capacity for single-input multiple-output (SIMO) channels. The analysis shows that the SIMO channel capacity can be approximated by a Gaussian random variable and that the MIMO channel capacity can be approximated as the sum of multiple SIMO capacities. The SIMO channel results are used to derive approximate closed-form expressions for the MIMO channel ergodic capacity and the complementary cumulative distribution function (CCDF) of the MIMO channel capacity (outage capacity). Simulations show that these theoretical results are good approximations for MIMO systems with an arbitrary number of transmit or receive antennas. Moreover, these analytical expressions are relatively simple which makes them very useful for practical computations.

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

    Directory of Open Access Journals (Sweden)

    Cheolwoo You

    2013-10-01

    Full Text Available 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.

  12. 基于MIMO的可见光通信中的信道均衡%Channel equalization in the visible-light communication based on MIMO

    Institute of Scientific and Technical Information of China (English)

    张妥; 梁忠诚; 刘学明; 张琪; 居秋琦

    2015-01-01

    针对基于多输入多输出(MIMO)的室内可见光通信(Visible-Light Communication,VLC)系统中存在的码间串扰(ISI)问题进行了分析,并提出了适用于MIMO可见光通信系统的信道均衡方案及实现方法.仿真实验结果表明,该方法可以有效降低MIMO可见光通信系统中的码间串扰的影响.

  13. 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...... interpolation is presented. The proposed technique provides a closed form solution for the PWS when the probe ring radius is infinite. The proposed technique shows that the impact of the antenna pattern on the induced received voltage accuracy is ruled by Nyquist sampling theory. Furthermore, the impact...... of the antenna pattern on spatial correlation accuracy for prefaded signal synthesis (PFS) technique is investigated as well. Simulation and measurement results show that the number of required probes depend directly on the DUT antenna pattern. To test realistic DUTs with higher variations in directivity, we...

  14. Comparison of Linear Precoding Schemes for the Massive MIMO Downlink

    OpenAIRE

    Hoydis, Jakob; Ten Brink, Stephan; Debbah, Mérouane

    2012-01-01

    978-1-4577-2052-9; International audience; We consider the downlink of a time-division duplexing (TDD) multicell multiuser MIMO system where the base stations (BSs) are equipped with a very large number of antennas. Assuming channel estimation through uplink pilots, arbitrary antenna correlation and user distributions, we derive approximations of achievable rates with linear precoding techniques, namely eigenbeamforming (BF) and regularized zero-forcing (RZF). The approximations are tight in ...

  15. 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.

  16. OUTPUT FEEDBACK CONTROL FOR MIMO NONLINEAR SYSTEMS WITH EXOGENOUS SIGNALS

    Institute of Scientific and Technical Information of China (English)

    Ying ZHOU; Yuqiang WU

    2006-01-01

    The paper addresses the global output tracking of a class of multi-input multi-output(MIMO) nonlinear systems affected by disturbances, which are generated by a known exosystem. An adaptive controller is designed based on the proposed observer and the backstepping approach to asymptotically track arbitrary reference signal and to guarantee the boundedness of all the signals in the closed loop system. Finally, the numerical simulation results illustrate the effectiveness of the proposed scheme.

  17. Compressive Sensing for Feedback Reduction in MIMO Broadcast Channels

    OpenAIRE

    Qaseem, Syed T.; Al-Naffouri, Tareq Y.

    2009-01-01

    We propose a generalized feedback model and compressive sensing based opportunistic feedback schemes for feedback resource reduction in MIMO Broadcast Channels under the assumption that both uplink and downlink channels undergo block Rayleigh fading. Feedback resources are shared and are opportunistically accessed by users who are strong, i.e. users whose channel quality information is above a certain fixed threshold. Strong users send same feedback information on all shared channels. They ar...

  18. Challenges for ΛCDM and MOND

    International Nuclear Information System (INIS)

    The Universe on large scales is well described by the ΛCDM cosmological model. There however remain some heavy clouds on our global understanding, especially on galaxy scales, which we review here. While some of these clouds might perhaps disappear through small compensatory adjustments of the model, such as changing the mass of the dark matter particles or accounting better for baryonic physics, others should rather be taken as strong indications that the physics of the dark sector is, at the very least, much richer and complex than currently assumed, and that our understanding of gravity and dynamics might also be at play. For instance, the empirically well-tested MOND phenomenology in galaxies, whatever its final explanation, should be understood in any model of galaxy formation and dynamics. Current alternatives to ΛCDM however bring with them many unsolved questions and challenges.

  19. Angular Distribution of Clustersin Skewed CDM Models

    CERN Document Server

    Borgani, S; Plionis, M

    1994-01-01

    We perform a detailed investigation of the statistical properties of the projected distribution of galaxy clusters obtained in Cold Dark Matter (CDM) models with both Gaussian and skewed primordial density fluctuations. We use N-body simulations to construct a set artificial Lick maps. An objective cluster--finding algorithm is used to identify clusters of different richness. For Gaussian models, the overall number of clusters is too small in the standard CDM case, but a model with higher normalisation fares much better; non--Gaussian models with negative skewness also fit faily well. We apply several statistical tests to compare real and simulated cluster samples, such as the 2-point correlation function, the minimal spanning tree construction, the multifractal analysis and the skewness of cell counts. The emerging picture is that Gaussian models, even with a higher normalization, are in trouble. Skew-positive models are also ruled out, while skew-negative models can reproduce the observed clustering of gala...

  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

    -based zero forcing (ZF) channel estimation algorithm is designed to compensate the polarization rotation and wireless multipath fading. A 797 Mb/s net data rate QPSK-OFDM signal with error free (<1 × 10-5) performance and a 1.59 Gb/s net data rate 16QAM-OFDM signal with BER performance of 1.2 × 10-2 are...

  1. 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.  

  2. Downlink scheduling of multiuser MIMO systems with transmit beamforming

    Institute of Scientific and Technical Information of China (English)

    SONG Xing-hua; WU Wei-ling

    2008-01-01

    This article deals with downlink scheduling for multiuser multiple-input multiple-output (MIMO) systems, where the base station communicates with multiple users simultaneously through transmit beamforming. Most of the existing transmission schemes for multiuser MIMO systems focus on optimizing sum rate performance of the system. The individual quality of service (QoS) requirements (such as packet delay and minimum transmission rate for the data traffic) are rarely considered. In this article, a novel scheduling strategy is proposed, where we try to optimize the global system performance under individual QoS constraints. By performing scheduling into two steps, namely successive user selection and power allocation, the scheduler can achieve efficient resource utilization while maintaining the QoS requirements of all users. Extensive simulations and analysis are given to show the effectiveness of the proposed scheduler.

  3. Effective user selection algorithm for quantized precoding in massive MIMO

    Directory of Open Access Journals (Sweden)

    Nayan fang

    2015-02-01

    Full Text Available The downlink of a multi-user massive MIMO wireless system is considered, where the base station equipped with a large number of antennas simultaneously servesmultiple users. In this paper, an effective user selection algorithm is proposed for quantized precoding in massive MIMO systems. The algorithm aims at minimizing the correlation of precoders among users by relaxing the optimal problem to be convex and solving it using the Primal Newton’s Barrier Method. The complexity of the proposed algorithm is relatively low and the performance shown by the numerical results is close to the exhaustive search method. The advantage of the proposed algorithm increasingly shows up as the transmit antennas increase significantly.

  4. A Waveform Adaptation Algorithm Based on Game Theory for MIMO Cognitive Radio%基于博弈论的MIMO认知无线电波形自适应算法

    Institute of Scientific and Technical Information of China (English)

    魏飞; 杨震

    2011-01-01

    The problem of waveform adaptation to maximize information rate in a multiple-in multiple-out cognitive radio ( MIMO-CR) network is investigated from a non-cooperative game theoretic viewpoint. The existence and uniqueness of the Nash e-quilibrium under certain circumstances is proved and a decentralized iterative water-filling algorithm with punishing price, MIMO-CR FWFA.is proposed to solve the above problem,the pricing mechanism is used to satisfy the interference-temperature constraint while achieving the Nash equilibrium, the conditions for the convergence of MIMO-CR IWFA are also provided. Simulation results show our MIMO-CR IWFA can satisfy the interference-temperature constraint perfectly and is fast convergent; and though con strained by PU' s interference-temperature, the performance of MMO-CR IWFA can still approach the classical MIMO IWFA, which does not consider the interference-temperature constraint, with the increase of co-channel interference between MIMO-CRs.%本文从非合作博弈的角度研究了MIMO认知无线电(MIMO-CR)网络中最大化信息速率的波形自适应问题,证明了在给定条件下Nash均衡的存在与唯一性,并提出了一种求解Nash均衡的带惩罚价格的分布式迭代注水算法——MIMO-CR IWFA,通过价格机制的运用使得MIMO-CR在满足主用户的干扰温度约束时最大化各自的信息速率;同时证明了在给定条件下MIMO-CR IWFA能够收敛到唯一Nash均衡解.仿真结果表明MIMO-CR IWFA具有快速收敛特性且能够很好的满足干扰温度约束;虽然受到主用户的干扰温度约束限制,MIMO-CR IWFA的性能能够随着MI-MO-CR链路之间的同信道干扰的增大而逐渐接近不考虑干扰温度约束的经典MIMO迭代注水算法(MIMO IWFA).

  5. Cognitive MIMO Frequency Diverse Array Radar with High LPI Performance

    Directory of Open Access Journals (Sweden)

    Ling Huang

    2016-01-01

    Full Text Available Frequency diverse array (FDA has its unique advantage in realizing low probability of intercept (LPI technology for its dependent beam pattern. In this paper, we proposed a cognitive radar based on the frequency diverse array multiple-input multiple-output (MIMO. To implement LPI of FDA MIMO transmit signals, a scheme for array weighting design is proposed, which is to minimize the energy of the target location and maximize the energy of the receiver. This is based on the range dependent characteristics of the frequency diverse array transmit beam pattern. To realize the objective problem, the algorithm is proposed as follows: the second-order nonconvex optimization problem is converted into a convex problem and solved by the bisection method and convex optimization. To get the information of target, the FDA MIMO radar is proposed to estimate the target parameters. Simulation results show that the proposed approach is effective in decreasing the detection probability of radar with lossless detection performance of the receive signal.

  6. 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.

  7. 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.

  8. 大规模MIMO系统中基于溢出概率的鲁棒协作波束设计%Robust Coordinated Beamforming Design Based on Outage Probability for Massive MIMO

    Institute of Scientific and Technical Information of China (English)

    李新民; 邱玲

    2015-01-01

    Massive MIMO technique can effectively increase system capacity in the fifth Generation (5G) cellular network, where Base Station (BS) is equipped with a very large number of antennas. Considering the impact of channel estimation error on performance, the transmission power minimization problem is formulated subject to the non-outage probability constraints of each user’s signal to interference plus noise ratio. In respect that the non-convex probability constraints make the downlink beamforming difficult to solve, Uplink-Downlink Duality Algorithm (UDDA) is proposed to design Coordinated BeamForming (CBF) by using the property of trace of the matrix to scale the non-convex probability constraint. To reduce the signaling overhead in Massive MIMO system, a Distributed Algorithm based on Large System Analysis (DALSA) is proposed, which only needs the large-scale channel information. The simulation results show that DALSA, in the targeted SINR constraint, not only reduces instantaneous channel state information transmission overhead in Massive MIMO system, but also performs well in robustness compared with UDDA.%大规模多输入多输出(Massive MIMO)技术通过在基站端配置大规模天线能有效提升5G蜂窝系统容量。考虑信道估计误差对系统性能的影响,该文在多小区大规模MIMO系统中形成了用户信干噪比的非溢出概率约束下最小化系统功率的优化问题。针对非凸概率约束中下行波束难于求解的问题,该文根据矩阵迹的性质将优化问题中的非凸约束缩放,进而提出上下行对偶算法求解波束矢量。为进一步减少多小区系统中信令开销,基于大系统分析,提出了仅采用大尺度信息的分布式算法。仿真结果表明,所提的分布式算法与对偶算法相比,在保证用户信干噪比的概率约束时,降低了大规模MIMO系统中传输瞬时信道状态信息的开销,同时具有良好的鲁棒性。

  9. 基于控制性能的MIMO非线性系统动态面控制%Dynamic Surface Control Based on Control Performance for a Class of MIMO Nonlinear Systems

    Institute of Scientific and Technical Information of China (English)

    余修端; 孙秀霞; 董文瀚; 刘树光

    2012-01-01

    An adaptive tracking control scheme is proposed for a class of uncertain nonlinear MIMO (multiple-input multiple-output) systems based on dynamic surface control method. Performance function and output error transformation are employed to guarantee that the output signals have the prespecified control indexes of output tracking speed, tracking error, overshoot, etc. In order to avoid control singularity problem, neural network is used to approximate desired intermediate control signals directly. Instead of estimating all the weights of the neural network, only one parameter's adaptive law needs to be designed. It is proved theoretically that all signals of the closed-loop system are bounded. Simulation results verify the effectiveness of the proposed scheme.%针对一类不确定非线性MIMO(multiple-input multiple-output)系统,在动态面控制方法的基础上,提出了自适应跟踪控制方案.通过引入性能函数和输出误差转换,保证输出信号具有指定的跟踪速度、跟踪误差、最大超调量.为了避免控制奇异问题,采用神经网络直接逼近期望控制信号.该方案无需估计神经网络的权值,仅对1个参数进行自适应律设计.理论证明了闭环系统所有信号有界,仿真结果验证了所提方案的有效性.

  10. MU-MIMO Downlink Proactive Scheduling Based on Associative Interference%MU-MIMO下行链路基于关联干扰的先验式用户调度

    Institute of Scientific and Technical Information of China (English)

    李钊; 刘瑞雪; 王琳; 马丹

    2014-01-01

    In this paper a proactive scheduling algorithm is proposed based on associative interference of spatial subchannels for MU-MIMO downlink (broadcast) channel. The strategy converts user scheduling into subchannel selection issue. With comprehensive consideration of candidate subchannel transmission gain, along with mutual interference among candidate and selected subchannels, as well as those to be selected potentially. A set of subchannels with less mutual interference are achieved. Simulation results show that by choosing proper associative interference parameters, the proposed algorithm can achieve good tradeoff between computational complexity and transmission performance, and improve system sum rate effectively.%该文针对 MU-MIMO 下行(广播)信道提出一种基于空间子信道关联干扰的先验式调度算法。该方法将用户调度转换为子信道的选择问题,通过综合考虑候选子信道的传输增益,以及候选者与已选的和潜在的、将来可能被选中的子信道间的相互干扰,获得一组相互干扰较小的子信道。仿真结果表明,合理地选取关联干扰参数,该算法能够获得计算复杂度与传输性能的良好折中,有效改善系统和速率。

  11. 双基地MIMO雷达发射功率聚焦的角度估计算法研究%Study on Angle Estimation of Bistatic MIMO Radar Based on Transmit Power Focus

    Institute of Scientific and Technical Information of China (English)

    黄中瑞; 张剑云; 周青松

    2015-01-01

    In order to solve the problem that the power is transmitted dispersedly in traditional bistatic MIMO radar, a method about the transmit power focus of the bistatic MIMO radar is proposed. Firstly, the mathematic model is constructed based on an effective optimal criterion that can not only constrain the maximum error of the optimal beam and the desire one less than the given value, but also minimize the peak side lobe power of the transmit pattern. At the same time, a special beam matrix of transmitting terminal is constructed, not only making equivalent transmit/receive steering vector possessing the character of rotational invariance property, but also simplifying the original optimized model in order to be fast solved via second-order cone programming theory. Secondly, the transmitting and receiving angle of space target is estimated by utilizing improved PARallel FACtor (PARFAC) algorithm. The initial iteration point in the least square algorithm of PARFAC interior is improved by integrating into rotation invariance of transmitting/receiving steering vector, which can effectively decrease the number of iteration. Furthermore, the Cramer-Rao Bound of multi-target angle estimation under bistatic MIMO radar transmitting power focusing is derived which prove the superiority of the proposed method. Finally, the simulation results show the effectiveness of the theoretical analysis.%该文针对传统双基地MIMO雷达发射功率在空间发散的问题,提出一种双基地MIMO雷达发射功率聚焦方法。首先,建立了双基地MIMO雷达发射功率聚焦的优化模型,其优化准则为:在感兴趣空域内严格约束优化波束与期望波束的最大误差小于给定门限的前提下,最小化发射方向图的峰值旁瓣功率。同时,构造特殊发射端波束矩阵,不仅能使等效发射/接收导向矢量具有旋转不变性,并且简化了原优化模型,以便采用二阶锥规划理论进行快速求解;其次,利

  12. 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...

  13. Hierarchical Interference Mitigation for Massive MIMO Cellular Networks

    Science.gov (United States)

    Liu, An; Lau, Vincent

    2014-09-01

    We propose a hierarchical interference mitigation scheme for massive MIMO cellular networks. The MIMO precoder at each base station (BS) is partitioned into an inner precoder and an outer precoder. The inner precoder controls the intra-cell interference and is adaptive to local channel state information (CSI) at each BS (CSIT). The outer precoder controls the inter-cell interference and is adaptive to channel statistics. Such hierarchical precoding structure reduces the number of pilot symbols required for CSI estimation in massive MIMO downlink and is robust to the backhaul latency. We study joint optimization of the outer precoders, the user selection, and the power allocation to maximize a general concave utility which has no closed-form expression. We first apply random matrix theory to obtain an approximated problem with closed-form objective. We show that the solution of the approximated problem is asymptotically optimal with respect to the original problem as the number of antennas per BS grows large. Then using the hidden convexity of the problem, we propose an iterative algorithm to find the optimal solution for the approximated problem. We also obtain a low complexity algorithm with provable convergence. Simulations show that the proposed design has significant gain over various state-of-the-art baselines.

  14. 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.

  15. 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.

  16. Downlink Assisted Uplink Zero Forcing for TDD Multiuser MIMO Systems

    Directory of Open Access Journals (Sweden)

    Komulainen Petri

    2009-01-01

    Full Text Available This paper proposes practical coordinated linear transmit-receive processing schemes for the uplink (UL of multiuser multiple-input multiple-output (MIMO systems in the time division duplex (TDD mode. The base station (BS computes the transmission parameters in a centralized manner and employs downlink (DL pilot signals to convey the information of the beam selection and beamformers to be used by the terminals. When coexisting with the DL transmit-receive zero forcing, the precoded DL demodulation pilots can be reused for UL beam allocation so that no additional pilot overhead is required. Furthermore, the locally available channel state information (CSI of the effective MIMO channel is sufficient for the terminals to perform transmit power and rate allocation independently. In order to reduce the UL pilot overhead as well, we propose reusing the precoded UL demodulation pilots in turn for partial CSI sounding. The achievable sum rate of the system is evaluated in time-varying fading channels and with channel estimation. According to the results, the proposed UL transmission strategy provides increased rates compared to single-user MIMO transmission combined with user selection as well as to UL antenna selection transmission, without being sensitive to CSI uncertainty.

  17. Spatial Modulation Concept for Massive Multiuser MIMO Systems

    Directory of Open Access Journals (Sweden)

    Khaled M. Humadi

    2014-01-01

    Full Text Available This paper presents the concept of spatial modulation (SM scheme for massive multiuser MIMO (MU-MIMO system. We consider a MU-MIMO system where K users, each equipped with multiple antennas, are jointly serviced by a multiantenna base station transmitter (BSTx using appropriate precoding scheme at the BSTx. The main idea introduced here is the utilization of the user’s subchannel index corresponding to the precoding matrix used at the BSTx, to convey extra useful information. This idea has not been explored, and it provides significant throughput enhancements in a multiuser system with large number of users. We examine the performance of the proposed scheme by numerical simulations. The results show that as the number of users and the receiving antennas for each user increase, the overall system throughput gets better, albeit at the cost of some degradation in the BER performance due to interantenna interference (IAI experienced at the receiver. We then explore zero-padding approach that helps to remove these IAI, in order to alleviate the BER degradations.

  18. Energy-Aware Adaptive Cooperative FEC Protocol in MIMO Channel for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yong Jin

    2013-01-01

    Full Text Available We propose an adaptive cooperative forward error correction (ACFEC based on energy efficiency combining Reed-Solomon (RS coder algorithm and multiple input multiple output (MIMO channel technology with monitoring signal-to-noise ratio (SNR in wireless sensor networks. First, we propose a new Markov chain model for FEC based on RS codes and derive the expressions for QoS on the basis of this model, which comprise four metrics: throughput, packet error rate, delay, and energy efficiency. Then, we apply RS codes with the MIMO channel technology to the cross-layer design. Numerical and simulation results show that the joint design of MIMO and adaptive cooperative FEC based on RS codes can achieve considerable spectral efficiency gain, real-time performance, reliability, and energy utility.

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

    International Nuclear Information System (INIS)

    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)

  20. CDM. Is it a 'win-win' strategy for rural poverty alleviation in India?

    Energy Technology Data Exchange (ETDEWEB)

    Sirohi, Smita [Department of Dairy Economics, Statistics and Management, National Dairy Research Institute, Karnal, Haryana, 132001 (India)

    2007-09-15

    India is perceived to be one of the most attractive Non-Annex I countries for CDM project development. There are more than 350 projects in the CDM pipeline, largely in the areas of renewable energy, energy efficiency in industries and fossil fuel switching. This paper examines the socio-economic component of sustainable development commitments of the CDM projects to see if they can make any impact on rural poverty in India, since the goal of poverty alleviation lies at the core of the country's development priorities. The study concludes that CDM is not contributing to rural poverty alleviation to any notable extent. Nearly all the projects have a business orientation and are not directed to the development of rural poor. Even the renewable energy projects will have limited role in up-liftment of the masses below poverty line due to their weak resource base. For CDM to emerge as a 'win-win' strategy for poverty alleviation projects should be aimed at the rural communities and designed to accelerate agricultural growth in the rain-fed regions of the country.

  1. Diversity of MIMO Linear Precoding

    CERN Document Server

    Mehana, Ahmed Hesham

    2012-01-01

    Linear precoding is a relatively simple method of MIMO signaling that can also be optimal in certain special cases. This paper is dedicated to high-SNR analysis of MIMO linear precoding. The Diversity-Multiplexing Tradeoff (DMT) of a number of linear precoders is analyzed. Furthermore, since the diversity at finite rate (also known as the fixed-rate regime, corresponding to multiplexing gain of zero) does not always follow from the DMT, linear precoders are also analyzed for their diversity at fixed rates. In several cases, the diversity at multiplexing gain of zero is found not to be unique, but rather to depend on spectral efficiency. The analysis includes the zero-forcing (ZF), regularized ZF, matched filtering and Wiener filtering precoders. We calculate the DMT of ZF precoding under two common design approaches, namely maximizing the throughput and minimizing the transmit power. It is shown that regularized ZF (RZF) or Matched filter (MF) suffer from error floors for all positive multiplexing gains. Howe...

  2. Orthogonal Waveforms for FMCW MIMO Radar

    NARCIS (Netherlands)

    Wit, J.J.M. de; Rossum, W.L. van; Jong, A.J. de

    2011-01-01

    Multiple input/multiple output (MIMO) radar system performance benefits from the capability to simultaneously transmit and receive multiple orthogonal waveforms. For pulse radars fitting orthogonal waveforms have been developed. These waveforms are however not necessarily suitable for frequencymodul

  3. Radar's LPI Analysis and Application Based on MIMO System%基于MIMO体制的雷达LPI性能分析和应用

    Institute of Scientific and Technical Information of China (English)

    张杰

    2007-01-01

    多输入多输出(MIMO, multiple-input multiple-out)系统在发射端和接收端均采用了多天线技术,利用间隔一定距离的阵元信号之间的独立性和目标闪烁特性提高探测的性能.在介绍MIMO原理的基础上,分析了将MIMO技术应用于实现低截获概率(LPI, low probability of intercept)雷达辐射功率的有效控制,以提高雷达的作战性能和战场生存能力.

  4. Beyond six parameters: Extending Λ CDM

    Science.gov (United States)

    Di Valentino, Eleonora; Melchiorri, Alessandro; Silk, Joseph

    2015-12-01

    Cosmological constraints are usually derived under the assumption of a six-parameter Λ CDM theoretical framework or simple one-parameter extensions. In this paper we present, for the first time, cosmological constraints in a significantly extended scenario, varying up to 12 cosmological parameters simultaneously, including the sum of neutrino masses, the neutrino effective number, the dark energy equation of state, the gravitational wave background and the running of the spectral index of primordial perturbations. Using the latest Planck 2015 data release (with polarization), we found no significant indication for extensions to the standard Λ CDM scenario, with the notable exception of the angular power spectrum lensing amplitude, Alens , which is larger than the expected value at more than 2 standard deviations, even when combining the Planck data with BAO and supernovae type Ia external data sets. In our extended cosmological framework, we find that a combined Planck+BAO analysis constrains the value of the rms density fluctuation parameter to σ8=0.781-0.063+0.065 at 95 % C.L., helping to relieve the possible tensions with the CFHTlenS cosmic shear survey. We also find a lower value for the reionization optical depth τ =0.058-0.043+0.040 at 95 % C.L. with respect to the one derived under the assumption of Λ CDM . The scalar spectral index nS is now compatible with a Harrison-Zeldovich spectrum to within 2.5 standard deviations. Combining the Planck data set with the Hubble Space Telescope prior on the Hubble constant provides a value for the equation of state w <-1 at more than 2 standard deviations, while the neutrino effective number is fully compatible with the expectations of the standard three neutrino framework.

  5. Capacity estimation of HF-MIMO systems.

    OpenAIRE

    N. Abbasi; Gunashekar, S.D.; Warrington, E. M.; Salous, S.; Feeney, S. M.; L. Bertel; Lemur, D.; Oger, M.

    2009-01-01

    Multiple input multiple output (MIMO) systems utilize multiple antennas at both the transmitter and the receiver. This paper describes some recent experimental work that has been carried out in order to investigate the feasibility of applying MIMO techniques within the high frequency (HF) band. It is a significant development because the potential increase in data rates will benefit not only the existing HF radio systems but also open this band to new low cost communication applications. The ...

  6. 学习CDM实施CDM

    Institute of Scientific and Technical Information of China (English)

    曾学敏

    2006-01-01

    @@ 实施清洁发展机制(CDM)项目,在我国已掀起热潮,截止4月上旬,已有25个CDM项目获国家发改委批准,报联合国CDM执行理事会(EB)批准的项目已有7个,减排CO2当量3亿吨,交易额达20多亿美元.

  7. Fixed-complexity vector perturbation with Block diagonalization for MU-MIMO systems

    CERN Document Server

    Mohaisen, Manar; Chang, KyungHi; Ji, Seunghwan; Joung, Jinsoup

    2009-01-01

    Block diagonalization (BD) is an attractive technique that transforms the multi-user multiple-input multiple-output (MU-MIMO) channel into parallel single-user MIMO (SU-MIMO) channels with zero inter-user interference (IUI). In this paper, we combine the BD technique with two deterministic vector perturbation (VP) algorithms that reduce the transmit power in MU-MIMO systems with linear precoding. These techniques are the fixed-complexity sphere encoder (FSE) and the QR-decomposition with M-algorithm encoder (QRDM-E). In contrast to the conventional BD VP technique, which is based on the sphere encoder (SE), the proposed techniques have fixed complexity and a tradeoff between performance and complexity can be achieved by controlling the size of the set of candidates for the perturbation vector. Simulation results and analysis demonstrate the properness of the proposed techniques for the next generation mobile communications systems which are latency and computational complexity limited. In MU-MIMO system with ...

  8. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands.

    Science.gov (United States)

    Maruta, Kazuki; Iwakuni, Tatsuhiko; Ohta, Atsushi; Arai, Takuto; Shirato, Yushi; Kurosaki, Satoshi; Iizuka, Masataka

    2016-01-01

    Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity.

  9. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands

    Directory of Open Access Journals (Sweden)

    Kazuki Maruta

    2016-07-01

    Full Text Available Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G. One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity.

  10. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands.

    Science.gov (United States)

    Maruta, Kazuki; Iwakuni, Tatsuhiko; Ohta, Atsushi; Arai, Takuto; Shirato, Yushi; Kurosaki, Satoshi; Iizuka, Masataka

    2016-01-01

    Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity. PMID:27399715

  11. An Imaging Method of MIMO-SAR with Compressed Echo Data%基于回波数据压缩的MIMO-SAR成像方法

    Institute of Scientific and Technical Information of China (English)

    谢矿生

    2015-01-01

    The amount of echo data is huge in multiple input multiple output synthetic aperture radar( MI-MO-SAR) imaging with high resolution. To solve this problem,an imaging method of MIMO-SAR based on compressed echo data is proposed. Firstly,the echo signal model of MIMO-SAR system is analyzed and the phase error induced by MIMO radar is compensated. Secondly,the echo signal is preprocessed by the Range Migration Algorithm( RMA) ,and also the sparsity of the processed data is analyzed. Then the pre-processed data is compressed and transmitted. In the ground receiver,the sparse expression of echo data in Range-Doppler( RD) domain is reconstructed. Finally,the simulation result shows that the amount of the transmitted data by the proposed method is less than that by the conventional MIMO-SAR imaging method.%针对多发多收合成孔径雷达( MIMO-SAR)高分辨成像的回波数据量过大问题,提出了一种基于数据压缩的MIMO-SAR成像方法。通过对MIMO-SAR回波数据的分析,补偿了由于MIMO雷达收发分置导致的相位误差;其次利用距离徙动算法( RMA)对回波数据进行预处理并分析了其稀疏性;然后针对预处理后的回波数据进行压缩传输,在接收端利用压缩感知重构算法获得回波数据在距离多普勒域的稀疏表示并进行成像处理。仿真结果表明,所提方法可以在大幅压缩MIMO-SAR回波数据的基础上实现准确成像。

  12. Reduction of PAPR and Efficient detection ordering scheme for MIMO Transmission Systems Using Power Control

    Directory of Open Access Journals (Sweden)

    V.Sreevani

    2015-12-01

    Full Text Available The technical challenges for communication engineers is the development of best performance wireless networks with negligible amount of distortions. We have to consider multipath propagation attenuation and radio spectrum inefficiency. Now a days, In MIMO (Multi Input Multi Output systems there is a huge demand for the networks with the high transmission rates and better quality of service which are having low PAPR ratio. Instead of OFDMA, filter banks are used in massive MIMO to reduce the complexity. But they are error prone to noise. This base paper discusses about PAPR reduction in MIMO systems using different precoding based OFDM systems. Mainly, minimization of multi-antenna systems by controlling the transmission power and reduction of PAPR using ZC (Zadoff-Chu matrix transform.

  13. PAR-Aware Large-Scale Multi-User MIMO-OFDM Downlink

    CERN Document Server

    Studer, Christoph

    2012-01-01

    We investigate an orthogonal frequency-division multiplexing (OFDM)-based downlink transmission scheme for large-scale multi-user (MU) multiple-input multiple-output (MIMO) wireless systems. The use of OFDM causes a high peak-to-average (power) ratio (PAR), which necessitates expensive and power-inefficient radio-frequency (RF) components at the base station. In this paper, we present a novel downlink transmission scheme, which exploits the massive degrees-of-freedom available in large-scale MU-MIMO-OFDM systems to achieve low PAR. Specifically, we propose to jointly perform MU precoding, OFDM modulation, and PAR reduction by solving a convex optimization problem. We develop a corresponding fast iterative truncation algorithm (FITRA) and show numerical results to demonstrate tremendous PAR-reduction capabilities. The significantly reduced linearity requirements eventually enable the use of low-cost RF components for the large-scale MU-MIMO-OFDM downlink.

  14. Experiments with Compact Antenna Arrays for MIMO Radio Communications

    CERN Document Server

    Browne, D W; Fitz, M P; Rahmat-Samii, Y

    2005-01-01

    The problem tackled in this study is one of MIMO transceiver implementation in which we consider how to design and test compact antenna arrays that have the ability to preserve the native information bearing capacity of a MIMO channel. Mutual coupling in antenna arrays is known to degrade the performance of a MIMO system. However, no tests involving compact arrays have been performed using a MIMO transceiver architecture that is capable of measuring the effect of mutual coupling on system performance. In this study, two novel compact MIMO antenna arrays were designed and integrated into a wideband MIMO radio testbed. These arrays are extremely compact yet have acceptable mutual coupling and radiation efficiency and resonate in three wide frequency bands. A measurement campaign was executed in which MIMO channel sounding measurements were taken using the compact arrays and dipole arrays in a variety of indoor environments. The MIMO transceiver used for channel sounding is able to measure the effect of mutual c...

  15. Co-benefits of CDM projects and policy implications

    OpenAIRE

    Sun, Qie; Xu, Bo; Wennersten, Ronald; Brandt, Nils

    2010-01-01

    This paper aims to study the co-benefits of clean development mechanism (CDM) projects, and further to discuss the policy of its implications. It has been found that many energy-related climate change mitigation (CCM) activities, including CDM projects, are able to produce a significant amount of co-benefits, while the policy implications have been limited. Through co-benefits assessment of Chinese CDM projects, it can be concluded that: (1) there are uncertainties relating to co-benefits ass...

  16. Comparison of Cluster Lensing Profiles with Lambda CDM Predictions

    CERN Document Server

    Broadhurst, Tom; Medezinski, Elinor; Oguri, Masamune; Rephaeli, Yoel

    2008-01-01

    We derive lens distortion and magnification profiles of four well known clusters observed with Subaru. Each cluster is very well fitted by the general form predicted for Cold Dark Matter (CDM) dominated halos, with good consistency found between the independent distortion and magnification measurements. The inferred level of mass concentration is surprisingly high, 8 = 10.39 \\pm 0.91), compared to the relatively shallow profiles predicted by the LCDM model, c_{vir} = 5.06 \\pm 1.10 (for =1.25\\times 10^{15} M_{\\odot}/h). This represents a 4\\sigma discrepancy, and includes the relatively modest effects of projection bias and profile evolution derived from N-body simulations, which oppose each other with little residual effect. In the context of CDM based cosmologies, this discrepancy implies some modification of the widely assumed spectrum of initial density perturbations, so clusters collapse earlier (z > 1) than predicted (z<0.5) when the Universe was correspondingly denser.

  17. 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.

  18. User Effect on the MIMO Performance of a Dual Antenna LTE Handset

    DEFF Research Database (Denmark)

    Buskgaard, Emil Feldborg; Tatomirescu, Alexandru; Barrio, Samantha Caporal Del;

    2014-01-01

    This study focuses on the user influence on a MIMO antenna system in a smart phone form factor. The antenna system is designed to have a low coupling and correlation between its two antennas. The study is based on time-domain simulations of the antenna system in free space and with a head and hand...... phantom using a commercially available Finite Element Method solver. The MIMO parameters are evaluated with three different channel models. A static grip only gives one case of the user effect so the hand phantom is modified with a moving finger that is swept across the backplane of the phone. Based on...

  19. Procesado Banda Base en sistemas MIMO basados en combinación analógica de antenas : del diseño teórico a la implementación FPGA : tesis doctoral

    OpenAIRE

    Elvira Arregui, Víctor

    2011-01-01

    ABSTRACT: In this thesis, we consider an analog antenna combining architecture for a MIMO wireless transceiver, while pointing out its advantages with respect to the traditional MIMO architectures. In the first part of this work, we focus on the transceiver design, especially the calculation of the beamformers that must be applied at the RF. This analysis is performed in an OFDM system under different assumptions on the channel state information. As a result, several criteria and algorithms f...

  20. Massive MIMO Systems: Signal Processing Challenges and Research Trends

    OpenAIRE

    de Lamare, R.C.

    2013-01-01

    This article presents a tutorial on multiuser multiple-antenna wireless systems with a very large number of antennas, known as massive multi-input multi-output (MIMO) systems. Signal processing challenges and future trends in the area of massive MIMO systems are presented and key application scenarios are detailed. A linear algebra approach is considered for the description of the system and data models of massive MIMO architectures. The operational requirements of massive MIMO systems are di...

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    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 handset...

  2. A new recipe for $\\Lambda$CDM

    CERN Document Server

    Sahni, Varun

    2015-01-01

    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 ${\\cal L} \\propto X^\\alpha - \\Lambda$ with $\\alpha \\geq 1$. In this case the kinetic term in the Lagrangian behaves just like a perfect fluid, whereas the potential term is the cosmological constant. For very large values, $\\alpha \\gg 1$, the equation of state of the kinetic term drops to zero and the expansion rate of the universe mimicks $\\Lambda$CDM. The velocity of sound in this model, and the associated gravitational clustering, is sensitive to the value of $\\alpha$. For very large values of $\\alpha$ the clustering properties of our model resemble those of cold dark matter (CDM). But for smaller values of $\\alpha$, gravitational clustering on small scales is suppressed, and our model has properties resembling t...

  3. The Role of Forestry Sinks in the CDM - Analysing the Effects of Policy Decisions on the Carbon Market

    OpenAIRE

    Jung, Martina

    2003-01-01

    The details on rules and modalities for the inclusion of forestry projects in the Clean Development Mechanism (CDM) are one of the last non resolved implementation issues of the Kyoto Protocol. We examine in detail the implications of different policy decisions concerning the inclusion of CDM forestry sink enhancement projects in the first commitment period of the climate regime (2008-2012). Our analysis is based on the development of marginal forestry cost curves which are implemented into t...

  4. Receive Diversity and Ergodic Performance of Interference Alignment on the MIMO Gaussian Interference Channel

    CERN Document Server

    Guillaud, Maxime

    2010-01-01

    We consider interference alignment (IA) over K-user Gaussian MIMO interference channel (MIMO-IC) when the SNR is not asymptotically high. We introduce a generalization of IA which enables receive diversity inside the interference-free subspace. We generalize the existence criterion of an IA solution proposed by Yetis et al. to this case, thereby establishing a multi-user diversity-multiplexing trade-off (DMT) for the interference channel. Furthermore, we derive a closed-form tight lower-bound for the ergodic mutual information achievable using IA over a Gaussian MIMO-IC with Gaussian i.i.d. channel coefficients at arbitrary SNR, when the transmitted signals are white inside the subspace defined by IA. Finally, as an application of the previous results, we compare the performance achievable by IA at various operating points allowed by the DMT, to a recently introduced distributed method based on game theory.

  5. Performance of RCPC-Encoded V-BLAST MIMO In Nakagami-m Fading Channel

    CERN Document Server

    Sari, L; Gunawan, D

    2010-01-01

    Multiple Input Multiple Output (MIMO) wireless communication link has been theoretically proven to be reliable and capable of achieving high capacity. However, these two advantageous characteristics tend to be addressed separately in many major researches. Researches on various approaches to attain both characteristics in a single MIMO system are still on-going and an established approach is yet to be concluded. To address this problem, in this paper a Vertical Bell Laboratories Layered Space-Time (V-BLAST) MIMO enhanced with Rate-Compatible Convolutional (RCPC) codes with Zero Forcing (ZF) and Minimum Mean Squared Error (MMSE)-based detection is proposed. The analytical BER of the system is presented and numerically analyzed. The system performance is analyzed in Nakagami-m fading channel, which provides accuracy and flexibility in matching the signals statistics compared to other fading models. The complexity which arises in the calculations of the RCPC codes parameters is significantly reduced by using equ...

  6. Blind Channel Estimation Enhancement for MIMO- OFDM Systems Under High Mobility Conditions

    Directory of Open Access Journals (Sweden)

    Aida Zaier

    2012-03-01

    Full Text Available In this paper, we propose an enhancement of a blind channel estimator based on a subspace approach in a MIMO OFDM context (Multi Input Multi Output Orthogonal Frequency Division Multiplexing in high mobility scenario. As known, the combination between the MIMO context and the OFDM system has stimulated mainly the evolution of the fourth generation broadband wireless communications. The simulations results have demonstrated the effectiveness of the approach for a 16 QAM modulation scheme and had been evaluated in term of bit error rate BER and mean square error MSE versus the signal to noise ratio SNR.

  7. Blind Channel Estimation Enhancement for Mimo- OFDM Systems under High Mobility Conditions

    CERN Document Server

    Zaier, Aida; 10.5121/ijwmn.2012.4115

    2012-01-01

    In this paper, we propose an enhancement of a blind channel estimator based on a subspace approach in a MIMO OFDM context (Multi Input Multi Output Orthogonal Frequency Division Multiplexing) in high mobility scenario. As known, the combination between the MIMO context and the OFDM system has stimulated mainly the evolution of the fourth generation broadband wireless communications. The simulations results have demonstrated the effectiveness of the approach for a 16 QAM modulation scheme and had been evaluated in term of bit error rate BER and mean square error MSE versus the signal to noise ratio SNR.

  8. Blind Carrier Frequency Offset Estimation via Power Spectrum Analysis in MIMO OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    WU Lu; ZHANG Xianda

    2009-01-01

    As a generalization of orthogonal frequency-division multiplexing (OFDM) systems,multi-input multi-output (MIMO) OFDM systems are very sensitive to carrier frequency offset (CFO).This paper proposes a blind CFO estimation method based on power spectrum analysis,which has high bandwidth efficiency and is much less complex.This method can be used to estimate the residual CFO,which is less than half of the subcarrier spacing.The method uses a cosine cost function to get a closed-form CFO estimate.Simulation results illustrate that the method is effective for MIMO OFDM systems.

  9. A Method of Time-Varying Rayleigh Channel Tracking in MIMO Radio System

    Institute of Scientific and Technical Information of China (English)

    GONG Yan-fei; HE Zi-shu; HAN Chun-lin

    2005-01-01

    A method of MIMO channel tracking based on Kalman filter and MMSE-DFE is proposed. The Kalman filter tracks the time-varying channel by using the MMSE-DFE decision and the MMSE-DFE conducts the next decision by using the channel estimates produced by the Kalman filter. Polynomial fitting is used to bridge the gap between the channel estimates produced by the Kalman filter and those needed for the DFE decision. Computer simulation demonstrates that this method can track the MIMO time-varying channel effectively.

  10. 阵列布局对机载 MIMO 信道容量影响%The Effect of Array Structures on Airborne MIMO Channel Capacity

    Institute of Scientific and Technical Information of China (English)

    陈自力; 高喜俊

    2015-01-01

    为进一步提高空地(air-to-ground,ATG)下行通信容量,建立了三维基于散射体分布的空地 MIMO 单跳同心椭圆环信道模型,结合机载多入多出(multiple input multiple output,MIMO)均匀线阵以及圆阵布局方案,推导了基于阵列结构分量的机载 MIMO 信道相关矩阵,为通过合理设计机载 MIMO 天线结构来提升 ATG 传输速率,分析了阵列结构参数对遍历容量的影响。仿真表明,受 ATG 远距离通信影响,需要扩大天线间隔来提高 MIMO信道容量,且相比于线阵布局,圆阵布局更加适应飞行姿态变化,获得较高的信道容量。%To improve the communication capacity of air-to-ground (ATG)downlinks,the three-dimensional geometrically based single bounce concentric elliptic ring scattering (GBSBCERS)channel model of ATG multiple input multiple output (MIMO)was set up.Combing with the linear array layout and circular array layout of airborne MIMO,the analytic formula of airborne MIMO channel correlation matrix and ergodic capacity was deduced based on array structures.Then the influ-ence of array structures on the ergodic capacity was analyzed to improve the ATG transmission rate by means of antennas layout.The simulation results shown that the MIMO channel capacity will increase along with the increase of antenna dis-tance in the influence of ATG remote communication,and the circular antenna layout which has more channel capacity than linear antenna layout can adapt to the UAV attitude change.

  11. 基于MIMO技术的可见光通信系统的研究%Research of the visible light communication system based on MIMO technology

    Institute of Scientific and Technical Information of China (English)

    王旭颖; 梁忠诚

    2013-01-01

    Discussed the application of MIMO in visible light parallel communication system, explore and, construct a more efficient VLC parallel communication system which is suitable for indoor. According to this plan set up a physical demonstration system and to validate its feasibility, the lens is applicated to build the imaging system, further improved the system model, the feasibility of this method has been verified by the experiment.%讨论了MIMO技术思想在可见光并行通信系统中的应用,探索并构建了一种更加高效的室内VLC并行通信系统.根据该方案搭建了实物演示系统,验证了其可行性,应用透镜搭建成像系统,进一步完善了系统模型,通过实验演示验证了其可行性.

  12. MIMO Precoding for Networked Control Systems with Energy Harvesting Sensors

    Science.gov (United States)

    Cai, Songfu; Lau, Vincent K. N.

    2016-09-01

    In this paper, we consider a MIMO networked control system with an energy harvesting sensor, where an unstable MIMO dynamic system is connected to a controller via a MIMO fading channel. We focus on the energy harvesting and MIMO precoding design at the sensor so as to stabilize the unstable MIMO dynamic plant subject to the energy availability constraint at the sensor. Using the Lyapunov optimization approach, we propose a closed-form dynamic energy harvesting and dynamic MIMO precoding solution, which has an event-driven control structure. Furthermore, the MIMO precoding solution is shown to have an eigenvalue water-filling structure, where the water level depends on the state estimation covariance, energy queue and the channel state, and the sea bed level depends on the state estimation covariance. The proposed scheme is also compared with various baselines and we show that significant performance gains can be achieved.

  13. Energy-efficient Resource Allocation Based on Multi-user Massive MIMO System%多用户大规模MIMO系统能效资源分配算法

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    该文针对多用户大规模多输入多输出(MIMO)移动通信上行系统,提出一种基于能效优化的资源分配算法。所提方法在采用最大比合并(MRC)接收情况下,满足用户数据速率和可容忍的干扰水平约束条件下,以最大化系统能效下界为准则建立优化模型。根据分数规划的性质,把原始的分数最优化问题转换成减式的形式,进而采用凸优化的方法,通过联合调整基站端的发射天线数和用户的发射功率来优化能效函数。仿真结果表明,所提算法与穷举算法在能效上的差距不足9%,并且有较好的系统频谱效率性能,同时算法复杂度得到了显著降低。%An energy-efficient resource allocation scheme is proposed for multi-user massive MIMO mobile communication uplink system. A mathematical formulation of optimization issue is provided with the objective of maximizing system energy efficiency lower bound under the data rate of user and tolerable interference level constraint, meanwhile the Base Station (BS) uses a Maximum-Ratio Combining (MRC) receiver. By transforming the originally fractional optimization problem into an equivalent subtractive form using the properties of fractional programming, then convex optimization is adopted to maximize the energy efficiency. Specifically, both the numbers of antenna arrays at the BS and the transmit data rate at the user are adjusted. Simulation results show that the energy-efficiency difference between the proposed algorithm and the exhaustive algorithm is less than 9%, at the same time, the performance of spectral-efficiency of the proposed algorithm is very well and the complexity is significantly reduced.

  14. Multi-user Detection Algorithm Based on Parallel Interference Cancellation for Massive MIMO Communications%大规模MIMO中基于并行干扰消除多用户检测算法

    Institute of Scientific and Technical Information of China (English)

    姜晓琳; 郑黎明; 王钢; 杨文超

    2015-01-01

    在发射与接收端天线数目相当的大规模多输入多输出( MIMO)系统中,线性检测算法的性能较差,而检测性能优异的检测算法复杂度偏高。针对该问题,提出增强型并行干扰消除算法(MMSE⁃ePIC),将搜索空间扩大到噪声增强方向矩阵的正交向量空间,同时利用近似对数似然方程值排序来减小复杂度。仿真结果表明,在误比特率为10-5时, MMSE⁃ePIC算法所需单位比特噪声功率谱密度比传统最小均方误差串行干扰消除( MMSE⁃SIC)算法小2 dB,复杂度较MMSE⁃SIC降低了25%,在保持良好检测性能的前提下,复杂度明显降低,可以较好地实现大规模MIMO的上行检测。%In MIMO systems,the linear detection algorithm is inferior when the number of receiving antennas is close to that of transmitting antennas,and the algorithms with good performance are usually of high complexity.To solve the problem,an MMSE⁃ePIC is proposed,where the searching space is expanded to normal eigenvector space of noise enhanced direction matrix,and the complexity is reduced based on the sorting of approximated log likelihood function values.The computer simulations show that the noise power spectral density of the proposed algorithm is 2 dB less than that of conventional MMSE⁃SIC,with decreased computational complexity of 25%. The modified MMSE detection algorithm has good detection performance and significantly decreased complexity,and approves to be a good option to implement uplink multi⁃user detection in large⁃scale MIMO communications.

  15. Transmitted Polarization Optimization for DOA Estimation Based on Vector Sensor MIMO Radar%基于矢量传感器MIMO雷达的发射极化优化DOA估计算法

    Institute of Scientific and Technical Information of China (English)

    郑桂妹; 陈伯孝; 杨明磊

    2014-01-01

    For the issue of the bad Direction Of Arrival (DOA) estimation accuracy entailed by not utilizing the transmitted polarization information in electromagnetic vector sensor MIMO radar, a transmitted polarization optimization algorithm is proposed based on minimizing the Cramér-Rao Bound (CRB). First, the signal model of electromagnetic vector sensor MIMO radar for DOA estimation is proposed. Second, the drawbacks of the existing fixed polarization DOA estimation algorithm are analyzed. Third, the CRB under arbitrary polarization is derived and the polarization state corresponding to the minimum CRB is computed. Finally, with the optimal polarization, the DOA can be estimated by the fixed polarization DOA estimation algorithm. The proposed algorithm can provide better estimation accuracy than the fixed polarization DOA estimation algorithm, and remain the advantages of automatic pairing between the two dimensional DOA estimation and arbitrary placement of the transmitted electromagnetic vector sensor antennas. Simulation results verify the effectiveness of the proposed algorithm.%针对常规矢量传感器MIMO雷达没有利用发射极化信息导致波达方向(DOA)估计精度较差的问题,该文提出一种克拉美罗界(CRB)最小化的发射极化优化算法。首先建立矢量传感器MIMO雷达的接收信号模型;然后分析固定发射极化矢量传感器MIMO雷达DOA估计算法的不足;接着推导任意发射极化状态下的CRB,计算最小CRB对应的极化状态;最后利用该优化极化状态采用固定极化DOA估计算法得到DOA估计。该算法的DOA估计精度高于固定极化DOA估计算法。且该算法的2维DOA估计可自动配对,发射电磁矢量传感天线位置可任意。仿真结果证明了该算法的有效性。

  16. 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)

  17. 基于混合建模技术的复合肥养分含量MIMO软测量模型%MIMO Soft-sensor Model of Nutrient Content for Compound Fertilizer Based on Hybrid Modeling Technique

    Institute of Scientific and Technical Information of China (English)

    傅永峰; 苏宏业; 褚健

    2007-01-01

    In compound fertilizer production, several quality variables need to be monitored and controlled simultaneously. It is very difficult to measure these variables on-line by existing instruments and sensors. So, soft-sensor technique becomes an indispensable method to implement real-time quality control. In this article, a new model of multi-inputs multi-outputs (MIMO) soft-sensor, which is constructed based on hybrid modeling technique, is proposed for these interactional variables. Data-driven modeling method and simplified first principle modeling method are combined in this model. Data-driven modeling method based on limited memory partial least squares (LM-PLS) algorithm is used to build soft-senor models for some secondary variables; then, the simplified first principle model is used to compute three primary variables on line. The proposed model has been used in practical process; the results indicate that the proposed model is precise and efficient, and it is possible to realize on line quality control for compound fertilizer process.

  18. Moessbauer-Spectrometer MIMOS II: Future applications

    Energy Technology Data Exchange (ETDEWEB)

    Klingelhoefer, Goestar; Blumers, Mathias; Schroeder, Christian; Fleischer, Iris; Lopez, Jordi G.; Sanchez, Jose F.; Hahn, Michaela; Upadhyay, Chandan [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg Universitaet, Staudinger Weg 9, 55128 Mainz (Germany); Rodionov, Daniel [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg Universitaet, Staudinger Weg 9, 55128 Mainz (Germany); Space Research Institute IKI, 117997 Moskau (Russian Federation)

    2007-07-01

    The Miniaturized Moessbauer Spectrometer MIMOS II operates on the surface of Mars for the last three years (part of NASA Mars Exploration Rovers scientific payload). Successful application of MIMOS II as a tool for detection/analysis of Fe-bearing minerals on the extraterrestrial surfaces has proven its use for other missions. Currently MIMOS II is a part of ExoMars and Phobos-Grunt missions. ExoMars is managed by the European Space Agency and planned to be launched in 2013. It involves the development of a sophisticated Mars rover with set of instruments to further characterize the biological environment on Mars in preparation for robotic missions and human exploration. Data from the mission should provide an input for broader studies of exobiology. Phobos-Grunt is developed by Russian Space Agency. Currently, launch is planned in 2009. The main goals of the mission are Phobos regolith sample return, Phobos in situ study and Mars/Phobos remote sensing.

  19. Compact UWB Antenna Design for MIMO Applications

    Directory of Open Access Journals (Sweden)

    Baskaran Kasi

    2013-12-01

    Full Text Available In this study, a compact printed Multiple-Input-Multiple-Output (MIMO antenna with a dimension of 32×70 mm2 has been proposed for Ultra-Wideband (UWB systems applications. The design constitutes of two identical UWB antenna elements, which is etched onto a Taconic TLC-30 printed circuit board. The proposed antenna has been designed and simulated using computer simulation software. For validation purposes, antenna prototype is fabricated and tested. The UWB-MIMO antenna yields an impedance bandwidth of 2.9 to 12 GHz with a return loss of less than-10 dB. Furthermore, the isolation characteristic between the two antenna elements is more than 15 dB within the operating frequency range. The designed structure is found to provide good MIMO/diversity characteristic across the UWB band.

  20. Power Efficient Low Complexity Precoding for Massive MIMO Systems

    OpenAIRE

    Sifaou, Houssem; Kammoun, Abla; Sanguinetti, Luca; Debbah, Merouane; Alouini, Mohamed-Slim

    2014-01-01

    International audience; 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 prec...

  1. Relationship Between Capacity and Pathloss for Indoor MIMO Channels

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Andersen, Jørgen Bach; Bauch, Gerhard;

    2006-01-01

    MIMO transmission systems exploit scattering in the radio channel to achieve high capacity for a given SNR. A high pathloss is generally expected for channels with rich scattering, suggesting that a high SNR and rich multipath are competing goals. The current work investigates this issue based...... capacity was found. However, the higher richness can not compensate for the decrease in capacity due to increased pathloss. Assuming a fixed Tx power, the median capacity was found to depend approximately linearly on the pathloss. The slope of the linear relation depends on the effective rank of the channel...

  2. Bayesian integer frequency offset estimator for MIMO-OFDM systems

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Carrier frequency offset (CFO) in MIMO-OFDM systems can be decoupled into two parts: fraction frequency offset (FFO) and integer frequency offset (IFO). The problem of IFO estimation is addressed and a new IFO estimator based on the Bayesian philosophy is proposed. Also, it is shown that the Bayesian IFO estimator is optimal among all the IFO estimators. Furthermore, the Bayesian estimator can take advantage of oversampling so that better performance can be obtained. Finally, numerical results show the optimality of the Bayesian estimator and validate the theoretical analysis.

  3. An Adaptive Channel Estimation Technique in MIMO OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    Pei-Sheng Pan; Bao-Yu Zheng

    2008-01-01

    In this paper, an adaptive channel estimation for MIMO OFDM is proposed. A set of pilot tones first are placed in each OFDM block, then the channel frequency response of these pilot tones are adaptively estimated by reeursive least squares (RLS) directly in frequency domain not in time domain. Then after the estimation of the channel frequency response of pilot tones, to obtain the channel frequency response of data tones, a new interpolation method based on DFT different from traditional linear interpolation method according to adjacent pilot tones is proposed. Simulation results show good performance of the technique.

  4. Spatial Correlation of PAN UWB-MIMO Channel Including User Dynamics

    DEFF Research Database (Denmark)

    Wang, Yu; Kovacs, Istvan Zsolt; Pedersen, Gert Frølund;

    In this paper we present and analyze spatial correlation properties of indoor 4x2 MIMO UWB channels in personal area network (PAN) scenarios. The presented results are based on measurement of radio links between an access point like device and a hand held or belt mounted device with dynamic user...

  5. Simultaneous 5GHz Co-channel MIMO Links at Microcellular Boundaries: Interference or Cooperation?

    DEFF Research Database (Denmark)

    Brown, Tim; Eggers, Patrick Claus F.; Olesen, Kim

    2006-01-01

    Simultaneous real time 4x4 MIMO measurements from three base stations to the same mobile are analysed. Such measurements can be applied to determine the scale of interference from neighbouring cells due to lack of orthogonality between their respective eigenvectors. This paper also considers new...

  6. 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...

  7. Dynamical history of the Local Group in ΛCDM

    Science.gov (United States)

    Banik, Indranil; Zhao, Hongsheng

    2016-06-01

    The positions and velocities of galaxies in the Local Group (LG) measure the gravitational field within it. This is mostly due to the Milky Way (MW) and Andromeda (M31). We constrain their masses using distance and radial velocity (RV) measurements of 32 LG galaxies. To do this, we follow the trajectories of many simulated particles starting on a pure Hubble flow at redshift 9. For each observed galaxy, we obtain a trajectory which today is at the same position. Its final velocity is the model prediction for the velocity of that galaxy. Unlike previous simulations based on spherical symmetry, ours are axisymmetric and include gravity from Centaurus A. We find the total LG mass is {4.33^{+0.37}_{-0.32}× {10}^{12} M_{⊙}}, with 0.14 ± 0.07 of this being in the MW. We approximately account for IC 342, M81, the Great Attractor and the Large Magellanic Cloud. No plausible set of initial conditions yields a good match to the RVs of our sample of LG galaxies. Observed RVs systematically exceed those predicted by the best-fitting Lambda Cold Dark Matter (ΛCDM) model, with a typical disagreement of {45.1^{+7.0}_{-5.7}} km s-1 and a maximum of 110 ± 13 km s-1 for DDO 99. Interactions between LG dwarf galaxies cannot easily explain this. One possibility is a past close flyby of the MW and M31. This arises in some modified gravity theories but not in ΛCDM. Gravitational slingshot encounters of material in the LG with either of these massive fast-moving galaxies could plausibly explain why some non-satellite LG galaxies are moving away from us even faster than a pure Hubble flow.

  8. 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...... 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, but...

  9. Research on Channel Loss of Tropospheric Scatter Communication Based on MIMO%基于MIMO的对流层散射通信信道损耗研究

    Institute of Scientific and Technical Information of China (English)

    唐夲; 张杰; 皮羽茜; 沈轩帆; 廖勇

    2016-01-01

    针对多输入多输出(Multiple-Input Multiple-Output,MIMO)场景下的对流层散射通信信道损耗进行了研究.在设计远距离MIMO通信系统时,链路损耗估计是其中的关键技术,而现有技术在损耗估计时都忽略了波束与散射体碰撞时的能量损耗.根据湍流非相干散射理论,首先将对流层建模为多条可微的曲线,从而与发射和接收天线阵列构成曲边梯形,根据此信道几何模型,计算入射角、反射角和散射角的角度关系;其次,建立了电磁波束射入散射体后散射波在散射体表面的能量分布模型;最后,根据波束传输距离,量化散射信道的损耗,推导得到基于MIMO对流层散射信道的衰落系数和信道矩阵.将仿真计算结果与实际数据进行对比,验证了所提模型在链路损耗估计问题上的有效性和准确性,同时根据仿真结果对接收天线的仰角设计提出了建议.

  10. Implementation of re-configurable Digital front end module of MIMO-OFDM module using NCO

    Directory of Open Access Journals (Sweden)

    Veena M.B.

    2011-09-01

    Full Text Available This paper focuses on FPGA implementation of Reconfigurable Digital Front end MIMO-OFDM module. The modeling of the MIMO-OFDM system was carried out in MATLAB followed by Verilog HDL implementation. Unlike the conventional OFDM based systems, the Numerically Controlled Oscillators (NCO is used for mapping modulated data onto the sub carriers. The use of NCO in the MIMO-OFDM system reduces the resource utilization of the design on FPGA along with reduced power consumption. The major modules that were designed, which constitute the digital front end module, are Quadrature Phase Shift Keying (QPSK modulator/demodulator, 16-Quadrature Amplitude Modulation (QAM modulator/demodulator and NCOs. Each of the modules was tested for their functionality by developing corresponding test benches. In order to achieve real time reconfigurability of the proposed architecture, the proposed approach is realized on FPGAs optimizing area, power and speed. Reconfigurability of the proposed approach is dependent upon user requirement. Hence the proposed approach can support future generation communication technologies that are based on MIMO-OFDM.

  11. A Survey on Frequency Synchronization in MIMO Systems%无线通信MIMO中的频率同步

    Institute of Scientific and Technical Information of China (English)

    邓凯

    2012-01-01

    分别针对无线通信集中式多入多出(MIMO)和分布式MIMO系统,对频偏估计和频偏补偿这两个方面的基本原理和研究现状进行了详细分析,总结出已有研究的不足之处在于对分布式MIMO中的频偏估计以及分布式MIMO-OFDM(正交频分复用)中的频偏补偿的研究尚不完善,指出未来可能的研究方向应主要集中在分布式MIMO中基于一般系统模型的频偏估计方法和分布式MIMO-OFDM中具有实用价值的低复杂度频偏补偿方法两个方面.%The fundamentals and state of the art of the estimation and compensation of carrier frequency offset(CFOs) for multi-input multi-output(MIMO) systems with co-located antennas and distributed antennas were addressed respectively.By analyzing the disadvantages of the existing research,it is indicated that the study on the CFO estimation for distributed MIMO and the CFO compensation for distributed MIMO-OFDM(orthogonal frequency division multiplexing) appear incomplete.So the further research interest may include the CFO estimation methods based on the general system model for distributed MIMO and the practical low-complexity CFO compensation methods for distributed MIMO-OFDM.

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

    International Nuclear Information System (INIS)

    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

  13. 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.

  14. Towards Very Large Aperture Massive MIMO

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...

  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. 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...

  17. 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.

  18. 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...

  19. MU-MIMO in LTE Systems

    DEFF Research Database (Denmark)

    Duplicy, Jonathan; Badic, Biljana; Balraj, Rajarajan;

    2011-01-01

    A relatively recent idea of extending the benefits of MIMO systems to multi-user scenarios seems promising in the context of achieving high data rates envisioned for future cellular standards after 3G (3rd Generation). Although substantial research has been done on the theoretical front, recent f...

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

    Directory of Open Access Journals (Sweden)

    Peter Willett

    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.

  1. Distributed Compressive CSIT Estimation and Feedback for FDD Multi-User Massive MIMO Systems

    Science.gov (United States)

    Rao, Xiongbin; Lau, Vincent K. N.

    2014-06-01

    To fully utilize the spatial multiplexing gains or array gains of massive MIMO, the channel state information must be obtained at the transmitter side (CSIT). However, conventional CSIT estimation approaches are not suitable for FDD massive MIMO systems because of the overwhelming training and feedback overhead. In this paper, we consider multi-user massive MIMO systems and deploy the compressive sensing (CS) technique to reduce the training as well as the feedback overhead in the CSIT estimation. The multi-user massive MIMO systems exhibits a hidden joint sparsity structure in the user channel matrices due to the shared local scatterers in the physical propagation environment. As such, instead of naively applying the conventional CS to the CSIT estimation, we propose a distributed compressive CSIT estimation scheme so that the compressed measurements are observed at the users locally, while the CSIT recovery is performed at the base station jointly. A joint orthogonal matching pursuit recovery algorithm is proposed to perform the CSIT recovery, with the capability of exploiting the hidden joint sparsity in the user channel matrices. We analyze the obtained CSIT quality in terms of the normalized mean absolute error, and through the closed-form expressions, we obtain simple insights into how the joint channel sparsity can be exploited to improve the CSIT recovery performance.

  2. Multiuser MIMO Downlink Made Practical: Achievable Rates with Simple Channel State Estimation and Feedback Schemes

    CERN Document Server

    Caire, Giuseppe; Kobayashi, Mari; Ravindran, Niranjay

    2007-01-01

    We consider a MIMO fading broadcast channel and compute achievable ergodic rates when channel state information is acquired at the receivers via downlink training and explicit channel feedback is performed to provide transmitter channel state information (CSIT). Both ``analog'' and quantized (digital) channel feedback are analyzed, and digital feedback is shown to be potentially superior when the feedback channel uses per channel coefficient is larger than 1. Also, we show that by proper design of the digital feedback link, errors in the feedback have a relatively minor effect even if simple uncoded modulation is used on the feedback channel. We extend our analysis to the case of fading MIMO Multiaccess Channel (MIMO-MAC) in the feedback link, as well as to the case of a time-varying channel and feedback delay. We show that by exploiting the MIMO-MAC nature of the uplink channel, a fully scalable system with both downlink multiplexing gain and feedback redundancy proportional to the number of base station ant...

  3. Impact of Feedback Channel on Measured MIMO Systems and Its Lower Bound

    Institute of Scientific and Technical Information of China (English)

    ZHANGDuo; WEIGuo; ZHUJinkang

    2005-01-01

    A lower bound of the rate in feedback channel from a receiver to a transmitter is presented for measured Multiple-input-multiple-output (MIMO) systems based on the formulae of the open-loop and the closedloop MIMO capacity, under the assumptions of quasi-static block-fading MIMO channel, independent nondispersive fading between each transmit and receive antenna, sampling with the period equal to the reciprocal of the signal bandwidth at the receiver, and zero feedback delay. Through Monte Carlo simulations~ we numerically validate the existence of the lower bound and show numerical results of the bound for system design. Also, we conclude that, the Signal-to-noise ratio (SNR) impacts little on the lower bound of the feedback rate for low antenna numbers, a closed-loop system with a feedback rate less than the lower bound is worse than a open-loop system, and the lower bound remains small with respect to the increase of antenna number for low SNRs. Finally, it is shown that the lower bound of the feedback rate and the conclusions are applicable to practical closed-loop MIMO systems.

  4. CDM/baryon isocurvature perturbations in a sneutrino curvaton model

    Energy Technology Data Exchange (ETDEWEB)

    Harigaya, Keisuke; Kawasaki, Masahiro [Kavli IPMU (WPI), TODIAS, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8583 (Japan); Hayakawa, Taku; Yokoyama, Shuichiro, E-mail: keisuke.harigaya@ipmu.jp, E-mail: taku1215@icrr.u-tokyo.ac.jp, E-mail: kawasaki@icrr.u-tokyo.ac.jp, E-mail: shuichiro@rikkyo.ac.jp [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)

    2014-10-01

    Matter isocurvature perturbations are strictly constrained from cosmic microwave background observations. We study a sneutrino curvaton model where both cold dark matter (CDM)/baryon isocurvature perturbations are generated. In our model, total matter isocurvature perturbations are reduced since the CDM/baryon isocurvature perturbations compensate for each other. We show that this model can not only avoid the stringent observational constraints but also suppress temperature anisotropies on large scales, which leads to improved agreement with observations.

  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. Distributed Relay Selection for MIMO-SDM Cooperative Networks

    Science.gov (United States)

    Tran, Xuan Nam; Nguyen, Vinh Hanh; Bui, Thanh Tam; Dinh, The Cuong; Karasawa, Yoshio

    In this paper, we consider an amplify-and-forward cooperative wireless network in which network nodes use multiple input multiple output (MIMO) spatial division multiplexing (SDM) to communicate with one another. We examine the problem of distributed cooperative relay selection and signal combining at the destination. First, we propose three distributed relay selection algorithms based on the maximum channel gains, the maximum harmonic mean of the channel gains, and the minimum mean squared error (MSE) of the signal estimation. Second, we propose a minimum mean square error (MMSE) signal combining scheme which jointly serves as the optimal signal combiner and interference canceler. It is shown that the MSE selection together with the MMSE combining achieves the maximal diversity gain. We also show that in MIMO-SDM cooperative networks increasing the number of candidate nodes does not help to improve the BER performance as opposed to the cooperative networks where each node is equipped with only single antenna. A practical approach to implementation of the combiner based on the current wireless access network protocols will also be presented.

  7. 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)

  8. MIMO Identical Eigenmode Transmission System (IETS) - a Channel Decomposition Perspective

    OpenAIRE

    Shakir, Muhammad Zeeshan; Durrani, Tariq

    2007-01-01

    In the past few years considerable attention has been given to the design of Multiple-Input Multiple-Output (MIMO) Eigenmode Transmission Systems (EMTS). This paper presents an in-depth analysis of a new MIMO eigenmode transmission strategy. The non-linear decomposition technique called Geometric Mean Decomposition (GMD) is employed for the formation of eigenmodes over MIMO flatfading channel. Exploiting GMD technique, identical, parallel and independent transmission pipes are created for dat...

  9. Efficient Coordinated Recovery of Sparse Channels in Massive MIMO

    Science.gov (United States)

    Masood, Mudassir; Afify, Laila H.; Al-Naffouri, Tareq Y.

    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 require a small number of pilots. Two algorithms based on this approach have been developed which 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.

  10. 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.

  11. 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.

  12. Bayes-Optimal Joint Channel-and-Data Estimation for Massive MIMO With Low-Precision ADCs

    Science.gov (United States)

    Wen, Chao-Kai; Wang, Chang-Jen; Jin, Shi; Wong, Kai-Kit; Ting, Pangan

    2016-05-01

    This paper considers a multiple-input multiple-output (MIMO) receiver with very low-precision analog-to-digital convertors (ADCs) with the goal of developing massive MIMO antenna systems that require minimal cost and power. Previous studies demonstrated that the training duration should be {\\em relatively long} to obtain acceptable channel state information. To address this requirement, we adopt a joint channel-and-data (JCD) estimation method based on Bayes-optimal inference. This method yields minimal mean square errors with respect to the channels and payload data. We develop a Bayes-optimal JCD estimator using a recent technique based on approximate message passing. We then present an analytical framework to study the theoretical performance of the estimator in the large-system limit. Simulation results confirm our analytical results, which allow the efficient evaluation of the performance of quantized massive MIMO systems and provide insights into effective system design.

  13. Modified Uniform Triangular Array for Online Full Azimuthal Coverage via JADE-MUSIC Algorithm over MIMO-CDMA Channel

    Directory of Open Access Journals (Sweden)

    Sami Ghnimi

    2010-07-01

    Full Text Available This paper investigates a Modified Uniform Triangular Array (MUTA to support online space-time MIMO-CDMA location based services with full azimuthal coverage via JADE-MUSIC algorithm. A new space-time lifting preprocessing (STLP scheme is introduced as a decorrelating process of coherent signals through the dense/NLOS multipath MIMO channel before applying the JADE-MUSIC estimator. Uniform- H-Array (UHA and Uniform-X-Array (UXA geometries are established for performance comparisons with the proposed MUTA. Computer simulations under environment Matlab are described to illustrate the performance of online joint angle/delay estimation with MUTA-MIMO base station applying JADE-MUSIC in conjunction with STLP scheme in 360 degrees azimuth region.

  14. 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

  15. 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

  16. MIMO-OFDM信道估计新方法%New Method for MIMO-OFDM Channel Estimation

    Institute of Scientific and Technical Information of China (English)

    李世杰; 刘毓

    2011-01-01

    A new method to estimate the channel of multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system with wavelet denoising is proposed based on wavelet transform to improve the performance of cannel estimation The channel estimation is performed by least square method, and then the estimated result is processed with wavelet denoising.The method need not know any statistical characteristic of channel in advance.The performance of the estimation is improved more obviously, compared with linear interpolation or DFT interpolation.The conclusion is proved by computer simulation.%利用小波变换思想,提出一种基于小波去噪的多输入多输出正交频分复用(MIMO-OFDM)系统信道估计方法,以提高信道估计性能.该方法首先利用最小二乘(LS)方法进行信道估计,然后对估计后的结果进行小波去噪处理.该方法不需要预先知道信道的统计特性,与传统最小二乘信道估计方法相比,性能有明显提高.

  17. Relativistic virialization in the Spherical Collapse model for Einstein-de Sitter and \\Lambda CDM cosmologies

    OpenAIRE

    Meyer, Sven; Pace, Francesco; Bartelmann, Matthias

    2012-01-01

    Spherical collapse has turned out to be a successful semi-analytic model to study structure formation in different DE models and theories of gravity. Nevertheless, the process of virialization is commonly studied on the basis of the virial theorem of classical mechanics. In the present paper, a fully generally-relativistic virial theorem based on the Tolman-Oppenheimer-Volkoff (TOV) solution for homogeneous, perfect-fluid spheres is constructed for the Einstein-de Sitter and \\Lambda CDM cosmo...

  18. 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

  19. Non-local gravity and comparison with observational datasets. II. Updated results and Bayesian model comparison with ΛCDM

    Science.gov (United States)

    Dirian, Yves; Foffa, Stefano; Kunz, Martin; Maggiore, Michele; Pettorino, Valeria

    2016-05-01

    We present a comprehensive and updated comparison with cosmological observations of two non-local modifications of gravity previously introduced by our group, the so called RR and RT models. We implement the background evolution and the cosmological perturbations of the models in a modified Boltzmann code, using CLASS. We then test the non-local models against the Planck 2015 TT, TE, EE and Cosmic Microwave Background (CMB) lensing data, isotropic and anisotropic Baryonic Acoustic Oscillations (BAO) data, JLA supernovae, H0 measurements and growth rate data, and we perform Bayesian parameter estimation. We then compare the RR, RT and ΛCDM models, using the Savage-Dickey method. We find that the RT model and ΛCDM perform equally well, while the performance of the RR model with respect to ΛCDM depends on whether or not we include a prior on H0 based on local measurements.

  20. Rateless Coding for MIMO Block Fading Channels

    CERN Document Server

    Fan, Yijia; Erkip, Elza; Poor, H Vincent

    2008-01-01

    In this paper the performance limits and design principles of rateless codes over fading channels are studied. The diversity-multiplexing tradeoff (DMT) is used to analyze the system performance for all possible transmission rates. It is revealed from the analysis that the design of such rateless codes follows the design principle of approximately universal codes for parallel multiple-input multiple-output (MIMO) channels, in which each sub-channel is a MIMO channel. More specifically, it is shown that for a single-input single-output (SISO) channel, the previously developed permutation codes of unit length for parallel channels having rate LR can be transformed directly into rateless codes of length L having multiple rate levels (R, 2R, . . ., LR), to achieve the DMT performance limit.

  1. Hybrid Transmission Scheme for MIMO Relay Channels

    Directory of Open Access Journals (Sweden)

    Guangming Xu

    2009-11-01

    Full Text Available To improve the achievable rate for the MIMO channels, we propose a hybrid transmission (HT scheme that mixes half-duplex decode-and-forward cooperative relaying transmission (DFRH)with direct transmission (DT. In the HT scheme, the source message is divided into two parts: one is transmitted by DFRH scheme and another is transmitted by DT scheme. Precoding and decoding are considered to convert the original MIMO relay channel into several parallel subchannels so that resource allocation can be easily performed. We focus on the spatial subchannel and power allocation problem. The objective of this problem is to maximize the total achievable rate under the constraints of joint total transmission power. Simulation results show that significant capacity gain can be achieved by the HT scheme compared to the DT scheme and the pure DFRH scheme.

  2. Distributed MIMO Systems with Oblivious Antennas

    CERN Document Server

    Simeone, Osvaldo; Poor, H Vincent; Shamai, Shlomo

    2008-01-01

    A scenario in which a single source communicates with a single destination via a distributed MIMO transceiver is considered. The source operates each of the transmit antennas via finite-capacity links, and likewise the destination is connected to the receiving antennas through capacity-constrained channels. Targeting a nomadic communication scenario, in which the distributed MIMO transceiver is designed to serve different standards or services, transmitters and receivers are assumed to be oblivious to the encoding functions shared by source and destination. Adopting a Gaussian symmetric interference network as the channel model (as for regularly placed transmitters and receivers), achievable rates are investigated and compared with an upper bound. It is concluded that in certain asymptotic and non-asymptotic regimes obliviousness of transmitters and receivers does not cause any loss of optimality.

  3. 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....

  4. 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...

  5. 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,...

  6. Discrete Artificial Bee Colony for Computationally Efficient Symbol Detection in Multidevice STBC MIMO Systems

    OpenAIRE

    Saeed Ashrafinia; Muhammad Naeem; Daniel Lee

    2013-01-01

    A Discrete Artificial Bee Colony (DABC) is presented for joint symbol detection at the receiver in a multidevice Space-Time Block Code (STBC) Mutli-Input Multi-Output (MIMO) communication system. Exhaustive search (maximum likelihood detection) for finding an optimal detection has a computational complexity that increases exponentially with the number of mobile devices, transmit antennas per mobile device, and the number of bits per symbol. ABC is a new population-based, swarm-based Evolution...

  7. 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.)

  8. Suitable scheme study of Chinese Building Energy Efficiency CDM Projects

    Science.gov (United States)

    Huang, Beijia; Yang, Haizhen; Wang, Shaoping; Wang, Feng

    2010-11-01

    China has great potential to develop Building Energy Efficiency Clean Development Mechanism (BEE CDM) projects, although have many challenges. Our results show that large-scale public buildings and urban residential buildings have relatively high BEE CDM potential, when comparing their characteristics to the CDM project requirements. The building enclosure, illumination energy conservation, air condition energy saving, solar thermal, and solar photovoltaic technology have relatively high application potential while considering the energy saving potential and marginal emission reduction cost. Case study of large-scale buildings shows that technology integration of building enclosure, illumination energy conservation, air condition energy saving, solar thermal can reduce required building number to 130 in order to meet the 1×105 tCO2 e/a reduction criteria. Some suggestions are also given in this paper.

  9. Constraints on deviations from ΛCDM within Horndeski gravity

    Science.gov (United States)

    Bellini, Emilio; Cuesta, Antonio J.; Jimenez, Raul; Verde, Licia

    2016-02-01

    Recent anomalies found in cosmological datasets such as the low multipoles of the Cosmic Microwave Background or the low redshift amplitude and growth of clustering measured by e.g., abundance of galaxy clusters and redshift space distortions in galaxy surveys, have motivated explorations of models beyond standard ΛCDM. Of particular interest are models where general relativity (GR) is modified on large cosmological scales. Here we consider deviations from ΛCDM+GR within the context of Horndeski gravity, which is the most general theory of gravity with second derivatives in the equations of motion. We adopt a parametrization in which the four additional Horndeski functions of time αi(t) are proportional to the cosmological density of dark energy ΩDE(t). Constraints on this extended parameter space using a suite of state-of-the art cosmological observations are presented for the first time. Although the theory is able to accommodate the low multipoles of the Cosmic Microwave Background and the low amplitude of fluctuations from redshift space distortions, we find no significant tension with ΛCDM+GR when performing a global fit to recent cosmological data and thus there is no evidence against ΛCDM+GR from an analysis of the value of the Bayesian evidence ratio of the modified gravity models with respect to ΛCDM, despite introducing extra parameters. The posterior distribution of these extra parameters that we derive return strong constraints on any possible deviations from ΛCDM+GR in the context of Horndeski gravity. We illustrate how our results can be applied to a more general frameworks of modified gravity models.

  10. LINEAR-DISPERSION DIVISION MULTIPLE-ACCESS FOR MIMO SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Deng Dan; Lv Xingzai; Zhu Jinkang

    2008-01-01

    Comprehensive study on novel Linear-Dispersion Division Multiple-Access (LDDMA) for multi-user uplink Multiple-Input Multiple-Output (MIMO) systems is proposed. In the new multi- plexing scheme, each user's information symbol is dispersed by a User-Specific Matrix (USM) both in space and time domain and linearly combined at base-station side. And a simple random search al- gorithm, based on capacity maximization criteria, is developed to generate a bank of USMs. Simulation results are presented to demonstrate the advantages of LDDMA. When the Bit Error Rate (BER) reaches 10, the performance gains are 3dB and 5dB, compared with Time-Division Linear Dispersion Codes (TD-LDC) and BLAST, respectively.

  11. Selective transmission and channel estimation in massive MIMO systems

    Institute of Scientific and Technical Information of China (English)

    杨睿哲

    2016-01-01

    Massive MIMO systems have got extraordinary spectral efficiency using a large number of base station antennas, but it is in the challenge of pilot contamination using the aligned pilots.To address this issue, a selective transmission is proposed using time-shifted pilots with cell grouping, where the strong interfering users in downlink transmission cells are temporally stopped during the pilots transmission in uplink cells.Based on the spatial characteristics of physical channel models, the strong interfering users are selected to minimize the inter-cell interference and the cell grouping is designed to have less temporally stopped users within a smaller area.Furthermore, a Kalman estima-tor is proposed to reduce the unexpected effect of residual interferences in channel estimation, which exploits both the spatial-time correlation of channels and the share of the interference information. The numerical results show that our scheme significantly improves the channel estimation accuracy and the data rates.

  12. On Feasibility of Interference Alignment in MIMO Interference Networks

    CERN Document Server

    Yetis, Cenk M; Jafar, Syed A; Kayran, Ahmet H

    2009-01-01

    We explore the feasibility of interference alignment in signal vector space -- based only on beamforming -- for K-user MIMO interference channels. Our main contribution is to relate the feasibility issue to the problem of determining the solvability of a multivariate polynomial system, considered extensively in algebraic geometry. It is well known, e.g. from Bezout's theorem, that generic polynomial systems are solvable if and only if the number of equations does not exceed the number of variables. Following this intuition, we classify signal space interference alignment problems as either proper or improper based on the number of equations and variables. Rigorous connections between feasible and proper systems are made through Bernshtein's theorem for the case where each transmitter uses only one beamforming vector. The multi-beam case introduces dependencies among the coefficients of a polynomial system so that the system is no longer generic in the sense required by both theorems. In this case, we show tha...

  13. How to Improve the Likelihood of CDM Approval?

    DEFF Research Database (Denmark)

    Brandt, Urs Steiner; Svendsen, Gert Tinggaard

    2014-01-01

    How can the likelihood of Clean Development Mechanism (CDM) approval be improved in the face of institutional shortcomings? To answer this question, we focus on the three institutional shortcomings of income sharing, risk sharing and corruption prevention concerning afforestation/reforestation (A....../R). Furthermore, three main stakeholders are identified, namely investors, governments and agents in a principal-agent model regarding monitoring and enforcement capacity. Developing countries such as West Africa have, despite huge potentials, not been integrated in A/R CDM projects yet. Remote sensing, however...

  14. 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)

  15. Adaptive rational block Arnoldi methods for model reductions in large-scale MIMO dynamical systems

    Directory of Open Access Journals (Sweden)

    Khalide Jbilou

    2016-04-01

    Full Text Available In recent years, a great interest has been shown towards Krylov subspace techniques applied to model order reduction of large-scale dynamical systems. A special interest has been devoted to single-input single-output (SISO systems by using moment matching techniques based on Arnoldi or Lanczos algorithms. In this paper, we consider multiple-input multiple-output (MIMO dynamical systems and introduce the rational block Arnoldi process to design low order dynamical systems that are close in some sense to the original MIMO dynamical system. Rational Krylov subspace methods are based on the choice of suitable shifts that are selected a priori or adaptively. In this paper, we propose an adaptive selection of those shifts and show the efficiency of this approach in our numerical tests. We also give some new block Arnoldi-like relations that are used to propose an upper bound for the norm of the error on the transfer function.

  16. A Low-Complexity Transceiver Design in Sparse Multipath Massive MIMO Channels

    Science.gov (United States)

    Yu, Yuehua; Wang, Peng; Chen, He; Li, Yonghui; Vucetic, Branka

    2016-10-01

    In this letter, we develop a low-complexity transceiver design, referred to as semi-random beam pairing (SRBP), for sparse multipath massive MIMO channels. By exploring a sparse representation of the MIMO channel in the virtual angular domain, we generate a set of transmit-receive beam pairs in a semi-random way to support the simultaneous transmission of multiple data streams. These data streams can be easily separated at the receiver via a successive interference cancelation (SIC) technique, and the power allocation among them are optimized based on the classical waterfilling principle. The achieved degree of freedom (DoF) and capacity of the proposed approach are analyzed. Simulation results show that, compared to the conventional singular value decomposition (SVD)-based method, the proposed transceiver design can achieve near-optimal DoF and capacity with a significantly lower computational complexity.

  17. Spatial MAC in MIMO Communications and its Application to Underlay Cognitive Radio

    CERN Document Server

    Noam, Yair

    2012-01-01

    We propose a learning technique for MIMO secondary users (SU) to spatially coexist with Primary Users (PU). By learning the null space of the interference channel to the PU, the SU can utilize idle degrees of freedom that otherwise would be unused by the PU. This learning process does not require any handshake or explicit information exchange between the PU and the SU. The only requirement is that the PU broadcasts a periodic beacon that is a function of its noise plus interference power, through a low rate control channel. The learning process is based on energy measurements, independent of the transmission schemes of both the PU and SU, i.e. independent of their modulation, coding etc.. The proposed learning technique also provides a novel spatial division multiple access mechanism for equal-priority MIMO users sharing a common channel that highly increases the spectrum utilization compared to time based or frequency multiple access.

  18. 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.

  19. Feedback Reduction for Random Beamforming in Multiuser MIMO Broadcast Channel

    CERN Document Server

    Li, Jin-Hao; Tsai, Yu-Lun

    2011-01-01

    For the multiuser multiple-input multiple-output (MIMO) downlink channel, the users feedback their channel state information (CSI) to help the base station (BS) schedule users and improve the system sum rate. However, this incurs a large aggregate feedback bandwidth which grows linearly with the number of users. In this paper, we propose a novel scheme to reduce the feedback load in a downlink orthogonal space division multiple access (SDMA) system with zero-forcing receivers by allowing the users to dynamically determine the number of feedback bits to use according to multiple decision thresholds. Through theoretical analysis, we show that, while keeping the aggregate feedback load of the entire system constant regardless of the number of users, the proposed scheme almost achieves the optimal asymptotic sum rate scaling with respect to the number of users (also known as the multiuser diversity). Specifically, given the number of thresholds, the proposed scheme can achieve a constant portion of the optimal su...

  20. 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...... array, 2m linear array and 25cm by 28cm squared 2D array) serving 8 users holding a handset with 2 antennas. The study of the measurements shows that the propagation characteristics of the channel are stable for all the measured frequencies. We also observe that user proximity and user handgrip...... stabilize the studied properties of the channel across the frequencies, and in such case the larger the aperture of the array the more stable the properties. The number of base station antennas improves the propagation characteristics of the channel and stabilizes the properties in the frequency domain....

  1. Robust Design of Pilot-symbol-aided MIMO Channel Estimation

    Institute of Scientific and Technical Information of China (English)

    LUO Zhen-dong; LIU Yuan-an; GAO Jin-chun

    2004-01-01

    This paper investigates pilot-symbol-aided channel estimation/prediction for Multiple-Input Multiple-Output (MIMO) systems in fast fading environments. We first derive the design criteria of the optimal pilot blocks for energy, power and bandwidth-limited systems, respectively. Then two low-complexity channel estimation schemes are provided. Finally, we present a robust Minimum Mean Square Error (MMSE) channel estimator based on channel time correlation. Simulation shows the proposed MMSE estimator is considerably insensitive to channel statistics and significantly outperforms the traditional estimators with a low additional complexity in fast fading environments. By simply adjusting some parameters, the MMSE estimator can work as an estimator and a predictor simultaneously.

  2. 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

  3. VARIABLE-RATE MULTIUSER DIVERSITY IN CORRELATED MIMO CHANNEL VIA VIRTUAL CHANNEL REPRESENTATION

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper studies the multiuser diversity with constellation selection based on a virtual representation of realistic Multiple Input Multiple Output (MIMO) correlated channels. To realize multiuser diversity in slow fading channels, random beamforming is adopted. Random beamforming matrix exploiting virtual channel representation is constructed, which can match the channel matrix of the desired user better. Simultaneously, adaptive coded modulation is applied to each sub-channel of the selected user to improve the system performance further.

  4. Asymptotic analysis of multiuser-MIMO networks with battery-constrained receivers

    OpenAIRE

    Rubio López, Javier; Pascual Iserte, Antonio; García Fernández, Juan José; García Armada, Ana; Font Bach, Oriol; Bartzoudis, Nikolaos

    2014-01-01

    In this paper, we present an asymptotic analysis of the behavior of a network where the mobile terminals are considered to be battery-powered devices provided with energy harvesting capabilities. The asymptotic analysis is based on a multiuser MIMO resource allocation strategy where the battery status of the mobile terminals are considered explicitly in the proposed allocation policy. We provide some numerical results and analytic expressions of the expected value of the data rates and the ba...

  5. Modeling of Transmission Functions and Crosstalk in Metallic Cables for Implementation of MIMO Concept

    OpenAIRE

    J. Vodrazka; P. Lafata

    2009-01-01

    The new promising wireless networks based on multi-carrier modulations (MCM) and multiple-input multiple-output concept (MIMO) will soon offer high-speed digital connections. Their access points are mostly connected by fixed metallic lines to core data and telecommunication networks. That is why it will also be necessary to increase the transmission speed and overall performance of these fixed access networks adequately in order to meet the expected requirements of wireless connections. It wo...

  6. Algorithm and Hardware Aspects of Pre-coding in Massive MIMO Systems

    OpenAIRE

    Prabhu, Hemanth; Rodrigues, Joachim; Liu, Liang; Edfors, Ove

    2015-01-01

    Massive Multiple-Input Multiple-Output (MIMO) systems have been shown to improve both spectral and energy efficiency one or more orders of magnitude by efficiently exploiting the spatial domain. Low-cost RF chains can be employed to reduce the Base Station (BS) cost, however this may require additional baseband processing to handle induced distortions due to the hardware impairments. In this article the reduction of Peak-to-Average power Ratio (PAR) of the transmitted signals and IQ imbalance...

  7. 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.

  8. A rigorous proof of MIMO channel capacity's increase with antenna number

    Institute of Scientific and Technical Information of China (English)

    GONG Jian-min; M.R. Soleymani; J.F.Hayes

    2008-01-01

    It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity, in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.

  9. Analysis and Design of Secure Massive MIMO Systems in the Presence of Hardware Impairments

    OpenAIRE

    Jun ZHU; Ng, Derrick Wing Kwan; Wang, Ning; Schober, Robert; Bhargava, Vijay K.

    2016-01-01

    To keep the hardware costs of future communications systems manageable, the use of low-cost hardware components is desirable. This is particularly true for the emerging massive multiple-input multiple-output (MIMO) systems which equip base stations (BSs) with a large number of antenna elements. However, low-cost transceiver designs will further accentuate the hardware impairments which are present in any practical communication system. In this paper, we investigate the impact of hardware impa...

  10. Massive MIMO Systems With Non-Ideal Hardware: Energy Efficiency, Estimation, and Capacity Limits

    OpenAIRE

    Bjornson, Emil; Hoydis, Jakob; Kountouris, Marios; Debbah, Merouane

    2014-01-01

    The use of large-scale antenna arrays can bring substantial improvements in energy and/or spectral efficiency to wireless systems due to the greatly improved spatial resolution and array gain. Recent works in the field of massive multiple-input multiple-output (MIMO) show that the user channels decorrelate when the number of antennas at the base stations (BSs) increases, thus strong signal gains are achievable with little inter-user interference. Since these results rely on asymptotics, it is...

  11. Scheduling techniques for improving call capacity for VoIP traffic in MIMO-OFDMA networks

    OpenAIRE

    Nicolaou, M.; Doufexi, A; Armour, SMD; Sun, Y

    2009-01-01

    Generation Networks will almost invariably adopt OFDMA (Orthogonal Frequency Division Multiple Access) and MIMO (Multiple Input-Multiple Output technologies, in order to meet high data rate and Quality of Service (QoS) requirements. The Worldwide Interoperability for Microwave Access (WiMAX) MAC Layer, which is based on the IEEE 802.16 standard, is designed to support a variety of applications, including voice and multimedia services. The problem of providing QoS in broadband wireless systems...

  12. 莱斯信道下分布式大规模MIMO系统基站选择算法的研究%Base Station Selection Algorithm for Distributed Massive MIMO System over Rician Fading Channels

    Institute of Scientific and Technical Information of China (English)

    李泳志; 陶成; 刘留; 卢艳萍; 刘凯

    2016-01-01

    该文考虑一种分布式大规模MIMO系统,假设基站端与用户之间的信道为莱斯信道,研究了该系统中基站选择的算法。首先给出了系统采用匹配滤波和迫零预编码时,用户下行可达速率的闭式表达式,并分析了系统的功率效率性能。然后基于此闭式表达式,以最大化系统的频谱效率为目标,提出了基于增量选择和基于用户优先级的基站选择算法。这两种算法只需要系统获取基站端与用户之间的信道统计特征信息,从而有效降低了系统开销。仿真结果表明,所提出的两种基站选择算法性能仍能逼近最优算法。特别地,当采用匹配滤波预编码且基站端天线数趋于无穷时,基于用户优先级的基站选择算法优于基于增量选择的算法。%The Base Station (BS) selection for distributed massive MIMO system is studied. The channels between the BSs and the users are assumed to be Rician fading. First the closed-form expressions of downlink achievable rates for Matched-Filter (MF) and Zero-Forcing (ZF) precoding are derived respectively, and the power efficiency performance of the system is investigated. Based on the closed-form expressions, the approximate incremental BS selection and the approximate user priority BS selection algorithms are proposed, both of which only require the statistical Channel State Information (CSI), to maximize the system spectral efficiency. Numerical results show that the proposed algorithms perform close to the optimal one. Specifically, it is shown that the approximate user priority BS selection algorithm outperforms the approximate incremental one when the BSs utilize the MF precoding in the large scale antenna limit.

  13. 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

  14. 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)

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

    International Nuclear Information System (INIS)

    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.

  16. How to attribute market leakage to CDM projects

    NARCIS (Netherlands)

    Vöhringer, F.; Kuosmanen, T.K.; Dellink, R.B.

    2006-01-01

    Economic studies suggest that market leakage rates of greenhouse gas abatement can reach the two-digit percentage range. Although the Marrakesh Accords require Clean Development Mechanism (CDM) projects to account for leakage, most projects neglect market leakage. Insufficient leakage accounting is

  17. 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…

  18. The Local Void: for or against $\\Lambda$CDM?

    CERN Document Server

    Xie, Lizhi; Guo, Qi

    2014-01-01

    The emptiness of the Local Void has been put forward as a serious challenge to the current standard paradigm of structure formation in $\\Lambda$CDM. We use a high resolution cosmological N-body simulation, the Millennium-II run, combined with a sophisticated semi-analytical galaxy formation model, to explore statistically whether the local void is allowed within our current knowledge of galaxy formation in $\\Lambda$CDM. We find that about $15$ percent of the Local Group analogue systems ($11$ of $77$) in our simulation are associated with nearby low density regions having size and 'emptiness' similar to those of the observed Local Void. This suggests that, rather than a crisis of the $\\Lambda$CDM, the emptiness of the Local Void is indeed a success of the standard $\\Lambda$CDM theory. The paucity of faint galaxies in such voids results from a combination of two factors: a lower amplitude of the halo mass function in the voids than in the field, and a lower galaxy formation efficiency in void haloes due to hal...

  19. 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.

  20. MIMO声呐目标检测性能分析%Analysis of MIMO sonar target detection performance

    Institute of Scientific and Technical Information of China (English)

    王福钋; 潘悦; 王永刚

    2012-01-01

    重点研究MIMO声呐的目标检测性能,为MIMO声呐布阵方式和工作模式等的选择提供理论依据.通过理论分析给出了MIMO声呐接收机工作特性(ROC)曲线的表达式,分别包括并列式和分布式MIMO声呐,同时给出了相控阵、SIMO和MISO等形式声呐的ROC表达式.通过示例比较了相同情况下并列式MIMO声呐、分布式MIMO声呐、相控阵声呐和常规多基地声呐的ROC曲线.结果表明,相同条件下相控阵声呐波束指向方向上的目标检测概率高于并列式MIMO声呐,做脉冲积累的并列式MIMO声呐可以得到与相控阵声呐相同的检测性能,低信噪比时并列式MIMO声呐和相控阵声呐的目标检测概率高于分布式MIMO声呐,高信噪比时分布式MIMO声呐可以得到较高的检测概率,采用多个发射阵元的分布式MIMO声呐性能优于使用一个发射阵元的常规多基地声呐.%Target detection performances of MIMO sonar are studied in this paper. They are one of the theoretic foundations of elements placement and work pattern. Receiver Expressions of Receiver Operating Characteristics ( ROC ) curves are given through theoretical analysis. Including collocated MIMO sonar and distributed MIMO sonar. Expressions of ROC curves such as phase array sonar, SIMO sonar and MISO sonar are also given. ROC curve comparisons of collocated MIMO sonar, distributed MIMO sonar, phase array sonar and multi-base sonar are given in the same condition. Results indicate that target detection performance of phase array sonar in the beam direction is better than collocated MIMO sonar. Collocated MIMO sonar with pulse accumulation can get the same performance as the phase array sonar. Performances of collocated MIMO sonar and phase array sonar are better than distributed MIMO sonar in low SNR condition. In high SNR condition, distributed MIMO sonar can get a better performance. Performance of distributed MIMO sonar with multiple transmitting notes is better than

  1. A RECONFIGURABLE ARCHITECTURE OF TURBO DECODER FOR MIMO-HIGH SPEED DOWNLINK PACKET ACCESS

    Directory of Open Access Journals (Sweden)

    T. Yasodha

    2014-01-01

    Full Text Available A novel channel based rescheduling scheme for modern turbo convolution code is proposed by the inclusion of suboptimal and low-complex max-log-MAP algorithm. Demands for dedicated custom solutions in mobile communications and its related applications leads to a reconfigurable architecture for Turbo convolution code. This study comprises the design and performance evolution of the proposed reconfigurable architecture for channel coding scheme in MIMO-High Speed Downlink Packet Access (MIMO-HSDPA. To attain effective performance close to shannon limit in a multi channel system, flexible reconfigurable architecture is realized with 28 nm cyclone V GX 5CGXFC5C6 FPGA. We achieved throughput of 13.5 Mbps compared with the conventional HSDPA standards while consuming 53 mW.

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

    Directory of Open Access Journals (Sweden)

    Xianpeng Wang

    2015-11-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2015-01-01

    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.

  4. In vivo measurement of human knee and hip dynamics using MIMO system identification.

    Science.gov (United States)

    Koopman, B; van Asseldonk, E F; van der Kooij, H

    2010-01-01

    This study presents a new method for the estimation of the dynamic impedance of multi-joint leg movements. The method is based on Multi Input Multi Output (MIMO) system identification techniques and is designed for continuous torque perturbations at the hip and knee joint. Preliminary results from this study indicate that MIMO system identification can successfully be used to estimate the hip and knee impedance and the interaction dynamics between both joints. It is also concluded that, in order to create a good model representation of the leg impedance, the effect of biarticular muscles needs to be taken into account. The obtained measures for joint impedance might be used for clinical assessment and follow up of patients, as well as for the development of supportive devices.

  5. Transmit Energy Focusing for DOA Estimation in MIMO Radar with Colocated Antennas

    CERN Document Server

    Hassanien, Aboulnasr

    2010-01-01

    In this paper, we propose a transmit beamspace energy focusing technique for multiple-input multiple-output (MIMO) radar with application to direction finding for multiple targets. The general angular directions of the targets are assumed to be located within a certain spatial sector. We focus the energy of multiple (two or more) transmitted orthogonal waveforms within that spatial sector using transmit beamformers which are designed to improve the signal-to-noise ratio (SNR) gain at each receive antenna. The subspace decomposition-based techniques such as MUSIC can then be used for direction finding for multiple targets. Moreover, the transmit beamformers can be designed so that matched-filtering the received data to the waveforms yields multiple (two or more) data sets with rotational invariance property that allows applying search-free direction finding techniques such as ESPRIT for two data sets or parallel factor analysis (PARAFAC) for more than two data sets. Unlike previously reported MIMO radar ESPRIT...

  6. 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....

  7. Near Optimum Power Control and Precoding under Fairness Constraints in Network MIMO Systems

    Directory of Open Access Journals (Sweden)

    Gábor Fodor

    2010-01-01

    needed to meet a sum-rate target. To evaluate the potential of our approach, we perform a semianalytical study in Mathematica using the augmented Lagrangian penalty function method. We find that the gain of the joint optimum SINR setting and power allocation may be significant depending on the degree of fairness that we impose. We develop a numerical technique, based on successive convexification, for real-time optimization of SINR targets and transmit powers. We benchmark our procedure against the globally optimal solution and demonstrate consistently strong performance in realistic network MIMO scenarios. Finally, we study the impact of near optimal precoding in a multicell MIMO environment and find that precoding helps to reduce the sum transmit power while meeting a capacity target.

  8. ERGODIC CAPACITY FORMULA OF MIMO-OFDM SYSTEMS UNDER CORRELATED FREQUENCY SELECTIVE RAYLEIGH FADING CHANNELS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An explicit formula for the ergodic capacity of Orthogonal Frequency Division Multiplexing (OFDM)-based Multiple-Input Multiple-Output (MIMO) systems under correlated frequency selective Rayleigh channels is derived, by simplifying the channel response matrix in frequency domain into the so-called Kronecker model composed of three kinds of correlations, i.e. multipath tap gain correlation and spatial fading correlations at both transmitter and receiver. The derived formula is very simple and convenient for one to estimate the effects of all three kinds of correlations on MIMO-OFDM capacity. If taps are independent, there is a very simple expression for the ergodic capacity. In case of tap correlation, the capacity formula could be further given in an integral expression. The validity of the new formula is verified and the effects of correlations, delay spread as well as the number of subcarriers on the ergodic capacity are evaluated via Monte Carlo simulations.

  9. Variable Structure Control for Unmatched MIMO Nonlinear System with Its Application to MCFC Stacks

    Institute of Scientific and Technical Information of China (English)

    Xu Chunshan(许春山); Sun Xingjin; Cao Guangyi; Zhu Xinjian

    2004-01-01

    A new Variable Structure Control (VSC) with Rapid-Smooth Reaching Law (RSRL) and Rapid-Convergent Sliding Mode (FCSM) is proposed, which is based on normal VSC system. When it is used to unmatched MIMO nonlinear system, the authors combine the method of Input/Output Linearizing (I/O L) with VSC: they use the I/O L method to solve the "Unmatched" problem and use the new VSC to get good result of control. After analyzing the robustness of the MIMO nonlinear system, they use this novel controller to the temperature and gas pressure control system of Molten Carbonate Fuel Cell (MCFC) Stacks. Simulation provides quite satisfactory performance with unmatched uncertainties and external disturbances. Its future actual application is practical.

  10. HIGH SNR SUM CAPACITY ANALYSIS OF BD MIMO BC SYSTEMS WITH IMPERFECT CSI

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Liu Zhanli; Wang Yan; You Xiaohu

    2009-01-01

    We investigate the sum capacity of Block Diagonalization precoding Multiple Input Multiple Output Broadcast Channels (BD MIMO BC) with imperfect Channel State Information (CSI) at the base station. Since it is difficult to obtain the exact expression, a lower and an upper bounds of the sum capacity under Gaussian channel estimation errors are drived instead. Analyses show that the gap between two bounds is considerably tight at all Signal to Noise Ratio (SNR) region. From the lower bound of the sum capacity, we can see that the multiplexing gain tends to be zero at high SNR region, which indicates that the BD MIMO BC system with channel estimation errors is interference-limited at high SNR.

  11. Carbon emission right as a new property right: rescue CDM developers in China from 2012

    OpenAIRE

    Pei, Q; Liu, L.; Zhang, DD

    2012-01-01

    Clean development mechanism (CDM) is encountering many uncertainties due to the coming end of the commitment period and critically suggested reformation. As the largest participant in the CDM market, China shoulders the biggest proportion of market risk. Among the studies on CDM in China, few have focused upon the legal aspect of CDM, which is crucial in defending developers’ interests. To fill this research gap in making the transition from policy to law, this paper claims that carbon emissi...

  12. SIRE: a MIMO radar for landmine/IED detection

    Science.gov (United States)

    Ojowu, Ode; Wu, Yue; Li, Jian; Nguyen, Lam

    2013-05-01

    Multiple-input multiple-output (MIMO) radar systems have been shown to have significant performance improvements over their single-input multiple-output (SIMO) counterparts. For transmit and receive elements that are collocated, the waveform diversity afforded by this radar is exploited for performance improvements. These improvements include but are not limited to improved target detection, improved parameter identifiability and better resolvability. In this paper, we present the Synchronous Impulse Reconstruction Radar (SIRE) Ultra-wideband (UWB) radar designed by the Army Research Lab (ARL) for landmine and improvised explosive device (IED) detection as a 2 by 16 MIMO radar (with collocated antennas). Its improvement over its SIMO counterpart in terms of beampattern/cross range resolution are discussed and demonstrated using simulated data herein. The limitations of this radar for Radio Frequency Interference (RFI) suppression are also discussed in this paper. A relaxation method (RELAX) combined with averaging of multiple realizations of the measured data is presented for RFI suppression; results show no noticeable target signature distortion after suppression. In this paper, the back-projection (delay and sum) data independent method is used for generating SAR images. A side-lobe minimization technique called recursive side-lobe minimization (RSM) is also discussed for reducing side-lobes in this data independent approach. We introduce a data-dependent sparsity based spectral estimation technique called Sparse Learning via Iterative Minimization (SLIM) as well as a data-dependent CLEAN approach for generating SAR images for the SIRE radar. These data-adaptive techniques show improvement in side-lobe reduction and resolution for simulated data for the SIRE radar.

  13. Detection performance analysis for MIMO radar with distributed apertures in Gaussian colored noise

    Institute of Scientific and Technical Information of China (English)

    GUAN Jian; HUANG Yong

    2009-01-01

    This paper establishes the classic linear model of signal of the MIMO radar system with distributed apertures.Based on this model,the design principle and detection performance of MIMO radar detector is investigated under conditions of Gaussian colored noise and partially correlated observation channels.First,the research on design principle of detector shows that the clutter suppression and matched filtering can be independently implemented at each receiving aperture,which greatly reduces the difficulty in implementation of these detectors.Based on these results,a Max detector is proposed for the case where partial channels are disabled due to strong noise and stealth techniques.The second part is the performance analysis of detector.The Fishier divergence coefficient and the statistical equivalent decomposition of limit statistics are used to theoretically analyze the detection performance of AMF detector,and then the analytical expressions of the detection performance of the AMF detector is derived.Analysis results show that both the colored nature of noise and the correlation among observation channels can reduce the capability of spatial diversity of the MIMO radar system,change the target RCSs among observation channels from quick fluctuation to slow fluctuation,and degenerate the detection performance of this radar system into that of the phased array radar system at high signal-to-noise ratio.

  14. Channel Acquisition for Massive MIMO-OFDM With Adjustable Phase Shift Pilots

    Science.gov (United States)

    You, Li; Gao, Xiqi; Swindlehurst, A. Lee; Zhong, Wen

    2016-03-01

    We propose adjustable phase shift pilots (APSPs) for channel acquisition in wideband massive multiple-input multiple-output (MIMO) systems employing orthogonal frequency division multiplexing (OFDM) to reduce the pilot overhead. Based on a physically motivated channel model, we first establish a relationship between channel space-frequency correlations and the channel power angle-delay spectrum in the massive antenna array regime, which reveals the channel sparsity in massive MIMO-OFDM. With this channel model, we then investigate channel acquisition, including channel estimation and channel prediction, for massive MIMO-OFDM with APSPs. We show that channel acquisition performance in terms of sum mean square error can be minimized if the user terminals' channel power distributions in the angle-delay domain can be made non-overlapping with proper phase shift scheduling. A simplified pilot phase shift scheduling algorithm is developed based on this optimal channel acquisition condition. The performance of APSPs is investigated for both one symbol and multiple symbol data models. Simulations demonstrate that the proposed APSP approach can provide substantial performance gains in terms of achievable spectral efficiency over the conventional phase shift orthogonal pilot approach in typical mobility scenarios.

  15. A Basic Unified Context for Evaluating the Beam Forming and MIMO Options in a Wireless Link

    CERN Document Server

    Chizhik, Dmitry; Valenzuela, Reinaldo A

    2011-01-01

    For one isolated wireless link we take a unified look at simple beamforming (BF) as contrasted with MIMO to see how both emerge and under which conditions advantage goes to one or the other. Communication is from a high base array to a user in clutter. The channel propagation model is derived from fundamentals. The base knows the power angular spectrum, but not the channel instantiation. Eigenstates of the field spatial autocorrelation are the preferred apodizations (APODs) which are drivers of the natural modes for exciting lectric fields. Preference for MIMO or BF depends on APOD spectra which are surveyed pointing to various asymptotic effects, including the maximum BF gain. Performance is studied under varying eigenmode power settings at 10% outage. We focus on (1,4) driving the strongest mode for BF and (4,4) driving the 4 strongest for MIMO. Results are obtained under representative parameter settings, e.g. an angular spread of 8 deg, 2 GHz carrier, 0 dB SNR and an array aperture of 1.68m (4 field decor...

  16. Game Theoretical Power Control for Open-Loop Overlaid Network MIMO Systems with Partial Cooperation

    CERN Document Server

    Yu, Hao; Lau, Vincent K N

    2010-01-01

    Network MIMO is considered to be a key solution for the next generation wireless systems in breaking the interference bottleneck in cellular systems. In the MIMO systems, open-loop transmission scheme is used to support mobile stations (MSs) with high mobilities because the base stations (BSs) do not need to track the fast varying channel fading. In this paper, we consider an open-loop network MIMO system with $K$ BSs serving K private MSs and $M^c$ common MS based on a novel partial cooperation overlaying scheme. Exploiting the heterogeneous path gains between the private MSs and the common MSs, each of the $K$ BSs serves a private MS non-cooperatively and the $K$ BSs also serve the $M^c$ common MSs cooperatively. The proposed scheme does not require closed loop instantaneous channel state information feedback, which is highly desirable for high mobility users. Furthermore, we formulate the long-term distributive power allocation problem between the private MSs and the common MSs at each of the $K$ BSs using...

  17. 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.

  18. 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.

  19. User selection strategies for multiuser MIMO systems with block diagonalization

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bei; XU Ning; WANG Ying; ZHANG Ping

    2008-01-01

    Block diagonalization (BD) is an efficient precodingtechnique that eliminates inter-user interference in downlinkmultiple-input multiple-output (MIMO) systems. User selectionstrategies applied to multiuser MIMO systems with BD areinvestigated in this article. To enhance the capacity of multiuserMIMO systems, an equivalent capacity maximum (ECM) userselection strategy is proposed with low computational complexity.Considering both the factors of channel correlations andchannel conditions, the proposed strategy can select a group ofusers to serve for maximizing the total throughput. Simulationresults indicate that, for various channel conditions, proposedECM strategy gains a better performance compared withtraditional user selection strategies, and achieves a near optimalthroughput as the exhaustive search.

  20. Quantum MIMO n-Systems and Conditions for Stability

    CERN Document Server

    Mansourbeigi, Seyed M H

    2009-01-01

    In this paper we present some conditions for the (strong) stabilizability of an n-D Quantum MIMO system P(X). It contains two parts. The first part is to introduce the n-D Quantum MIMO systems where the coefficients vary in the algebra of Q-meromorphic functions. Then we introduce some conditions for the stabilizability of these systems. The second part is to show that this Quantum system has the n-D system as its quantum limit and the results for the SISO,SIMO,MISO,MIMO are obtained again as special cases.

  1. A novel turbo-MIMO transceiver

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang; LI JianDong; PANG JiYong

    2009-01-01

    A novel BLAST transceiver named turbo-like BLAST (TLBLAST) for MIMO communications is proposed,which combines the characteristics of HBLAST and VBLAST with the structure of turbo encoder.The high data rate transmission can be implemented and in each transmitted antenna,different encode schemes can be used to supply different protection levels.The system performance is improved effectively through serially concatenating a soft input soft output (SISO) detector and decoder by iterative process with comparable complexity of VBLAST.Simulation results show that the performance of TLBLAST is better than HBLAST and VBLAST in Rayleigh flat fading channels.

  2. Frequency-domain L2-stability conditions for time-varying linear and nonlinear MIMO systems

    Institute of Scientific and Technical Information of China (English)

    Zhihong HUANG; Y. V. VENKATESH; Cheng XIANG; Tong Heng LEE

    2014-01-01

    The paper deals with the L2-stability analysis of multi-input-multi-output (MIMO) systems, governed by integral equations, with a matrix of periodic/aperiodic time-varying gains and a vector of monotone, non-monotone and quasi-monotone nonlin-earities. For nonlinear MIMO systems that are described by differential equations, most of the literature on stability is based on an application of quadratic forms as Lyapunov-function candidates. In contrast, a non-Lyapunov framework is employed here to derive new and more general L2-stability conditions in the frequency domain. These conditions have the following features:i) They are expressed in terms of the positive definiteness of the real part of matrices involving the transfer function of the linear time-invariant block and a matrix multiplier function that incorporates the minimax properties of the time-varying linear/nonlinear block. ii) For certain cases of the periodic time-varying gain, they contain, depending on the multiplier function chosen, no restrictions on the normalized rate of variation of the time-varying gain, but, for other periodic/aperiodic time-varying gains, they do. Overall, even when specialized to periodic-coefficient linear and nonlinear MIMO systems, the stability conditions are distinct from and less restrictive than recent results in the literature. No comparable results exist in the literature for aperiodic time-varying gains. Furthermore, some new stability results concerning the dwell-time problem and time-varying gain switching in linear and nonlinear MIMO systems with periodic/aperiodic matrix gains are also presented. Examples are given to illustrate a few of the stability theorems.

  3. Comparison between MC-CDMA and CDMA-OFDM/OQAM systems in presence of MIMO channel

    Directory of Open Access Journals (Sweden)

    Radhia Gharsallah

    2012-07-01

    Full Text Available In this paper, we present a comparison between MC-CDMA and CDMA-OFDM/OQAM systems in the case of MIMO channel. The advanced Multi Carrier CDMA OFDM/OQAM modulation is a combination of CDMA and OFDM/OQAM. This combination takes advantages from multicarrier modulation and spread spectrum. Indeed, the use of OFDM has proved its ability to fight against frequency selective channels but the insertion of guard interval yields spectral efficiency loss and sensitivity to frequency dispersion due to the use of rectangular pulse shape. Thus, cyclic prefix OFDM is replaced by an advanced #64257;lterbank-based multicarrier system OFDM/OQAM that operates without guard interval. However, OFDM/OQAM provides orthogonality only on the real domain, so transmitted symbols must be real valued. In the other hand, the CDMA component has two advantages: multiple access interference cancellation and providing orthogonality in the complex domain. From the orthogonality property provided, the Alamouti ST code can be combined with MC-CDMA-OQAM system in order to exploit space and time diversity. Numerical results show the utility of this new wireless communication system MIMO-CDMA-OFDM/OQAM in comparison with MIMO-MC-CDMA system

  4. An efficient user scheduling scheme for downlink Multiuser MIMO-OFDM systems with Block Diagonalization

    Directory of Open Access Journals (Sweden)

    Mounir Esslaoui

    2013-06-01

    Full Text Available The combination of multiuser multiple-input multiple-output (MU-MIMO technology with orthogonal frequency division multiplexing (OFDM is an attractive solution for next generation of wireless local area networks (WLANs, currently standardized within IEEE 802.11ac, and the fourth-generation (4G mobile cellular wireless systems to achieve a very high system throughput while satisfying quality of service (QoS constraints. In particular, Block Diagonalization (BD scheme is a low-complexity precoding technique for MU-MIMO downlink channels, which completely pre-cancels the multiuser interference. The major issue of the BD scheme is that the number of users that can be simultaneously supported is limited by the ratio of the number of base station transmit antennas to the number of user receive antennas. When the number of users is large, a subset of users must be selected, and selection algorithms should be designed to maximize the total system throughput. In this paper, the BD technique is extended to MU-MIMO-OFDM systems and a low complexity user scheduling algorithm is proposed to find the optimal subset of users that should transmit simultaneously, in light of the instantaneous channel state information (CSI, such that the total system sum-rate capacity is maximized. Simulation results show that the proposed scheduling algorithm achieves a good trade-off between sum-rate capacity performance and computational complexity.

  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. An Improved Multicell MMSE Channel Estimation in a Massive MIMO System

    Directory of Open Access Journals (Sweden)

    Ke Li

    2014-01-01

    Full Text Available Massive MIMO is a promising technology to improve both the spectrum efficiency and the energy efficiency. The key problem that impacts the throughput of a massive MIMO system is the pilot contamination due to the nonorthogonality of the pilot sequences in different cells. Conventional channel estimation schemes cannot mitigate this problem effectively, and the computational complexity is increasingly becoming larger in views of the large number of antennas employed in a massive MIMO system. Furthermore, the channel estimation is always carried out with some ideal assumptions such as the complete knowledge of large-scale fading. In this paper, a new channel estimation scheme is proposed by utilizing interference cancellation and joint processing. Highly interfering users in neighboring cells are identified based on the estimation of large-scale fading and then included in the joint channel processing; this achieves a compromise between the effectiveness and efficiency of the channel estimation at a reasonable computational cost, and leads to an improvement in the overall system performance. Simulation results are provided to demonstrate the effectiveness of the proposed scheme.

  7. Hardware Impairments Aware Transceiver for Full-Duplex Massive MIMO Relaying

    Science.gov (United States)

    Xia, Xiaochen; Zhang, Dongmei; Xu, Kui; Ma, Wenfeng; Xu, Youyun

    2015-12-01

    This paper studies the massive MIMO full-duplex relaying (MM-FDR), where multiple source-destination pairs communicate simultaneously with the help of a common full-duplex relay equipped with very large antenna arrays. Different from the traditional MM-FDR protocol, a general model where sources/destinations are allowed to equip with multiple antennas is considered. In contrast to the conventional MIMO system, massive MIMO must be built with low-cost components which are prone to hardware impairments. In this paper, the effect of hardware impairments is taken into consideration, and is modeled using transmit/receive distortion noises. We propose a low complexity hardware impairments aware transceiver scheme (named as HIA scheme) to mitigate the distortion noises by exploiting the statistical knowledge of channels and antenna arrays at sources and destinations. A joint degree of freedom and power optimization algorithm is presented to further optimize the spectral efficiency of HIA based MM-FDR. The results show that the HIA scheme can mitigate the "ceiling effect" appears in traditional MM-FDR protocol, if the numbers of antennas at sources and destinations can scale with that at the relay.

  8. DMT-optimal, Low ML-Complexity STBC-Schemes for Asymmetric MIMO Systems

    CERN Document Server

    Srinath, K Pavan

    2012-01-01

    For an $n_t$ transmit, $n_r$ receive antenna ($n_t\\times n_r$) MIMO system with quasi-static Rayleigh fading, it was shown by Elia et. al that schemes based on minimal-delay space-time block codes (STBCs) with a symbol rate of $n_t$ complex symbols per channel use (rate-$n_t$) and a {\\it non-vanishing determinant} (NVD) are diversity-multiplexing gain tradeoff (DMT)-optimal for arbitrary values of $n_r$. Further, explicit linear STBC-schemes (LSTBC-schemes) with the NVD property were also constructed. However, for asymmetric MIMO systems (where $n_r < n_t$), with the exception of the Alamouti code-scheme for the $2 \\times 1$ system and rate-1, diagonal STBC-schemes with NVD for an $n_t \\times 1$ system, no known minimal-delay, rate-$n_r$ STBC-scheme has been shown to be DMT-optimal. In this paper, we first obtain an enhanced sufficient criterion for an STBC-scheme to be DMT optimal and using this result, we show that for certain asymmetric MIMO systems, many well-known LSTBC-schemes which have low ML-decod...

  9. 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.

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

    International Nuclear Information System (INIS)

    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

  11. A Hybrid of Bacterial Foraging and Modified Cuckoo Search Optimization for Pilot Symbol Design in MIMO-OFDM Systems

    Directory of Open Access Journals (Sweden)

    R. Manjith

    2014-08-01

    Full Text Available Modern mobile telecommunication systems are using MIMO combined with OFDM, which is known as MIMO-OFDM systems, to provide robustness and higher spectrum efficiency. The major challenge in this scenario is to obtain an accurate channel estimation to detect information symbols, once the receiver must have the channel state information to equalize and process the received signal. Channel estimation is an essential task in MIMO-OFDM systems for coherent demodulation and data detection. Also designing pilot tones that affect the channel estimation performance is an important issue for these systems. For this reason, in this study we propose a Hybrid optimization algorithm (HBFOMCS based on Bacterial Foraging Optimization (BFO and Modified Cuckoo Search algorithm (MCS to optimize placement of the pilot tones that are used for Least Square (LS channel estimation in MIMO-OFDM systems. Simulation results show that designing pilot tones using the hybrid algorithm outperforms other considered placement strategies in terms of high system performance and low computational complexity.

  12. Modified PTS with FECs for PAPR Reduction in MIMO-OFDM System with Different Subblocks and Subcarriers

    Directory of Open Access Journals (Sweden)

    Mukunthan Pandurangan

    2011-07-01

    Full Text Available Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM systems have been proposed in the recent past for providing high data-rate services over wireless channels. When combined with space time coding it provides the advantages of space-time coding and OFDM, resulting in a spectrally efficient wideband communication system. However, MIMO OFDM systems suffer with the problem of inherent high peak-to-average power ratio (PAPR due to the intersymbol interference between the subcarriers. In order to obtain optimal PAPR reduction using the partial transmitted sequence (PTS, the total search for the number of subblocks and the rotation factors must be accomplished. As the number of subblocks and rotation factors increases, PAPR reduction improves. The number of calculation increases as the number of subblocks increases, such that complexity increases exponentially and the process delay occurs simultaneously. In this paper, a generalised framework for PAPR reduction for MIMO OFDM systems based on modified PTS using forward error-correcting codes (FECs such as Turbo codes and Golay codes are employed. PAPR reduction is jointly optimised in both the real and imaginary part by use of fast Fourier transform (FFT algorithm in the modified PTS which can be utilized for finding the optimum phase weighting factors, and can achieve the lower PAPR and computational complexity of MIMO OFDM systems. The simulation results show that the combined FEC with modified PTS technique significantly provides better PAPR reduction with reduced computational complexity compared to original PTS technique in the MIMOOFDM systems.

  13. 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.

  14. 基于二次虚拟孔径扩展的双基地MIMO雷达相干分布式目标中心角度估计%Central Angle Estimation of Coherently Distributed Sources for Bistatic MIMO Radar Based on Second Virtual Array Aperture Extension

    Institute of Scientific and Technical Information of China (English)

    徐旭宇; 李小波; 梁浩; 牛朝阳; 董杰

    2014-01-01

    A new central angle estimation method of the coherently distributed sources for bistatic MIMO radar is proposed based on second virtual array aperture extension. Firstly, the bistatic MIMO radar data model for the coherently distributed sources with the identical deterministic angular distribution function and distribution parameter is built based on nonuniform array. The second virtual array aperture extension is also realized by the colocated difference arrays of the minimum redundancy arrays. Furthermore, the new correlation matrix is obtained via transformal, eliminating redundant and changeable dimensional matrix. Finally, the central angles of DODs and DOAs are estimated without pairing algorithm by the idea of ESPRIT. Because of the second virtual array aperture extension, the proposed method provides much more parameter identifiability and better parameter estimation performance than the conventional bistatic MIMO radar. The effectiveness of the proposed method is verified with the computer simulation.%该文提出了基于二次虚拟孔径扩展的双基地MIMO雷达相干分布式目标中心角度估计算法。首先构造了基于非均匀阵列的具有相同确定性角信号分布函数和分布参数的相干分布式目标的双基地MIMO雷达信号模型,再利用基于最小冗余的差分共置阵列思想,实现了阵元二次虚拟扩展;然后通过构造置换、去冗余和换维矩阵,得到了新的协方差矩阵;最后利用 ESPRIT 算法思想,估计出相干分布式目标的发射、接收中心角,并且实现了角度参数的自动配对。由于该文算法实现了阵元二次虚拟扩展,因此相比于传统MIMO雷达能识别更多的目标,具有更高的估计精度。实验仿真结果证明了该文算法的有效性。

  15. Joint Unitary Triangularization for MIMO Networks

    CERN Document Server

    Khina, Anatoly; Erez, Uri

    2010-01-01

    This work considers communication networks where individual links can be described as MIMO channels. Unlike orthogonal modulation methods (such as the singular-value decomposition), we allow interference between sub-channels, which can be removed by the receivers via successive cancellation. The degrees of freedom earned by this relaxation are used for obtaining a basis which is simultaneously good for more than one link. Specifically, we derive necessary and sufficient conditions for shaping the ratio vector of sub-channel gains of two broadcast-channel receivers. We then apply this to two scenarios: First, in digital multicasting we present a practical capacity-achieving scheme which only uses scalar codes and linear processing. Then, we consider the joint source-channel problem of transmitting a Gaussian source over a two-user MIMO channel, where we show the existence of non-trivial cases, where the optimal distortion pair (which for high signal-to-noise ratios equals the point-to-point distortions of the ...

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

    Directory of Open Access Journals (Sweden)

    Juho Lee

    2009-01-01

    Full Text Available 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.

  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. 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.

  19. A Switched Diversity Scheme for Massive MIMO Systems

    Directory of Open Access Journals (Sweden)

    Qianya Wang

    2014-01-01

    Full Text Available With the constraint of antenna space, spatial correlation and mutual coupling must be considered to accurately predict the system performance for massive MIMO systems. Increasing the antenna quantity can degrade the system performance due to mutual coupling. Antenna selection systems have better performance and lower hardware cost than full-MIMO systems. However, the conventional selection combining (SC scheme consumes a great amount of training overhead and has high operational complexity in the presence of mutual coupling. This paper proposes a group switch-and-examine combining (GSEC scheme for massive MIMO systems with the spatial correlation and mutual coupling existing at both the transmitter and receiver. Simulation results demonstrate that the proposed GSEC scheme provides better effective capacity performance and lower operational complexity than the conventional selection combining (SC and full-MIMO scheme.

  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 need...... standard test methods to evaluate MIMO device performance. Due to its capability to reproduce radio multipath environments in a shielded laboratory, the multi-probe anechoic chamber method has attracted great research attention. This thesis addresses various aspects related to OTA testing of MIMO capable...... devices, where the focus is on techniques to emulate radio channels in multi-probe setups with a limited number of probes. Several channel emulation techniques are proposed to create realistic 2D and 3D spatial channel models in the thesis. A novel method to calculate probe weights for the prefaded signal...

  1. On Degrees of Freedom Region of MIMO Networks without CSIT

    CERN Document Server

    Huang, Chiachi; Shamai, Shlomo; Vishwanath, Sriram

    2009-01-01

    In this paper, we study the effect of the absence of channel knowledge for multiple-input-multiple-output (MIMO) networks. Specifically, we assume perfect channel state information at the receivers, no channel state information at the transmitter(s), and independent identically distributed (i.i.d.) Rayleigh fading across antennas, users and time slots. We provide the characterization of the degrees of freedom (DoF) region for a 2-user MIMO broadcast channel. We then provide a DoF region outer bound for a 2-user MIMO interference channel. This bound is shown to be tight for all possible combinations of the number of antennas at each node except for one case. As a byproduct of this analysis we point out the potential of interference alignment in the 2-user MIMO interference channel with no CSIT.

  2. Beyond $\\Lambda$CDM: Problems, solutions, and the road ahead

    CERN Document Server

    Bull, Philip; Adamek, Julian; Baker, Tessa; Bellini, Emilio; Jiménez, Jose Beltrán; Bentivegna, Eloisa; Camera, Stefano; Clesse, Sébastien; Davis, Jonathan H; Di Dio, Enea; Enander, Jonas; Finelli, Fabio; Heavens, Alan; Heisenberg, Lavinia; Hu, Bin; Llinares, Claudio; Maartens, Roy; Mörtsell, Edvard; Nadathur, Seshadri; Noller, Johannes; Pasechnik, Roman; Pawlowski, Marcel S; Pereira, Thiago S; Quartin, Miguel; Ricciardone, Angelo; Riemer-Sørensen, Signe; Rinaldi, Massimiliano; Sakstein, Jeremy; Saltas, Ippocratis D; Salzano, Vincenzo; Sawicki, Ignacy; Solomon, Adam R; Spolyar, Douglas; Starkman, Glenn D; Steer, Danièle; Tereno, Ismael; Verde, Licia; Villaescusa-Navarro, Francisco; von Strauss, Mikael; Winther, Hans A

    2015-01-01

    Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, $\\Lambda$CDM. This is motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm. In this paper, we summarize the current status of $\\Lambda$CDM as a physical theory, and review investigations into possible alternatives along a number of different lines, with a particular focus on highlighting the most promising directions. While the fundamental problems are proving reluctant to yield, the study of alternative cosmologies has led to considerable progress, with much more to come if hopes about forthcoming high-precision observations and new theoretical ideas are fulfilled.

  3. Which spectral distortions does $\\Lambda$CDM actually predict?

    CERN Document Server

    Chluba, Jens

    2016-01-01

    Ever refined cosmological measurements have established the $\\Lambda$CDM concordance model, with the key cosmological parameters being determined to percent-level precision today. This allows us to make explicit predictions for the spectral distortions of the cosmic microwave background (CMB) created by various processes occurring in the early Universe. Here, we summarize all guaranteed CMB distortions and assess their total uncertainty within $\\Lambda$CDM. We also compare simple methods for approximating them, highlighting some of the subtle aspects when it comes to interpreting future distortion measurements. Under simplified assumptions, we briefly study how well a PIXIE-like experiment may measure the main distortion parameters (i.e., $\\mu$ and $y$). Next generation CMB spectrometers are expected to detect the distortion caused by reionization and structure formation at extremely high significance. They will also be able to constrain the small-scale power spectrum through the associated $\\mu$-distortion, ...

  4. Beyond Λ CDM: Problems, solutions, and the road ahead

    Science.gov (United States)

    Bull, Philip; Akrami, Yashar; Adamek, Julian; Baker, Tessa; Bellini, Emilio; Beltrán Jiménez, Jose; Bentivegna, Eloisa; Camera, Stefano; Clesse, Sébastien; Davis, Jonathan H.; Di Dio, Enea; Enander, Jonas; Heavens, Alan; Heisenberg, Lavinia; Hu, Bin; Llinares, Claudio; Maartens, Roy; Mörtsell, Edvard; Nadathur, Seshadri; Noller, Johannes; Pasechnik, Roman; Pawlowski, Marcel S.; Pereira, Thiago S.; Quartin, Miguel; Ricciardone, Angelo; Riemer-Sørensen, Signe; Rinaldi, Massimiliano; Sakstein, Jeremy; Saltas, Ippocratis D.; Salzano, Vincenzo; Sawicki, Ignacy; Solomon, Adam R.; Spolyar, Douglas; Starkman, Glenn D.; Steer, Danièle; Tereno, Ismael; Verde, Licia; Villaescusa-Navarro, Francisco; von Strauss, Mikael; Winther, Hans A.

    2016-06-01

    Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, Λ CDM. This is motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm. In this paper, we summarize the current status of Λ CDM as a physical theory, and review investigations into possible alternatives along a number of different lines, with a particular focus on highlighting the most promising directions. While the fundamental problems are proving reluctant to yield, the study of alternative cosmologies has led to considerable progress, with much more to come if hopes about forthcoming high-precision observations and new theoretical ideas are fulfilled.

  5. Construction of MIMO MAC Codes Achieving the Pigeon Hole Bound

    CERN Document Server

    Ernvall, Toni

    2012-01-01

    This paper provides a general construction method for multiple-input multiple-output multiple access channel codes (MIMO MAC codes) that have so called generalized full rank property. The achieved constructions give a positive answer to the question whether it is generally possible to reach the so called pigeon hole bound, that is an upper bound for the decay of determinants of MIMO-MAC channel codes.

  6. Multipair Massive MIMO Relaying with Pilot-Data Transmission Overlay

    OpenAIRE

    Pan, Leyuan; Dai, Yongyu; Xu, Wei; Dong, Xiaodai

    2016-01-01

    We propose a pilot-data transmission overlay scheme for multipair massive multiple-input multiple-output (MIMO) relaying systems employing either half- or full-duplex (HD or FD) communications at the relay station (RS). In the proposed scheme, pilots are transmitted in partial overlap with data to decrease the channel estimation overhead. The RS can detect the source data with minimal destination pilot interference by exploiting the asymptotic orthogonality of massive MIMO channels. Then pilo...

  7. Linear Precoding Performance of Massive MU-MIMO downlink System

    OpenAIRE

    Pakdeejit, Eakkamol

    2013-01-01

    Nowadays, multiuser Multiple-In Multiple-Out systems (MU-MIMO) are used in a new generation wireless technologies. Due to that wireless technology improvement is ongoing, the numbers of users and applications increase rapidly. Then, wireless communications need the high data rate and link reliability at the same time. Therefore, MU-MIMO improvements have to consider 1) providing the high data rate and link reliability, 2) support all users in the same time and frequency resource, and 3) using...

  8. Design of Massive-MIMO-NOMA With Limited Feedback

    Science.gov (United States)

    Ding, Zhiguo; Poor, H. Vincent

    2016-05-01

    In this letter, a low-feedback non-orthogonal multiple access (NOMA) scheme using massive multiple-input multiple-output (MIMO) transmission is proposed. In particular, the proposed scheme can decompose a massive-MIMO-NOMA system into multiple separated single-input single-output NOMA channels, and analytical results are developed to evaluate the performance of the proposed scheme for two scenarios, with perfect user ordering and with one-bit feedback, respectively.

  9. Estimating the CDM market under the Bonn Agreement

    OpenAIRE

    Jotzo, Frank; Michaelowa, Axel

    2001-01-01

    We analyse the impact of the agreement on implementation of the Kyoto Protocol achieved at COP6bis in Bonn in July 2001 on investment in greenhouse gas emission reduction projects in developing countries through the Clean Development Mechanism (CDM). The required actual emission reductions for participating Annex B countries overall will be relatively small, as the United States do not intend to ratify the Protocol and significant amounts of carbon sequestered in domestic sinks will be credit...

  10. Beyond ΛCDM: Problems, solutions, and the road ahead

    OpenAIRE

    Bull, Philip

    2016-01-01

    Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, ΛCDM. This is motivated by a range of apparently serious theoretical issues, involving such questions as the cosmological constant problem, the particle nature of dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on small scales, and the predictivity and testability of the inflationary paradigm. I...

  11. 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.

  12. Linear perturbation theory for tidal streams and the small-scale CDM power spectrum

    OpenAIRE

    Bovy, Jo; Erkal, Denis; Sanders, Jason L.

    2016-01-01

    Tidal streams in the Milky Way are sensitive probes of the population of dark-matter subhalos predicted in cold-dark-matter (CDM) simulations. We present a new calculus for computing the effect of subhalo fly-bys on cold tidal streams based on the action-angle representation of streams. The heart of this calculus is a line-of-parallel-angle approach that calculates the perturbed distribution function of a given stream segment by undoing the effect of all impacts. This approach allows one to c...

  13. WarmAndFuzzy: the halo model beyond CDM

    CERN Document Server

    Marsh, David J E

    2016-01-01

    Cold dark matter (CDM) is a well established paradigm to describe cosmological structure formation, and works extraordinarily well on large, linear, scales. Progressing further in dark matter physics requires being able to understand structure formation in the non-linear regime, both for CDM and its alternatives. This short note describes a calculation, and accompanying code, WarmAndFuzzy, incorporating the popular models of warm and fuzzy dark matter (WDM and FDM) into the standard halo model to compute the non-linear matter power spectrum. The FDM halo model power spectrum has not been computed before. The FDM implementation models ultralight axions and other scalar fields with $m_a\\approx 10^{-22}\\text{ eV}$. The WDM implementation models thermal WDM with mass $m_X\\approx 1\\text{ keV}$. The halo model shows that differences between WDM, FDM, and CDM survive at low redshifts in the quasi-linear and fully non-linear regimes. The code uses analytic transfer functions for the linear power spectrum, modified co...

  14. 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.

  15. 大规模MIMO系统中基于EVD半盲信道估计的导频污染研究%Pilot contamination on EVD-based channel estimation in massive MIMO systems

    Institute of Scientific and Technical Information of China (English)

    胡丞; 宋荣方

    2016-01-01

    文中分析了天线数量有限的大规模多输入多输出(MIMO)蜂窝系统中,基于特征值分解(EVD)的信道估计的导频污染和信号扰动问题.首先,基于一个完整的多小区多用户MIMO系统(MCMU-MIMO)模型,分析了EVD方法在有限接收天线数量下,信道估计误差产生的原因:空间上天线数量有限带来的扰动、导频污染以及相关矩阵采样数的有限性.其次,推导了基于导频的信道估计方法和EVD半盲信道估计方法的信干噪比.最后,数值仿真结果表明EVD半盲信道估计值的归一化均方误差和误比特率与天线之间的关系符合文中的推导.

  16. On the Feasibility of Linear Interference Alignment for MIMO Interference Broadcast Channels with Constant Coefficients

    OpenAIRE

    Liu, Tingting; Yang, Chenyang

    2012-01-01

    In this paper, we analyze the feasibility of linear interference alignment (IA) for multi-input-multi-output (MIMO) interference broadcast channel (MIMO-IBC) with constant coefficients. We pose and prove the necessary conditions of linear IA feasibility for general MIMO-IBC. Except for the proper condition, we find another necessary condition to ensure a kind of irreducible interference to be eliminated. We then prove the necessary and sufficient conditions for a special class of MIMO-IBC, wh...

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

    International Nuclear Information System (INIS)

    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 tCO2/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

  18. 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

  19. Reciprocity Calibration for Base Station Antenna in Massive MIMO Time Division Duplex Systems%大规模MIMO时分双工系统的基站天线互易校准算法

    Institute of Scientific and Technical Information of China (English)

    顾浙骐; 张忠培

    2015-01-01

    对于采用大规模MIMO技术的时分双工系统,基站天线的互易误差会破坏上下行基带信道互易特性,大幅降低系统下行传输性能。考虑到大规模MIMO技术所带来的基站天线间的耦合效应,该文设计了基于总体最小二乘估计的基站天线互易校准算法,以实现对基站的天线互易误差的补偿。该算法以增加计算复杂度为代价,以及通过增加信道测量样本,克服了上下行信道估计误差对现有天线互易误差校准算法的影响。同时,该文通过瑞利商迭代求解降低了该算法的复杂度。若忽略用户天线互易误差,计算机仿真结果表明,该算法相对于现有的基站天线互易误差校正算法,具有1.8 dB左右的性能增益。若考虑用户天线互易误差,该算法相对于已有的算法,具有随信道估计误差方差减小而增大的增益。%The downlink transmission performance of the massive MIMO Time Division Duplex (TDD) system is bottlenecked by the channel reciprocity errors called antenna reciprocity errors. Antenna reciprocity errors are caused by the mismatch and mutual coupling between antennas. In order to compensate antenna reciprocity errors of the base station, a reciprocity calibration algorithm is proposed in this paper, which can reduce the impact of channel estimate errors by using total least square estimation and increasing channel measurement samples. Rayleigh quotient iteration is also used to reduce the complexity of the reciprocity calibration algorithm in this paper. Simulation results reveal that the algorithm proposed in this paper can achieve 1.8 dB performance gain with respect to the traditional one proposed in references when the antenna reciprocity errors of user equipments are ignored. When the antenna reciprocity errors of user equipments are considered, the performance of the proposed algorithm increases with the decreasing variance of the channel estimation errors.

  20. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xuemei [Department of Economics, California State University, 1250 Bellflower Blvd., Long Beach, CA 90840 (United States)

    2010-02-15

    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. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xuemei, E-mail: xliu2@csulb.ed [Department of Economics, California State University, 1250 Bellflower Blvd., Long Beach, CA 90840 (United States)

    2010-02-15

    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.

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

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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. (author)

  5. Resource allocation algorithm for multi-user MIMO-OFDM downlink with correlated channels

    Institute of Scientific and Technical Information of China (English)

    Chengwen ZHANG; Zhongzhao ZHANG; Weixiao MENG

    2008-01-01

    To minimize transmitting power,an adaptive resource allocation algorithm is proposed for multi-user multiple input multiple output-orthogonal frequency divi sion multiplexing(MIMO-OFDM)downlink with correlated channels,which,based on the user's grouping according to their spatial correlations,combines the shared manner and the exclusive manner to allocate sub-carriers.Between different groups the shared manner with a null steering method based on group marginal users is applied,whereas within a group the exclusive manner is applied.The simulations show that the power efficiency and spectral efficiency are improved;the base station transmitting antenna number and the computational complexity is decreased.

  6. Layered MAP algorithm for MIMO ISI channels

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The layered maximum a posteriori (L-MAP) algorithm has been proposed to detect signals under frequency selective fading multiple input multiple output (MIMO) channels. Compared to the optimum MAP detector, the L-MAP algorithm can efficiently identify signal bits, and the complexity grows linearly with the number of input antennas. The basic idea of L-MAP is to operate on each input sub-stream with an optimum MAP sequential detector separately by assuming the other streams are Gaussian noise. The soft output can also be forwarded to outer channel decoder for iterative decoding. Simulation results show that the proposed method can converge with a small number of iterations under different channel conditions and outperforms other sub-optimum detectors for rank-deficient channels.

  7. Energy Efficiency Optimization for MIMO Broadcasting Channels

    CERN Document Server

    Xu, Jie

    2012-01-01

    Optimizing the energy efficiency (EE) for the MIMO broadcasting channels (BC) is addressed in this paper, taking into account the transmit independent power which is related to the active transmit antenna number. A new optimization framework is proposed, in which transmit covariance optimization under fixed active transmit antenna sets is first performed and active transmit antenna selection (ATAS) is utilized then. To optimize the EE under a fixed transmit antenna set, we propose an energy efficient iterative waterfilling scheme according to the block-coordinate ascent algorithm, through transforming the problem into a concave fractional optimization via uplink-downlink duality. It is proved that the proposed scheme converges to the global optimality. After that, ATAS is employed to determine the active transmit antenna set and to turn off the rest inactive antennas. ATAS can balance the active transmit antenna number related EE gain with higher capacity gain and the EE loss with more transmit independent po...

  8. 大规模MIMO系统研究进展%Overview of Massive MIMO System

    Institute of Scientific and Technical Information of China (English)

    戚晨皓; 黄永明; 金石

    2015-01-01

    With the rapid development of wireless communications and the popularization of smartphones , higher data rate of the service is required .The demand can be efficiently and conveniently satisfied by in‐creasing the number of antennas at base station (BS) ,thus resulting in a massive MIMO system .The massive MIMO system can exploit the spatial degree of freedom ,and therefore BS is enabled to simulta‐neously serve several user equipments (UE) with the same temporal and frequency resource .Three key techniques are presented in the massive MIMO system ,including the pilot contamination issue and the corresponding solutions ,the theoretical and practical channel model that fits for the massive MIMO sys‐tem ,and the low complexity transmission and implement methods .Compared with the existing MIMO system ,the massive M IM O system can distinctively increase the spectral efficiency ,the energy efficien‐cy ,and the system robustness .As one of the most promising topics on the fifth generation (5G) of wire‐less communication systems ,the massive MIMO system has attracted the extensive attention worldwide . Nevertheless ,the research of massive MIMO systems is still at its early stage ,with a lot of technical problems to be solved .%随着无线通信技术的快速发展和智能手机的迅速普及,人们对数据传输速率提出了更高的需求。为进一步提高数据传输速率,通过增加基站天线数目构建大规模M IM O系统,是一种高效而相对便捷的方式。大规模M IM O系统能深度发掘空间维的自由度,使得基站能够利用同一时频资源服务于多个用户。本文探讨了大规模MIMO系统的导频污染问题及解决方案、适用于大规模MIMO系统的信道模型以及低复杂度的传输技术与实现方法三项关键技术。与现有MIMO系统相比,大规模MIMO系统能显著提高频谱效率、能量效率和系统的鲁棒性能。作为第五代移动通信(5G )最具潜力

  9. Effect of Attitude Change on Unmanned Aerial Vehicle MIMO Channel Capacity%姿态变化对无人机MIMO信道容量的影响

    Institute of Scientific and Technical Information of China (English)

    陈登伟; 高喜俊; 许鑫; 齐伟伟

    2015-01-01

    考虑无人机多天线通信需求,在无人机上以圆阵方式布置4元天线。为分析无人机多入多出( Multi⁃Input Multi⁃Output, MIMO)通信系统,建立了统一的坐标系,并构建了基于四发两收的无人机MIMO三维GBSBCM信道模型,采用信道矩阵分解、信道系数归一化的方法,推导了无人机的MIMO平均信道相关矩阵。仿真分析了无人机姿态变化参数对无人机MIMO信道容量的影响,对合理调整无人机姿态参数来提高无人机MIMO通信容量提供理论参考。%Aiming at the demand of Unmanned Aerial Vehicle for Multi⁃Input Multi⁃Output ( UAV⁃MIMO) communication,four antennas are laid as circular array in UAV.To analyze UAV⁃MIMO communication system,the uniform coordinate is built,and also the 3D⁃GBSBCM ( Geometrically Based Single Bounce Cylinder Model) channel model of UAV⁃MIMO based on four transmitters and two receivers is constructed.The method of channel matrix factorization and channel coefficient normalization are put forward to deduce the average channel correlation matrix of UAV MIMO.At last,the effect of UAV attitude change parameters on UAV MIMO channel capacity is simulated and analyzed.The simulation results provides theory reference for improving UAV⁃MIMO system capacity by changing the attitude parameters.

  10. 用于SFBC MIMO-OFDM系统的改进SLM算法%An Improved SLM Algorithm for SFBC MIMO-OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    罗仁泽; 李芮; 杨娇; 牛娜

    2014-01-01

    In the multiple-input multiple-output ( MIMO ) orthogonal frequency division multiplexing ( OFDM) system with space-frequency block coding ( SFBC) , the transmission symbols have problem with high peak-to-average power ratio( PAPR) . The selective mapping ( SLM) algorithm is proposed to reduce the PAPR effectively, but with the increase of transmitting antenna number, more inverse fast Fourier transform( IFFT) will increase the computational complexity of the system. This paper constructs an F ma-trix and proposes an improved SLM algorithm based on the F matrix for SFBC MIMO-OFDM system. The F matrix is used as phase sequences to deal with the signal after Space-Frequency Blocking Coding ( SF-BC) to obtain the optimal phase sequence and its conjugation. In the conjugation sequence, two factors form one unit, within which they exchange their location. The sequence scrambles signals from each anten-na after SFBC. Therefore, the number of IFFT for each of the transmitting antenna is reduced. Theoretical analysis and MATLAB simulation show that the method achieves good peak-to-average power ratio ( PA-PR) performance as well as reduces the computational complexity of the system.%在空频编码( SFBC)多输入多输出正交频分复用( MIMO-OFDM)系统中传输符号存在较高峰均功率比( PAPR)问题,采用SLM算法能够有效降低系统峰均功率比,但随着发射天线数的增加,较多的快速傅里叶反变换( IFFT)会增加系统的计算复杂度,因此,构造F矩阵并提出了一种基于F矩阵SFBC MIMO-OFDM系统的改进SLM算法。采用F矩阵作为相位序列组对空频编码信号进行独立处理,获得最优相位序列取共轭,将共轭序列中每两个旋转因子为一个单位交换位置,并扰码SFBC后各天线的信号,以此减少了每根发射天线上的IFFT次数。理论和MATLAB仿真分析表明,该算法获得了良好的峰均比性能,同时也降低了系统的计算复杂度。

  11. 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

  12. Optimal Channel Training in Uplink Network MIMO Systems

    CERN Document Server

    Hoydis, Jakob; Debbah, Merouane

    2011-01-01

    We consider a multi-cell frequency-selective fading uplink channel (network MIMO) from K single-antenna user terminals (UTs) to B cooperative base stations (BSs) with M antennas each. The BSs, assumed to be oblivious of the applied codebooks, forward compressed versions of their observations to a central station (CS) via capacity limited backhaul links. The CS jointly decodes the messages from all UTs. Since the BSs and the CS are assumed to have no prior channel state information (CSI), the channel needs to be estimated during its coherence time. Based on a lower bound of the ergodic mutual information, we determine the optimal fraction of the coherence time used for channel training, taking different path losses between the UTs and the BSs into account. We then study how the optimal training length is impacted by the backhaul capacity. Although our analytical results are based on a large system limit, we show by simulations that they provide very accurate approximations for even small system dimensions.

  13. A Versatile Propagation Channel Simulator for MIMO Link Level Simulation

    Directory of Open Access Journals (Sweden)

    Conrat Jean-Marc

    2007-01-01

    Full Text Available This paper presents a propagation channel simulator for polarized bidirectional wideband propagation channels. The generic channel model implemented in the simulator is a set of rays described by geometrical and propagation features such as the delay, 3D direction at the base station and mobile station and the polarization matrix. Thus, most of the wideband channel models including tapped delay line models, tap directional models, scatterer or geometrical models, ray-tracing or ray-launching results can be simulated. The simulator is composed of two major parts: firstly the channel complex impulse responses (CIR generation and secondly the channel filtering. CIRs (or CIR matrices for MIMO configurations are processed by specifying a propagation model, an antenna array configuration, a mobile direction, and a spatial sampling factor. For each sensor, independent arbitrary 3D vectorial antenna patterns can be defined. The channel filtering is based on the overlap-and-add method. The time-efficiency and parameterization of this method are discussed with realistic simulation setups. The global processing time for the CIR generation and the channel filtering is also evaluated for realistic configuration. A simulation example based on a bidirectional wideband channel model in urban environments illustrates the usefulness of the simulator.

  14. Analysis of BER Performance in Free-Space Optical MIMO-OFDM Communication Systems Over the Gamma-Gamma Atmospheric Turbulence%Gamma-Gamma大气湍流下自由空间光通信MIMO-OFDM系统误比特率分析

    Institute of Scientific and Technical Information of China (English)

    寿钦; 张涛; 王涵

    2013-01-01

    Multiple input multiple output (MIMO) technology using phase shift keying orthogonal frequency division multiplexing modulation (PSK-OFDM) in free-space optical (FSO) communication is studied and MMO-OFDM communication system based on Gamma-Gamma atmospheric turbulence channel is analyzed. A closed-form expression of bit error rate (BER) for FSO communication is derived with Meijer G function. The simulation result shows that MIMO technology which uses PSK-OFDM modulation can reduce BER effectively over different atmospheric turbulence. As the turbulence intensity becomes stronger, the effect of MIMO technology in reducing BER is gradually enhanced.%研究了在自由空间光通信(FSO)中采用相移键控-正交频分复用(PSK-OFDM)调制下的多输入多输出(MIMO)技术,分析了基于Gamma-Gamma大气湍流信道的MIMO-OFDM系统,并利用Meijer G函数得出误比特率的闭合形式的表达式.仿真结果表明,在不同湍流强度下以PSK-OFDM为调制方式的MIMO技术能有效地减少FSO的误比特率,随着湍流强度的加强,MIMO技术降低误比特率的效果逐渐增强.

  15. Legal system research on clean development mechanism(CDM)in China%中国清洁发展机制法律制度探讨

    Institute of Scientific and Technical Information of China (English)

    杨越

    2011-01-01

    According to the aim, establishing requirements and procedures, supervisory system of the Clean Development Mechanism (CDM) in Kyoto Protocol, this paper showed the tremendous environmental, social and economic profits China has made in running CDM. It also pointed out its problems in the aspects of project scale, potential project recognition, additional bank certification, CER legal right definition, project issue, etc. Referring to CDM's development tendency of the international world, this paper predicted that CDM, in a long term in future, will be an effective system against the global greenhouse gases discharge, and the tenets of CDM will be renewed and the detailed implementing institution of the CDM project will be perfected. In this paper, some suggestions on the legal institutions construction concerning China's CDM: a basic law of energy should be enacted urgently to offer legal bases for the measures including CDM against climatic changes; in legislation, the principle of the energy's sustained development should be established to specify CDM projects' proper standard, cancel the traditional unitary ownership pattern, explicit the CER legal authority and ownership and perfect the CDM projects' supervisory system to lower the danger the CDM projects have to face when pursuing economic profits, reinforce the CDM's profession norms and increase the CER issuing rate.%根据《京都议定书》关于清洁发展机制(Clean Development Mechanism,CDM)的目标、设立条件、步骤和监管制度的规定,指出了中国在实施清洁发展机制中所获得的环境、社会和经济方面的巨大利益,同时,也分析了目前中国实施清洁发展机制在项目发展规模、潜在项目识别、额外行证明、CER法律权属界定、项目签发等方面存在的问题.文章结合国际社会清洁发展制度的趋势走向,预测在今后相当长的时期内清洁发展机制仍将作为全球温室气体减排的有效制度而存在,并

  16. 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.

  17. A New Generation Method for Spatial-Temporal Correlated MIMO Nakagami Fading Channel

    Directory of Open Access Journals (Sweden)

    Qiu-Ming Zhu

    2012-01-01

    Full Text Available A new generation method for spatial and temporal correlated multiple-input multiple-output (MIMO Nakagami fading channel is proposed, which has low complexity and is applicable for arbitrary fading parameters and prespecified correlation coefficients of different subchannel. The new scheme can be divided into two steps: (1 generate independent Nakagami fading sequences for each subchannel based on a novel rejection method; (2 introduce the temporal and spatial correlation based on the relationships between Rayleigh, Gamma, and Nakagami random processes. The analysis and simulation results show that the proposed simulator has a good agreement with the theoretical model on fading envelope distribution, spatial-temporal correlation characteristic.

  18. A Selfish Linear Precoding Strategy for Downlink Two-User MIMO Systems Using Limited Rate Feedback

    Directory of Open Access Journals (Sweden)

    Lei Lv

    2013-07-01

    Full Text Available This letter proposes a limited feedback-based selfish linear precoding (SLP strategy for downlink two-user MIMO systems. In the proposed strategy, each user selfishly chooses the other user’s precoding matrix which minimizes its capacity loss. The proposed SLP strategy has two advantages comparing with traditional linear precoding strategies. First, SLP improves the system capacity by resisting interference more effectively. Second, the computing complexity of transmitter is reduced since the base station needs not to calculate precoding matrix. Simulation results verify the effectiveness of SLP on system capacity improvement comparing to limited feedback block diagonalization (LFBD algorithm, especially when feedback bits are insufficient.

  19. Research on Receiving Technology Based on Blind Signal Separation for Satellite MIMO Communication System%基于盲分离的卫星MIMO系统接收技术研究

    Institute of Scientific and Technical Information of China (English)

    辛吉荣; 万坚; 陈绍贺; 程建

    2013-01-01

    针对卫星MIMO(Multi-Input Multi-Output)通信系统,提出采用盲分离的思路对各卫星信号进行接收.考虑到盲分离性能易受噪声、混合矩阵病态性的影响,分析了噪声对接收性能影响最小时信道传输矩阵(即盲分离中的混合矩阵)应满足的条件,并给出了满足此条件的等距线阵的构建方式.通过计算机仿真分析了在此方式下,等距线阵的方位角、间距以及信号频率对盲分离接收的影响,最后得出对天线阵列建设具有一定指导意义的结论,为进一步进行实验奠定基础.%Methods of using blind signal processing was proposed to receive the communication signal in Satellite MIMO (Multi-Input Multi-Output) system. Since the receiving performance was affected by noise and illness of mixing matrix, the channel transfer matrix (also called mixing matrix in blind signal processing) that minimized the noise affection was analyzed. The relationship between the transfer matrix and the uniform linear array's parameter such as azimuth angle, distance between two adjacent antennas and the frequency was also analyzed by simulation. Final, some conclusions useful in designing an antenna array in satellite communication system were given out.

  20. Clean development Mechanism (CDM) Policy and Implementation in China

    OpenAIRE

    Zeng, Lei

    2006-01-01

    China is the second largest emitter of greenhouse gases (GHG) in the world. Since 68% of its primary energy is from coal, China’s average energy intensity is 7.5 times higher than the EU and 4.3 times higher than the US (EU, 2003). Therefore, introducing advanced clean technologies and management to China represents opportunities for Annex I countries to obtain low-cost CERs through CDM projects, and access to one of the largest energy conservation markets in the world. The Chinese government...

  1. $\\Lambda$CDM-type cosmological model and observational constraints

    CERN Document Server

    Goswami, G K; Mishra, Mandwi

    2014-01-01

    In the present work, we have searched the existence of $\\Lambda$CDM-type cosmological model in anisotropic Heckmann-Schucking space-time. The matter source that is responsible for the present acceleration of the universe consist of cosmic fluid with $p = \\omega\\rho$, where $\\omega$ is the equation of state parameter. The Einstein's field equations have been solved explicitly under some specific choice of parameters that isotropizes the model under consideration. It has been found that the derived model is in good agreement with recent SN Ia observations. Some physical aspects of the model has been discussed in detail.

  2. High redshift evolution of optically and IR-selected galaxies a comparison with CDM scenarios

    CERN Document Server

    Fontana, A; D'Odorico, S; Giallongo, E; Poli, F; Cristiani, S; Moorwood, A F M; Saracco, P

    1999-01-01

    A combination of ground-based (NTT and VLT) and HST (HDF-N and HDF-S) public imaging surveys have been used to collect a sample of 1712 I-selected and 319 $K\\leq 21$ galaxies. Photometric redshifts have been obtained for all these galaxies. The results have been compared with the prediction of an analytic rendition of the current CDM hierarchical models for galaxy formation. We focus in particular on two observed quantities: the galaxy redshift distribution at K2. This result strongly supports hierarchical scenarios where present-day massive galaxies are the result of merging processes. The observed UV luminosity density in the I-selected sample is confined within a factor of 4 over the whole range 03. CDM models in $\\Lambda$-dominated universe are in better agreement at 3

  3. Acoustic MIMO Communications in a Very Shallow Water Channel

    Institute of Scientific and Technical Information of China (English)

    Yuehai Zhou; Xiuling Cao; Feng Tong

    2015-01-01

    Underwater acoustic channels pose a great difficulty for the development of high speed communication due to highly limited band-width as well as hostile multipath interference. Enlightened by rapid progress of multiple-input multiple-output (MIMO) technologies in wireless communication scenarios, MIMO systems offer a potential solution by enabling multiple spatially parallel communication channels to improve communication performance as well as capacity. For MIMO acoustic communications, deep sea channels offer substantial spatial diversity among multiple channels that can be exploited to address simultaneous multipath and co-channel interference. At the same time, there are increasing requirements for high speed underwater communication in very shallow water area (for example, a depth less than 10 m). In this paper, a space-time multichannel adaptive receiver consisting of multiple decision feedback equalizers (DFE) is adopted as the receiver for a very shallow water MIMO acoustic communication system. The performance of multichannel DFE receivers with relatively small number of receiving elements are analyzed and compared with that of the multichannel time reversal receiver to evaluate the impact of limited spatial diversity on multi-channel equalization and time reversal processing. The results of sea trials in a very shallow water channel are presented to demonstrate the feasibility of very shallow water MIMO acoustic communication.

  4. 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.

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

    Science.gov (United States)

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

    2014-10-01

    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 standardized approaches would require a large percentage of the precious downlink and uplink resources in FDD massive MIMO be used for training signal transmissions and channel state information (CSI) feedback. To reduce the overhead of the downlink training phase, we propose practical open-loop and closed-loop training frameworks in this paper. We assume the base station and the user share a common set of training signals in advance. In open-loop training, the base station transmits training signals in a round-robin manner, and the user successively estimates the current channel using long-term channel statistics such as temporal and spatial correlations and previous channel estimates. In closed-loop training, the user feeds back the best training signal to be sent in the future based on channel prediction and the previously received training signals. With a small amount of feedback from the user to the base station, closed-loop training offers better performance in the data communication phase, especially when the signal-to-noise ratio is low, the number of transmit antennas is large, or prior channel estimates are not accurate at the beginning of the communication setup, all of which would be mostly beneficial for massive MIMO systems.

  6. Two-Stage Over-the-Air (OTA Test Method for LTE MIMO Device Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Ya Jing

    2012-01-01

    Full Text Available With MIMO technology being adopted by the wireless communication standards LTE and HSPA+, MIMO OTA research has attracted wide interest from both industry and academia. Parallel studies are underway in COST2100, CTIA, and 3GPP RAN WG4. The major test challenge for MIMO OTA is how to create a repeatable scenario which accurately reflects the MIMO antenna radiation performance in a realistic wireless propagation environment. Different MIMO OTA methods differ in the way to reproduce a specified MIMO channel model. This paper introduces a novel, flexible, and cost-effective method for measuring MIMO OTA using a two-stage approach. In the first stage, the antenna pattern is measured in an anechoic chamber using a nonintrusive approach, that is without cabled connections or modifying the device. In the second stage, the antenna pattern is convolved with the chosen channel model in a channel emulator to measure throughput using a cabled connection.

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

    International Nuclear Information System (INIS)

    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.

  8. Outage capacity and outage rate performance of MIMO free-space optical system over strong turbulence channel

    Science.gov (United States)

    Hasan, Omar M.; Taha, Mohamed; Abu Sharkh, Osama

    2016-06-01

    In this paper, we investigate outage capacity, outage probability, and outage rate performance of multiple-input multiple-output (MIMO) free-space optical system operating over strong turbulence channels. The MIMO optical system employs intensity modulation direct detection with on-off signaling, and equal gain combining technique at the receiver. We derived novel closed-form expressions for three system metrics, namely, outage capacity, outage probability, and outage rate. Expressions derived here are based on the generalized Gamma-Gamma channel model, which is based on scintillation theory that assumes that the irradiance of the received optical wave is modeled as the product of small-scale and large-scale turbulence eddies. The results are evaluated for different values of received signal-to-noise ratios, strong turbulence conditions, and several values of transmit/receive diversity.

  9. CDM Post-2012 - New CDM Baseline and Governance Approaches for Grid Emission Factor Calculations in the Central American Region

    OpenAIRE

    Canu, Federico A.

    2013-01-01

    The Kyoto commitment period has come to an end in 2012, and new discussions have started on how the new commitment period and its market mechanism will be shaped. It seems like the CDM will continue to exist in the future, either as a parallel system to the new one, or as an integrated part. The thesis addresses how the CDM’s environmental integrity and the uneven country participation to the mechanism can be enhanced. The research focuses on the UNFCCC methodology tool to calculate the emiss...

  10. 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.

  11. Which spectral distortions does ΛCDM actually predict?

    Science.gov (United States)

    Chluba, Jens

    2016-07-01

    Ever refined cosmological measurements have established the ΛCDM concordance model, with the key cosmological parameters being determined to per cent-level precision today. This allows us to make explicit predictions for the spectral distortions of the cosmic microwave background (CMB) created by various processes occurring in the early Universe. Here, we summarize all guaranteed CMB distortions and assess their total uncertainty within ΛCDM. We also compare simple methods for approximating them, highlighting some of the subtle aspects when it comes to interpreting future distortion measurements. Under simplified assumptions, we briefly study how well a PIXIE-like experiment may measure the main distortion parameters (i.e. μ and y). Next-generation CMB spectrometers are expected to detect the distortion caused by reionization and structure formation at extremely high significance. They will also be able to constrain the small-scale power spectrum through the associated μ-distortion, improving limits on running of the spectral index. Distortions from the recombination era, adiabatic cooling of matter relative to the CMB and dark matter annihilation require a higher sensitivity than PIXIE in its current design. The crucial next step is an improved modelling of foregrounds and instrumental aspects, as we briefly discuss here.

  12. Sustainable waste management in Africa through CDM projects

    International Nuclear Information System (INIS)

    Highlights: ► This is a compendium on GHG reductions via improved waste strategies in Africa. ► This note provides a strategic framework for Local Authorities in Africa. ► Assists LAs to select Zero Waste scenarios and achieve sustained GHG reduction. - Abstract: 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.

  13. Constraints on deviations from {\\Lambda}CDM within Horndeski gravity

    CERN Document Server

    Bellini, Emilio; Jimenez, Raul; Verde, Licia

    2015-01-01

    Recent anomalies found in cosmological datasets such as the low multipoles of the Cosmic Microwave Background or the low redshift amplitude and growth of clustering measured by e.g., abundance of galaxy clusters and redshift space distortions in galaxy surveys, have motivated explorations of models beyond standard {\\Lambda}CDM. Of particular interest are models where general relativity (GR) is modified on large cosmological scales. Here we consider deviations from {\\Lambda}CDM+GR within the context of Horndeski gravity, which is the most general theory of gravity with second derivatives in the equations of motion. We adopt a parametrization in which the four additional Horndeski functions of time {\\alpha}_i(t) are proportional to the cosmological density of dark energy {\\Omega}_DE(t). Constraints on this extended parameter space using a suite of state-of-the art cosmological observations are presented for the first time. Although the theory is able to accommodate the low multipoles of the Cosmic Microwave Bac...

  14. The $\\Lambda$CDM simulations of Keller and Wadsley do not account for the MOND mass-discrepancy-acceleration relation

    CERN Document Server

    Milgrom, Mordehai

    2016-01-01

    Keller and Wadsley (2016) have smugly suggested, recently, that the end of MOND may be in view. This is based on their claim that their highly-restricted sample of $\\Lambda$CDM-simulated galaxies are "consistent" with the observed MOND mass-discrepancy-acceleration relation (MDAR), in particular, with its recent update by McGaugh et al. (2016), based on the SPARC sample. From this they extrapolate to "$\\Lambda$CDM is fully consistent" with the MDAR. I explain why these simulated galaxies do not show that $\\Lambda$CDM accounts for the MDAR. a. Their sample of simulated galaxies contains only 18 high-mass galaxies, within a narrow range of one order of magnitude in baryonic mass, at the very high end of the observed, SPARC sample, which spans 4.5 orders of magnitude in mass. More importantly, the simulated sample has none of the low-mass, low-acceleration galaxies -- abundant in SPARC -- which encapsulate the crux and the nontrivial aspects of the predicted and observed MDAR. The low-acceleration part of the si...

  15. 基于有色信源MIMO-FIR信道的盲均衡准则%Blind equalization criteria for MIMO-FIR channels driven by colored signal

    Institute of Scientific and Technical Information of China (English)

    郭滨; 白雪梅

    2012-01-01

    针对有色信源具有的统计特性,分析了该类信源的二阶与四阶相关统计量在时间和空间上所呈现的规律,提出了一种在对信源要求比较弱的条件下MIMO-FIR信道的新盲均衡准则,并构建了基于该准则的盲均衡算法.通过计算机仿真验证了提出算法的有效性.%In view of the statistic characteristics of the colored source,the law presented by the second and the fourth order correlative statistics of this kind of source is analyzed. A blind equalization criterion for MIMO-FIR channel was proposed,and the blind equalization algorithm based on this criterion was also constructed. The validity of the proposed algorithm is demonstrated by computer simulations.

  16. Massive MIMO: How many antennas do we need?

    CERN Document Server

    Hoydis, Jakob; Debbah, Merouane

    2011-01-01

    We consider a multicell MIMO uplink channel where each base station (BS) is equipped with a large number of antennas N. Recent work has shown that, as N grows infinitely large, (i) the simplest form of user detection, i.e., the matched filter (MF), becomes optimal, (ii) the transmit power per user terminal (UT) can be made arbitrarily small, (iii) the system performance is limited by pilot contamination. The aim of this paper is to assess to which extent the above conclusions hold true for large, but finite N. In particular, we derive how many antennas per UT are needed to achieve \\eta % of the ultimate performance. We then study how much can be gained through more sophisticated minimum-mean-square-error (MMSE) detection and how many more antennas are needed with the MF to achieve the same performance. Our analysis relies on novel results from random matrix theory which allow us to derive tight approximations of the signal-to-interference-plus-noise-ratio (SINR) of a class of linear receivers.

  17. Nonconcave Utility Maximisation in the MIMO Broadcast Channel

    Science.gov (United States)

    Brehmer, Johannes; Utschick, Wolfgang

    2008-12-01

    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.

  18. 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.

  19. An Energy-Efficient MIMO Algorithm with Receive Power Constraint

    CERN Document Server

    Glazunov, Andrés Alayón

    2012-01-01

    We consider the energy-efficiency of Multiple-Input Multiple-Output (MIMO) systems with constrained received power rather than constrained transmit power. A Energy-Efficient Water-Filling (EEWF) algorithm that maximizes the ratio of the transmission rate to the total transmit power has been derived. The EEWF power allocation policy establishes a trade-off between the transmission rate and the total transmit power under the total receive power constraint. The static and the uncorrelated fast fading Rayleigh channels have been considered, where the maximization is performed on the instantaneous realization of the channel assuming perfect information at both the transmitter and the receiver with equal number of antennas. We show, based on Monte Carlo simulations that the energy-efficiency provided by the EEWF algorithm can be more than an order of magnitude greater than the energy-efficiency corresponding to capacity achieving Water-Filling (WF) algorithm. We also show that the energy-efficiency increases with b...

  20. 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.