WorldWideScience

Sample records for indoor wireless channel

  1. Modeling, Real-Time Estimation, and Identification of UWB Indoor Wireless Channels

    Energy Technology Data Exchange (ETDEWEB)

    Olama, Mohammed M [ORNL; Djouadi, Seddik M [ORNL; Li, Yanyan [ORNL; Fathy, Aly [University of Tennessee (UT)

    2013-01-01

    In this paper, stochastic differential equations (SDEs) are used to model ultrawideband (UWB) indoor wireless channels. We show that the impulse responses for time-varying indoor wireless channels can be approximated in a mean square sense as close as desired by impulse responses that can be realized by SDEs. The state variables represent the inphase and quadrature components of the UWB channel. The expected maximization and extended Kalman filter are employed to recursively identify and estimate the channel parameters and states, respectively, from online received signal strength measured data. Both resolvable and non-resolvable multipath received signals are considered and represented as small-scaled Nakagami fading. The proposed models together with the estimation algorithm are tested using UWB indoor measurement data demonstrating the method s viability and the results are presented.

  2. An Empirical Path-Loss Model for Wireless Channels in Indoor Short-Range Office Environment

    Directory of Open Access Journals (Sweden)

    Ye Wang

    2012-01-01

    Full Text Available A novel empirical path-loss model for wireless indoor short-range office environment at 4.3–7.3 GHz band is presented. The model is developed based on the experimental datum sampled in 30 office rooms in both line of sight (LOS and non-LOS (NLOS scenarios. The model is characterized as the path loss to distance with a Gaussian random variable X due to the shadow fading by using linear regression. The path-loss exponent n is fitted by the frequency using power function and modeled as a frequency-dependent Gaussian variable as the standard deviation σ of X. The presented works should be available for the research of wireless channel characteristics under universal indoor short-distance environments in the Internet of Things (IOT.

  3. Characterizing Ultra-wide Band indoor line-of-sight wireless channel

    Institute of Scientific and Technical Information of China (English)

    Wang Yang; Zhang Naitong; Zhang Qinyu; Zhang Zhongzhao

    2007-01-01

    By exploring the deterministic characteristics of the measurement data, a new propagation model with two deterministic clusters and stochastic arriving rays within each cluster is proposed. When considering the cumulative distribution function (CDF) of the three key channel statistics, the proposed model fits the measurement data better than SV/IEEE 802.15.3, a model which is known as a standard model for UWB indoor propagation channel. Therefore, with the additional knowledge of the specific environment geometry, the proposed model generating impulse responses "resemble" the measured channel impulse responses better than IEEE model. Moreover, the proposed model's parameters obtaining procedure is simplified by utilizing simple parameters of the environment.

  4. Pedestrian effects in indoor UWB off-body communication channels

    NARCIS (Netherlands)

    Ali, A.J.; Scanlon, W.G.; Cotton, S.L.

    2010-01-01

    Ultra-wideband (UWB) technology offers a promising solution for future indoor high-speed, low-power wireless body centric communications. Development and design of such systems requires detailed understanding of the indoor off-body UWB channel, which to date has been scarcely investigated. This pape

  5. Wideband Parameters Analysis and Validation for Indoor radio Channel at 60/70/80GHz for Gigabit Wireless Communication employing Isotropic, Horn and Omni directional Antenna

    Directory of Open Access Journals (Sweden)

    E. Affum

    2013-07-01

    Full Text Available recently, applications of millimeter (mm waves for high-speed broadband wireless local area network communication systems in indoor environment are increasingly gaining recognition as it provides gigabit-speed wireless communications with carrier-class performances over distances of a mile or more due to spectrum availability and wider bandwidth requirements. Collectively referred to as E-Band, the millimeter wave wireless technology present the potential to offer bandwidth delivery comparable to that of fiber optic, but without the financial and logistic challenges of deploying fiber. This paper investigates the wideband parameters using the ray tracing technique for indoor propagation systems with rms delay spread for Omni-directional and Horn Antennas for Bent Tunnel at 80GHz. The results obtained were 2.03and 1.95 respectively, besides, the normalized received power with 0.55×?10?^8excess delay at 70GHz for Isotropic Antenna which was at 0.97.

  6. Statistical Modelling and Characterization of Experimental mm-Wave Indoor Channels for Future 5G Wireless Communication Networks.

    Science.gov (United States)

    Al-Samman, A M; Rahman, T A; Azmi, M H; Hindia, M N; Khan, I; Hanafi, E

    This paper presents an experimental characterization of millimeter-wave (mm-wave) channels in the 6.5 GHz, 10.5 GHz, 15 GHz, 19 GHz, 28 GHz and 38 GHz frequency bands in an indoor corridor environment. More than 4,000 power delay profiles were measured across the bands using an omnidirectional transmitter antenna and a highly directional horn receiver antenna for both co- and cross-polarized antenna configurations. This paper develops a new path-loss model to account for the frequency attenuation with distance, which we term the frequency attenuation (FA) path-loss model and introduce a frequency-dependent attenuation factor. The large-scale path loss was characterized based on both new and well-known path-loss models. A general and less complex method is also proposed to estimate the cross-polarization discrimination (XPD) factor of close-in reference distance with the XPD (CIX) and ABG with the XPD (ABGX) path-loss models to avoid the computational complexity of minimum mean square error (MMSE) approach. Moreover, small-scale parameters such as root mean square (RMS) delay spread, mean excess (MN-EX) delay, dispersion factors and maximum excess (MAX-EX) delay parameters were used to characterize the multipath channel dispersion. Multiple statistical distributions for RMS delay spread were also investigated. The results show that our proposed models are simpler and more physically-based than other well-known models. The path-loss exponents for all studied models are smaller than that of the free-space model by values in the range of 0.1 to 1.4 for all measured frequencies. The RMS delay spread values varied between 0.2 ns and 13.8 ns, and the dispersion factor values were less than 1 for all measured frequencies. The exponential and Weibull probability distribution models best fit the RMS delay spread empirical distribution for all of the measured frequencies in all scenarios.

  7. Design of an Omnidirectional Multibeam Transmitter for High-Speed Indoor Wireless Communications

    OpenAIRE

    Jaw-Luen Tang; Yao-Wen Chang

    2010-01-01

    For future high speed indoor wireless communication, diffuse wireless optical communications offer more robust optical links against shadowing than line-of-sight links. However, their performance may be degraded by multipath dispersion arising from surface reflections. We have developed a multipath diffusive propagation model capable of providing channel impulse responses data. It is aimed to design and simulate any multibeam transmitter under a variety of indoor environments. In this paper,...

  8. Channel characterization for high-speed W-band wireless communication links

    DEFF Research Database (Denmark)

    Rommel, Simon; Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José

    2015-01-01

    We present and discuss results from an experimental characterization of the W-band indoor wireless channel, including both large and small scale fading phenomena as well as corresponding channel parameters and their impact on system performance....

  9. The Myth of Spatial Reuse with Directional Antennas in Indoor Wireless Networks

    Science.gov (United States)

    Lakshmanan, Sriram; Sundaresan, Karthikeyan; Rangarajan, Sampath; Sivakumar, Raghupathy

    Interference among co-channel users is a fundamental problem in wireless networks, which prevents nearby links from operating concurrently. Directional antennas allow the radiation patterns of wireless transmitters to be shaped to form directed beams. Conventionally, such beams are assumed to improve the spatial reuse (i.e. concurrency) in indoor wireless networks. In this paper, we use experiments in an indoor office setting of Wifi Access points equipped with directional antennas, to study their potential for interference mitigation and spatial reuse. In contrast to conventional wisdom, we observe that the interference mitigation benefits of directional antennas are minimal. On analyzing our experimental traces we observe that directional links do not reduce interference to nearby links due to the lack of signal confinement due to indoor multipath fading. We then use the insights derived from our study to develop an alternative approach that provides better interference reduction in indoor networks compared to directional links.

  10. Indoor Wireless RF Energy Transfer for Powering Wireless Sensors

    Directory of Open Access Journals (Sweden)

    H. Visser

    2012-12-01

    Full Text Available For powering wireless sensors in buildings, rechargeable batteries may be used. These batteries will be recharged remotely by dedicated RF sources. Far-field RF energy transport is known to suffer from path loss and therefore the RF power available on the rectifying antenna or rectenna will be very low. As a consequence, the RF-to-DC conversion efficiency of the rectenna will also be very low. By optimizing not only the subsystems of a rectenna but also taking the propagation channel into account and using the channel information for adapting the transmit antenna radiation pattern, the RF energy transport efficiency will be improved. The rectenna optimization, channel modeling and design of a transmit antenna are discussed.

  11. Wireless Communication over Dispersive Channels

    NARCIS (Netherlands)

    Fang, K.

    2010-01-01

    Broadband wireless communication systems require high transmission rates, where the bandwidth of the transmitted signal is larger than the channel coherence bandwidth. This gives rise to time dispersion of the transmitted symbols or frequency-selectivity with different frequency components exhibitin

  12. Training sequence based channel estimation for indoor visible light communication system

    Institute of Scientific and Technical Information of China (English)

    WANG Jun-bo; JIAO Yuan; DANG Xiao-yu; CHEN Ming; XIE Xiu-xiu; CAO Ling-ling

    2011-01-01

    Channel estimation is a key technology in indoor wireless visible light communications (VLCs). Using the training se- quence (TS), this paper investigates the channel estimation in indoor wireless visible light communications. Based on the propagation and signal modulation characteristics of visible light, a link model for the indoor wireless visible light commu- nications is established. Using the model, three channel estimation methods, i.e., the correlation method, the least square (LS) method and the minimum mean square error (MMSE) method, are proposed. Moreover, the performances of the proposed three methods are evaluated by computer simulation. The results show that the performance of the correlation method is the worst, the LS method is suitable for higher signal to noise ratio (SNR), and the MMSE method obtains the best performance at the expense of highest complexity.

  13. Recent Advances in Wireless Indoor Localization Techniques and System

    Directory of Open Access Journals (Sweden)

    Zahid Farid

    2013-01-01

    Full Text Available The advances in localization based technologies and the increasing importance of ubiquitous computing and context-dependent information have led to a growing business interest in location-based applications and services. Today, most application requirements are locating or real-time tracking of physical belongings inside buildings accurately; thus, the demand for indoor localization services has become a key prerequisite in some markets. Moreover, indoor localization technologies address the inadequacy of global positioning system inside a closed environment, like buildings. Based on this, though, this paper aims to provide the reader with a review of the recent advances in wireless indoor localization techniques and system to deliver a better understanding of state-of-the-art technologies and motivate new research efforts in this promising field. For this purpose, existing wireless localization position system and location estimation schemes are reviewed, as we also compare the related techniques and systems along with a conclusion and future trends.

  14. Low VHF Channel Measurements and Simulations in Indoor and Outdoor Scenarios

    Science.gov (United States)

    2015-05-01

    bands, ray tracing approaches are often used to simulate wave propagation. Ray tracing is relatively straightforward and computationally tractable...4164. 20. Kaya A, Greenstein L, Trappe W. Characterizing indoor wireless channels via ray tracing combined with stochastic modeling. Wireless...GNU Radio project50 and a custom MATLAB -USRP-Library (MUL)51 to control the USRPs and conduct our experiments. GNU Radio enables the implementation of

  15. Accurate simulation of 802.11 indoor links: a “bursty” channel model based on real measurements

    OpenAIRE

    Luis Muñoz; Ramón Agüero; Marta García-Arranz

    2010-01-01

    We propose a novel channel model to be used for simulating indoor wireless propagation environments. An extensive measurement campaign was carried out to assess the performance of different transport protocols over 802.11 links. This enabled us to better adjust our approach, which is based on an autoregressive filter. One of the main advantages of this proposal lies in its ability to reflect the “bursty” behavior which characterizes indoor wireless scenarios, having a great impact...

  16. REVIEW OF WIRELESS MIMO CHANNEL MODELS

    African Journals Online (AJOL)

    user

    communication channel represents a major component that ... antenna systems at both ends of a communication link otherwise .... These models apply the fundamental laws of wave ... model for the macro-cellular wireless network [1, 2,. 9].

  17. Design of an Omnidirectional Multibeam Transmitter for High-Speed Indoor Wireless Communications

    Directory of Open Access Journals (Sweden)

    Jaw-Luen Tang

    2010-01-01

    Full Text Available For future high speed indoor wireless communication, diffuse wireless optical communications offer more robust optical links against shadowing than line-of-sight links. However, their performance may be degraded by multipath dispersion arising from surface reflections. We have developed a multipath diffusive propagation model capable of providing channel impulse responses data. It is aimed to design and simulate any multibeam transmitter under a variety of indoor environments. In this paper, a multi-beam transmitter system associated with hemisphere structure is proposed to fight against the diverse effects of multipath distortion albeit, at the cost of increased laser power and cost. Simulation results of multiple impulse responses showed that this type of multi-beam transmitter can significantly improve the performance of BER suitable for high bit rate application. We present the performance and simulation results for both line-of-sight and diffuse link configurations. We propose a design of power radiation pattern for a transmitter in achieving uniform and full coverage of power distributions for diffuse indoor optical wireless systems.

  18. Tracking Mobile Robot in Indoor Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Liping Zhang

    2014-01-01

    Full Text Available This work addresses the problem of tracking mobile robots in indoor wireless sensor networks (WSNs. Our approach is based on a localization scheme with RSSI (received signal strength indication which is used widely in WSN. The developed tracking system is designed for continuous estimation of the robot’s trajectory. A WSN, which is composed of many very simple and cheap wireless sensor nodes, is deployed at a specific region of interest. The wireless sensor nodes collect RSSI information sent by mobile robots. A range-based data fusion scheme is used to estimate the robot’s trajectory. Moreover, a Kalman filter is designed to improve tracking accuracy. Experiments are provided to assess the performance of the proposed scheme.

  19. Low RF Complexity Photonically Enabled Indoor and Building-to-Building W-Band Wireless Link

    DEFF Research Database (Denmark)

    Rommel, Simon; Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José;

    2015-01-01

    We demonstrate W-band wireless transmission over distances covering both indoor and building-to-building scenarios with a setup of reduced complexity in the RF domain, employing a passive wireless transmitter and envelope detection at the receiver......We demonstrate W-band wireless transmission over distances covering both indoor and building-to-building scenarios with a setup of reduced complexity in the RF domain, employing a passive wireless transmitter and envelope detection at the receiver...

  20. UWB channel modeling for indoor line-of-sight environment

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    SV/IEEE 802.15.3a model has been the standard model for Ultra-wide bandwidth (UWB) indoor non-line-of-sight (NLOS) wireless propagation, but for line-of-sight (LOS) case, it is not well defined. In this paper, a new statistical distribution model exclusively used for LOS environment is proposed based on investigation of the experimental data. By reducing the number of the visible random arriving clusters, the model itself and the parameters estimating of the corresponding model are simplified in comparison with SV/IEEE 802.15.3a model. The simulation result indicates that the proposed model is more accurate in modeling smallscale LOS environment than SV/IEEE 802.15.3a model when considering cumulative distribution functions(CDFs) for the three key channel impulse response (CIR) statistics.

  1. SIMO channel performance evaluation on indoor environment at 2.4 GHz

    Science.gov (United States)

    Votis, Constantinos I.; Christofilakis, Vasilis; Kostarakis, Panos

    2016-04-01

    This work presents an experimental study of single-input multiple-output (SIMO) channel performance in the indoor radio propagation environment. Indoor channel measurements at the 2.4-GHz ISM frequency band have been conducted using a versatile channel sounder test-bed platform. A single transmitting antenna, four receiving antennas with two proposed geometries and a four-branch receiver circuitry were used in order to achieve channel sounder measurements exploiting baseband signal-processing techniques. In-depth investigation of SIMO wireless channel performance was realised through three types of metrics: signal strength, gain coefficient and capacity. Performance results indicate SIMO channel capacity enhancement and illustrate differences between the two proposed geometries.

  2. Indoor Wireless Localization-hybrid and Unconstrained Nonlinear Optimization Approach

    Directory of Open Access Journals (Sweden)

    R. Jayabharathy

    2013-07-01

    Full Text Available In this study, a hybrid TOA/RSSI wireless localization is proposed for accurate positioning in indoor UWB systems. The major problem in indoor localization is the effect of Non-Line of Sight (NLOS propagation. To mitigate the NLOS effects, an unconstrained nonlinear optimization approach is utilized to process Time-of-Arrival (TOA and Received Signal Strength (RSS in the location system.TOA range measurements and path loss model are used to discriminate LOS and NLOS conditions. The weighting factors assigned by hypothesis testing, is used for solving the objective function in the proposed approach. This approach is used for describing the credibility of the TOA range measurement. Performance of the proposed technique is done based on MATLAB simulation. The result shows that the proposed technique performs well and achieves improved positioning under severe NLOS conditions.

  3. Wireless Sensor Networks Framework for Indoor Temperature Regulation

    DEFF Research Database (Denmark)

    Stojkoska, Biljana; Popovska Avramova, Andrijana

    2013-01-01

    transmissions through prediction methods. Additionally the framework explores techniques for localization, such that the location of the nodes is used for optimization of the temperature settings. Information on node location is used to provide the most optimal tradeo between the time it takes to reach......Wireless Sensor Networks take a major part in our everyday lives by enhancing systems for home automation, health-care, temperature control, energy consumption monitoring etc. In this paper we focus on a system used for temperature regulation for homes, educational, industrial, commercial premises...... etc. We propose a framework for indoor regulation and optimization of temperature using wireless sensor networks based on ZigBee. Methods for optimal temperature regulation are suggested and discussed. The framework is based on methods that provide energy savings by reducing the amount of data...

  4. Application of Wireless Sensor Networks for Indoor Temperature Regulation

    DEFF Research Database (Denmark)

    Stojkoska, Biljana Risteska; Popovska Avramova, Andrijana; Chatzimisios, Periklis

    2014-01-01

    Wireless sensor networks take a major part in our everyday lives by enhancing systems for home automation, healthcare, temperature control, energy consumption monitoring, and so forth. In this paper we focus on a system used for temperature regulation for residential, educational, industrial......, and commercial premises, and so forth. We propose a framework for indoor temperature regulation and optimization using wireless sensor networks based on ZigBee platform. This paper considers architectural design of the system, as well as implementation guidelines. The proposed system favors methods that provide...... energy savings by reducing the amount of data transmissions through the network. Furthermore, the framework explores techniques for localization, such that the location of the nodes can be used by algorithms that regulate temperature settings....

  5. RECEIVED SIGNAL STRENGTH INDICATION MODELING IN INDOOR WIRELESS SENSOR NETWORKS

    Directory of Open Access Journals (Sweden)

    Edson Taira Procopio

    2013-01-01

    Full Text Available This study aims to identify mathematical models that represent the relation between Received Signal Strength Indication (RSSI and objects in an indoor Wireless Sensor Network (WSN. Using the Least Squares Method, four linear models have been identified: The first one relates uplink RSSI and objects; the second one relates downlink RSSI and objects; the third one relates uplink RSSI and obstacles and the fourth one relates downlink RSSI and obstacles. The obtained results, characterized by small residual values, attest the validation of all four models.

  6. Accurate Simulation of 802.11 Indoor Links: A "Bursty" Channel Model Based on Real Measurements

    Directory of Open Access Journals (Sweden)

    Agüero Ramón

    2010-01-01

    Full Text Available We propose a novel channel model to be used for simulating indoor wireless propagation environments. An extensive measurement campaign was carried out to assess the performance of different transport protocols over 802.11 links. This enabled us to better adjust our approach, which is based on an autoregressive filter. One of the main advantages of this proposal lies in its ability to reflect the "bursty" behavior which characterizes indoor wireless scenarios, having a great impact on the behavior of upper layer protocols. We compare this channel model, integrated within the Network Simulator (ns-2 platform, with other traditional approaches, showing that it is able to better reflect the real behavior which was empirically assessed.

  7. Holographic optical receiver front end for wireless infrared indoor communications.

    Science.gov (United States)

    Jivkova, S; Kavehrad, M

    2001-06-10

    Multispot diffuse configuration (MSDC) for indoor wireless optical communications, utilizing multibeam transmitter and angle diversity detection, is one of the most promising ways of achieving high capacities for use in high-bandwidth islands such as classrooms, hotel lobbies, shopping malls, and train stations. Typically, the optical front end of the receiver consists of an optical concentrator to increase the received optical signal power and an optical bandpass filter to reject the ambient light. Using the unique properties of holographic optical elements (HOE), we propose a novel design for the receiver optical subsystem used in MSDC. With a holographic curved mirror as an optical front end, the receiver would achieve more than an 10-dB improvement in the electrical signal-to-noise ratio compared with a bare photodetector. Features such as multifunctionality of the HOE and the receiver's small size, light weight, and low cost make the receiver front end a promising candidate for a user's portable equipment in broadband indoor wireless multimedia access.

  8. Design and optimization of indoor optical wireless positioning systems

    Science.gov (United States)

    Bergen, Mark H.; Guerrero, Daniel; Jin, Xian; Hristovski, Blago A.; Chaves, Hugo A. L. F.; Klukas, Richard; Holzman, Jonathan F.

    2016-03-01

    Optical wireless (OW) technologies are an emerging field utilizing optical sources to replace existing radio wavelength technologies. The vast majority of work in OW focuses on communication; however, one smaller emerging field is indoor OW positioning. This emerging field essentially aims to replace GPS indoors. One of the primary competing methods in indoor OW positioning is angle-of-arrival (AOA). AOA positioning uses the received vectors from several optical beacons to triangulate its position. The reliability of this triangulation is fundamentally based on two aspects: the geometry of the optical receiver's location compared to the optical beacon locations, and the ability for the optical receiver to resolve the incident vectors correctly. The optical receiver is quantified based on the standard deviation of the azimuthal and polar angles that define the measured vector. The quality of the optical beacon geometry is quantified using dilution of precision (DOP). This proceeding discusses the AOA standard deviation of an ultra-wide field-of-view (FOV) lens along with the DOP characteristics for several optical beacon geometries. The optical beacon geometries used were simple triangle, square, and hexagon optical beacon geometries. To assist the implementation of large optical beacon geometries it is proposed to use both frequency and wavelength division multiplexing. It is found that with an ultra-wide FOV lens, coupled with the appropriately sized optical beacon geometry, allow for high accuracy positioning over a large area. The results of this work will enable reliable OW positioning deployments.

  9. COOPERATIVE ARQ PROTOCOL FOR CORRELATED WIRELESS CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Yu Guanding; Zhang Zhaoyang; Qiu Peiliang

    2006-01-01

    A novel Automatic repeat ReQuest (ARQ) protocol called cooperative ARQ is presented in this letter, where a relay terminal is requested to retransmit an erroneously received packet, instead of the source terminal. The data link layer Packet Error Rate (PER) performance of cooperative ARQ is derived in correlated wireless channel. The results show that even though the relay-destination channel is worse than the sourcedestination channel, the new protocol outperforms the traditional one as long as the average SNR of the relaydestination channel is better than a certain threshold. It is also demonstrated that a second order diversity gain can be achieved with the cooperative ARQ protocol.

  10. Acemind new indoor full duplex optical wireless communication prototype

    Science.gov (United States)

    Bouchet, Olivier; Perrufel, Micheline; Topsu, Suat; Guan, Hongyu

    2016-09-01

    For over a century and Mr. Guglielmo Marconi invention, systems using radio waves have controlled over wireless telecommunication solutions; from Amplitude Modulation (AM) radio products to satellite communications for instance. But beyond an increasingly negative opinion face to radio waves and radio spectrum availability more and more reduced; there is an unprecedented opportunity with LED installation in displays and lighting to provide optical wireless communication solutions. As a result, technologically mature solutions are already commercially available for services such as Location Based Services (LBS), broadcast diffusion or Intelligent Transport Services (ITS). Pending finalization of the standard review process IEEE 802.15.7 r1, our paper presents the results of the European collaborative project named "ACEMIND". It offers an indoor bilateral optical wireless communication prototype having the following characteristics: use of the existing electrical infrastructure, through judicious combination with Light Fidelity (LiFi), Power Line Communication (PLC) and Ethernet to reduce the implementation cost. We propose a bilateral optical wireless communication even when the light is switched off by using Visible Light Communication (VLC) and Infra-Red Communication (IRC) combined to a remote optical switch. Dimensionally optimized LiFi module is presented in order to offer the possibility for integration inside a laptop. Finally, there is operational mechanism implementation such as OFDM/DMT to increase throughput. After the introduction, we will present the results of a market study from Orange Labs customers about their opinion on LiFi components. Then we will detail the LiFi prototype, from the physical layer aspect to MAC layer before concluding on commercial development prospects.

  11. Wireless Sensor Networks: Performance Analysis in Indoor Scenarios

    Directory of Open Access Journals (Sweden)

    G. Ferrari

    2007-03-01

    Full Text Available We evaluate the performance of realistic wireless sensor networks in indoor scenarios. Most of the considered networks are formed by nodes using the Zigbee communication protocol. For comparison, we also analyze networks based on the proprietary standard Z-Wave. Two main groups of network scenarios are proposed: (i scenarios with direct transmissions between the remote nodes and the network coordinator, and (ii scenarios with routers, which relay the packets between the remote nodes and the coordinator. The sensor networks of interest are evaluated considering different performance metrics. In particular, we show how the received signal strength indication (RSSI behaves in the considered scenarios. Then, the network behavior is characterized in terms of end-to-end delay and throughput. In order to confirm the experiments, analytical and simulation results are also derived.

  12. Indoor infrared wireless communication system based on Ethernet network

    Science.gov (United States)

    Yang, Xin; Gong, Mali; Zhang, Kai; Zhang, Haitao; Yan, Ping; Jin, Wei; Jiang, Feng; Meng, Yu; Zou, Shanshan

    2002-12-01

    In this paper, we present an infrared wireless indoor communication system that bases on Ethernet network. The bit rate of Ethernet is 10Mbps, but after Manchester coding, in the physical layer the actual bit rate is 20Mbps. In our designs, the transmitter uses laser diodes (LDs). The transmitter consists of differential input circuit, LD driver circuit. The receiver consists of a coated truncated spherical concentrator whose field of view (FOV) is 40 degree, a large area Si PIN photo-detector followed by transimpedance amplifier, second-stage amplifier, low-pass filter (LPF), high-pass filter (HPF), limiting amplifier and differential output circuit. The network is constructed as a base-terminals configuration and two transit wavelengths are used for base and terminals respectively to avoid collision. Experimental testing was conducted in a room with size 5m × 5m × 3m and the network could work well.

  13. Wireless sensor networks for indoor air quality monitoring.

    Science.gov (United States)

    Yu, Tsang-Chu; Lin, Chung-Chih; Chen, Chun-Chang; Lee, Wei-Lun; Lee, Ren-Guey; Tseng, Chao-Heng; Liu, Shi-Ping

    2013-02-01

    The purpose of this study is to build an indoor air quality monitoring system based on wireless sensor networks (WSNs) technology. The main functions of the system include (1) remote parameter adjustment and firmware update mechanism for the sensors to enhance the flexibility and convenience of the system, (2) sensor nodes are designed by referring to the IEEE 1451.4 standard. This way, sensor nodes can automatically adjust and be plug and play, and (3) calibration method to strength the measurement value's sensitivity and accuracy. The experimental results show that transmission speed improves 30% than Trickle, transmission volume reduced to 42% of the original volume, updating task in 5*5 network topology can be executed 1.79 times and power consumption reduced to 30%. When baseline drifts, we can use the firmware update mechanism to adjust the reference value. The way can reduce error percentage from 15% to 7%. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

  14. CMOS indoor light energy harvesting system for wireless sensing applications

    CERN Document Server

    Ferreira Carvalho, Carlos Manuel

    2016-01-01

    This book discusses in detail the CMOS implementation of energy harvesting.  The authors describe an integrated, indoor light energy harvesting system, based on a controller circuit that dynamically and automatically adjusts its operation to meet the actual light circumstances of the environment where the system is placed.  The system is intended to power a sensor node, enabling an autonomous wireless sensor network (WSN). Although designed to cope with indoor light levels, the system is also able to work with higher levels, making it an all-round light energy harvesting system.  The discussion includes experimental data obtained from an integrated manufactured prototype, which in conjunction with a photovoltaic (PV) cell, serves as a proof of concept of the desired energy harvesting system.  ·         Discusses several energy sources which can be used to power energy harvesting systems and includes an overview of PV cell technologies  ·         Includes an introduction to voltage step-...

  15. Indoor Positioning System Using Depth Maps and Wireless Networks

    Directory of Open Access Journals (Sweden)

    Jaime Duque Domingo

    2016-01-01

    Full Text Available This work presents a new Indoor Positioning System (IPS based on the combination of WiFi Positioning System (WPS and depth maps, for estimating the location of people. The combination of both technologies improves the efficiency of existing methods, based uniquely on wireless positioning techniques. While other positioning systems force users to wear special devices, the system proposed in this paper just requires the use of smartphones, besides the installation of RGB-D sensors in the sensing area. Furthermore, the system is not intrusive, being not necessary to know people’s identity. The paper exposes the method developed for putting together and exploiting both types of sensory information with positioning purposes: the measurements of the level of the signal received from different access points (APs of the wireless network and the depth maps provided by the RGB-D cameras. The obtained results show a significant improvement in terms of positioning with respect to common WiFi-based systems.

  16. General Model for Infrastructure Multi-channel Wireless LANs

    OpenAIRE

    Fayez Gebali; Abdelsalam Amer

    2010-01-01

    In this paper we develop an integrated model for request mechanism and data transmission in multi-channel wireless local area networks. We calculated the performance parameters for single and multi-channel wireless networks when the channel is noisy. The proposed model is general it can be applied to different wireless networks such as IEEE802.11x, IEEE802.16, CDMA operated networks and Hiperlan\\2.

  17. Achieving single channel, full duplex wireless communication

    KAUST Repository

    Choi, Jung Il

    2010-01-01

    This paper discusses the design of a single channel full-duplex wireless transceiver. The design uses a combination of RF and baseband techniques to achieve full-duplexing with minimal effect on link reliability. Experiments on real nodes show the full-duplex prototype achieves median performance that is within 8% of an ideal full-duplexing system. This paper presents Antenna Cancellation, a novel technique for self-interference cancellation. In conjunction with existing RF interference cancellation and digital baseband interference cancellation, antenna cancellation achieves the amount of self-interference cancellation required for full-duplex operation. The paper also discusses potential MAC and network gains with full-duplexing. It suggests ways in which a full-duplex system can solve some important problems with existing wireless systems including hidden terminals, loss of throughput due to congestion, and large end-to-end delays. Copyright 2010 ACM.

  18. Capacity Bounds for Parallel Optical Wireless Channels

    KAUST Repository

    Chaaban, Anas

    2016-01-01

    A system consisting of parallel optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. Under perfect channel-state information at the transmitter (CSIT), the bounds have to be optimized with respect to the power allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the KKT conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose low-complexity power allocation algorithms which are nearly optimal. The optimized capacity lower bound nearly coincides with the capacity at high SNR. Without CSIT, our capacity bounds lead to upper and lower bounds on the outage probability. The outage probability bounds meet at high SNR. The system with average and peak intensity constraints is also discussed.

  19. Indoor Optical Wireless Receiver – Theory And Design

    Directory of Open Access Journals (Sweden)

    M.F.L. Abdullah

    2011-12-01

    Full Text Available This paper presents a systematic approach to the design of receiver for indoor optical wireless communication. In particular, it is concerned with how one can properly chooses the front-end preamplifier and biasing circuitry for the photodetector. A comparison between differences types of amplifier, and bandwidth enhancement technique is also discussed. For most photodetector applications, large values of RL and CD would severely restrict bandwidth. It is shown that a proper front-end design incorporates a transimpedance preamplifier which tends to integrate the detector output. Such a design provides significant reduction in photodiode capacitance and increase bandwidth when compared to a design which does not integrate initially. Two novel techniques, using bandwidth adjustment for better service quality with a bootstrapped transimpedance amplifier and bootstrapped composite transimpedance amplifier is presented. A controllable capacitance is introduced at the output of the second stage of the amplifier. These technique permits a bandwidth adjustment from 52Hz to 233MHz for a capacitance range of 10uF to 1pF, while the composite amplifier bandwidth adjustment of the circuit can be controlled in the frequency range of 6MHz to 60MHz for a capacitance range of 50pF to 1nF.

  20. A Review of Wireless and PLC Propagation Channel Characteristics for Smart Grid Environments

    Directory of Open Access Journals (Sweden)

    Sabih Güzelgöz

    2011-01-01

    Full Text Available Wireless, power line communication (PLC, fiber optic, Ethernet, and so forth are among the communication technologies on which smart grid communication infrastructure is envisioned to be built. Among these, wireless and PLC-based solutions are attractive considering the cost of initial deployment. Wireless communication deployment in smart grid covers a variety of environments such as indoor, outdoor, and electric-power-system facilities. Similar diversity is expected in PLC deployment as well covering low voltage (LV, medium voltage (MV, and high voltage (HV segments of the grid. In spite of being attractive, wireless and PLC channels are very harsh posing great challenges to performance of communication systems. In proposing solutions to smart grid communication needs, two approaches are likely to be followed. One is based on the use of existing wireless and PLC technologies with some modifications, and the other relies upon developing novel communication protocols particularly addressing the smart grid needs. Both of these approaches require an in-depth knowledge of communication channel characteristics. The aim of this study is to reveal the wireless and PLC channel characteristics of smart grid environments in terms of several parameters such as path loss and attenuation, time dispersion, time selectivity, amplitude statistics, and noise characteristics.

  1. Deterministic simulation of UWB indoor propagation channel

    Institute of Scientific and Technical Information of China (English)

    Wang Yang; Zhang Naitong; Zhang Qinyu; Zhang Zhongzhao

    2008-01-01

    A site-specific model of UWB pulse propagation in indoor environment is addressed. The simulation utilizes the principles of geometrical optics (GO) for direct and reflected paths' tracing and the time domain technique for describing the transient electromagnetic field reflected from wall, floor, ceiling, and objects. The polarization of the received waveform is determined by taking into account the radiation pattern of the transmitting and receiving antennas, as well as the polarization changes owing to every reflection. The model provides more intrinsical interpretations for UWB pulse propagation in realistic indoor environment.

  2. Short-Range Optical Wireless Communications for Indoor and Interconnects Applications

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; Ampalavanapillai Nirmalathas; Christina Lim; SONG Tingting; LIANG Tian; Kamal Alameh; Efstratios Skafidas

    2016-01-01

    Optical wireless communications have been widely studied during the past decade in short⁃range applications, such as indoor high⁃speed wireless networks and interconnects in data centers and high⁃performance computing. In this paper, recent developments in high⁃speed short⁃range optical wireless communications are reviewed, including visible light communications (VLCs), infrared in⁃door communication systems, and reconfigurable optical interconnects. The general architecture of indoor high⁃speed optical wire⁃less communications is described, and the advantages and limitations of both visible and infrared based solutions are discussed. The concept of reconfigurable optical interconnects is presented, and key results are summarized. In addition, the challenges and potential future directions of short⁃range optical wireless communications are discussed.

  3. 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.

  4. Wireless Fading Channel Models: From Classical to Stochastic Differential Equations

    Energy Technology Data Exchange (ETDEWEB)

    Olama, Mohammed M [ORNL; Djouadi, Seddik M [ORNL; Charalambous, Prof. Charalambos [University of Cyprus

    2010-01-01

    later expanded to three-dimensions (3D) by Aulin. An indoor STF was introduced. Most of these STF models provide information on the frequency response of the channel, described by the Doppler power spectral density (DPSD). Aulin presented a methodology to find the Doppler power spectrum by computing the Fourier transform of the autocorrelation function of the channel impulse response with respect to time. A different approach, leading to the same Doppler power spectrum relation was presented by Gans. These STF models suggest various distributions for the received signal amplitude such as Rayleigh, Rician, or Nakagami. Models based on autoregressive and moving averages (AR) are proposed. However, these models assume that the channel state is completely observable, which in reality is not the case due to additive noise, and requires long observation intervals. First order Markov models for Raleigh fading have been proposed, and the usefulness of a finite-state Markov channel model is argued. Mobile-to-mobile (or ad hoc) wireless networks comprise nodes that freely and dynamically self-organize into arbitrary and/or temporary network topology without any fixed infrastructure support. They require direct communication between a mobile transmitter and a mobile receiver over a wireless medium. Such mobile-to-mobile communication systems differ from the conventional cellular systems, where one terminal, the base station, is stationary, and only the mobile station is moving. As a consequence, the statistical properties of mobile-to-mobile links are different from cellular ones. Copious ad hoc networking research exists on layers in the open system interconnection (OSI) model above the physical layer. However, neglecting the physical layer while modeling wireless environment is error prone and should be considered more carefully. The experimental results show that the factors at the physical layer not only affect the absolute performance of a protocol, but because their impact

  5. Channel coding techniques for wireless communications

    CERN Document Server

    Deergha Rao, K

    2015-01-01

    The book discusses modern channel coding techniques for wireless communications such as turbo codes, low-density parity check (LDPC) codes, space–time (ST) coding, RS (or Reed–Solomon) codes and convolutional codes. Many illustrative examples are included in each chapter for easy understanding of the coding techniques. The text is integrated with MATLAB-based programs to enhance the understanding of the subject’s underlying theories. It includes current topics of increasing importance such as turbo codes, LDPC codes, Luby transform (LT) codes, Raptor codes, and ST coding in detail, in addition to the traditional codes such as cyclic codes, BCH (or Bose–Chaudhuri–Hocquenghem) and RS codes and convolutional codes. Multiple-input and multiple-output (MIMO) communications is a multiple antenna technology, which is an effective method for high-speed or high-reliability wireless communications. PC-based MATLAB m-files for the illustrative examples are provided on the book page on Springer.com for free dow...

  6. Performance of Ultrawideband Wireless Tags for On-Body Radio Channel Characterisation

    Directory of Open Access Journals (Sweden)

    Mohammad Monirujjaman Khan

    2012-01-01

    Full Text Available Experimental characterisation of on-body radio channel for ultrawideband (UWB wireless active tags is reported in this paper. The aim of this study is to investigate the performance of the commercially available wireless tags on the UWB on-body radio channel characterisation. Measurement campaigns are performed in the chamber and in an indoor environment. Statistical path loss parameters of nine different on-body radio channels for static and dynamic cases are shown and analyzed. Results demonstrated that lognormal distribution provides the best fits for on-body propagation channels path loss model. The path loss was modeled as a function of distance for 34 different receiver locations for propagation along the front part of the body. A reduction of 11.46% path loss exponent is noticed in case of indoor environment as compared to anechoic chamber. In addition, path loss exponent is also extracted for different body parts (trunk, arms, and legs. Second-order channel parameters as fade probability (FP, level crossing rate (LCR, and average fade duration (AFD are also investigated.

  7. Cable television transmission over a 1550-nm infrared indoor optical wireless link

    Science.gov (United States)

    Sakib Chowdhury, M. I.; Kavehrad, Mohsen; Zhang, Weizhi

    2013-10-01

    We experimentally demonstrate transmission of cable television (CATV) radio frequency signals over a pointed indoor optical wireless link. The length of the optical link was 15 m. Collimators used at both the transmitter and the receiver sides required good alignment before sufficient optical power could be received. The system was placed at a height of 2 m, which is more than average human height, so human movements throughout the room did not obstruct the link. The optical wireless propagation path was almost lossless. The originality in this experimental demonstration is the transmission of full range of CATV signals compared to other works in this area. This experiment of radio over free-space optics showed that point-to-point indoor optical wireless links can be utilized as an alternative means for transmission of multimedia data.

  8. Performance Analysis of IEEE 802.15.4 Compliant Wireless Devices for Heterogeneous Indoor Home Automation Environments

    Directory of Open Access Journals (Sweden)

    Juan Antonio Nazabal

    2012-01-01

    Full Text Available The influence of topology as well as morphology of complex indoor scenarios in the deployment of wireless sensor networks and wireless systems applied to home and building automation systems is analyzed. The existence of loss mechanisms such as material absorption (walls, furniture, etc. and strong multipath components as well as the increase in the number of wireless sensors within indoor scenarios increases the relevance in the configuration of the heterogeneous wireless systems. Simulation results by means of empirical-based models are compared with an in-house 3D ray launching code as well as measurement results from wireless sensor networks illustrate the strong influence of the indoor scenario in the overall performance. The use of adequate radioplanning strategies lead to optimal wireless network deployments in terms of capacity, quality of service, and reduced power consumption.

  9. Spatial Dynamics of Indoor Radio Wideband Channels

    Directory of Open Access Journals (Sweden)

    Hayar Aawatif

    2010-01-01

    Full Text Available The multipath components of superwideband (2–17.2 GHz nonline-of-sight channel responses measured inside several buildings are stable along sections that are 27 cm long on average with a standard deviation of 16 cm. The stability regions of multipath components have an approximately log-normal histogram. An analysis of measured channels that explicitly includes finite spatial areas of visibility of the multipath components is superior to the classic analysis that attributes spatial dynamics to interference of the multipath. The spatial stability of measured responses, that is, the size of the typical area of visibility of each multipath component, decreases as the carrier frequency increases but does not depend on bandwidth. The results offer insight into the nature of the diffuse part of the radio channel.

  10. Error Resilient Image Transmission over Wireless Fading Channels

    Directory of Open Access Journals (Sweden)

    M Padmaja,

    2010-05-01

    Full Text Available Nowadays transferring images and video over wireless channels is becoming more use of the medium. However, a wireless medium is not very reliable in the way that it adds unwanted components and noise to the wireless transmission. So there may be a loss of data. Due to this possible loss of data without the capability of resending a correct version we need a system to protect and correct such losses. The transmission of images over wireless channels is examined using reorganization of the compressed images into error-resilient, product-coded streams. The product-code consists of Turbo-codes or Reed–Solomon codes which are optimized using an iterative process. The wireless channel used for the testing phase is a Rayleigh Fading channel with Additive White Gaussian Noise (AWGN added as a noisecomponent. In this paper we propose protection techniques for image transmission and compare the performance of various protection methods for all JPEG standards. The proposed image standard model was found to perform very well in protecting the images against quality degradation during transmission over wireless channels. The strength of the protection plays a large part in the protection of the image and should be chosen to suit the particular channel in use. Thedefault protection also provides very strong protection for the user who does not wish to choose their own setting.

  11. Video coding bit allocation algorithm over wireless transmission channel

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; ZHOU Yuan-hua

    2006-01-01

    For two-way video communications over wireless channels using the automatic repeat request (ARQ) retransmission scheme, TMN8 rate control scheme is not effective in minimizing the number of frames skipped and cannot guarantee video quality during the retransmissions of error packets. This paper presents a joint source channel bit allocation scheme that allocates target bits according to encoder buffer fullness and estimation of channel condition by retransmission information. The results obtained from implementing our scheme in H. 263 + coder over wireless channel model show that our proposed scheme encodes the video sequences with lower and steadier buffer delay, fewer frames skipped and higher average PSNR compared to TMN8.

  12. Radiofrequency Field Distribution Assessment in Indoor Areas Covered by Wireless Local Area Network

    Directory of Open Access Journals (Sweden)

    HELBET, R.

    2009-02-01

    Full Text Available Electromagnetic environment becomes day by day more congested. Radio communication systems in the short range are now part of everyday life, and there is a need to also assess the pollution level due to their emission if we take into account human health and protection. There is consistent scientific evidence that environmental electromagnetic field may cause undesirable biological effects or even health hazards. Present paper aims at giving a view on exposure level due to wireless local area networks (WLAN emission solely, as part of environmental radiofrequency pollution. Highly accurate measurements were made indoor by using a frequency-selective measurement system and identifying the correct settings for an error-minimum assessment. We focused on analysis of the electric flux density distribution inside a room, in the far field of the emitting antennas, in case of a single network communication channel. We analyze the influence the network configuration parameters have on the field level. Distance from the source and traffic rate are also important parameters that affect the exposure level. Our measurements indicate that in the immediate vicinity of the WLAN stations the average field may reach as much as 13% from the present accepted reference levels given in the human exposure standards.

  13. Channel Characterization and Robust Tracking for Diversity Reception over Time-Variant Off-Body Wireless Communication Channels

    Science.gov (United States)

    Van Torre, Patrick; Vallozzi, Luigi; Rogier, Hendrik; Moeneclaey, Marc; Verhaevert, Jo

    2010-12-01

    In the 2.45 GHz band, indoor wireless off-body data communication by a moving person can be problematic due to time-variant signal fading and the consequent variation in channel parameters. Off-body communication specifically suffers from the combined effects of fading, shadowing, and path loss due to time-variant multipath propagation in combination with shadowing by the human body. Measurements are performed to analyze the autocorrelation, coherence time, and power spectral density for a person equipped with a wearable receive system moving at different speeds for different configurations and antenna positions. Diversity reception with multiple textile antennas integrated in the clothing provides a means of improving the reliability of the link. For the dynamic channel estimation, a scheme using hard decision feedback after MRC with adaptive low-pass filtering is demonstrated to be successful in providing robust data detection for long data bursts, in the presence of dramatic channel variation.

  14. Propagation channel characterization, parameter estimation, and modeling for wireless communications

    CERN Document Server

    Yin, Xuefeng

    2016-01-01

    Thoroughly covering channel characteristics and parameters, this book provides the knowledge needed to design various wireless systems, such as cellular communication systems, RFID and ad hoc wireless communication systems. It gives a detailed introduction to aspects of channels before presenting the novel estimation and modelling techniques which can be used to achieve accurate models. To systematically guide readers through the topic, the book is organised in three distinct parts. The first part covers the fundamentals of the characterization of propagation channels, including the conventional single-input single-output (SISO) propagation channel characterization as well as its extension to multiple-input multiple-output (MIMO) cases. Part two focuses on channel measurements and channel data post-processing. Wideband channel measurements are introduced, including the equipment, technology and advantages and disadvantages of different data acquisition schemes. The channel parameter estimation methods are ...

  15. Performance analysis of OFDM modulation on indoor broadband PLC channels

    Science.gov (United States)

    Antonio Cortés, José; Díez, Luis; Cañete, Francisco Javier; Sánchez-Martínez, Juan José; Entrambasaguas, José Tomás

    2011-12-01

    Indoor broadband power-line communications is a suitable technology for home networking applications. In this context, orthogonal frequency-division multiplexing (OFDM) is the most widespread modulation technique. It has recently been adopted by the ITU-T Recommendation G.9960 and is also used by most of the commercial systems, whose number of carriers has gone from about 100 to a few thousands in less than a decade. However, indoor power-line channels are frequency-selective and exhibit periodic time variations. Hence, increasing the number of carriers does not always improves the performance, since it reduces the distortion because of the frequency selectivity, but increases the one caused by the channel time variation. In addition, the long impulse response of power-line channels obliges to use an insufficient cyclic prefix. Increasing its value reduces the distortion, but also the symbol rate. Therefore, there are optimum values for both modulation parameters. This article evaluates the performance of an OFDM system as a function of the number of carriers and the cyclic prefix length, determining their most appropriate values for the indoor power-line scenario. This task must be accomplished by means of time-consuming simulations employing a linear time-varying filtering, since no consensus on a tractable statistical channel model has been reached yet. However, this study presents a simpler procedure in which the distortion because of the frequency selectivity is computed using a time-invariant channel response, and an analytical expression is derived for the one caused by the channel time variation.

  16. Distributed Joint Source-Channel Coding in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2009-06-01

    Full Text Available Considering the fact that sensors are energy-limited and the wireless channel conditions in wireless sensor networks, there is an urgent need for a low-complexity coding method with high compression ratio and noise-resisted features. This paper reviews the progress made in distributed joint source-channel coding which can address this issue. The main existing deployments, from the theory to practice, of distributed joint source-channel coding over the independent channels, the multiple access channels and the broadcast channels are introduced, respectively. To this end, we also present a practical scheme for compressing multiple correlated sources over the independent channels. The simulation results demonstrate the desired efficiency.

  17. Modeling the Noise for Indoor Power Line Channel

    Directory of Open Access Journals (Sweden)

    Syed Samser Ali

    2013-07-01

    Full Text Available Electromagnetic interference, man-made noise, and multipath effects are main causes of bit errors in power-line communication. To design an efficient powerline transmission system, the channel characterization has to be known and this paper deals with a statistical noise model (SNM for the indoor powerline channel in a frequency band from 1 MHz to 30 MHz . The SNM parameters are obtained from large-scale measurements of the noise density spectrum on a real powerline channel. All measurements are between line and neutral at different locations in the same grid. The SNM is used for simulation of the noise density spectrum and offline analysis on the powerline channel

  18. Energy Harvesting - Wireless Sensor Networks for Indoors Applications Using IEEE 802.11

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Sørensen, Thomas; Madsen, Jan

    2014-01-01

    The paper investigates the feasibility of using IEEE 802.11 in energy harvesting low-power sensing applications. The investigation is based on a prototype carbon dioxide sensor node that is powered by artificial indoors light. The wireless communication module of the sensor node is based on the RTX......4100 module. RTX4100 incorporates a wireless protocol that duty-cycles the radio while being compatible with IEEE 802.11 access points. The presented experiments demonstrate sustainable operation but indicate a trade-off between the benefits of using IEEE 802.11 in energy harvesting applications...

  19. A Three-Dimensional Wireless Indoor Localization System

    Directory of Open Access Journals (Sweden)

    Ping Yi

    2014-01-01

    Full Text Available Indoor localization, an emerging technology in location based service (LBS, is now playing a more and more important role both in commercial and in civilian industry. Global position system (GPS is the most popular solution in outdoor localization field, and the accuracy is around 10 meter error in positioning. However, with complex obstacles in buildings, problems rise in the “last mile” of localization field, which encourage a momentum of indoor localization. The traditional indoor localization system is either range-based or fingerprinting-based, which requires a lot of time and efforts to do the predeployment. In this paper, we present a 3-dimensional on-demand indoor localization system (3D-ODIL, which can be fingerprint-free and deployed rapidly in a multistorey building. The 3D-ODIL consists of two phases, vertical localization and horizontal localization. On vertical direction, we propose multistorey differential (MSD algorithm and implement it to fulfill the vertical localization, which can greatly reduce the number of anchors deployed. We use enhanced field division (EFD algorithm to conduct the horizontal localization. EFD algorithm is a range-free algorithm, the main idea of which is to dynamically divide the field within different signature area and position the target. The accuracy and performance have been validated through our extensive analysis and systematic experiments.

  20. A Survey of Indoor Positioning Systems for Wireless Personal Networks

    NARCIS (Netherlands)

    Gu, Y.; Lo, A.; Niemegeers, I.

    2009-01-01

    Recently, indoor positioning systems (IPSs) have been designed to provide location information of persons and devices. The position information enables location-based protocols for user applications. Personal networks (PNs) are designed to meet the users' needs and interconnect users' devices equipp

  1. Multi-channel Support for Dense Wireless Sensor Networking

    NARCIS (Netherlands)

    Durmaz, O.; Dulman, S.O.; Jansen, P.G.; Havinga, Paul J.M.; Havinga, P.J.M.; Lijding, M.E.M.; Meratnia, N.; Meratnia, Nirvana; Wegdam, M.

    2006-01-01

    Currently, most wireless sensor network applications assume the presence of single-channel Medium Access Control (MAC) protocols. When sensor nodes are densely deployed, single-channel MAC protocols may be inadequate due to the higher demand for the limited bandwidth. To overcome this drawback, we

  2. Channel-Based Key Generation for Encrypted Body-Worn Wireless Sensor Networks

    Science.gov (United States)

    Van Torre, Patrick

    2016-01-01

    Body-worn sensor networks are important for rescue-workers, medical and many other applications. Sensitive data are often transmitted over such a network, motivating the need for encryption. Body-worn sensor networks are deployed in conditions where the wireless communication channel varies dramatically due to fading and shadowing, which is considered a disadvantage for communication. Interestingly, these channel variations can be employed to extract a common encryption key at both sides of the link. Legitimate users share a unique physical channel and the variations thereof provide data series on both sides of the link, with highly correlated values. An eavesdropper, however, does not share this physical channel and cannot extract the same information when intercepting the signals. This paper documents a practical wearable communication system implementing channel-based key generation, including an implementation and a measurement campaign comprising indoor as well as outdoor measurements. The results provide insight into the performance of channel-based key generation in realistic practical conditions. Employing a process known as key reconciliation, error free keys are generated in all tested scenarios. The key-generation system is computationally simple and therefore compatible with the low-power micro controllers and low-data rate transmissions commonly used in wireless sensor networks. PMID:27618051

  3. Channel-Based Key Generation for Encrypted Body-Worn Wireless Sensor Networks.

    Science.gov (United States)

    Van Torre, Patrick

    2016-09-08

    Body-worn sensor networks are important for rescue-workers, medical and many other applications. Sensitive data are often transmitted over such a network, motivating the need for encryption. Body-worn sensor networks are deployed in conditions where the wireless communication channel varies dramatically due to fading and shadowing, which is considered a disadvantage for communication. Interestingly, these channel variations can be employed to extract a common encryption key at both sides of the link. Legitimate users share a unique physical channel and the variations thereof provide data series on both sides of the link, with highly correlated values. An eavesdropper, however, does not share this physical channel and cannot extract the same information when intercepting the signals. This paper documents a practical wearable communication system implementing channel-based key generation, including an implementation and a measurement campaign comprising indoor as well as outdoor measurements. The results provide insight into the performance of channel-based key generation in realistic practical conditions. Employing a process known as key reconciliation, error free keys are generated in all tested scenarios. The key-generation system is computationally simple and therefore compatible with the low-power micro controllers and low-data rate transmissions commonly used in wireless sensor networks.

  4. Using LS-SVM Based Motion Recognition for Smartphone Indoor Wireless Positioning

    Directory of Open Access Journals (Sweden)

    Ruizhi Chen

    2012-05-01

    Full Text Available The paper presents an indoor navigation solution by combining physical motion recognition with wireless positioning. Twenty-seven simple features are extracted from the built-in accelerometers and magnetometers in a smartphone. Eight common motion states used during indoor navigation are detected by a Least Square-Support Vector Machines (LS-SVM classification algorithm, e.g., static, standing with hand swinging, normal walking while holding the phone in hand, normal walking with hand swinging, fast walking, U-turning, going up stairs, and going down stairs. The results indicate that the motion states are recognized with an accuracy of up to 95.53% for the test cases employed in this study. A motion recognition assisted wireless positioning approach is applied to determine the position of a mobile user. Field tests show a 1.22 m mean error in “Static Tests” and a 3.53 m in “Stop-Go Tests”.

  5. Using LS-SVM based motion recognition for smartphone indoor wireless positioning.

    Science.gov (United States)

    Pei, Ling; Liu, Jingbin; Guinness, Robert; Chen, Yuwei; Kuusniemi, Heidi; Chen, Ruizhi

    2012-01-01

    The paper presents an indoor navigation solution by combining physical motion recognition with wireless positioning. Twenty-seven simple features are extracted from the built-in accelerometers and magnetometers in a smartphone. Eight common motion states used during indoor navigation are detected by a Least Square-Support Vector Machines (LS-SVM) classification algorithm, e.g., static, standing with hand swinging, normal walking while holding the phone in hand, normal walking with hand swinging, fast walking, U-turning, going up stairs, and going down stairs. The results indicate that the motion states are recognized with an accuracy of up to 95.53% for the test cases employed in this study. A motion recognition assisted wireless positioning approach is applied to determine the position of a mobile user. Field tests show a 1.22 m mean error in "Static Tests" and a 3.53 m in "Stop-Go Tests".

  6. Validation of Three-Dimensional Ray-Tracing Algorithm for Indoor Wireless Propagations

    OpenAIRE

    Majdi Salem; Mahamod Ismail; Norbahiah Misran

    2011-01-01

    A 3D ray tracing simulator has been developed for indoor wireless networks. The simulator uses geometrical optics (GOs) to propagate the electromagnetic waves inside the buildings. The prediction technique takes into account multiple reflections and transmissions of the propagated waves. An interpolation prediction method (IPM) has been proposed to predict the propagated signal and to make the ray-tracing algorithm faster, accurate, and simple. The measurements have been achieved by using a s...

  7. Development of an Indoor Location Based Service Test Bed and Geographic Information System with a Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Shau-Shiun Jan

    2010-03-01

    Full Text Available In order to provide the seamless navigation and positioning services for indoor environments, an indoor location based service (LBS test bed is developed to integrate the indoor positioning system and the indoor three-dimensional (3D geographic information system (GIS. A wireless sensor network (WSN is used in the developed indoor positioning system. Considering the power consumption, in this paper the ZigBee radio is used as the wireless protocol, and the received signal strength (RSS fingerprinting positioning method is applied as the primary indoor positioning algorithm. The matching processes of the user location include the nearest neighbor (NN algorithm, the K-weighted nearest neighbors (KWNN algorithm, and the probabilistic approach. To enhance the positioning accuracy for the dynamic user, the particle filter is used to improve the positioning performance. As part of this research, a 3D indoor GIS is developed to be used with the indoor positioning system. This involved using the computer-aided design (CAD software and the virtual reality markup language (VRML to implement a prototype indoor LBS test bed. Thus, a rapid and practical procedure for constructing a 3D indoor GIS is proposed, and this GIS is easy to update and maintenance for users. The building of the Department of Aeronautics and Astronautics at National Cheng Kung University in Taiwan is used as an example to assess the performance of various algorithms for the indoor positioning system.

  8. Development of an indoor location based service test bed and geographic information system with a wireless sensor network.

    Science.gov (United States)

    Jan, Shau-Shiun; Hsu, Li-Ta; Tsai, Wen-Ming

    2010-01-01

    In order to provide the seamless navigation and positioning services for indoor environments, an indoor location based service (LBS) test bed is developed to integrate the indoor positioning system and the indoor three-dimensional (3D) geographic information system (GIS). A wireless sensor network (WSN) is used in the developed indoor positioning system. Considering the power consumption, in this paper the ZigBee radio is used as the wireless protocol, and the received signal strength (RSS) fingerprinting positioning method is applied as the primary indoor positioning algorithm. The matching processes of the user location include the nearest neighbor (NN) algorithm, the K-weighted nearest neighbors (KWNN) algorithm, and the probabilistic approach. To enhance the positioning accuracy for the dynamic user, the particle filter is used to improve the positioning performance. As part of this research, a 3D indoor GIS is developed to be used with the indoor positioning system. This involved using the computer-aided design (CAD) software and the virtual reality markup language (VRML) to implement a prototype indoor LBS test bed. Thus, a rapid and practical procedure for constructing a 3D indoor GIS is proposed, and this GIS is easy to update and maintenance for users. The building of the Department of Aeronautics and Astronautics at National Cheng Kung University in Taiwan is used as an example to assess the performance of various algorithms for the indoor positioning system.

  9. Indoor Trajectory Tracking Scheme Based on Delaunay Triangulation and Heuristic Information in Wireless Sensor Networks.

    Science.gov (United States)

    Qin, Junping; Sun, Shiwen; Deng, Qingxu; Liu, Limin; Tian, Yonghong

    2017-06-02

    Object tracking and detection is one of the most significant research areas for wireless sensor networks. Existing indoor trajectory tracking schemes in wireless sensor networks are based on continuous localization and moving object data mining. Indoor trajectory tracking based on the received signal strength indicator (RSSI) has received increased attention because it has low cost and requires no special infrastructure. However, RSSI tracking introduces uncertainty because of the inaccuracies of measurement instruments and the irregularities (unstable, multipath, diffraction) of wireless signal transmissions in indoor environments. Heuristic information includes some key factors for trajectory tracking procedures. This paper proposes a novel trajectory tracking scheme based on Delaunay triangulation and heuristic information (TTDH). In this scheme, the entire field is divided into a series of triangular regions. The common side of adjacent triangular regions is regarded as a regional boundary. Our scheme detects heuristic information related to a moving object's trajectory, including boundaries and triangular regions. Then, the trajectory is formed by means of a dynamic time-warping position-fingerprint-matching algorithm with heuristic information constraints. Field experiments show that the average error distance of our scheme is less than 1.5 m, and that error does not accumulate among the regions.

  10. GIS management system of power plant staff based on wireless fidelity indoor location technology

    Science.gov (United States)

    Zhang, Ting

    2017-05-01

    The labor conditions and environment of electric power production are quite complicated. It is very difficult to realize the real-time supervision of the employees' working conditions and safety. Using the existing base stations in the power plant, the wireless fidelity network is established to realize the wireless coverage of the work site. We can use mobile phone to communicate and achieve positioning. The main content of this project is based on the special environment of the power plant, designed a suitable for ordinary Android mobile phone indoor wireless fidelity positioning system, real-time positioning and record the scene of each employee's movement trajectory, has achieved real-time staff check Gang, Staff in place, and for the safety of employees to provide a guarantee.

  11. Information-theoretically Secret Key Generation for Fading Wireless Channels

    CERN Document Server

    Ye, Chunxuan; Reznik, Alex; Shah, Yogendra; Trappe, Wade; Mandayam, Narayan

    2009-01-01

    The multipath-rich wireless environment associated with typical wireless usage scenarios is characterized by a fading channel response that is time-varying, location-sensitive, and uniquely shared by a given transmitter-receiver pair. The complexity associated with a richly scattering environment implies that the short-term fading process is inherently hard to predict and best modeled stochastically, with rapid decorrelation properties in space, time and frequency. In this paper, we demonstrate how the channel state between a wireless transmitter and receiver can be used as the basis for building practical secret key generation protocols between two entities. We begin by presenting a scheme based on level crossings of the fading process, which is well-suited for the Rayleigh and Rician fading models associated with a richly scattering environment. Our level crossing algorithm is simple, and incorporates a self-authenticating mechanism to prevent adversarial manipulation of message exchanges during the protoco...

  12. A Joint Source and Channel Video Coding Algorithmfor H.223 Based Wireless Channel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Robust video streaming through high error-prone wireless channel has attracted much attention.In this paper the authors introduce an effective al gorithm by joining the Unequal Error Protection ability of the channel multiplexing prot ocol H.223 Annex D,and the new H.263++ Annex V Data Partition together. Bas ed on the optimal trade-off of these two technologies,the Joint Source and Channel Coding algorithm can result in stronger error resilience.The simulation results have shown its superiority against separate coding mode and some Unequal Error Protection mode under recommended wireless channel error patterns.

  13. Theory of Stochastic Local Area Channel Modeling for Wireless Communications

    OpenAIRE

    Durgin, Gregory David

    2000-01-01

    This dissertation outlines work accomplished in the pursuit of this degree. This report is also designed to be a general introduction to the concepts and techniques of small-scale radio channel modeling. At the present time, there does not exist a comprehensive introduction and overview of basic concepts in this field. Furthermore, as the wireless industry continues to mature and develop technology, the need is now greater than ever for more sophisticated channel modeling research. Eac...

  14. A Hybrid Stochastic Approach for Self-Location of Wireless Sensors in Indoor Environments

    Directory of Open Access Journals (Sweden)

    Alejandro Canovas

    2009-05-01

    Full Text Available Indoor location systems, especially those using wireless sensor networks, are used in many application areas. While the need for these systems is widely proven, there is a clear lack of accuracy. Many of the implemented applications have high errors in their location estimation because of the issues arising in the indoor environment. Two different approaches had been proposed using WLAN location systems: on the one hand, the so-called deductive methods take into account the physical properties of signal propagation. These systems require a propagation model, an environment map, and the position of the radio-stations. On the other hand, the so-called inductive methods require a previous training phase where the system learns the received signal strength (RSS in each location. This phase can be very time consuming. This paper proposes a new stochastic approach which is based on a combination of deductive and inductive methods whereby wireless sensors could determine their positions using WLAN technology inside a floor of a building. Our goal is to reduce the training phase in an indoor environment, but, without an loss of precision. Finally, we compare the measurements taken using our proposed method in a real environment with the measurements taken by other developed systems. Comparisons between the proposed system and other hybrid methods are also provided.

  15. Robot Assisted Wireless Sensor Network for Monitoring and Detection of Explosives in Indoor Environment

    Directory of Open Access Journals (Sweden)

    Joshua D Freeman,

    2011-05-01

    Full Text Available In recent years, remote environment monitoring has been significantly improved with wireless sensor networking technology. This paper presents the real time streaming of an indoor environment using a wireless sensor network and a set of self-navigating robots. Mobile robots with mounted sensors will autonomously navigate through an indoor area with unknown obstacles. The robots will be able toavoid obstacles and move around the region. The robots sense the environmental parameters of the region, and send that data to the remote monitoring terminals using an underlying wireless sensornetwork. This design is applicable to networks where some of the sensors may not have sufficient range to sense data more accurately and closer monitoring is required. Effective path planning for the mobile robot is achieved by combining a map of the area, the sensor readings and the radio strength of the sensor network. Email alerts can be sent to officials if the sensed data goes above a predefined threshold level, thus successfully detecting the presence of explosives in a given area. This system streams the data in realtimeto the Internet making it possible for authorized personnel to view the status of the environment online.

  16. Fundamental Limits of Parallel Optical Wireless Channels: Capacity Results and Outage Formulation

    KAUST Repository

    Chaaban, Anas

    2016-10-26

    Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space optical communications, or multi-user timedivision multiple access for indoors visible-light communications, e.g., can be modeled as parallel channels. Multi-input multioutput OWC systems can also be transformed, possibly with some performance loss, to parallel channels using pre-/postcoding. Studying the performance of such MC-OWC systems requires characterizing the capacity of the underlying parallel channels. In this paper, upper and lower bounds on the capacity of constant parallel OWC channels with a total average intensity constraint are derived. Then, the paper focuses on finding intensity allocations that maximize the lower bounds given channel-state information at the transmitter (CSIT). Due to its nonconvexity, the KKT conditions are used to describe a list of candidate allocations. Instead searching exhaustively for the best solution, low-complexity near-optimal algorithms are proposed. The resulting optimized lower bound nearly coincides with capacity at high signal-to-noise ratio (SNR). Under a quasi-static channel model and in the absence of CSIT, outage probability upper and lower bounds are derived. Those bounds also meet at high SNR, thus characterizing the outage capacity in this regime. Finally, the results are extended to a system with both average and peak intensity constraints.

  17. Investigation of practical and theoretical accuracy of wireless indoor-positioning system UBISENSE

    Science.gov (United States)

    Wozniak, Marek; Odziemczyk, Waldemar; Nagorski, Kamil

    2013-04-01

    The development of Real Time Locating Systems has become an important add-on to many existing location aware systems. While Global Navigation Satelite System has solved most of the outdoor problems, it fails to repeat this success indoors. Wireless indoor positioning systems have become very popular in recent years. One of them is UBISENSE system. This system requires to carry an identity tag that is detected by sensors, which typically use triangulation to determine location. This paper presents the results of the investigation of accuracy of tag position using precise geodetic measurements and geometric analysis. Experimental measurements were carried out on the field polygon using precise tacheometer TCRP 1201+ and complete equipment of Ubisense. Results of experimental measurements were analyzed and presented graphically using Surfer 8. The paper presents the results of the investigation the teoretical and practical positioning accuracy according to the various working conditions.

  18. Steerable pencil beams for multi-Gbps indoor optical wireless communication.

    Science.gov (United States)

    Oh, C W; Tangdiongga, E; Koonen, A M J

    2014-09-15

    We report a novel optical wireless communication (OWC) system solution that supports multi-Gbps (Gigabit-per-second) capacity for indoors. Narrow beams, termed as pencil beams, are directed to wireless users using a tunable laser and a passive diffractive optical element. This enables a wide coverage of ultra-high-capacity communication links to serve multiple network users simultaneously. Experimental results demonstrating data rates of up to 10 Gbps, with on-off keying modulation format, over a distance of more than 2.5 m, are reported. Error-free links beam-steered over a total wavelength range of 130 nm, with steering angle of 17.16°, have been achieved. This system is proposed for short-range OWC and is promising for seamless integration in in-building optical networks.

  19. Mobile-to-mobile wireless channels

    CERN Document Server

    Zajic, Alenka

    2013-01-01

    Present-day mobile communications systems can be classified as fixed-to-mobile because they allow mobility on only one end (e.g. the mobile phone to a fixed mobile operator's cell tower). In answer to the consumer demand for better coverage and quality of service, emerging mobile-to-mobile (M-to-M) communications systems allow mobile users or vehicles to directly communicate with each other. This practical book provides a detailed introduction to state-of-the-art M-to-M wireless propagation. Moreover, the book offers professionals guidance for rapid implementation of these communications syste

  20. Ultra-broadband indoor optical wireless communication system with multimode fiber.

    Science.gov (United States)

    Wang, Ke; Nirmalathas, Ampalavanapillai; Lim, Christina; Skafidas, Efstratios

    2012-05-01

    In this paper we experimentally demonstrate an ultra-broadband indoor full-duplex WDM optical wireless communication system with multimode fiber. The multimode fiber is used because it is employed in most of the already installed in-building fiber distribution networks. Simultaneous error-free (BERfiber will induce ~2.4 cm reduction in the maximum error-free beam footprint in the downlink, the bit rate of the uplink can be much higher compared to the system with single-mode fiber.

  1. Designing coherent optical wireless systems for high speed indoor telecom applications

    Science.gov (United States)

    Kamalakis, Thomas; Kanakis, Panagiotis; Bogris, Adonis; Dalakas, Vasilis; Dede, Georgia

    2016-01-01

    This paper focuses on several design issues of coherent optical wireless systems as a means of providing high data rate optical links in indoor environments enabling the realization of ultra-broadband wireless local area networks. We show how the performance specifications can be translated into signal-to-noise ratio requirements inside the coverage area, taking into account the laser phase noise mitigation scheme. We then discuss the power budget details using Gaussian beam optics incorporating the transceiver positioning and the optical systems used at the transmitter and receiver side. We also treat the influence of ambient light noise. We show that coherent optical wireless systems are characterized by excellent signal-to-noise performance enabling networking at very high data rates. Our results indicate that 2 Gb/s and 10 Gb/s data rates can be easily sustained at 3 m distances over a circular coverage area of 1 m radius using Class-1 lasers for the transmitter and the local oscillator. We also discuss the power gain compared to intensity modulated/direct detection optical wireless and show that it can be as high as 20 dB, especially near the edge of the coverage area.

  2. Field-trial demonstration of an extended-reach GPON-supporting 60-GHz indoor wireless access

    Science.gov (United States)

    Giannoulis, G.; Moraitis, N.; Argyris, N.; Dris, S.; Lessi, C.; Perdikouris, S.; Kostikidou, L.; Apostolopoulos, D.; Spatharakis, C.; Papafili, I.; Agapiou, G.; Panagopoulos, A. D.; Avramopoulos, H.

    2017-02-01

    The 5G era is nearly upon us, and poses several challenges for system designers; one important question is how the (soon to be standardized) mmWave bands of wireless mobile access can coexist harmoniously with optical links in fixed telecom networks. To this end, we present a Radio-over-Fiber (RoF) backhauling concept, interfaced to a 60-GHz indoor femto-cell via a field-installed optical fiber link. We successfully demonstrate generation of a RoF signal up to 1 Gb/s and transmit it optically over 43 km of deployed Single Mode Fiber (SMF), as well as investigate the performance of the 60-GHz access link as a function of distance. The optical link introduces negligible degradation, contrasting the effect of multipath fading in the 60-GHz wireless channel; the latter requires adaptive equalization using offline DSP. The proposed scheme is further validated by demonstration of a 60-GHz Remote Antenna Unit (RAU) concept, handling real traffic from commercial Gigabit Passive Optical Network (GPON) equipment. Proper RAU operation at 1.25 Gb/s is achieved, accommodating true data packets from a Media Converter emitting at 1310 nm through an in-building fiber link. System performance is confirmed through Bit Error Rate (BER) and Error Vector Magnitude (EVM) measurements. EVMs of 11 and 19% are achieved with BPSK signals, for distances of 1 and 2 m respectively. As standardization of mmWave technologies moves from 5G testbeds to field-trial prototypes, successful demonstration of such 60-GHz wireless access scenarios over a telecom operator's commercial fiber infrastructure is even more relevant.

  3. Joint Minimization of Uplink and Downlink Whole-Body Exposure Dose in Indoor Wireless Networks

    Directory of Open Access Journals (Sweden)

    D. Plets

    2015-01-01

    Full Text Available The total whole-body exposure dose in indoor wireless networks is minimized. For the first time, indoor wireless networks are designed and simulated for a minimal exposure dose, where both uplink and downlink are considered. The impact of the minimization is numerically assessed for four scenarios: two WiFi configurations with different throughputs, a Universal Mobile Telecommunications System (UMTS configuration for phone call traffic, and a Long-Term Evolution (LTE configuration with a high data rate. Also, the influence of the uplink usage on the total absorbed dose is characterized. Downlink dose reductions of at least 75% are observed when adding more base stations with a lower transmit power. Total dose reductions decrease with increasing uplink usage for WiFi due to the lack of uplink power control but are maintained for LTE and UMTS. Uplink doses become dominant over downlink doses for usages of only a few seconds for WiFi. For UMTS and LTE, an almost continuous uplink usage is required to have a significant effect on the total dose, thanks to the power control mechanism.

  4. A New Technique of Removing Blind Spots to Optimize Wireless Coverage in Indoor Area

    Directory of Open Access Journals (Sweden)

    A. W. Reza

    2013-01-01

    Full Text Available Blind spots (or bad sampling points in indoor areas are the positions where no signal exists (or the signal is too weak and the existence of a receiver within the blind spot decelerates the performance of the communication system. Therefore, it is one of the fundamental requirements to eliminate the blind spots from the indoor area and obtain the maximum coverage while designing the wireless networks. In this regard, this paper combines ray-tracing (RT, genetic algorithm (GA, depth first search (DFS, and branch-and-bound method as a new technique that guarantees the removal of blind spots and subsequently determines the optimal wireless coverage using minimum number of transmitters. The proposed system outperforms the existing techniques in terms of algorithmic complexity and demonstrates that the computation time can be reduced as high as 99% and 75%, respectively, as compared to existing algorithms. Moreover, in terms of experimental analysis, the coverage prediction successfully reaches 99% and, thus, the proposed coverage model effectively guarantees the removal of blind spots.

  5. Joint minimization of uplink and downlink whole-body exposure dose in indoor wireless networks.

    Science.gov (United States)

    Plets, D; Joseph, W; Vanhecke, K; Vermeeren, G; Wiart, J; Aerts, S; Varsier, N; Martens, L

    2015-01-01

    The total whole-body exposure dose in indoor wireless networks is minimized. For the first time, indoor wireless networks are designed and simulated for a minimal exposure dose, where both uplink and downlink are considered. The impact of the minimization is numerically assessed for four scenarios: two WiFi configurations with different throughputs, a Universal Mobile Telecommunications System (UMTS) configuration for phone call traffic, and a Long-Term Evolution (LTE) configuration with a high data rate. Also, the influence of the uplink usage on the total absorbed dose is characterized. Downlink dose reductions of at least 75% are observed when adding more base stations with a lower transmit power. Total dose reductions decrease with increasing uplink usage for WiFi due to the lack of uplink power control but are maintained for LTE and UMTS. Uplink doses become dominant over downlink doses for usages of only a few seconds for WiFi. For UMTS and LTE, an almost continuous uplink usage is required to have a significant effect on the total dose, thanks to the power control mechanism.

  6. Dense Clustered Multi-Channel Wireless Sensor Cloud

    Directory of Open Access Journals (Sweden)

    Sivaramakrishnan Sivakumar

    2015-08-01

    Full Text Available Dense Wireless Sensor Network Clouds have an inherent issue of latency and packet drops with regards to data collection. Though there is extensive literature that tries to address these issues through either scheduling, channel contention or a combination of the two, the problem still largely exists. In this paper, a Clustered Multi-Channel Scheduling Protocol (CMSP is designed that creates a Voronoi partition of a dense network. Each partition is assigned a channel, and a scheduling scheme is adopted to collect data within the Voronoi partitions. This scheme collects data from the partitions concurrently and then passes it to the base station. CMSP is compared using simulation with other multi-channel protocols like Tree-based Multi-Channel, Multi-Channel MAC and Multi-frequency Media Access Control for wireless sensor networks. Results indicate CMSP has higher throughput and data delivery ratio at a lower power consumption due to network partitioning and hierarchical scheduling that minimizes load on the network.

  7. On Reliable Transmission of Data over Simple Wireless Channels

    Directory of Open Access Journals (Sweden)

    Pawel Gburzynski

    2009-01-01

    Full Text Available Standard protocols for reliable data transmission over unreliable channels are based on various Automatic Repeat reQuest (ARQ schemes, whereby the sending node receives feedback from the receiver and retransmits the missing data. We discuss this issue in the context of one-way data transmission over simple wireless channels characteristic of many sensing and monitoring applications. Using a specific project as an example, we demonstrate how the constraints of a low-cost embedded wireless system get in the way of a workable solution precluding the use of popular schemes based on windows and periodic acknowledgments. We also propose an efficient solution to the problem and demonstrate its advantage over the traditional protocols.

  8. Wireless channel characterization for mm-size neural implants.

    Science.gov (United States)

    Mark, Michael; Bjorninen, Toni; Chen, Yuhui David; Venkatraman, Subramaniam; Ukkonen, Leena; Sydanheimo, Lauri; Carmena, Jose M; Rabaey, Jan M

    2010-01-01

    This paper discusses an approach to modeling and characterizing wireless channel properties for mm-size neural implants. Full-wave electromagnetic simulation was employed to model signal propagation characteristics in biological materials. Animal tests were carried out, proving the validity of the simulation model over a wide range of frequency from 100MHz to 6GHz. Finally, effects of variability and uncertainty in human anatomy and dielectric properties of tissues on these radio links are explored.

  9. Design of Wireless Communication Systems -- Issues on Synchronization, Channel Estimation and Multi-Carrier Systems

    OpenAIRE

    Tufvesson, Fredrik

    2000-01-01

    This thesis deals with certain aspects in the design of wireless communications systems. It is focused on problems related to the mobile or wireless channel: synchronization, channel estimation and design of wireless orthogonal frequency division multiplex (OFDM) systems. There is a short introduction to the field of wireless systems and a deeper review of pervious work and the state of the art in each of the research fields. Throughout the thesis the goal has been to analyze the problems ana...

  10. A New Three-Dimensional Indoor Positioning Mechanism Based on Wireless LAN

    Directory of Open Access Journals (Sweden)

    Jiujun Cheng

    2014-01-01

    Full Text Available The researches on two-dimensional indoor positioning based on wireless LAN and the location fingerprint methods have become mature, but in the actual indoor positioning situation, users are also concerned about the height where they stand. Due to the expansion of the range of three-dimensional indoor positioning, more features must be needed to describe the location fingerprint. Directly using a machine learning algorithm will result in the reduced ability of classification. To solve this problem, in this paper, a “divide and conquer” strategy is adopted; that is, first through k-medoids algorithm the three-dimensional location space is clustered into a number of service areas, and then a multicategory SVM with less features is created for each service area for further positioning. Our experiment shows that the error distance resolution of the approach with k-medoids algorithm and multicategory SVM is higher than that of the approach only with SVM, and the former can effectively decrease the “crazy prediction.”

  11. Spatial sparsity based indoor localization in wireless sensor network for assistive healthcare.

    Science.gov (United States)

    Pourhomayoun, Mohammad; Jin, Zhanpeng; Fowler, Mark

    2012-01-01

    Indoor localization is one of the key topics in the area of wireless networks with increasing applications in assistive healthcare, where tracking the position and actions of the patient or elderly are required for medical observation or accident prevention. Most of the common indoor localization methods are based on estimating one or more location-dependent signal parameters like TOA, AOA or RSS. However, some difficulties and challenges caused by the complex scenarios within a closed space significantly limit the applicability of those existing approaches in an indoor assistive environment, such as the well-known multipath effect. In this paper, we develop a new one-stage localization method based on spatial sparsity of the x-y plane. In this method, we directly estimate the location of the emitter without going through the intermediate stage of TOA or signal strength estimation. We evaluate the performance of the proposed method using Monte Carlo simulation. The results show that the proposed method is (i) very accurate even with a small number of sensors and (ii) very effective in addressing the multi-path issues.

  12. Stabilization of Unmanned Air Vehicles Over Wireless Communication Channels

    Directory of Open Access Journals (Sweden)

    Qingquan Liu

    2013-03-01

    Full Text Available This paper addresses the stabilization problem for unmanned air vehicles over digital and wireless communication channels with time delay. In particular, the case with band-limited channels is considered. An observer-based state feedback control policy is employed to stabilize the linear control system of unmanned air vehicles. A sufficient condition on the minimum data rate for mean square stabilization is derived, and a new quantization, coding, and control policy is presented. Simulation results show the validity of the proposed scheme.

  13. Challenges in Wireless System Integration as Enablers for Indoor Context Aware Environments

    Directory of Open Access Journals (Sweden)

    Peio López-Iturri

    2017-07-01

    Full Text Available The advent of fully interactive environments within Smart Cities and Smart Regions requires the use of multiple wireless systems. In the case of user-device interaction, which finds multiple applications such as Ambient Assisted Living, Intelligent Transportation Systems or Smart Grids, among others, large amount of transceivers are employed in order to achieve anytime, anyplace and any device connectivity. The resulting combination of heterogeneous wireless network exhibits fundamental limitations derived from Coverage/Capacity relations, as a function of required Quality of Service parameters, required bit rate, energy restrictions and adaptive modulation and coding schemes. In this context, inherent transceiver density poses challenges in overall system operation, given by multiple node operation which increases overall interference levels. In this work, a deterministic based analysis applied to variable density wireless sensor network operation within complex indoor scenarios is presented, as a function of topological node distribution. The extensive analysis derives interference characterizations, both for conventional transceivers as well as wearables, which provide relevant information in terms of individual node configuration as well as complete network layout.

  14. Challenges in Wireless System Integration as Enablers for Indoor Context Aware Environments.

    Science.gov (United States)

    López-Iturri, Peio; Aguirre, Erik; Azpilicueta, Leyre; Astrain, José Javier; Villandangos, Jesús; Falcone, Francisco

    2017-07-12

    The advent of fully interactive environments within Smart Cities and Smart Regions requires the use of multiple wireless systems. In the case of user-device interaction, which finds multiple applications such as Ambient Assisted Living, Intelligent Transportation Systems or Smart Grids, among others, large amount of transceivers are employed in order to achieve anytime, anyplace and any device connectivity. The resulting combination of heterogeneous wireless network exhibits fundamental limitations derived from Coverage/Capacity relations, as a function of required Quality of Service parameters, required bit rate, energy restrictions and adaptive modulation and coding schemes. In this context, inherent transceiver density poses challenges in overall system operation, given by multiple node operation which increases overall interference levels. In this work, a deterministic based analysis applied to variable density wireless sensor network operation within complex indoor scenarios is presented, as a function of topological node distribution. The extensive analysis derives interference characterizations, both for conventional transceivers as well as wearables, which provide relevant information in terms of individual node configuration as well as complete network layout.

  15. Deconvolution techniques for characterizing indoor UWB wireless channel

    Institute of Scientific and Technical Information of China (English)

    Wang Yang; Zhang Naitong; Zhang Qinyu; Zhang Zhongzhao

    2008-01-01

    A deconvolution algorithm is proposed to account for the distortions of impulse shape introduced by propagation process.By finding the best correlation of the received waveform with the multiple templates,the number of multipath components is reduced as the result of eliminating the"phantom paths",and the captured energy increases.Moreover,it needs only a single reference measurement in real measurement environment(do not need the anechoic chamber),which by far simplifies the templates acquiring procedure.

  16. Traffic-Aware Channel Assignment in Wireless Sensor Networks

    Science.gov (United States)

    Wu, Yafeng; Keally, Matthew; Zhou, Gang; Mao, Weizhen

    Existing frequency assignment efforts in wireless sensor network research focus on balancing available physical frequencies among neighboring nodes, without paying attention to the fact that different nodes have different traffic volumes. Ignoring the different traffic requirements in different nodes in frequency assignment design leads to poor MAC performance. Therefore, in this paper, we are motivated to propose traffic-aware frequency assignment, which considers nodes’ traffic volumes when making frequency decisions. We incorporate our traffic-aware frequency assignment design into an existing multi-channel MAC, and compare the performance with two conventional frequency assignment schemes. Our performance evaluation demonstrates that traffic-aware channel assignment can greatly improve multi-channel MAC performance. Our traffic-aware assignment scheme greatly enhances the packet delivery ratio and system throughput, while reducing channel access delay and energy consumption.

  17. Weighted OFDM for wireless multipath channels

    DEFF Research Database (Denmark)

    Prasad, Ramjee; Nikookar, H.

    2000-01-01

    In this paper the novel method of "weighted OFDM" is addressed. Different types of weighting factors (including Rectangular, Bartlett, Gaussian. Raised cosine, Half-sin and Shanon) are considered. The impact of weighting of OFDM on the peak-to-average power ratio (PAPR) is investigated by means...... of simulation and is compared for the above mentioned weighting factors. Results show that by weighting of the OFDM signal the PAPR reduces. Bit error performance of weighted multicarrier transmission over a multipath channel is also investigated. Results indicate that there is a trade off between PAPR...... reduction and bit error performance degradation by weighting....

  18. Weighted OFDM for wireless multipath channels

    DEFF Research Database (Denmark)

    Prasad, Ramjee; Nikookar, H.

    2000-01-01

    In this paper the novel method of "weighted OFDM" is addressed. Different types of weighting factors (including Rectangular, Bartlett, Gaussian. Raised cosine, Half-sin and Shanon) are considered. The impact of weighting of OFDM on the peak-to-average power ratio (PAPR) is investigated by means...... of simulation and is compared for the above mentioned weighting factors. Results show that by weighting of the OFDM signal the PAPR reduces. Bit error performance of weighted multicarrier transmission over a multipath channel is also investigated. Results indicate that there is a trade off between PAPR...

  19. Low complexity source and channel coding for mm-wave hybrid fiber-wireless links

    DEFF Research Database (Denmark)

    Lebedev, Alexander; Vegas Olmos, Juan José; Pang, Xiaodan;

    2014-01-01

    performance of several encoded high-definition video sequences constrained by the channel bitrate and the packet size. We argue that light video compression and low complexity channel coding for the W-band fiber-wireless link enable low-delay multiple channel 1080p wireless HD video transmission....

  20. 室内直达与非直达环境无线传播综合信道建模∗%Indo or wireless propagation under line of sight and no line of sight comprehensive channel mo deling

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    This paper mainly deals with the indoor wireless propagation channel under line of sight (LOS) and non-line of sight (NLOS) propagation conditions, introducing the reference model and studing the design and simulation of modeling and the relevant statistical properties. This paper will present a comprehensive and improved indoor reference channel model based on a geometric scattering model. The reference channel model assumes that infinite number of scatterers will be uniformly distributed on the two-dimensional (2D) horizontal plane of a three-dimensional space. This paper also derives analytical expressions for the probability density function (PDF) of the angle-of-arrival (AOA), the Doppler power spectral density (PSD), and the temporal autocorrelation function (ACF) of an electromagnetic arrival signal; it also analyzes the influences of the important parameters of the functions. It presents a highly efficient sum-of-cisoids (SOC) channel simulation model from the unrealistic reference model, also proposes two efficient parameter computation methods for the design of sum-of-cisoids indoor channel simulation model and compares the computing performances of both. It is shown by simulation results that the statistical properties of the sum-of-cisoids channel simulation model match perfectly the reference channel model. It turns out that the indoor reference model can be approximated by an SOC channel simulation model. Meanwhile the channel simulation model can be well applied to evaluate the performance of indoor wireless communication systems. It also extends the research for indoor wireless channel modeling while reduces the realization expenditure.

  1. Modeling of outdoor-to-indoor radio channels via propagation graphs

    DEFF Research Database (Denmark)

    Pedersen, Troels; Steinböck, Gerhard; Fleury, Bernard Henri

    2014-01-01

    We formulate a model for the outdoor-to-indoor radio channel in terms of a propagation graph. The model accounts for outdoor scattering and in-room reverberation. It is observed from the model how such a scenario results in channels with several room excitations leading to "clusters" in the simul......We formulate a model for the outdoor-to-indoor radio channel in terms of a propagation graph. The model accounts for outdoor scattering and in-room reverberation. It is observed from the model how such a scenario results in channels with several room excitations leading to "clusters......" in the simulated channel impulse responses. Simulation studies further indicate that the outdoor-to-indoor and inroom channels differ in terms of spatial envelope correlation. Published in:...

  2. A Time Variant Outdoor-to-Indoor Channel Model for Mobile Radio Based Navigation Applications

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2015-01-01

    Full Text Available Time based positioning with terrestrial mobile radio signals has gained remarkable attention. To develop and validate positioning algorithms under realistic conditions, an accurate knowledge of the propagation channel is significant. However, there is still a lack of outdoor-to-indoor channel models suitable for positioning applications. To be applicable for positioning, the channel model has to fulfill three requirements that have not been accurately considered so far: the non-line-of-sight bias (affecting ranging accuracy, nondiscrete valued channel parameters (affecting algorithm performance, and the evolution of individual multipath components (MPCs with time (affecting tracking performance. In this paper, an outdoor-to-indoor channel model is proposed based on an extension of the geometry-based stochastic modeling approach to fulfill the requirements. We consider MPCs occurring due to reflection, scattering, and combinations of both. In the model, three different types of MPCs are modeled separately according to their characteristics. Each MPC is represented by a fixed scatterer, which has a fixed position while the receiver antenna is moving. The parameters of the outdoor-to-indoor channel model are extracted from two channel measurement campaigns. The proposed outdoor-to-indoor channel model is capable of accurately simulating the time variant channel. A comparison of the channel model with the channel measurement data is performed by comparing statistics.

  3. Capacity bounds for parallel IM-DD optical wireless channels

    KAUST Repository

    Chaaban, Anas

    2016-07-26

    A system consisting of parallel intensity-modulation direct-detection optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. If channel-state information is available at the transmitter, the bounds have to be optimized with respect to intensity allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the Karush-Kuhn-Tucker conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose a low-complexity intensity allocation algorithm which is nearly optimal. The optimized capacity lower bound coincides with the capacity at high signal-to-noise ratio. © 2016 IEEE.

  4. Wireless Indoor Location Estimation Based on Neural Network RSS Signature Recognition (LENSR)

    Energy Technology Data Exchange (ETDEWEB)

    Kurt Derr; Milos Manic

    2008-06-01

    Location Based Services (LBS), context aware applications, and people and object tracking depend on the ability to locate mobile devices, also known as localization, in the wireless landscape. Localization enables a diverse set of applications that include, but are not limited to, vehicle guidance in an industrial environment, security monitoring, self-guided tours, personalized communications services, resource tracking, mobile commerce services, guiding emergency workers during fire emergencies, habitat monitoring, environmental surveillance, and receiving alerts. This paper presents a new neural network approach (LENSR) based on a competitive topological Counter Propagation Network (CPN) with k-nearest neighborhood vector mapping, for indoor location estimation based on received signal strength. The advantage of this approach is both speed and accuracy. The tested accuracy of the algorithm was 90.6% within 1 meter and 96.4% within 1.5 meters. Several approaches for location estimation using WLAN technology were reviewed for comparison of results.

  5. A Method to Estimate the Horizontal Handover Decision Effect on Indoor Wireless Conversational Video Quality

    Directory of Open Access Journals (Sweden)

    Jose I. Alonso

    2008-05-01

    Full Text Available One of the most interesting and valuable services considered in fixed mobile convergence is video telephony. The success of this conversational video service will depend on the conversational video quality achieved in the multicell wireless indoor scenarios. One of the essential elements in the quality is the effect of the horizontal handovers in the conversational video. This paper analyzes the handover decision based on the probability calculation of handover events in the case of relative signal strength with hysteresis threshold (RSSHT approach, and it proposes a new handover decision mechanism, variable hysteresis, to avoid unnecessary handovers. The paper presents the impact of the number of handovers and their duration time on the video's effective frame rate. Moreover, the effect of video stream modification during a short handover is also analyzed. Probability and handover duration approaches are combined and a new simple method for video quality evaluation is caused by the handovers in multicell indoor WLAN scenarios. Finally, the model proposed has been applied to a real office scenario.

  6. An Integrated Wireless Wearable Sensor System for Posture Recognition and Indoor Localization.

    Science.gov (United States)

    Huang, Jian; Yu, Xiaoqiang; Wang, Yuan; Xiao, Xiling

    2016-10-31

    In order to provide better monitoring for the elderly or patients, we developed an integrated wireless wearable sensor system that can realize posture recognition and indoor localization in real time. Five designed sensor nodes which are respectively fixed on lower limbs and a standard Kalman filter are used to acquire basic attitude data. After the attitude angles of five body segments (two thighs, two shanks and the waist) are obtained, the pitch angles of the left thigh and waist are used to realize posture recognition. Based on all these attitude angles of body segments, we can also calculate the coordinates of six lower limb joints (two hip joints, two knee joints and two ankle joints). Then, a novel relative localization algorithm based on step length is proposed to realize the indoor localization of the user. Several sparsely distributed active Radio Frequency Identification (RFID) tags are used to correct the accumulative error in the relative localization algorithm and a set-membership filter is applied to realize the data fusion. The experimental results verify the effectiveness of the proposed algorithms.

  7. An Integrated Wireless Wearable Sensor System for Posture Recognition and Indoor Localization

    Directory of Open Access Journals (Sweden)

    Jian Huang

    2016-10-01

    Full Text Available In order to provide better monitoring for the elderly or patients, we developed an integrated wireless wearable sensor system that can realize posture recognition and indoor localization in real time. Five designed sensor nodes which are respectively fixed on lower limbs and a standard Kalman filter are used to acquire basic attitude data. After the attitude angles of five body segments (two thighs, two shanks and the waist are obtained, the pitch angles of the left thigh and waist are used to realize posture recognition. Based on all these attitude angles of body segments, we can also calculate the coordinates of six lower limb joints (two hip joints, two knee joints and two ankle joints. Then, a novel relative localization algorithm based on step length is proposed to realize the indoor localization of the user. Several sparsely distributed active Radio Frequency Identification (RFID tags are used to correct the accumulative error in the relative localization algorithm and a set-membership filter is applied to realize the data fusion. The experimental results verify the effectiveness of the proposed algorithms.

  8. Robust Floor Determination Algorithm for Indoor Wireless Localization Systems under Reference Node Failure

    Directory of Open Access Journals (Sweden)

    Kriangkrai Maneerat

    2016-01-01

    Full Text Available One of the challenging problems for indoor wireless multifloor positioning systems is the presence of reference node (RN failures, which cause the values of received signal strength (RSS to be missed during the online positioning phase of the location fingerprinting technique. This leads to performance degradation in terms of floor accuracy, which in turn affects other localization procedures. This paper presents a robust floor determination algorithm called Robust Mean of Sum-RSS (RMoS, which can accurately determine the floor on which mobile objects are located and can work under either the fault-free scenario or the RN-failure scenarios. The proposed fault tolerance floor algorithm is based on the mean of the summation of the strongest RSSs obtained from the IEEE 802.15.4 Wireless Sensor Networks (WSNs during the online phase. The performance of the proposed algorithm is compared with those of different floor determination algorithms in literature. The experimental results show that the proposed robust floor determination algorithm outperformed the other floor algorithms and can achieve the highest percentage of floor determination accuracy in all scenarios tested. Specifically, the proposed algorithm can achieve greater than 95% correct floor determination under the scenario in which 40% of RNs failed.

  9. TrackCC: A Practical Wireless Indoor Localization System Based on Less-Expensive Chips

    Science.gov (United States)

    Li, Xiaolong; Zheng, Yan; Cai, Jun; Yi, Yunfei

    2017-01-01

    This paper aims at proposing a new wireless indoor localization system (ILS), called TrackCC, based on a commercial type of low-power system-on-chip (SoC), nRF24LE1. This type of chip has only l output power levels and acute fluctuation for a received minimum power level in operation, which give rise to many practical challenges for designing localization algorithms. In order to address these challenges, we exploit the Markov theory to construct a (l+1)×(l+1) -sized state transition matrix to remove the fluctuation, and then propose a priority-based pattern matching algorithm to search for the most similar match in the signal map to estimate the real position of unknown nodes. The experimental results show that, compared to two existing wireless ILSs, LANDMARC and SAIL, which have meter level positioning accuracy, the proposed TrackCC can achieve the decimeter level accuracy on average in both line-of-sight (LOS) and non-line-of-sight (NLOS) senarios. PMID:28617313

  10. Secure Position Verification for Wireless Sensor Networks in Noisy Channels

    CERN Document Server

    Mandal, Partha Sarathi

    2011-01-01

    Position verification in wireless sensor networks (WSNs) is quite tricky in presence of attackers (malicious sensor nodes), who try to break the verification protocol by reporting their incorrect positions (locations) during the verification stage. In the literature of WSNs, most of the existing methods of position verification have used trusted verifiers, which are in fact vulnerable to attacks by malicious nodes. They also depend on some distance estimation techniques, which are not accurate in noisy channels (mediums). In this article, we propose a secure position verification scheme for WSNs in noisy channels without relying on any trusted entities. Our verification scheme detects and filters out all malicious nodes from the network with very high probability.

  11. Channel Assignment Algorithms for MRMC Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Mohammad A Hoque

    2011-11-01

    Full Text Available The wireless mesh networksare considered as one of the vital elements in today’s converged networks,providing high bandwidth and connectivity over large geographical areas. Mesh routers equipped with multiple radios can significantly overcome the capacity problem and increase the aggregate throughput of the network where single radio nodessuffer from performancedegradation. Moreover, the market availability of cheap radios or network interfaces also makes multi-radio solutions more feasible.A key issue in such networks is how to efficiently design a channel assignmentscheme that utilizes the available channels as well as increases overall performance of the network. This paper provides an overall review on the issues pertaining to the channel assignment in WMNs and the most relevant approaches and solutions developed in the area. They include design challenges, goals and criteria; routing considerations, graph based solutions and challenges of partially overlapped channels. We conclude that the assignment of channels to the radio interfaces continuously poses significant challenges. Many research issues remain open for further investigation.

  12. Analysis of Wireless Sensor Network Topology and Estimation of Optimal Network Deployment by Deterministic Radio Channel Characterization

    Directory of Open Access Journals (Sweden)

    Erik Aguirre

    2015-02-01

    Full Text Available One of the main challenges in the implementation and design of context-aware scenarios is the adequate deployment strategy for Wireless Sensor Networks (WSNs, mainly due to the strong dependence of the radiofrequency physical layer with the surrounding media, which can lead to non-optimal network designs. In this work, radioplanning analysis for WSN deployment is proposed by employing a deterministic 3D ray launching technique in order to provide insight into complex wireless channel behavior in context-aware indoor scenarios. The proposed radioplanning procedure is validated with a testbed implemented with a Mobile Ad Hoc Network WSN following a chain configuration, enabling the analysis and assessment of a rich variety of parameters, such as received signal level, signal quality and estimation of power consumption. The adoption of deterministic radio channel techniques allows the design and further deployment of WSNs in heterogeneous wireless scenarios with optimized behavior in terms of coverage, capacity, quality of service and energy consumption.

  13. A design and construction of 4 channel biotelemetry device employing indoor.

    Science.gov (United States)

    Fidan, Ugur; Güler, Nihal Fatma

    2007-06-01

    In this study, 4 channel biotelemetry device was designed and implemented for monitoring physiological and biological signals of the patients at indoor. Body temperature, respiratory rate, heart rate, electrocardiogram (ECG) and electromyogram (EMG) signals were transmitted using 10 mW 433 MHz and 500 mW 868 MHz FM/FSK transmitter with 9.6 Kps transmission speed. At indoor, receive signal strength indicator (RSSI) levels were measured and compared with 433 and 868 MHz carrier frequency. The placement of repeater at indoor was decided as a result of RSSI measurement.

  14. Space and time diversity in indoor wireless optical links achieving higher data rate

    Science.gov (United States)

    Alqudah, Yazan A.

    2013-02-01

    Multispot diffusing configuration (MSDC) in optical wireless links provide uniform optical power needed for multiaccess and spatial dependence that can be used to allow space diversity techniques over the link. The spatial channels are furnished in MSDC through utilizing multibeam transmitter that produces spatially confined diffusing spots, and a multibranch receiver with small enough branch field-of-view (FOV) to restrict the number of diffusing spots within its FOV. Here, we study different encoding techniques that use space and time diversity to reduce the bit error rate. An improved technique, constellation rotation, is proposed for pulse amplitude modulated (PAM) to increase the Euclidian distance between signal points, and thus reduce bit error. Our study shows that when a cap is placed on the amount of power allocated per channel, the performance of the improved 4-PAM using three spatial channels and soft binary decision provide the optimal performance. When the power allocated per user is restricted, the best performance is obtained through soft binary decision and by using symbols identified by their level and spatial channel to carry 2 bits per signal level-channel.

  15. A Wireless 32-Channel Implantable Bidirectional Brain Machine Interface

    Directory of Open Access Journals (Sweden)

    Yi Su

    2016-09-01

    Full Text Available All neural information systems (NIS rely on sensing neural activity to supply commands and control signals for computers, machines and a variety of prosthetic devices. Invasive systems achieve a high signal-to-noise ratio (SNR by eliminating the volume conduction problems caused by tissue and bone. An implantable brain machine interface (BMI using intracortical electrodes provides excellent detection of a broad range of frequency oscillatory activities through the placement of a sensor in direct contact with cortex. This paper introduces a compact-sized implantable wireless 32-channel bidirectional brain machine interface (BBMI to be used with freely-moving primates. The system is designed to monitor brain sensorimotor rhythms and present current stimuli with a configurable duration, frequency and amplitude in real time to the brain based on the brain activity report. The battery is charged via a novel ultrasonic wireless power delivery module developed for efficient delivery of power into a deeply-implanted system. The system was successfully tested through bench tests and in vivo tests on a behaving primate to record the local field potential (LFP oscillation and stimulate the target area at the same time.

  16. A Wireless 32-Channel Implantable Bidirectional Brain Machine Interface.

    Science.gov (United States)

    Su, Yi; Routhu, Sudhamayee; Moon, Kee S; Lee, Sung Q; Youm, WooSub; Ozturk, Yusuf

    2016-01-01

    All neural information systems (NIS) rely on sensing neural activity to supply commands and control signals for computers, machines and a variety of prosthetic devices. Invasive systems achieve a high signal-to-noise ratio (SNR) by eliminating the volume conduction problems caused by tissue and bone. An implantable brain machine interface (BMI) using intracortical electrodes provides excellent detection of a broad range of frequency oscillatory activities through the placement of a sensor in direct contact with cortex. This paper introduces a compact-sized implantable wireless 32-channel bidirectional brain machine interface (BBMI) to be used with freely-moving primates. The system is designed to monitor brain sensorimotor rhythms and present current stimuli with a configurable duration, frequency and amplitude in real time to the brain based on the brain activity report. The battery is charged via a novel ultrasonic wireless power delivery module developed for efficient delivery of power into a deeply-implanted system. The system was successfully tested through bench tests and in vivo tests on a behaving primate to record the local field potential (LFP) oscillation and stimulate the target area at the same time.

  17. Robust MSE precoder for imperfectly known MIMO wireless correlated channel

    Institute of Scientific and Technical Information of China (English)

    MA Peng-fei; ZHAO Hui; WANG Wen-bo

    2009-01-01

    Aimed at that only one form of channel statistic information is utilized in traditional robust precoder schemes: either the channel mean or the transmit antenna correlation in multiple-input multiple-output (MIMO) wireless system, this paper proposes robust precoder designs which exploit both of statistic information to minimize the equalization mean-square error (MSE) with power constraint. Two different power constraints are studied. Besides the usual sum power constraint over all antennas, the per-antenna power constraint is imposed at transmitter in this paper. Since each antenna has its own amplifier, individual power constraint on each antenna is more realistic. Especially in MIMO-OFDM systems, the Peak-to-Average Ratio (PAR) is one of main practical problems. Simulations show that the proposed schemes have better performance than traditional normalized zero forcing schemes for imperfectly known correlated channel. Moreover, per-antenna power constraint can efficiently decrease the demand of dynamic range of power amplifier on each transmit antenna, especially in MIMO-OFDM systems.

  18. Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy

    Science.gov (United States)

    Medina, Carlos; Segura, José Carlos; De la Torre, Ángel

    2013-01-01

    This paper describes the TELIAMADE system, a new indoor positioning system based on time-of-flight (TOF) of ultrasonic signal to estimate the distance between a receiver node and a transmitter node. TELIAMADE system consists of a set of wireless nodes equipped with a radio module for communication and a module for the transmission and reception of ultrasound. The access to the ultrasonic channel is managed by applying a synchronization algorithm based on a time-division multiplexing (TDMA) scheme. The ultrasonic signal is transmitted using a carrier frequency of 40 kHz and the TOF measurement is estimated by applying a quadrature detector to the signal obtained at the A/D converter output. Low sampling frequencies of 17.78 kHz or even 12.31 kHz are possible using quadrature sampling in order to optimize memory requirements and to reduce the computational cost in signal processing. The distance is calculated from the TOF taking into account the speed of sound. An excellent accuracy in the estimation of the TOF is achieved using parabolic interpolation to detect of maximum of the signal envelope at the matched filter output. The signal phase information is also used for enhancing the TOF measurement accuracy. Experimental results show a root mean square error (rmse) less than 2 mm and a standard deviation less than 0.3 mm for pseudorange measurements in the range of distances between 2 and 6 m. The system location accuracy is also evaluated by applying multilateration. A sub-centimeter location accuracy is achieved with an average rmse of 9.6 mm. PMID:23486218

  19. Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy

    Directory of Open Access Journals (Sweden)

    Ángel De la Torre

    2013-03-01

    Full Text Available This paper describes the TELIAMADE system, a new indoor positioning system based on time-of-flight (TOF of ultrasonic signal to estimate the distance between a receiver node and a transmitter node. TELIAMADE system consists of a set of wireless nodes equipped with a radio module for communication and a module for the transmission and reception of ultrasound. The access to the ultrasonic channel is managed by applying a synchronization algorithm based on a time-division multiplexing (TDMA scheme. The ultrasonic signal is transmitted using a carrier frequency of 40 kHz and the TOF measurement is estimated by applying a quadrature detector to the signal obtained at the A/D converter output. Low sampling frequencies of 17.78 kHz or even 12.31 kHz are possible using quadrature sampling in order to optimize memory requirements and to reduce the computational cost in signal processing. The distance is calculated from the TOF taking into account the speed of sound. An excellent accuracy in the estimation of the TOF is achieved using parabolic interpolation to detect of maximum of the signal envelope at the matched filter output. The signal phase information is also used for enhancing the TOF measurement accuracy. Experimental results show a root mean square error (rmse less than 2 mm and a standard deviation less than 0.3 mm for pseudorange measurements in the range of distances between 2 and 6 m. The system location accuracy is also evaluated by applying multilateration. A sub-centimeter location accuracy is achieved with an average rmse of 9.6 mm.

  20. Minimum Interference Channel Assignment Algorithm for Multicast in a Wireless Mesh Network.

    Science.gov (United States)

    Choi, Sangil; Park, Jong Hyuk

    2016-12-02

    Wireless mesh networks (WMNs) have been considered as one of the key technologies for the configuration of wireless machines since they emerged. In a WMN, wireless routers provide multi-hop wireless connectivity between hosts in the network and also allow them to access the Internet via gateway devices. Wireless routers are typically equipped with multiple radios operating on different channels to increase network throughput. Multicast is a form of communication that delivers data from a source to a set of destinations simultaneously. It is used in a number of applications, such as distributed games, distance education, and video conferencing. In this study, we address a channel assignment problem for multicast in multi-radio multi-channel WMNs. In a multi-radio multi-channel WMN, two nearby nodes will interfere with each other and cause a throughput decrease when they transmit on the same channel. Thus, an important goal for multicast channel assignment is to reduce the interference among networked devices. We have developed a minimum interference channel assignment (MICA) algorithm for multicast that accurately models the interference relationship between pairs of multicast tree nodes using the concept of the interference factor and assigns channels to tree nodes to minimize interference within the multicast tree. Simulation results show that MICA achieves higher throughput and lower end-to-end packet delay compared with an existing channel assignment algorithm named multi-channel multicast (MCM). In addition, MICA achieves much lower throughput variation among the destination nodes than MCM.

  1. Performance analysis of LDPC codes on OOK terahertz wireless channels

    Science.gov (United States)

    Chun, Liu; Chang, Wang; Jun-Cheng, Cao

    2016-02-01

    Atmospheric absorption, scattering, and scintillation are the major causes to deteriorate the transmission quality of terahertz (THz) wireless communications. An error control coding scheme based on low density parity check (LDPC) codes with soft decision decoding algorithm is proposed to improve the bit-error-rate (BER) performance of an on-off keying (OOK) modulated THz signal through atmospheric channel. The THz wave propagation characteristics and channel model in atmosphere is set up. Numerical simulations validate the great performance of LDPC codes against the atmospheric fading and demonstrate the huge potential in future ultra-high speed beyond Gbps THz communications. Project supported by the National Key Basic Research Program of China (Grant No. 2014CB339803), the National High Technology Research and Development Program of China (Grant No. 2011AA010205), the National Natural Science Foundation of China (Grant Nos. 61131006, 61321492, and 61204135), the Major National Development Project of Scientific Instrument and Equipment (Grant No. 2011YQ150021), the National Science and Technology Major Project (Grant No. 2011ZX02707), the International Collaboration and Innovation Program on High Mobility Materials Engineering of the Chinese Academy of Sciences, and the Shanghai Municipal Commission of Science and Technology (Grant No. 14530711300).

  2. Dynamic channel assignment scheme for multi-radio wireless mesh networks

    CSIR Research Space (South Africa)

    Kareem, TR

    2008-09-01

    Full Text Available This paper investigates the challenges involve in designing a dynamic channel assignment (DCA) scheme for wireless mesh networks, particularly for multi-radio systems. It motivates the need for fast switching and process coordination modules...

  3. Comparison of Three Non-Imaging Angle-Diversity Receivers as Input Sensors of Nodes for Indoor Infrared Wireless Sensor Networks: Theory and Simulation.

    Science.gov (United States)

    Mendoza, Beatriz R; Rodríguez, Silvestre; Pérez-Jiménez, Rafael; Ayala, Alejandro; González, Oswaldo

    2016-07-14

    In general, the use of angle-diversity receivers makes it possible to reduce the impact of ambient light noise, path loss and multipath distortion, in part by exploiting the fact that they often receive the desired signal from different directions. Angle-diversity detection can be performed using a composite receiver with multiple detector elements looking in different directions. These are called non-imaging angle-diversity receivers. In this paper, a comparison of three non-imaging angle-diversity receivers as input sensors of nodes for an indoor infrared (IR) wireless sensor network is presented. The receivers considered are the conventional angle-diversity receiver (CDR), the sectored angle-diversity receiver (SDR), and the self-orienting receiver (SOR), which have been proposed or studied by research groups in Spain. To this end, the effective signal-collection area of the three receivers is modelled and a Monte-Carlo-based ray-tracing algorithm is implemented which allows us to investigate the effect on the signal to noise ratio and main IR channel parameters, such as path loss and rms delay spread, of using the three receivers in conjunction with different combination techniques in IR links operating at low bit rates. Based on the results of the simulations, we show that the use of a conventional angle-diversity receiver in conjunction with the equal-gain combining technique provides the solution with the best signal to noise ratio, the lowest computational capacity and the lowest transmitted power requirements, which comprise the main limitations for sensor nodes in an indoor infrared wireless sensor network.

  4. Comparison of Three Non-Imaging Angle-Diversity Receivers as Input Sensors of Nodes for Indoor Infrared Wireless Sensor Networks: Theory and Simulation

    Science.gov (United States)

    Mendoza, Beatriz R.; Rodríguez, Silvestre; Pérez-Jiménez, Rafael; Ayala, Alejandro; González, Oswaldo

    2016-01-01

    In general, the use of angle-diversity receivers makes it possible to reduce the impact of ambient light noise, path loss and multipath distortion, in part by exploiting the fact that they often receive the desired signal from different directions. Angle-diversity detection can be performed using a composite receiver with multiple detector elements looking in different directions. These are called non-imaging angle-diversity receivers. In this paper, a comparison of three non-imaging angle-diversity receivers as input sensors of nodes for an indoor infrared (IR) wireless sensor network is presented. The receivers considered are the conventional angle-diversity receiver (CDR), the sectored angle-diversity receiver (SDR), and the self-orienting receiver (SOR), which have been proposed or studied by research groups in Spain. To this end, the effective signal-collection area of the three receivers is modelled and a Monte-Carlo-based ray-tracing algorithm is implemented which allows us to investigate the effect on the signal to noise ratio and main IR channel parameters, such as path loss and rms delay spread, of using the three receivers in conjunction with different combination techniques in IR links operating at low bit rates. Based on the results of the simulations, we show that the use of a conventional angle-diversity receiver in conjunction with the equal-gain combining technique provides the solution with the best signal to noise ratio, the lowest computational capacity and the lowest transmitted power requirements, which comprise the main limitations for sensor nodes in an indoor infrared wireless sensor network. PMID:27428966

  5. 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...

  6. Active Learning and Engagement with the Wireless Indoor Location Device (WILD) Learning System

    Science.gov (United States)

    Moldwin, M.; Samson, P. J.; Ojeda, L.; Miller, T.; Yu, J.

    2016-12-01

    The Wireless Indoor Location Device (WILD) Learning System being developed at the University of Michigan and the Education Technology company A2 Motus LLC provides a unique platform for social learning by allowing students to become active participants in live simulations of complex systems, like hurricane formation. The WILD Learning System enables teachers to engage students in kinesthetic activities that explore complex models from a wide variety of STEAM (Science, Technology, Engineering, Art and Math) disciplines. The system provides students' location, orientation and motion within the classroom and assigns each student different parameters depending on the activity. For example, students learning about hurricanes could be assigned atmospheric pressure levels and asked to arrange themselves around the room to simulate a hurricane. The Wild Learning System software then takes the students' pressure readings and locations and projects their locations overlaid onto a real-time generated simulated pressure weather map enabling the observation of how their arrangement influences the pressure structure. The teacher then could have the students orient themselves in the direction they think the resulting wind field will be based on the pressure contours as the system can show an arrow originating from each of the students position in the direction that they are facing. The system also could incorporate a student response-type system for the instructor to then directly question students about other concepts and record their response to both the kinesthetic activity and other formative assessment questions. The WILD Learning System consists of a sensor package for each student in the class, beacons to enable precise localization of the students, software to calculate student location information, and educational software for a variety of activities. In addition, a software development kit (SDK) is under development that would allow others to create additional learning

  7. A Broadcast Channel Assignment Mechanism based on The Broadcast Tree for Multi-radio Multi-channel Wireless Mesh Networks

    Science.gov (United States)

    Xia, Yan; Zeng, Yingzhi

    2016-02-01

    This paper proposed a broadcast Channel Assignment Mechanism on base of optimized Broadcast Tree for wireless Mesh network (WMN), which is created by Branch and Bound Method. The simulations show that our algorithm not only reduces the broadcast redundancy but also avoids the potential channel interferences produced by unnecessary relay nodes.

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

    Directory of Open Access Journals (Sweden)

    Jeffrey H. Reed

    2005-09-01

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

  9. Design and Development of a Nearable Wireless System to Control Indoor Air Quality and Indoor Lighting Quality.

    Science.gov (United States)

    Salamone, Francesco; Belussi, Lorenzo; Danza, Ludovico; Galanos, Theodore; Ghellere, Matteo; Meroni, Italo

    2017-05-04

    The article describes the results of the project "open source smart lamp" aimed at designing and developing a smart object able to manage and control the indoor environmental quality (IEQ) of the built environment. A first version of this smart object, built following a do-it-yourself (DIY) approach using a microcontroller, an integrated temperature and relative humidity sensor, and techniques of additive manufacturing, allows the adjustment of the indoor thermal comfort quality (ICQ), by interacting directly with the air conditioner. As is well known, the IEQ is a holistic concept including indoor air quality (IAQ), indoor lighting quality (ILQ) and acoustic comfort, besides thermal comfort. The upgrade of the smart lamp bridges the gap of the first version of the device providing the possibility of interaction with the air exchange unit and lighting system in order to get an overview of the potential of a nearable device in the management of the IEQ. The upgraded version was tested in a real office equipped with mechanical ventilation and an air conditioning system. This office was occupied by four workers. The experiment is compared with a baseline scenario and the results show how the application of the nearable device effectively optimizes both IAQ and ILQ.

  10. Design and Development of a Nearable Wireless System to Control Indoor Air Quality and Indoor Lighting Quality

    Directory of Open Access Journals (Sweden)

    Francesco Salamone

    2017-05-01

    Full Text Available The article describes the results of the project “open source smart lamp” aimed at designing and developing a smart object able to manage and control the indoor environmental quality (IEQ of the built environment. A first version of this smart object, built following a do-it-yourself (DIY approach using a microcontroller, an integrated temperature and relative humidity sensor, and techniques of additive manufacturing, allows the adjustment of the indoor thermal comfort quality (ICQ, by interacting directly with the air conditioner. As is well known, the IEQ is a holistic concept including indoor air quality (IAQ, indoor lighting quality (ILQ and acoustic comfort, besides thermal comfort. The upgrade of the smart lamp bridges the gap of the first version of the device providing the possibility of interaction with the air exchange unit and lighting system in order to get an overview of the potential of a nearable device in the management of the IEQ. The upgraded version was tested in a real office equipped with mechanical ventilation and an air conditioning system. This office was occupied by four workers. The experiment is compared with a baseline scenario and the results show how the application of the nearable device effectively optimizes both IAQ and ILQ.

  11. Channel Sounding System for MM-Wave Bands and Characterization of Indoor Propagation at 28 GHz

    DEFF Research Database (Denmark)

    Hejselbæk, Johannes; Ji, Yilin; Fan, Wei

    2017-01-01

    The aim of this work is to present a vector network analyzer (VNA) based channel sounding sys- tem capable of performing measurements in the range from 2 to 50 GHz. Further, this paper describes an indoor measurement campaign performed at 26 to 30 GHz. The sounding system is capable of receiving...... way. The measurement has been conducted with 42 measurement positions dis- tributed along a 10 m long path through an indoor lab- oratory environment. The transmitter was positioned such that measurements were conducted both in line- of-sight (LOS) and non-line-of-sight (NLOS) scenarios...

  12. Wireless medical ultrasound video transmission through noisy channels.

    Science.gov (United States)

    Panayides, A; Pattichis, M S; Pattichis, C S

    2008-01-01

    Recent advances in video compression such as the current state-of-the-art H.264/AVC standard in conjunction with increasingly available bitrate through new technologies like 3G, and WiMax have brought mobile health (m-Health) healthcare systems and services closer to reality. Despite this momentum towards m-Health systems and especially e-Emergency systems, wireless channels remain error prone, while the absence of objective quality metrics limits the ability of providing medical video of adequate diagnostic quality at a required bitrate. In this paper we investigate different encoding schemes and loss rates in medical ultrasound video transmission and come to conclusions involving efficiency, the trade-off between bitrate and quality, while we highlight the relationship linking video quality and the error ratio of corrupted P and B frames. More specifically, we investigate IPPP, IBPBP and IBBPBBP coding structures under packet loss rates of 2%, 5%, 8% and 10% and derive that the latter attains higher SNR ratings in all tested cases. A preliminary clinical evaluation shows that for SNR ratings higher than 30 db, video diagnostic quality may be adequate, while above 30.5 db the diagnostic information available in the reconstructed ultrasound video is close to that of the original.

  13. Hybrid Model For Reverberant Indoor Radio Channels Using Rays and Graphs

    DEFF Research Database (Denmark)

    Steinböck, Gerhard; Gan, Mingming; Meissner, Paul

    2016-01-01

    efficient calculation of the channel transfer function considering infinitely many components. We use ray-tracing and the theory of room electromagnetics to obtain the parameter settings for the propagation graph. Thus the proposed hybrid model does not require new or additional parameters in comparison......Ray-tracing tools allow for deterministic simulation of the channel impulse response. Studies show that these tools work well when the impulse response consists only of a few distinct components. However, measurements of the channel impulse response in indoor environments show a diffuse tail...

  14. Joint Channel Assignment and Routing in Multiradio Multichannel Wireless Mesh Networks: Design Considerations and Approaches

    Directory of Open Access Journals (Sweden)

    Omar M. Zakaria

    2016-01-01

    Full Text Available Multiradio wireless mesh network is a promising architecture that improves the network capacity by exploiting multiple radio channels concurrently. Channel assignment and routing are underlying challenges in multiradio architectures since both determine the traffic distribution over links and channels. The interdependency between channel assignments and routing promotes toward the joint solutions for efficient configurations. This paper presents an in-depth review of the joint approaches of channel assignment and routing in multiradio wireless mesh networks. First, the key design issues, modeling, and approaches are identified and discussed. Second, existing algorithms for joint channel assignment and routing are presented and classified based on the channel assignment types. Furthermore, the set of reconfiguration algorithms to adapt the network traffic dynamics is also discussed. Finally, the paper presents some multiradio practical implementations and test-beds and points out the future research directions.

  15. Analysis and Design of Timing Recovery Schemes for DMT Systems over Indoor Power-Line Channels

    Directory of Open Access Journals (Sweden)

    Cortés José Antonio

    2007-01-01

    Full Text Available Discrete multitone (DMT modulation is a suitable technique to cope with main impairments of broadband indoor power-line channels: spectral selectivity and cyclic time variations. Due to the high-density constellations employed to achieve the required bit-rates, synchronization issues became an important concern in these scenarios. This paper analyzes the performance of a conventional DMT timing recovery scheme designed for linear time-invariant (LTI channels when employed over indoor power lines. The influence of the channel cyclic short-term variations and the sampling jitter on the system performance is assessed. Bit-rate degradation due to timing errors is evaluated in a set of measured channels. It is shown that this synchronization mechanism limits the system performance in many residential channels. Two improvements are proposed to avoid this end: a new phase error estimator that takes into account the short-term changes in the channel response, and the introduction of notch filters in the timing recovery loop. Simulations confirm that the new scheme eliminates the bit-rate loss in most situations.

  16. Experimental characteristics of indoor wideband MIMO radio channels and their impact on stochastic modelling

    DEFF Research Database (Denmark)

    Steinböck, Gerhard; Yin, Xuefeng; Pedersen, Troels

    2009-01-01

    We compare two methods for estimation of path-component spreads in bi-azimuth and delay, namely the clustering approach and the density approach, in indoor environments. Monte Carlo simulations reveal possible shortcomings of the clustering approach. Published estimates of component spreads in de...... stress the obvious, but apparently sometimes forgotten, importance of validating the behavior and performance of channel parameter estimation techniques before using these tools to extract empirical information from measurement data....

  17. Maximizing Networking Capacity in Multi-Channel Multi-Radio Wireless Networks

    Institute of Scientific and Technical Information of China (English)

    万鹏俊; 万志国

    2014-01-01

    Providing each node with one or more multi-channel radios offers a promising avenue for enhancing the network capacity by simultaneously exploiting multiple non-overlapping channels through different radio interfaces and mitigating interferences through proper channel assignment. However, it is quite challenging to effectively utilize multiple channels and/or multiple radios to maximize throughput capacity. The National Natural Science Foundation of China (NSFC) Pro ject 61128005 conducted comprehensive algorithmic-theoretic and queuing-theoretic studies of maximizing wireless networking capacity in multi-channel multi-radio (MC-MR) wireless networks under the protocol interference model and fundamentally advanced the state of the art. In addition, under the notoriously hard physical interference model, this project has taken initial algorithmic studies on maximizing the network capacity, with or without power control. We expect the new techniques and tools developed in this project will have wide applications in capacity planning, resource allocation and sharing, and protocol design for wireless networks, and will serve as the basis for future algorithm developments in wireless networks with advanced features, such as multi-input multi-output (MIMO) wireless networks.

  18. RCFD: A Frequency Based Channel Access Scheme for Full Duplex Wireless Networks

    OpenAIRE

    Luvisotto, Michele; Sadeghi, Alireza; Lahouti, Farshad; Vitturi, Stefano; Zorzi, Michele

    2016-01-01

    Recently, several working implementations of in--band full--duplex wireless systems have been presented, where the same node can transmit and receive simultaneously in the same frequency band. The introduction of such a possibility at the physical layer could lead to improved performance but also poses several challenges at the MAC layer. In this paper, an innovative mechanism of channel contention in full--duplex OFDM wireless networks is proposed. This strategy is able to ensure efficient t...

  19. Analysis of Topological Impact on Wireless Channel Performance on Intelligent Street Lighting System

    Directory of Open Access Journals (Sweden)

    L. Azpilicueta

    2014-04-01

    Full Text Available In this work, an analysis of the physical radio channel propagation for the deployment of a wireless sensor network for intelligent street lighting is presented based on an in house implemented 3D ray launching code. Simulation as well as measurement results from a deployed wireless sensor network for an intelligent street light control system confirm the topological and morphological dependence of the considered scenario. The results can be applied to the optimal radioplanning of the wireless systems prior to deployment phase, in order to achieve maximum system performance while minimizing power consumption.

  20. Four-Tap RF Canceller Evaluation for Indoor In-Band Full-Duplex Wireless Operation

    Science.gov (United States)

    2016-07-24

    I. INTRODUCTION In-band full-duplex (IBFD) wireless operation can help alleviate the frequency spectrum congestion issues faced by current system...at the same time. This idea can be applied to 5G cellular, cognitive radio and wireless relay applications, among others, to reduce spectrum crowding

  1. Experimental Investigation of Subject-Specific On-Body Radio Propagation Channels for Body-Centric Wireless Communications

    Directory of Open Access Journals (Sweden)

    Mohammad Monirujjaman Khan

    2014-01-01

    Full Text Available In this paper, subject-specific narrowband (2.45 GHz and ultra-wideband (3–10.6 GHz on-body radio propagation studies in wireless body area networks (WBANs were performed by characterizing the path loss for eight different human subjects of different shapes and sizes. The body shapes and sizes of the test subjects used in this study are characterised as thin, medium build, fatty, shorter, average height and taller. Experimental investigation was made in an indoor environment using a pair of printed monopoles (for the narrowband case and a pair of tapered slot antennas (for the ultra-wideband (UWB case. Results demonstrated that, due to the different sizes, heights and shapes of the test subjects, the path loss exponent value varies up to maximum of 0.85 for the narrowband on-body case, whereas a maximum variation of the path loss exponent value of 1.15 is noticed for the UWB case. In addition, the subject-specific behaviour of the on-body radio propagation channels was compared between narrowband and UWB systems, and it was deduced that the on-body radio channels are subject-specific for both narrowband and UWB system cases, when the same antennas (same characteristics are used. The effect of the human body shape and size variations on the eight different on-body radio channels is also studied for both the narrowband and UWB cases.

  2. Asymptotic SER performance comparison of MPSK and MDPSK in wireless fading channels

    KAUST Repository

    Song, Xuegui

    2015-02-01

    We propose a general framework to investigate asymptotic relative performance between M-ary phase-shift keying (MPSK) and M-ary differential phase-shift keying (MDPSK) in wireless fading channels. Using this framework, we provide an alternative derivation for the closed-form expression of the asymptotic performance loss of MDPSK w.r.t. MPSK in an additive white Gaussian noise channel. The same performance loss is also shown to be true for the lognormal fading channels.

  3. Multi-channel distributed coordinated function over single radio in wireless sensor networks.

    Science.gov (United States)

    Campbell, Carlene E-A; Loo, Kok-Keong Jonathan; Gemikonakli, Orhan; Khan, Shafiullah; Singh, Dhananjay

    2011-01-01

    Multi-channel assignments are becoming the solution of choice to improve performance in single radio for wireless networks. Multi-channel allows wireless networks to assign different channels to different nodes in real-time transmission. In this paper, we propose a new approach, Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks (WSNs) over 802.11 networks. We presented simulation experiments in order to investigate the characteristics of multi-channel communication in wireless sensor networks using an NS2 platform. Nodes only use a single radio and perform channel switching only after specified threshold is reached. Single radio can only work on one channel at any given time. All nodes initiate constant bit rate streams towards the receiving nodes. In this work, we studied the impact of non-overlapping channels in the 2.4 frequency band on: constant bit rate (CBR) streams, node density, source nodes sending data directly to sink and signal strength by varying distances between the sensor nodes and operating frequencies of the radios with different data rates. We showed that multi-channel enhancement using our proposed algorithm provides significant improvement in terms of throughput, packet delivery ratio and delay. This technique can be considered for WSNs future use in 802.11 networks especially when the IEEE 802.11n becomes popular thereby may prevent the 802.15.4 network from operating effectively in the 2.4 GHz frequency band.

  4. Simple statistical channel model for weak temperature-induced turbulence in underwater wireless optical communication systems

    KAUST Repository

    Oubei, Hassan M.

    2017-06-16

    In this Letter, we use laser beam intensity fluctuation measurements to model and describe the statistical properties of weak temperature-induced turbulence in underwater wireless optical communication (UWOC) channels. UWOC channels with temperature gradients are modeled by the generalized gamma distribution (GGD) with an excellent goodness of fit to the measured data under all channel conditions. Meanwhile, thermally uniform channels are perfectly described by the simple gamma distribution which is a special case of GGD. To the best of our knowledge, this is the first model that comprehensively describes both thermally uniform and gradient-based UWOC channels.

  5. Spectral Subtraction Approach for Interference Reduction of MIMO Channel Wireless Systems

    Directory of Open Access Journals (Sweden)

    Tomohiro Ono

    2005-08-01

    Full Text Available In this paper, a generalized spectral subtraction approach for reducing additive impulsive noise, narrowband signals, white Gaussian noise and DS-CDMA interferences in MIMO channel DS-CDMA wireless communication systems is investigated. The interference noise reduction or suppression is essential problem in wireless mobile communication systems to improve the quality of communication. The spectrum subtraction scheme is applied to the interference noise reduction problems for noisy MIMO channel systems. The interferences in space and time domain signals can effectively be suppressed by selecting threshold values, and the computational load with the FFT is not large. Further, the fading effects of channel are compensated by spectral modification with the spectral subtraction process. In the simulations, the effectiveness of the proposed methods for the MIMO channel DS-CDMA is shown to compare with the conventional MIMO channel DS-CDMA.

  6. A Robust Indoor Autonomous Positioning System Using Particle Filter Based on ISM Band Wireless Communications

    Science.gov (United States)

    Ikeda, Takeshi; Kawamoto, Mitsuru; Sashima, Akio; Suzuki, Keiji; Kurumatani, Koichi

    In the field of the ubiquitous computing, positioning systems which can provide users' location information have paid attention as an important technical element which can be applied to various services, for example, indoor navigation services, evacuation services, market research services, guidance services, and so on. A lot of researchers have proposed various outdoor and indoor positioning systems. In this paper, we deal with indoor positioning systems. Many conventional indoor positioning systems use expensive infrastructures, because the propagated times of radio waves are used to measure users' positions with high accuracy. In this paper, we propose an indoor autonomous positioning system using radio signal strengths (RSSs) based on ISM band communications. In order to estimate users' positions, the proposed system utilizes a particle filter that is one of the Monte Carlo methods. Because the RSS information is used in the proposed system, the equipments configuring the system are not expensive compared with the conventional indoor positioning systems and it can be installed easily. Moreover, because the particle filter is used to estimate user's position, even if the RSS fluctuates due to, for example, multi-paths, the system can carry out position estimation robustly. We install the proposed system in one floor of a building and carry out some experiments in order to verify the validity of the proposed system. As a result, we confirmed that the average of the estimation errors of the proposed system was about 1.8 m, where the result is enough accuracy for achieving the services mentioned above.

  7. LTE-advanced and next generation wireless networks channel modelling and propagation

    CERN Document Server

    de la Roche, Guillaume; Allen, Ben

    2012-01-01

    LTE- A and Next Generation Wireless Networks: Channel Modeling and Performance describes recent advances in propagation and channel modeling necessary for simulating next generation wireless systems. Due to the radio spectrum scarcity, two fundamental changes are anticipated compared to the current status. Firstly, the strict reservation of a specific band for a unique standard could evolve toward a priority policy allowing the co-existence of secondary users in a band allocated to a primary system. Secondly, a huge increase of the number of cells is expected by combining outdoor base station

  8. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    Science.gov (United States)

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

  9. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs

    Science.gov (United States)

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network. PMID:26571042

  10. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    Directory of Open Access Journals (Sweden)

    Yuanfu Mo

    Full Text Available In a vehicular ad hoc network (VANET, the periodic exchange of single-hop status information broadcasts (beacon frames produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

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

    Directory of Open Access Journals (Sweden)

    Junjun Gao

    2012-01-01

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

  12. Multi-channel wireless sensor networks : protocols, design and evaluation

    NARCIS (Netherlands)

    Durmaz Incel, Özlem

    2009-01-01

    Pervasive systems, which are described as networked embedded systems integrated with everyday environments, are considered to have the potential to change our daily lives by creating smart surroundings and by their ubiquity, just as the Internet. In the last decade, “Wireless Sensor Networks” have a

  13. Multi-Channel Wireless Sensor Networks: Protocols, Design and Evaluation

    NARCIS (Netherlands)

    Durmaz, O.

    2009-01-01

    Pervasive systems, which are described as networked embedded systems integrated with everyday environments, are considered to have the potential to change our daily lives by creating smart surroundings and by their ubiquity, just as the Internet. In the last decade, “Wireless Sensor Networks��? have

  14. A Cross Layer Based Scalable Channel Slot Re-Utilization Technique for Wireless Mesh Network

    Directory of Open Access Journals (Sweden)

    Asha C N

    2016-04-01

    Full Text Available Due to tremendous growth of the wireless based appl ication services are increasing the demand for wireless communication techniques that use band width more effectively. Channel slot re- utilization in multi-radio wireless mesh networks i s a very challenging problem. WMNs have been adopted as back haul to connect various networ ks such as Wi-Fi (802.11, WI-MAX (802.16e etc. to the internet. The slot re-utiliza tion technique proposed so far suffer due to high collision due to improper channel slot usage approx imation error. To overcome this here the author propose the cross layer optimization techniq ue by designing a device classification based channel slot re-utilization routing strategy which considers the channel slot and node information from various layers and use some of the se parameters to approximate the risk involve in channel slot re-utilization in order to improve the QoS of the network. The simulation and analytical results show the effectiveness of ou r proposed approach in term of channel slot re-utilization efficiency and thus helps in reducin g latency for data transmission and reduce channel slot collision.

  15. 15 Gbit/s indoor optical wireless systems employing fast adaptation and imaging reception in a realistic environment

    Science.gov (United States)

    Alsaadi, Fuad E.

    2016-03-01

    Optical wireless systems are promising candidates for next-generation indoor communication networks. Optical wireless technology offers freedom from spectrum regulations and, compared to current radio-frequency networks, higher data rates and increased security. This paper presents a fast adaptation method for multibeam angle and delay adaptation systems and a new spot-diffusing geometry, and also considers restrictions needed for complying with eye safety regulations. The fast adaptation algorithm reduces the computational load required to reconfigure the transmitter in the case of transmitter and/or receiver mobility. The beam clustering approach enables the transmitter to assign power to spots within the pixel's field of view (FOV) and increases the number of such spots. Thus, if the power per spot is restricted to comply with eye safety standards, the new approach, in which more spots are visible within the FOV of the pixel, leads to enhanced signal-to-noise ratio (SNR). Simulation results demonstrate that the techniques proposed in this paper lead to SNR improvements that enable reliable operation at data rates as high as 15 Gbit/s. These results are based on simulation and not on actual measurements or experiments.

  16. Antenna Array Structures Effect on Water-Filling Capacity of Indoor NLOS MIMO Channel

    Institute of Scientific and Technical Information of China (English)

    L(U) Jian-gang; L(U) Ying-hua; DU Juan; LI Yun-zhuang; WANG Xu-ying

    2005-01-01

    A 2-D Shooting and Bouncing Ray-tracing method (SBR) is used to analyze the different antenna array structure effect on the water-filling Capacity Complementary Cumulative Distribution Functions (CCDFS) of indoor Non-Line-of-Sight (NLOS) Multiple-Input Multiple-Output (MIMO) channel. The results have shown that in NLOS indoor environment different antenna array structures affect on the CCDFS differently. The CCDFS of MIMO systems with antenna spacing 5λ change slightly with antenna array structures and all approach the in independent and identically distribution (i.i.d.) rayleigh channel water-filling capacity. When antenna spacing decreased to 0.5λ, the capacities of MIMO systems drop also, and change with antenna array structures greatly. The results on outage water-filling capacity also show that there exist a fixed relationship that i.i.d. rayleigh channel capacity is larger than the capacity equipped with linear antenna array which is larger than the capacity equipped with rectangular antenna array and the capacity equipped with circular antenna array.

  17. Average capacity for optical wireless communication systems over exponentiated Weibull distribution non-Kolmogorov turbulent channels.

    Science.gov (United States)

    Cheng, Mingjian; Zhang, Yixin; Gao, Jie; Wang, Fei; Zhao, Fengsheng

    2014-06-20

    We model the average channel capacity of optical wireless communication systems for cases of weak to strong turbulence channels, using the exponentiation Weibull distribution model. The joint effects of the beam wander and spread, pointing errors, atmospheric attenuation, and the spectral index of non-Kolmogorov turbulence on system performance are included. Our results show that the average capacity decreases steeply as the propagation length L changes from 0 to 200 m and decreases slowly down or tends to a stable value as the propagation length L is greater than 200 m. In the weak turbulence region, by increasing the detection aperture, we can improve the average channel capacity and the atmospheric visibility as an important issue affecting the average channel capacity. In the strong turbulence region, the increase of the radius of the detection aperture cannot reduce the effects of the atmospheric turbulence on the average channel capacity, and the effect of atmospheric visibility on the channel information capacity can be ignored. The effect of the spectral power exponent on the average channel capacity in the strong turbulence region is higher than weak turbulence region. Irrespective of the details determining the turbulent channel, we can say that pointing errors have a significant effect on the average channel capacity of optical wireless communication systems in turbulence channels.

  18. Analysis of Traffic Parameter Estimation and Its Impacts on Wireless Channel

    Institute of Scientific and Technical Information of China (English)

    徐玉滨; 沙学军; 强蔚

    2004-01-01

    Wide band or broadband access was paid much attention with the development of radio transmission technique. The wireless access control procedure play an important role in this type of system and efficiency of control algorithm has a great impact on throughput of channel resource. Based on wide band network control model and the characteristics of radio channel, this paper proposed a channel traffic estimation method and then performed a dynamic parameter control procedure and give detail analysis on estimation error and its impact on channel throughput and delay performance. Computation and simulation of system performance show a positive solution on system design.

  19. Multiple-state based power control for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2009-01-01

    Full Text Available backbone nodes (e.g., MPs) can be equipped with multiple radios and/or operate on multiple frequency channels [2]. Each radio has a single or multiple orthogonal channels [3]. In this scenario, an MP node has each radio with its own MAC and physical... of a self-managing and high capacity wireless mesh network [4]. However, utilizing multiple-radios and channels for each node simultaneously, results in striping related problems [11]. First, the use of multiple radios on multiple channels...

  20. Energy Efficient Spectrum Sensing for State Estimation over A Wireless Channel

    OpenAIRE

    Cao, Xianghui; Zhou, Xiangwei; Cheng, Yu

    2014-01-01

    The performance of remote estimation over wireless channel is strongly affected by sensor data losses due to interference. Although the impact of interference can be alleviated by performing spectrum sensing and then transmitting only when the channel is clear, the introduction of spectrum sensing also incurs extra energy expenditure. In this paper, we investigate the problem of energy efficient spectrum sensing for state estimation of a general linear dynamic system, and formulate an optimiz...

  1. A Simulation Study on the Throughput Performance of TCP over Wireless Fading Channel

    Institute of Scientific and Technical Information of China (English)

    YAO Ling; JI Hong; YUE Guang-xin

    2004-01-01

    Using Markov model and the network simulator-NS, this paper studies the TCP throughput performance in wireless fading channel where the packets losses are always caused by high and burst errors. The results show that the burstiness in packet errors caused by slow multipath fading benefits Reno compared to i.i.d packet errors.

  2. Survey on the cryptanalysis of wireless sensor networks using side-channel analysis

    CSIR Research Space (South Africa)

    Moabalobelo, T

    2012-09-01

    Full Text Available as they are deployed in open environments with no protective physical shielding. In this survey paper, we give an overview of the side channel attacks (particularly power analysis attacks) against wireless sensor networks and in addition discuss some of the suggested...

  3. Ultra-wideband wireless receiver front-end for high-speed indoor applications

    Directory of Open Access Journals (Sweden)

    Zhe-Yang Huang

    2014-12-01

    Full Text Available Low-noise, ultra-wideband (UWB wireless receiver front-end circuits were presented in this study. A two-stage common-source low-noise amplifier with wideband input impedance matching network, an active-balun and a double-balanced down-conversion mixer were adopted in the UWB wireless receiver front-end. The proposed wireless receiver front-end circuits were implemented in 0.18 μm radio-frequency-CMOS process. The maximum down-conversion power gain of the front-end is 25.8 dB; minimum single-sideband noise figure of the front-end is 4.9 dB over complete UWB band ranging from 3.1 to 10.6 GHz. Power consumption including buffers is 39.2 mW.

  4. Wireless multi-antenna channels modeling and simulation

    CERN Document Server

    Primak, Serguei

    2011-01-01

    This book offers a practical guide on how to use and apply channel models for system evaluation In this book, the authors focus on modeling and simulation of multiple antennas channels, including multiple input multiple output (MIMO) communication channels, and the impact of such models on channel estimation and system performance. Both narrowband and wideband models are addressed. Furthermore, the book covers topics related to modeling of MIMO channel, their numerical simulation, estimation and prediction, as well as applications to receive diversity, capacity and space-time c

  5. Channel Measurements for a Optical Fiber-Wireless Transmission System in the 75-110 GHz Band

    DEFF Research Database (Denmark)

    Pang, Xiaodan; Yu, Xianbin; Zhao, Ying;

    2011-01-01

    We report on measured optical fiber W-band wireless channel characteristics such as frequency response, channel loss and fading, directivity, channel capacity and phase noise. Our proposed system performs a sextuple frequency up-conversion after 20 km of fiber transmission, followed by a W......-band wireless link. Our experimental measurements are intended to provide engineering rules for designing hybrid multi-gigabit W band transmission links....

  6. An Adaptive Channel Access Method for Dynamic Super Dense Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Chunyang Lei

    2015-12-01

    Full Text Available Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT, Machine-to-Machine (M2M communications, Vehicular-to-Vehicular (V2V communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95 % of the theoretical optimal throughput and 0 . 97 of fairness index especially in dynamic and dense networks.

  7. An Adaptive Channel Access Method for Dynamic Super Dense Wireless Sensor Networks.

    Science.gov (United States)

    Lei, Chunyang; Bie, Hongxia; Fang, Gengfa; Zhang, Xuekun

    2015-12-03

    Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95 % of the theoretical optimal throughput and 0 . 97 of fairness index especially in dynamic and dense networks.

  8. AN EVOLUTIONARY ALGORITHM FOR CHANNEL ASSIGNMENT PROBLEM IN WIRELESS MOBILE NETWORKS

    Directory of Open Access Journals (Sweden)

    Yee Shin Chia

    2012-12-01

    Full Text Available The channel assignment problem in wireless mobile network is the assignment of appropriate frequency spectrum to incoming calls while maintaining a satisfactory level of electromagnetic compatibility (EMC constraints. An effective channel assignment strategy is important due to the limited capacity of frequency spectrum in wireless mobile network. Most of the existing channel assignment strategies are based on deterministic methods. In this paper, an adaptive genetic algorithm (GA based channel assignment strategy is introduced for resource management and to reduce the effect of EMC interferences. The most significant advantage of the proposed optimization method is its capability to handle both the reassignment of channels for existing calls as well as the allocation of channel to a new incoming call in an adaptive process to maximize the utility of the limited resources. It is capable to adapt the population size to the number of eligible channels for a particular cell upon new call arrivals to achieve reasonable convergence speed. The MATLAB simulation on a 49-cells network model for both uniform and nonuniform call traffic distributions showed that the proposed channel optimization method can always achieve a lower average new incoming call blocking probability compared to the deterministic based channel assignment strategy.

  9. A Survey of Wireless Fair Queuing Algorithms with Location-Dependent Channel Errors

    Directory of Open Access Journals (Sweden)

    Anca VARGATU

    2011-01-01

    Full Text Available The rapid development of wireless networks has brought more and more attention to topics related to fair allocation of resources, creation of suitable algorithms, taking into account the special characteristics of wireless environment and insurance fair access to the transmission channel, with delay bound and throughput guaranteed. Fair allocation of resources in wireless networks requires significant challenges, because of errors that occur only in these networks, such as location-dependent and bursty channel errors. In wireless networks, frequently happens, because interference of radio waves, that a user experiencing bad radio conditions during a period of time, not to receive resources in that period. This paper analyzes some resource allocation algorithms for wireless networks with location dependent errors, specifying the base idea for each algorithm and the way how it works. The analyzed fair queuing algorithms differ by the way they treat the following aspects: how to select the flows which should receive additional services, how to allocate these resources, which is the proportion received by error free flows and how the flows affected by errors are compensated.

  10. Upper Capacity Bounds of MIMO Wireless Systems Through Fading Channels

    Directory of Open Access Journals (Sweden)

    Rachna Mahey

    2015-01-01

    Full Text Available This paper investigates the upper capacity bounds of MIMO systems with correlation and antenna selection techniques in general fading environments. With Antenna Selection techniques, the increased hardware complexity due to multiple antennas and large number of RF chains can be reduced to a substantial amount, retaining the diversity benefits of MIMO systems. The channel Correlation also affects the capacity of MIMO fading channels. Hence, to evaluate the upper bounds of capacity through fading channels, performance of MIMO systems is exemplified under Nakagami-m and Rayleigh fading channels while considering that the channel characteristics are known at a transmitter. The obtained results give an assessment to the better understanding to the effect of antenna selection and correlation on the capacity of MIMO channels, and how they can be used in different fading environments.

  11. A wireless multi-channel bioimpedance measurement system for personalized healthcare and lifestyle.

    Science.gov (United States)

    Ramos, Javier; Ausín, José Luis; Lorido, Antonio Manuel; Redondo, Francisco; Duque-Carrillo, Juan Francisco

    2013-01-01

    Miniaturized, noninvasive, wearable sensors constitute a fundamental prerequisite for pervasive, predictive, and preventive healthcare systems. In this sense, this paper presents the design, realization, and evaluation of a wireless multi-channel measurement system based on a cost-effective high-performance integrated circuit for electrical bioimpedance (EBI) measurements in the frequency range from 1 kHz to 1 MHz. The resulting on-chip spectrometer provides high measuring EBI capabilities and together with a low-cost, commercially available radio frequency transceiver device. It provides reliable wireless communication, constitutes the basic node to build EBI wireless sensor networks (EBI-WSNs). The proposed EBI-WSN behaves as a high-performance wireless multi-channel EBI spectrometer, where the number of channels is completely scalable and independently configurable to satisfy specific measurement requirements of each individual. A prototype of the EBI node leads to a very small printed circuit board of approximately 8 cm2 including chip-antenna, which can operate several years on one 3-V coin cell battery and make it suitable for long-term preventive healthcare monitoring.

  12. Outage probability analysis of wireless sensor networks in the presence of channel fading and spatial correlation

    KAUST Repository

    Al-Murad, Tamim M.

    2011-07-01

    Evaluating the reliability of wireless sensor networks is becoming more important as theses networks are being used in crucial applications. The outage probability defined as the probability that the error in the system exceeds a maximum acceptable threshold has recently been used as a measure of the reliability of such systems. In this work we find the outage probability of wireless sensor network in different scenarios of distributed sensing where sensors\\' readings are affected by spatial correlation and in the presence of channel fading. © 2011 IEEE.

  13. A Greedy link scheduler for Wireless Networks having Gaussian Broadcast and Multiple Access Channels

    CERN Document Server

    Sridharan, Arun; Uysal-Biyikoglu, Elif

    2010-01-01

    Information theoretic Broadcast Channels (BC) and Multiple Access Channels (MAC) enable a single node to transmit data simultaneously to multiple nodes, and multiple nodes to transmit data simultaneously to a single node respectively. In this paper, we address the problem of link scheduling in multihop wireless networks containing nodes with BC and MAC capabilities. We first propose an interference model that extends protocol interference models, originally designed for point to point channels, to include the possibility of BC and MAC. Due to the high complexity of optimal link schedulers, we introduce the Multiuser Greedy Maximum Weight algorithm for link scheduling in multihop wireless networks containing BCs and MACs. Given a network graph, we develop new local pooling conditions and show that the performance of our algorithm can be fully characterized using the associated parameter, the multiuser local pooling factor. We provide examples of some network graphs, on which we apply local pooling conditions a...

  14. Key Generation in Wireless Sensor Networks Based on Frequency-selective Channels - Design, Implementation, and Analysis

    CERN Document Server

    Wilhelm, Matthias; Schmitt, Jens B

    2010-01-01

    Key management in wireless sensor networks faces several new challenges. The scale, resource limitations, and new threats such as node capture necessitate the use of an on-line key generation by the nodes themselves. However, the cost of such schemes is high since their secrecy is based on computational complexity. Recently, several research contributions justified that the wireless channel itself can be used to generate information-theoretic secure keys. By exchanging sampling messages during movement, a bit string can be derived that is only known to the involved entities. Yet, movement is not the only possibility to generate randomness. The channel response is also strongly dependent on the frequency of the transmitted signal. In our work, we introduce a protocol for key generation based on the frequency-selectivity of channel fading. The practical advantage of this approach is that we do not require node movement. Thus, the frequent case of a sensor network with static motes is supported. Furthermore, the...

  15. Analysis on the performance dependency of channel models in a wireless peer-to-peer network

    Science.gov (United States)

    Wang, Yupeng; Liu, Tianlong; Yu, Zelong; Li, Yufeng

    2017-08-01

    In order to reduce the simulation complexity and time of peer-to-peer network such as Ad Hoc network, most simulations only use the simplified Free Space Model or Two Ray Ground model to approximate the attenuation due to the wireless transmission without considering the dependency between system performance and channel models. In this paper, the effects of channel models on the wireless peer-to-peer network performance is analyzed in more details by using the conventional routing and medium access control algorithm to find the system performance sensitivity to different channel models. Through the computer simulation using network simulator 2, we found that some aspects of the system performance is only sensitive to the large scale fading effects, while others are not.

  16. Spherical Arrays for Wireless Channel Characterization and Emulation

    DEFF Research Database (Denmark)

    Franek, Ondrej; Pedersen, Gert Frølund

    2014-01-01

    Three types of spherical arrays for use in wireless communication research are presented. First, a spherical array of 32 monopoles with beam steering in arbitrary direction and with arbitrary polarization is described. Next, a spherical array with 16 quad-ridged open-flared horns is introduced, o......, offering better wideband performance and easier beam steering. Finally, a multi-probe setup for over-the-air testing of multiple-input multiple-output mobile devices is presented, being essentially a spherical array with inward radiation....

  17. Optimal Channel Width Adaptation, Logical Topology Design, and Routing in Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Li Li

    2009-01-01

    Full Text Available Radio frequency spectrum is a finite and scarce resource. How to efficiently use the spectrum resource is one of the fundamental issues for multi-radio multi-channel wireless mesh networks. However, past research efforts that attempt to exploit multiple channels always assume channels of fixed predetermined width, which prohibits the further effective use of the spectrum resource. In this paper, we address how to optimally adapt channel width to more efficiently utilize the spectrum in IEEE802.11-based multi-radio multi-channel mesh networks. We mathematically formulate the channel width adaptation, logical topology design, and routing as a joint mixed 0-1 integer linear optimization problem, and we also propose our heuristic assignment algorithm. Simulation results show that our method can significantly improve spectrum use efficiency and network performance.

  18. Realization of Low Power High-Speed Channel Filters with Stringent Adjacent Channel Attenuation Specifications for Wireless Communication Receivers

    Science.gov (United States)

    Mathew, Jimson; Mahesh, R.; Vinod, A. P.; Lai, Edmund M.-K.

    Finite impulse response (FIR) filtering is the most computationally intensive operation in the channelizer of a wireless communication receiver. Higher order FIR channel filters are needed in the channelizer to meet the stringent adjacent channel attenuation specifications of wireless communications standards. The computational cost of FIR filters is dominated by the complexity of the coefficient multipliers. Even though many methods for reducing the complexity of filter multipliers have been proposed in literature, these works focused on lower order filters. This paper presents a coefficient-partitioning-based binary subexpression elimination method for realizing low power FIR filters. We show that the FIR filters implemented using proposed method consume less power and achieve speed improvement compared to existing filter implementations. Design examples of the channel filters employed in the Digital Advanced Mobile Phone System (D-AMPS) and Personal Digital Cellular (PDC) receivers show that the proposed method achieved 23% average reductions of full adder and power consumption and 23.3% reduction of delay over the best existing method. Synthesis results show that the proposed method offers average area reduction of 8% and power reduction of 22% over the best known method in literature.

  19. A Wearable Wireless Sensor Network for Indoor Smart Environment Monitoring in Safety Applications

    Science.gov (United States)

    Antolín, Diego; Medrano, Nicolás; Calvo, Belén; Pérez, Francisco

    2017-01-01

    This paper presents the implementation of a wearable wireless sensor network aimed at monitoring harmful gases in industrial environments. The proposed solution is based on a customized wearable sensor node using a low-power low-rate wireless personal area network (LR-WPAN) communications protocol, which as a first approach measures CO2 concentration, and employs different low power strategies for appropriate energy handling which is essential to achieving long battery life. These wearables nodes are connected to a deployed static network and a web-based application allows data storage, remote control and monitoring of the complete network. Therefore, a complete and versatile remote web application with a locally implemented decision-making system is accomplished, which allows early detection of hazardous situations for exposed workers. PMID:28216556

  20. A Wearable Wireless Sensor Network for Indoor Smart Environment Monitoring in Safety Applications

    Directory of Open Access Journals (Sweden)

    Diego Antolín

    2017-02-01

    Full Text Available This paper presents the implementation of a wearable wireless sensor network aimed at monitoring harmful gases in industrial environments. The proposed solution is based on a customized wearable sensor node using a low-power low-rate wireless personal area network (LR-WPAN communications protocol, which as a first approach measures CO2 concentration, and employs different low power strategies for appropriate energy handling which is essential to achieving long battery life. These wearables nodes are connected to a deployed static network and a web-based application allows data storage, remote control and monitoring of the complete network. Therefore, a complete and versatile remote web application with a locally implemented decision-making system is accomplished, which allows early detection of hazardous situations for exposed workers.

  1. A Wearable Wireless Sensor Network for Indoor Smart Environment Monitoring in Safety Applications.

    Science.gov (United States)

    Antolín, Diego; Medrano, Nicolás; Calvo, Belén; Pérez, Francisco

    2017-02-14

    This paper presents the implementation of a wearable wireless sensor network aimed at monitoring harmful gases in industrial environments. The proposed solution is based on a customized wearable sensor node using a low-power low-rate wireless personal area network (LR-WPAN) communications protocol, which as a first approach measures CO₂ concentration, and employs different low power strategies for appropriate energy handling which is essential to achieving long battery life. These wearables nodes are connected to a deployed static network and a web-based application allows data storage, remote control and monitoring of the complete network. Therefore, a complete and versatile remote web application with a locally implemented decision-making system is accomplished, which allows early detection of hazardous situations for exposed workers.

  2. CAPACITY EVALUATION OF MULTI-CHANNEL WIRELESS AD HOC NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Li Jiandong; Zygmunt J. Haas; Min Sheng

    2003-01-01

    In this paper, the capacity of multi-channel, multi-hop ad hoc network is evaluated.In particular, the performance of multi-hop ad hoc network with single channel IEEE 802.11MAC utilizing different topologies is shown. Also the scaling laws of throughputs for large-scale ad hoc networks and the theoretical guaranteed throughput bounds for multi-channel gridtopology systems are proposed. The results presented in this work will help researchers to choosethe proper parameter settings in evaluation of protocols for multi-hop ad hoc networks.

  3. The Indoor Localization and Tracking Estimation Method of Mobile Targets in Three-Dimensional Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Zixi Jia

    2015-11-01

    Full Text Available Indoor localization is a significant research area in wireless sensor networks (WSNs. Generally, the nodes of WSNs are deployed in the same plane, i.e., the floor, as the target to be positioned, which causes the sensing signal to be influenced or even blocked by unpredictable obstacles, like furniture. However, a 3D system, like Cricket, can reduce the negative impact of obstacles to the maximum extent and guarantee the sensing signal transmission by using the line of sight (LOS. However, most of the traditional localization methods are not available for the new deployment mode. In this paper, we propose the self-localization of beacons method based on the Cayley–Menger determinant, which can determine the positions of beacons stuck in the ceiling; and differential sensitivity analysis (DSA is also applied to eliminate measurement errors in measurement data fusion. Then, the calibration of beacons scheme is proposed to further refine the locations of beacons by the mobile robot. According to the robot’s motion model based on dead reckoning, which is the process of determining one’s current position, we employ the H ∞ filter and the strong tracking filter (STF to calibrate the rough locations, respectively. Lastly, the optimal node selection scheme based on geometric dilution precision (GDOP is presented here, which is able to pick the group of beacons with the minimum GDOP from all of the beacons. Then, we propose the GDOP-based weighting estimation method (GWEM to associate redundant information with the position of the target. To verify the proposed methods in the paper, we design and conduct a simulation and an experiment in an indoor setting. Compared to EKF and the H ∞ filter, the adopted STF method can more effectively calibrate the locations of beacons; GWEM can provide centimeter-level precision in 3D environments by using the combination of beacons that minimizes GDOP.

  4. The Indoor Localization and Tracking Estimation Method of Mobile Targets in Three-Dimensional Wireless Sensor Networks.

    Science.gov (United States)

    Jia, Zixi; Wu, Chengdong; Li, Zhao; Zhang, Yunzhou; Guan, Bo

    2015-11-24

    Indoor localization is a significant research area in wireless sensor networks (WSNs). Generally, the nodes of WSNs are deployed in the same plane, i.e., the floor, as the target to be positioned, which causes the sensing signal to be influenced or even blocked by unpredictable obstacles, like furniture. However, a 3D system, like Cricket, can reduce the negative impact of obstacles to the maximum extent and guarantee the sensing signal transmission by using the line of sight (LOS). However, most of the traditional localization methods are not available for the new deployment mode. In this paper, we propose the self-localization of beacons method based on the Cayley-Menger determinant, which can determine the positions of beacons stuck in the ceiling; and differential sensitivity analysis (DSA) is also applied to eliminate measurement errors in measurement data fusion. Then, the calibration of beacons scheme is proposed to further refine the locations of beacons by the mobile robot. According to the robot's motion model based on dead reckoning, which is the process of determining one's current position, we employ the H∞ filter and the strong tracking filter (STF) to calibrate the rough locations, respectively. Lastly, the optimal node selection scheme based on geometric dilution precision (GDOP) is presented here, which is able to pick the group of beacons with the minimum GDOP from all of the beacons. Then, we propose the GDOP-based weighting estimation method (GWEM) to associate redundant information with the position of the target. To verify the proposed methods in the paper, we design and conduct a simulation and an experiment in an indoor setting. Compared to EKF and the H∞ filter, the adopted STF method can more effectively calibrate the locations of beacons; GWEM can provide centimeter-level precision in 3D environments by using the combination of beacons that minimizes GDOP.

  5. Robust Video Transmission Over Broadband Wireless Fading Channels Using Improved MPEG-4 DataPartitioning

    Institute of Scientific and Technical Information of China (English)

    WANGDonghua; ZHOUYuanhua; SUPengcheng; GEJingyan

    2004-01-01

    A robust video transmission scheme based on space-time coded Orthogonal frequency division multiplexing (OFDM) over broadband wireless fading channels is proposed. Considering the MPEG-4 standardized data partitioning method doesn't take care of important high frequency information of IVOP and Direct current (DC) coefficients of PVOP and has poor error concealment effects for lost texture data with abundant details, a more robust data partitioning method called NewDP is designed after significances of some MPEG-4 Simple profile (SP) bitstreams' syntactical elements are carefully analyzed and tested. Then, the UEP method based on Systemic ratecompatible punctured convolutional channel codes (SRCPC) is applied to protect layered video bitstreams with different priorities. For fighting with fading and noise in wireless channels, Space-time block codes (STBC) combined with OFDM are applied in our scheme. STBC can provide diversity gains by multiple transmit antennae while OFDM can effectively alleviate frequency-selective fading effects, making our scheme more robust as well as higher transmitting rates. Simulation results show that our scheme can get better video transmission effects over broadband wireless fading channels than the schemes using the Equal error protection method (EEP) or based on the MPEG-4 standardized data partitioning methods.

  6. A New OFDM System Based on Lifting Wavelet Transform for Wireless Channel

    Institute of Scientific and Technical Information of China (English)

    GAO Jian-bo; ZHAO Er-yuan

    2005-01-01

    It is well known that the Orthogonal Frequency Division Multiplexing(OFDM) system has a high ability to overcome the effect of multipath and can obtain high spectral efficiency in the wireless communication channel. However, avoid Interchannel Interference (ICI) and Intersymbol Interference (ISI) in wireless channel, a guard interval longer than channel delay is used in conventional OFDM system, which cause the efficiency of bandwidth usage reduced. Due to the superior spectral containment of wavelets, this paper proposed a new OFDM system based on Lifting Wavelet Transform (LWT-OFDM), which adopts lifting wavelet transform to replace the conventional Fourier transform. This new OFDM system doesn't need the Cyclic Prefix (CP) so its structure is more simply than FFT-OFDM and its algorithm is as simply as FFT-OFDM. The new LWT-OFDM system can mitigates some disadvantages of FFT-OFDM system, such as a relatively large peak-to-average power ratio, more sensitive to carrier frequency offset and phase noise. Simulations show that the LWT-OFDM system is more effective and attractive than conversional FFT-OFDM in wireless channel.

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

    DEFF Research Database (Denmark)

    Pang, Xiaodan; Zhao, Ying; Deng, Lei

    2011-01-01

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

  8. The Channel Estimation and Modeling in High Altitude Platform Station Wireless Communication Dynamic Network

    Directory of Open Access Journals (Sweden)

    Xiaoyang Liu

    2017-01-01

    Full Text Available In order to analyze the channel estimation performance of near space high altitude platform station (HAPS in wireless communication system, the structure and formation of HAPS are studied in this paper. The traditional Least Squares (LS channel estimation method and Singular Value Decomposition-Linear Minimum Mean-Squared (SVD-LMMS channel estimation method are compared and investigated. A novel channel estimation method and model are proposed. The channel estimation performance of HAPS is studied deeply. The simulation and theoretical analysis results show that the performance of the proposed method is better than the traditional methods. The lower Bit Error Rate (BER and higher Signal Noise Ratio (SNR can be obtained by the proposed method compared with the LS and SVD-LMMS methods.

  9. Detecting Multi-ChannelWireless Microphone User Emulation Attacks in White Space with Noise

    Directory of Open Access Journals (Sweden)

    Dan Shan

    2014-07-01

    Full Text Available Cognitive radio networks (CRNs are susceptible to primary user emulation (PUE attacks. Conventional PUE attack detection approaches consider television broadcasting as the primary user. In this work, however, we study a special kind of PUE attack named wireless microphone user emulation (WMUE attack. Existing work on WMUE attack detection deals with single channel senario. Although multi-channelWM(MCWM systems are common, detecting WMUE attacks under a multi-channel setting in noisy environments has not been well studied. In this work, we propose a novelmulti-channelWMUEattack detection scheme which operates in low signal-to-noise ratio (SNR environments with low computational complexity, thanks to the first 1.5-bit FM demodulator whose outputs are represented by only 0, 1 and -1. Experimental results show that, the proposed scheme can effectively detect multi-channel WMUE attacks within 0.25 second when SNR is lower than 6 dB.

  10. Modified Spatial Channel Model for MIMO Wireless Systems

    Directory of Open Access Journals (Sweden)

    Pekka Kyösti

    2007-12-01

    Full Text Available The third generation partnership Project's (3GPP spatial channel model (SCM is a stochastic channel model for MIMO systems. Due to fixed subpath power levels and angular directions, the SCM model does not show the degree of variation which is encountered in real channels. In this paper, we propose a modified SCM model which has random subpath powers and directions and still produces Laplace shape angular power spectrum. Simulation results on outage MIMO capacity with basic and modified SCM models show that the modified SCM model gives constantly smaller capacity values. Accordingly, it seems that the basic SCM gives too small correlation between MIMO antennas. Moreover, the variance in capacity values is larger using the proposed SCM model. Simulation results were supported by the outage capacity results from a measurement campaign conducted in the city centre of Oulu, Finland.

  11. Algorithm for Hybrid Optical Fiber-Wireless Photonic Channel Allocation for Millimeter-waveband 5G Networks

    DEFF Research Database (Denmark)

    Gomez Gonzalvo, A.; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2014-01-01

    This paper presents a performance assessment of an algorithm for hybrid fiber-wireless photonic channel allocation in 5G using radio-over-fiber with active delivery. Simulations show reductions of network blocking probability in 98% of the tested cases......This paper presents a performance assessment of an algorithm for hybrid fiber-wireless photonic channel allocation in 5G using radio-over-fiber with active delivery. Simulations show reductions of network blocking probability in 98% of the tested cases...

  12. A Hybrid Indoor Ambient Light and Vibration Energy Harvester for Wireless Sensor Nodes

    Directory of Open Access Journals (Sweden)

    Hua Yu

    2014-05-01

    Full Text Available To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.

  13. A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.

    Science.gov (United States)

    Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei

    2014-05-19

    To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT) for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si) solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.

  14. Load-Adaptive Practical Multi-Channel Communications in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Choong Seon Hong

    2010-09-01

    Full Text Available In recent years, a significant number of sensor node prototypes have been designed that provide communications in multiple channels. This multi-channel feature can be effectively exploited to increase the overall capacity and performance of wireless sensor networks (WSNs. In this paper, we present a multi-channel communications system for WSNs that is referred to as load-adaptive practical multi-channel communications (LPMC. LPMC estimates the active load of a channel at the sink since it has a more comprehensive view of the network behavior, and dynamically adds or removes channels based on the estimated load. LPMC updates the routing path to balance the loads of the channels. The nodes in a path use the same channel; therefore, they do not need to switch channels to receive or forward packets. LPMC has been evaluated through extensive simulations, and the results demonstrate that it can effectively increase the delivery ratio, network throughput, and channel utilization, and that it can decrease the end-to-end delay and energy consumption.

  15. Simulation of devices mobility to estimate wireless channel quality metrics in 5G networks

    Science.gov (United States)

    Orlov, Yu.; Fedorov, S.; Samuylov, A.; Gaidamaka, Yu.; Molchanov, D.

    2017-07-01

    The problem of channel quality estimation for devices in a wireless 5G network is formulated. As a performance metrics of interest we choose the signal-to-interference-plus-noise ratio, which depends essentially on the distance between the communicating devices. A model with a plurality of moving devices in a bounded three-dimensional space and a simulation algorithm to determine the distances between the devices for a given motion model are devised.

  16. DMesh: Incorporating Practical Directional Antennas in Multi-Channel Wireless Mesh Networks

    OpenAIRE

    Das, Saumitra M.; Pucha, Himabindu; Koutsonikolas, Dimitrios; Hu, Y. Charlie; Peroulis, Dimitrios

    2005-01-01

    Wireless mesh networks (WMNs) have been proposed as an effective solution for ubiquitous lastmile broadband access. Three key factors that affect the usability of WMNs are high throughput, costeffectiveness and ease of deployability. Recent research has focused on increasing WMN throughput assuming the use of multiple radios equipped with omnidirectional antennas accompanied with channel assignment to enable frequency separation between contending transmissions. Compared to omni antennas, dir...

  17. Performance evaluation of multi-channel wireless mesh networks with embedded systems.

    Science.gov (United States)

    Lam, Jun Huy; Lee, Sang-Gon; Tan, Whye Kit

    2012-01-01

    Many commercial wireless mesh network (WMN) products are available in the marketplace with their own proprietary standards, but interoperability among the different vendors is not possible. Open source communities have their own WMN implementation in accordance with the IEEE 802.11s draft standard, Linux open80211s project and FreeBSD WMN implementation. While some studies have focused on the test bed of WMNs based on the open80211s project, none are based on the FreeBSD. In this paper, we built an embedded system using the FreeBSD WMN implementation that utilizes two channels and evaluated its performance. This implementation allows the legacy system to connect to the WMN independent of the type of platform and distributes the load between the two non-overlapping channels. One channel is used for the backhaul connection and the other one is used to connect to the stations to wireless mesh network. By using the power efficient 802.11 technology, this device can also be used as a gateway for the wireless sensor network (WSN).

  18. Optimal Relay Selection with Channel Probing in Wireless Sensor Networks

    CERN Document Server

    Naveen, K P

    2011-01-01

    Motivated by the problem of distributed geographical packet forwarding in a wireless sensor network with sleep-wake cycling nodes, we propose a local forwarding model comprising a node that wishes to forward a packet towards a destination, and a set of next-hop relay nodes, each of which is associated with a reward that summarises the cost/benefit of forwarding the packet through that relay. The relays wake up at random times, at which instants they reveal only the probability distributions of their rewards (e.g., by revealing their locations). To determine a relay's exact reward, the forwarding node has to further probe the relay, incurring a probing cost. Thus, at each relay wake-up instant, the source, given a set of relay reward distributions, has to decide whether to stop (and forward the packet to an already probed relay), continue waiting for further relays to wake-up, or probe an unprobed relay. We formulate the problem as a Markov decision process, with the objective being to minimize the packet forw...

  19. A New Approach for Performance Evaluation of TCP over Interference-Limited Wireless Channels

    Institute of Scientific and Technical Information of China (English)

    LUO Rui; FAN Pingzhi

    2003-01-01

    A new metric for performance evaluation of transport control protocol(TCP) over wireless channels based on the interference-limited characteristics of code division multiple address(CDMA) system is proposed. According to the new metric, the performance of TCP over CDMA correlated channel for different protocol parameters and different versions is investigated. The results show that appropriate selection of protocol parameters and packet error rate(PER) operation point can improve significantly the capacity of packet-switched CDMA-based network.

  20. Impact of Wireless Channel Model on 802.15.6 Standard Performance for Wireless Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Maryam El azhari

    2016-05-01

    Full Text Available Wireless Body Sensor Network (WBAN is a set of wearable and implantable devices capable of measuring physiological parameters and monitoring patient with chronic disease where early diagnosis is highly demanded. Several models introduced the general characterization of WBAN devices path loss considering possible shadowing due to obstruction of the signal (by the human body or any other obstacles as well as the different postures of the human body. This paper aims at reporting an overview of WBSNs technologies, particular applications, system architecture and channel modeling. Emphasis is given to the IEEE 802.15.6 standard which enables the development of WBAN for medical and non-medical applications. The standard's performance within a time based variation and log-distance path loss is presented based on various simulations.

  1. Channel Modeling for Air-to-Ground Wireless Communication

    Institute of Scientific and Technical Information of China (English)

    Yingcheng Shi; Di He; Bin Li; Jianwu Dou

    2015-01-01

    In this paper, we discuss several large⁃scale fading models for different environments. The COST231⁃Hata model is adapted for air⁃to⁃ground modeling. We propose two criteria for air⁃to⁃ground channel modelling based on test data derived from field testing in Beijing. We develop a new propagation model that is more suitable for air⁃to⁃ground communication that pre⁃vious models. We focus on improving this propagation model using the field test data.

  2. Wireless Energy Harvesting Using Signals from Multiple Fading Channels

    KAUST Repository

    Chen, Yunfei

    2017-08-01

    In this paper, we study the average, the probability density function and the cumulative distribution function of the harvested power. In the study, the signals are transmitted from multiple sources. The channels are assumed to be either Rician fading or Gamma-shadowed Rician fading. The received signals are then harvested by using either a single harvester for simultaneous transmissions or multiple harvesters for transmissions at different frequencies, antennas or time slots. Both linear and nonlinear models for the energy harvester at the receiver are examined. Numerical results are presented to show that, when a large amount of harvested power is required, a single harvester or the linear range of a practical nonlinear harvester are more efficient, to avoid power outage. Further, the power transfer strategy can be optimized for fixed total power. Specifically, for Rayleigh fading, the optimal strategy is to put the total power at the source with the best channel condition and switch off all other sources, while for general Rician fading, the optimum magnitudes and phases of the transmitting waveforms depend on the channel parameters.

  3. Performance Evaluation of Proportional Fair Scheduling Algorithm with Measured Channels

    DEFF Research Database (Denmark)

    Sørensen, Troels Bundgaard; Pons, Manuel Rubio

    2005-01-01

    subjected to measured channel traces. Specifically, we applied measured signal fading recorded from GSM cell phone users making calls on an indoor wireless office system. Different from reference channel models, these measured channels have much more irregular fading between users, which as we show...

  4. Two-stage coordination multi-radio multi-channel mac protocol for wireless mesh networks

    CERN Document Server

    Zhao, Bingxuan

    2011-01-01

    Within the wireless mesh network, a bottleneck problem arises as the number of concurrent traffic flows (NCTF) increases over a single common control channel, as it is for most conventional networks. To alleviate this problem, this paper proposes a two-stage coordination multi-radio multi-channel MAC (TSC-M2MAC) protocol that designates all available channels as both control channels and data channels in a time division manner through a two-stage coordination. At the first stage, a load balancing breadth-first-search-based vertex coloring algorithm for multi-radio conflict graph is proposed to intelligently allocate multiple control channels. At the second stage, a REQ/ACK/RES mechanism is proposed to realize dynamical channel allocation for data transmission. At this stage, the Channel-and-Radio Utilization Structure (CRUS) maintained by each node is able to alleviate the hidden nodes problem; also, the proposed adaptive adjustment algorithm for the Channel Negotiation and Allocation (CNA) sub-interval is ab...

  5. Indoor Off-Body Wireless Communication: Static Beamforming versus Space-Time Coding

    Directory of Open Access Journals (Sweden)

    Patrick Van Torre

    2012-01-01

    Full Text Available The performance of beamforming versus space-time coding using a body-worn textile antenna array is experimentally evaluated for an indoor environment, where a walking rescue worker transmits data in the 2.45 GHz ISM band, relying on a vertical textile four-antenna array integrated into his garment. The two transmission scenarios considered are static beamforming at low-elevation angles and space-time code based transmit diversity. Signals are received by a base station equipped with a horizontal array of four dipole antennas providing spatial receive diversity through maximum-ratio combining. Signal-to-noise ratios, bit error rate characteristics, and signal correlation properties are assessed for both off-body transmission scenarios. Without receiver diversity, the performance of space-time coding is generally better. In case of fourth-order receiver diversity, beamforming is superior in line-of-sight conditions. For non-line-of-sight propagation, the space-time codes perform better as soon as bit error rates are low enough for a reliable data link.

  6. 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.

  7. Robust Network FEC-Embedded Video Transmission Over Error-Prone Wireless Channels

    Directory of Open Access Journals (Sweden)

    Ghaida Al Suhail

    2012-07-01

    Full Text Available Most wireless networks incline to include FEC code (Forward error correction to recover the corruptedpackets without retransmission. The sequential packets transmitted over wireless channel are likely to be infected with various errors like noise or deep fading. In this paper, therefore, a frame-level FEC isadded across packets at the application layer to define two analytical packet loss models. At the network layer level, Gilbert Elliot Model (GEM and Extended Gilbert Model (EGM are considered to characterize the MPEG-4 packets loss over the bursty error-prone wireless channels. The resultant video quality in terms of playable frame rate (PFR is estimated at the client end when using the underlyingTCP-Friendly protocol. Numerical results point out that the EGM-FEC model introduces a robust measure in estimating the perceived video quality in particular at higher packet loss rate and lower effect of packet correlation. Moreover, it is also found that the GEM-FEC model outperforms EGM-FEC but when ignoring the effect of packet correlation.

  8. Transmission with Energy Harvesting Nodes in Fading Wireless Channels: Optimal Policies

    CERN Document Server

    Ozel, Omur; Yang, Jing; Ulukus, Sennur; Yener, Aylin

    2011-01-01

    Wireless systems comprised of rechargeable nodes have a significantly prolonged lifetime and are sustainable. A distinct characteristic of these systems is the fact that the nodes can harvest energy throughout the duration in which communication takes place. As such, transmission policies of the nodes need to adapt to these harvested energy arrivals. In this paper, we consider optimization of point-to-point data transmission with an energy harvesting transmitter which has a limited battery capacity, communicating in a wireless fading channel. We consider two objectives: maximizing the throughput by a deadline, and minimizing the transmission completion time of the communication session. We optimize these objectives by controlling the time sequence of transmit powers subject to energy storage capacity and causality constraints. We, first, study optimal offline policies. We introduce a directional water-filling algorithm which provides a simple and concise interpretation of the necessary optimality conditions. ...

  9. Novel Covert Data Channel in Wireless Sensor Networks Using Compressive Sensing

    Directory of Open Access Journals (Sweden)

    Jiping Xiong

    2012-10-01

    Full Text Available Wireless sensor networks (WSN is a novel data centered self-organizing network that can be used in acquiring and processing information. With the limited energy of sensor nodes and the increasing requirement of secure data transmission, how to save nodes energy as well as realize a transmission of sensitive information in WSN effectively is becoming an interesting research problem recently. In this paper, we present a novel scheme to transmit sensitive information in the pattern of energy efficient way by utilizing compressive sensing (CS which is an emerging technology in recent years. In this method, sensor nodes need not to do complex computing but simple linear operations which can save the energy extensively, and thus extend the life time of the wireless sensor networks. Theory analysis and detail simulation results demonstrate the effective of our method, and the sensitive information can be accurately reconstructed even when the communication channel is lossy.

  10. Low-SNR Capacity of Parallel IM-DD Optical Wireless Channels

    KAUST Repository

    Chaaban, Anas

    2016-11-29

    The capacity of parallel intensity-modulation and direct-detection (IM-DD) optical wireless channels with total average intensity and per-channel peak intensity constraints is studied. The optimal intensity allocation at low signal-to-noise ratio (SNR) is derived, leading to the capacity-achieving onoff keying (OOK) distribution. Interestingly, while activating the strongest channel is optimal if (i) the peak intensity is fixed, this is not the case if (ii) the peak intensity is proportional to the average intensity. The minimum average optical intensity per bit is also studied, and is characterized for case (i) where it is achievable at low SNR. However, in case (ii), the average optical intensity per bit grows indefinitely as SNR decreases, indicating that lower optical intensity per bit can be achieved at moderate SNR than at low SNR.

  11. Flow Oriented Channel Assignment for Multi-radio Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Niu Zhisheng

    2010-01-01

    Full Text Available We investigate channel assignment for a multichannel wireless mesh network backbone, where each router is equipped with multiple interfaces. Of particular interest is the development of channel assignment heuristics for multiple flows. We present an optimization formulation and then propose two iterative flow oriented heuristics for the conflict-free and interference-aware cases, respectively. To maximize the aggregate useful end-to-end flow rates, both algorithms identify and resolve congestion at instantaneous bottleneck link in each iteration. Then the link rate is optimally allocated among contending flows that share this link by solving a linear programming (LP problem. A thorough performance evaluation is undertaken as a function of the number of channels and interfaces/node and the number of contending flows. The performance of our algorithm is shown to be significantly superior to best known algorithm in its class in multichannel limited radio scenarios.

  12. Investigating the performance of single- and multichannel wireless receivers in generic-K fading channels

    Directory of Open Access Journals (Sweden)

    Jyoteesh Malhotra

    2011-03-01

    Full Text Available By using versatile generic-K statistical model, a performance analysis of wireless system has been carried out through the composite fading channel scenarios. The composite fading model used here is flexible enough to represent all forms of mixed shadowed-fading channel conditions. With the aid of moment generating function (MGF approach and Padé approximation (PA technique, different performance measures such as outage probability and average bit error rate (ABER have been evaluated for a variety of digital modulation formats. In contrast to previously obtained relatively complicated expressions in terms of MeijerG & Whittaker special functions, the PA technique has been used here to find tractable rational expressions for the MGF of output SNR. Using these simple rational expressions, the performance evaluations have been done for both single- and multichannel receivers under different shadowed-fading channel conditions. The numerical results are also validated through computer simulations, which show a perfect match.

  13. Securing OFDM over Wireless Time-Varying Channels Using Subcarrier Overloading with Joint Signal Constellations

    Directory of Open Access Journals (Sweden)

    Gill R. Tsouri

    2009-01-01

    Full Text Available A method of overloading subcarriers by multiple transmitters to secure OFDM in wireless time-varying channels is proposed and analyzed. The method is based on reverse piloting, superposition modulation, and joint decoding. It makes use of channel randomness, reciprocity, and fast decorrelation in space to secure OFDM with low overheads on encryption, decryption, and key distribution. These properties make it a good alternative to traditional software-based information security algorithms in systems where the costs associated with such algorithms are an implementation obstacle. A necessary and sufficient condition for achieving information theoretic security in accordance with channel and system parameters is derived. Security by complexity is assessed for cases where the condition for information theoretic security is not satisfied. In addition, practical means for implementing the method are derived including generating robust joint constellations, decoding data with low complexity, and mitigating the effects of imperfections due to mobility, power control errors, and synchronization errors.

  14. Flow Oriented Channel Assignment for Multi-Radio Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Fei Ye

    2010-01-01

    Full Text Available We investigate channel assignment for a multichannel wireless mesh network backbone, where each router is equipped with multiple interfaces. Of particular interest is the development of channel assignment heuristics for multiple flows. We present an optimization formulation and then propose two iterative flow oriented heuristics for the conflict-free and interference-aware cases, respectively. To maximize the aggregate useful end-to-end flow rates, both algorithms identify and resolve congestion at instantaneous bottleneck link in each iteration. Then the link rate is optimally allocated among contending flows that share this link by solving a linear programming (LP problem. A thorough performance evaluation is undertaken as a function of the number of channels and interfaces/node and the number of contending flows. The performance of our algorithm is shown to be significantly superior to best known algorithm in its class in multichannel limited radio scenarios.

  15. An Improved Approach for RSSI-Based only Calibration-Free Real-Time Indoor Localization on IEEE 802.11 and 802.15.4 Wireless Networks

    Directory of Open Access Journals (Sweden)

    Marco Passafiume

    2017-03-01

    Full Text Available Assuming a reliable and responsive spatial contextualization service is a must-have in IEEE 802.11 and 802.15.4 wireless networks, a suitable approach consists of the implementation of localization capabilities, as an additional application layer to the communication protocol stack. Considering the applicative scenario where satellite-based positioning applications are denied, such as indoor environments, and excluding data packet arrivals time measurements due to lack of time resolution, received signal strength indicator (RSSI measurements, obtained according to IEEE 802.11 and 802.15.4 data access technologies, are the unique data sources suitable for indoor geo-referencing using COTS devices. In the existing literature, many RSSI based localization systems are introduced and experimentally validated, nevertheless they require periodic calibrations and significant information fusion from different sensors that dramatically decrease overall systems reliability and their effective availability. This motivates the work presented in this paper, which introduces an approach for an RSSI-based calibration-free and real-time indoor localization. While switched-beam array-based hardware (compliant with IEEE 802.15.4 router functionality has already been presented by the author, the focus of this paper is the creation of an algorithmic layer for use with the pre-existing hardware capable to enable full localization and data contextualization over a standard 802.15.4 wireless sensor network using only RSSI information without the need of lengthy offline calibration phase. System validation reports the localization results in a typical indoor site, where the system has shown high accuracy, leading to a sub-metrical overall mean error and an almost 100% site coverage within 1 m localization error.

  16. An Improved Approach for RSSI-Based only Calibration-Free Real-Time Indoor Localization on IEEE 802.11 and 802.15.4 Wireless Networks.

    Science.gov (United States)

    Passafiume, Marco; Maddio, Stefano; Cidronali, Alessandro

    2017-03-29

    Assuming a reliable and responsive spatial contextualization service is a must-have in IEEE 802.11 and 802.15.4 wireless networks, a suitable approach consists of the implementation of localization capabilities, as an additional application layer to the communication protocol stack. Considering the applicative scenario where satellite-based positioning applications are denied, such as indoor environments, and excluding data packet arrivals time measurements due to lack of time resolution, received signal strength indicator (RSSI) measurements, obtained according to IEEE 802.11 and 802.15.4 data access technologies, are the unique data sources suitable for indoor geo-referencing using COTS devices. In the existing literature, many RSSI based localization systems are introduced and experimentally validated, nevertheless they require periodic calibrations and significant information fusion from different sensors that dramatically decrease overall systems reliability and their effective availability. This motivates the work presented in this paper, which introduces an approach for an RSSI-based calibration-free and real-time indoor localization. While switched-beam array-based hardware (compliant with IEEE 802.15.4 router functionality) has already been presented by the author, the focus of this paper is the creation of an algorithmic layer for use with the pre-existing hardware capable to enable full localization and data contextualization over a standard 802.15.4 wireless sensor network using only RSSI information without the need of lengthy offline calibration phase. System validation reports the localization results in a typical indoor site, where the system has shown high accuracy, leading to a sub-metrical overall mean error and an almost 100% site coverage within 1 m localization error.

  17. Massive MIMO for Wireless Sensing With a Coherent Multiple Access Channel

    Science.gov (United States)

    Jiang, Feng; Chen, Jie; Swindlehurst, A. Lee; Lopez-Salcedo, Jose A.

    2015-06-01

    We consider the detection and estimation of a zero-mean Gaussian signal in a wireless sensor network with a coherent multiple access channel, when the fusion center (FC) is configured with a large number of antennas and the wireless channels between the sensor nodes and FC experience Rayleigh fading. For the detection problem, we study the Neyman-Pearson (NP) Detector and Energy Detector (ED), and find optimal values for the sensor transmission gains. For the NP detector which requires channel state information (CSI), we show that detection performance remains asymptotically constant with the number of FC antennas if the sensor transmit power decreases proportionally with the increase in the number of antennas. Performance bounds show that the benefit of multiple antennas at the FC disappears as the transmit power grows. The results of the NP detector are also generalized to the linear minimum mean squared error estimator. For the ED which does not require CSI, we derive optimal gains that maximize the deflection coefficient of the detector, and we show that a constant deflection can be asymptotically achieved if the sensor transmit power scales as the inverse square root of the number of FC antennas. Unlike the NP detector, for high sensor power the multi-antenna ED is observed to empirically have significantly better performance than the single-antenna implementation. A number of simulation results are included to validate the analysis.

  18. A 32-channel fully implantable wireless neurosensor for simultaneous recording from two cortical regions.

    Science.gov (United States)

    Aceros, Juan; Yin, Ming; Borton, David A; Patterson, William R; Nurmikko, Arto V

    2011-01-01

    We present a fully implantable, wireless, neurosensor for multiple-location neural interface applications. The device integrates two independent 16-channel intracortical microelectrode arrays and can simultaneously acquire 32 channels of broadband neural data from two separate cortical areas. The system-on-chip implantable sensor is built on a flexible Kapton polymer substrate and incorporates three very low power subunits: two cortical subunits connected to a common subcutaneous subunit. Each cortical subunit has an ultra-low power 16-channel preamplifier and multiplexer integrated onto a cortical microelectrode array. The subcutaneous epicranial unit has an inductively coupled power supply, two analog-to-digital converters, a low power digital controller chip, and microlaser-based infrared telemetry. The entire system is soft encapsulated with biocompatible flexible materials for in vivo applications. Broadband neural data is conditioned, amplified, and analog multiplexed by each of the cortical subunits and passed to the subcutaneous component, where it is digitized and combined with synchronization data and wirelessly transmitted transcutaneously using high speed infrared telemetry.

  19. Bounds on Minimum Energy per Bit for Optical Wireless Relay Channels

    Directory of Open Access Journals (Sweden)

    A. D. Raza

    2014-09-01

    Full Text Available An optical wireless relay channel (OWRC is the classical three node network consisting of source, re- lay and destination nodes with optical wireless connectivity. The channel law is assumed Gaussian. This paper studies the bounds on minimum energy per bit required for reliable communication over an OWRC. It is shown that capacity of an OWRC is concave and energy per bit is monotonically increasing in square of the peak optical signal power, and consequently the minimum energy per bit is inversely pro- portional to the square root of asymptotic capacity at low signal to noise ratio. This has been used to develop upper and lower bound on energy per bit as a function of peak signal power, mean to peak power ratio, and variance of channel noise. The upper and lower bounds on minimum energy per bit derived in this paper correspond respectively to the decode and forward lower bound and the min-max cut upper bound on OWRC capacity

  20. Analog and digital transport of RF channels over converged 5G wireless-optical networks

    Science.gov (United States)

    Binh, Le Nguyen

    2016-02-01

    Under the exponential increase demand by the emerging 5G wireless access networking and thus data-center based Internet, novel and economical transport of RF channels to and from wireless access systems. This paper presents the transport technologies of RF channels over the analog and digital domain so as to meet the demands of the transport capacity reaching multi-Tbps, in the followings: (i) The convergence of 5G broadband wireless and optical networks and its demands on capacity delivery and network structures; (ii) Analog optical technologies for delivery of both the information and RF carriers to and from multiple-input multiple-output (MIMO) antenna sites so as to control the beam steering of MIMO antenna in the mmW at either 28.6 GHz and 56.8 GHz RF carrier and delivery of channels of aggregate capacity reaching several Tbps; (ii) Transceiver employing advanced digital modulation formats and digital signal processing (DSP) so as to provide 100G and beyond transmission rate to meet the ultra-high capacity demands with flexible spectral grids, hence pay-on-demand services. The interplay between DSP-based and analog transport techniques is examined; (iii) Transport technologies for 5G cloud access networks and associate modulation and digital processing techniques for capacity efficiency; and (iv) Finally the integrated optic technologies with novel lasers, comb generators and simultaneous dual function photonic devices for both demultiplexing/multiplexing and modulation are proposed, hence a system on chip structure can be structured. Quantum dot lasers and matrixes of micro ring resonators are integrated on the same Si-on-Silica substrate are proposed and described.

  1. Practical and Simple Wireless Channel Models for Use in Multipolarized Antenna Systems

    Directory of Open Access Journals (Sweden)

    KwangHyun Jeon

    2014-01-01

    Full Text Available The next-generation wireless systems are expected to support data rates of more than 100 Mbps in outdoor environments. In order to support such large payloads, a polarized antenna may be employed as one of the candidate technologies. Recently, the third generation partnership standards bodies (3GPP/3GPP2 have defined a cross-polarized channel model in SCM-E for MIMO systems; however, this model is quite complex since it considers a great many channel-related parameters. Furthermore, the SCM-E channel model combines the channel coefficients of all the polarization links into one complex output, making it impossible to exploit the MIMO spatial multiplexing or diversity gains in the case of employing polarized antenna at transmitter and receiver side. In this paper, we present practical and simple 2D and 3D multipolarized multipath channel models, which take into account both the cross-polarization discrimination (XPD and the Rician factor. After verifying the proposed channel models, the BER and PER performances and throughput using the EGC and MRC combining techniques are evaluated in multipolarized antenna systems.

  2. Compression and Combining Based on Channel Shortening and Rank Reduction Technique for Cooperative Wireless Sensor Networks

    KAUST Repository

    Ahmed, Qasim Zeeshan

    2013-12-18

    This paper investigates and compares the performance of wireless sensor networks where sensors operate on the principles of cooperative communications. We consider a scenario where the source transmits signals to the destination with the help of L sensors. As the destination has the capacity of processing only U out of these L signals, the strongest U signals are selected while the remaining (L?U) signals are suppressed. A preprocessing block similar to channel-shortening is proposed in this contribution. However, this preprocessing block employs a rank-reduction technique instead of channel-shortening. By employing this preprocessing, we are able to decrease the computational complexity of the system without affecting the bit error rate (BER) performance. From our simulations, it can be shown that these schemes outperform the channel-shortening schemes in terms of computational complexity. In addition, the proposed schemes have a superior BER performance as compared to channel-shortening schemes when sensors employ fixed gain amplification. However, for sensors which employ variable gain amplification, a tradeoff exists in terms of BER performance between the channel-shortening and these schemes. These schemes outperform channel-shortening scheme for lower signal-to-noise ratio.

  3. Two-Way Training Design for Discriminatory Channel Estimation in Wireless MIMO Systems

    CERN Document Server

    Huang, Chao-Wei

    2011-01-01

    This work examines the use of two-way training in multiple-input multiple-output (MIMO) wireless systems to discriminate the channel estimation performances between a legitimate receiver (LR) and an unauthorized receiver (UR). This thesis extends upon the previously proposed discriminatory channel estimation (DCE) scheme that allows only the transmitter to send training signals. The goal of DCE is to minimize the channel estimation error at LR while requiring the channel estimation error at UR to remain beyond a certain level. If the training signal is sent only by the transmitter, the performance discrimination between LR and UR will be limited since the training signals help both receivers perform estimates of their downlink channels. In this work, we consider instead the two-way training methodology that allows both the transmitter and LR to send training signals. In this case, the training signal sent by LR helps the transmitter obtain knowledge of the transmitter-to-LR channel, but does not help UR estim...

  4. The Model of Communication Channel in the 802.11b Standard Wireless Network

    Directory of Open Access Journals (Sweden)

    Zdenek Nemec

    2008-01-01

    Full Text Available The paper deals with software modelling of a communication channel in the 802.11b standard wireless network physical layer. A computer model of signal processing was created to verify possibility of the proposal of localisation system. Functionality of the signal generation and processing model was verified by the Spectrum Analyzer. Simulations run inSimulink/Matlab SW. The Simulink is used for the signal processor model and a pure Matlab software is used for mathematical evaluations of data processor model and for determination of initial conditions.

  5. Node Isolation Probability of Wireless Adhoc Networks in Nagakami Fading Channel

    CERN Document Server

    Babu, A V; 10.5121/ijcnc.2010.2202

    2010-01-01

    This paper investigates the issue of connectivity of a wireless adhoc network in the presence of channel impairments. We derive analytical expressions for the node isolation probability in an adhoc network in the presence of Nakagami-m fading with superimposed lognormal shadowing. The node isolation probability is the probability that a randomly chosen node is not able to communicate with none of the other nodes in the network. An extensive investigation into the impact of path loss exponent, lognormal shadowing, Nakagami fading severity index, node density, and diversity order on the node isolation probability is conducted. The presented results are beneficial for the practical design of ad hoc networks.

  6. Statistical Modeling of Ultrawideband Body-Centric Wireless Channels Considering Room Volume

    Directory of Open Access Journals (Sweden)

    Miyuki Hirose

    2012-01-01

    Full Text Available This paper presents the results of a statistical modeling of onbody ultrawideband (UWB radio channels for wireless body area network (WBAN applications. Measurements were conducted in five different rooms. A measured delay profile can be divided into two domains; in the first domain (04 ns has multipath components that are dominant and dependent on room volume. The first domain was modeled with a conventional power decay law model, and the second domain with a modified Saleh-Valenzuela model considering the room volume. Realizations of the impulse responses are presented based on the composite model and compared with the measured average power delay profiles.

  7. DynaChanAl: Dynamic Channel Allocation with Minimal End-to-end Delay for Wireless Sensor Networks

    CERN Document Server

    Ko, JeongGil

    2010-01-01

    With recent advances in wireless communication, networking, and low power sensor technology, wireless sensor network (WSN) systems have begun to take significant roles in various applications ranging from environmental sensing to mobile healthcare sensing. While some WSN applications only require a lim- ited amount of bandwidth, new emerging applications operate with a notice- ably large amount of data transfers. One way to deal with such applications is to maximize the available capacity by utilizing the use of multiple wireless channels. This work proposes DynaChannAl, a distributed dynamic wireless channel algorithm with the goal of effectively distributing nodes on multiple wireless channels in WSN systems. Specifically, DynaChannAl targets applica- tions where mobile nodes connect to a pre-existing wireless backbone and takes the expected end-to-end queuing delay as its core metric. We use the link qual- ity indicator (LQI) values provided by IEEE 802.15.4 radios white-list potential links with good link...

  8. Joint Source-Channel Decoding Scheme for Image Transmission over Wireless Channel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We improve the iterative decoding algorithm by utilizing the "leaked" residual redundancy at the output of the source encoder without changing the encoder structure for the noisy channel.The experimental results show that using the residual redundancy of the compressed source in channel decoding is an effective method to improve the error correction performance.

  9. Adaptive Cooperative FEC Based on Combination of Network Coding and Channel Coding for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yong Jin

    2014-02-01

    Full Text Available The data delivery over wireless links with QoS-guarantee is a big challenge because of the unreliable and dynamic characteristics of wireless sensor networks, as well as QoS diversity requirements of applications. In this paper, we propose an adaptive cooperative Forward Error Correction algorithm based on network coding, in the hope quality of experience could be satisfied on receivers with high quality. The algorithm, based on wireless link and distance, adjusts the RS coder parameter and selects the optimal relay nodes. On the other hand, we combine the channel coding and network coding technology at the data link layer to fulfil the requirements of QoS diversity. Both mathematical analysis and NS simulation results demonstrate the proposed mechanism is superior to the traditional FEC and cooperative FEC alone at the reliability, real time performance and energy efficiency. In addition, the proposed mechanism can significantly improve quality of media streaming, in terms of playable frame rate on the receiving side. 

  10. Channel estimation for MIMO-OFDM systems in wireless mobile channels

    Institute of Scientific and Technical Information of China (English)

    Lu Zhen; Ge Jianhua

    2008-01-01

    New training sequences and frame structure are proposed to estimate time-varying channel for multiple-input multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) systems. The training sequences are modulatable orthogonal polyphase sequences, which have both good autocorrelations and cross-correlations. The channel impulse response (CIR) can be obtained by measuring the correlation between the received training sequence and the locally generated training sequence. The training sequences are used as guard interval instead of cyclic prefix, which not only improve the transmission efficiency but also enable the channel estimator to track time-varying channel. The simulation results show that the proposed method has about 2dB SNR gain over conventional methods in fast time-varying channel.

  11. 一种无线室内空气污染物监测装置的研制%Development of Wireless Indoor Air Pollution Monitoring Device

    Institute of Scientific and Technical Information of China (English)

    冯勇; 王继红; 蒋铭凯

    2016-01-01

    In order to be more convenient,accurate and fast to obtain the concentration of pollutants in the indoor air,an indoor air pollutant monitoring device based on wireless sensor network technology was developed ,and this device used a variety of gas sensors in the data acquisition part to acquire 7 kinds of pollutants and temperature and humidity parameters in the indoor air at the same time. The device used high precision A/D conversion chip in data processing part to realize digital conversion of the signal. It used wireless WiFi module in wireless communication part and mature WiFi communication technology to upload the monitoring regional site data ,and can connect to the Internet. The mobile devices (tablet computer or cellphone)can be used as the data view terminal to query data of the sensor devices in different monitoring areas at any time,so as to directly perceive the concentration of indoor air pollutants.%为了更加方便快捷准确地获得室内空气中污染物浓度,研制了一种基于无线传感网络技术的室内空气污染物监测装置.该装置在数据采集部分采用了多种类型气体传感器,实现被测室内空气中7种污染物和温湿度参数的同时获取;在数据处理部分应用了高精度A/D转换芯片,实现信号的数字化转换;在无线通信部分使用无线WiFi模块,应用成熟的WiFi通信技术,实现监测区域现场数据上传的无线通信,可连接到Internet网络;采用移动设备(平板电脑、手机)作为数据查看终端,随时随地对不同监测区域中的传感装置进行数据查询,从而直观感知室内空气污染物浓度状况.

  12. A Rate Adaptation Scheme According to Channel Conditions in Wireless LANs

    Science.gov (United States)

    Numoto, Daisuke; Inai, Hiroshi

    Rate adaptation in wireless LANs is to select the most suitable transmission rate automatically according to channel condition. If the channel condition is good, a station can choose a higher transmission rate, otherwise, it should choose a lower but noise-resistant transmission rate. Since IEEE 802.11 does not specify any rate adaptation scheme, several schemes have been proposed. However those schemes provide low throughput or unfair transmission opportunities among stations especially when the number of stations increases. In this paper, we propose a rate adaptation scheme under which the transmission rate quickly closes and then stays around an optimum rate even in the presence of a large number of stations. Via simulation, our scheme provides higher throughput than existing ones and almost equal fairness.

  13. 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.

  14. Survey of Channel and Radio Propagation Models for Wireless MIMO Systems

    Directory of Open Access Journals (Sweden)

    A. Burr

    2007-02-01

    Full Text Available This paper provides an overview of the state-of-the-art radio propagation and channel models for wireless multiple-input multiple-output (MIMO systems. We distinguish between physical models and analytical models and discuss popular examples from both model types. Physical models focus on the double-directional propagation mechanisms between the location of transmitter and receiver without taking the antenna configuration into account. Analytical models capture physical wave propagation and antenna configuration simultaneously by describing the impulse response (equivalently, the transfer function between the antenna arrays at both link ends. We also review some MIMO models that are included in current standardization activities for the purpose of reproducible and comparable MIMO system evaluations. Finally, we describe a couple of key features of channels and radio propagation which are not sufficiently included in current MIMO models.

  15. Equalization and Decoding for Multiple-Input Multiple-Output Wireless Channels

    Directory of Open Access Journals (Sweden)

    Proakis John G

    2002-01-01

    Full Text Available We consider multiple-input, multiple-output (MIMO wireless communication systems that employ multiple transmit and receive antennas to increase the data rate and achieve diversity in fading multipath channels. We begin by focusing on an uncoded system and define optimal and suboptimal receiver structures for this system in Rayleigh fading with and without intersymbol interference. Next, we consider coded MIMO systems. We view the coded system as a serially concatenated convolutional code (SCCC in which the code and the multipath channel take on the roles of constituent codes. This enables us to analyze the performance using the same performance analysis tools as developed previously for SCCCs. Finally, we present an iterative ("turbo" MAP-based equalization and decoding scheme and evaluate its performance when applied to a system with transmit antennas and receive antennas. We show that by performing recursive precoding prior to transmission, significant interleaving gains can be realized compared to systems without precoding.

  16. Survey of Channel and Radio Propagation Models for Wireless MIMO Systems

    Directory of Open Access Journals (Sweden)

    Kyösti P

    2007-01-01

    Full Text Available This paper provides an overview of the state-of-the-art radio propagation and channel models for wireless multiple-input multiple-output (MIMO systems. We distinguish between physical models and analytical models and discuss popular examples from both model types. Physical models focus on the double-directional propagation mechanisms between the location of transmitter and receiver without taking the antenna configuration into account. Analytical models capture physical wave propagation and antenna configuration simultaneously by describing the impulse response (equivalently, the transfer function between the antenna arrays at both link ends. We also review some MIMO models that are included in current standardization activities for the purpose of reproducible and comparable MIMO system evaluations. Finally, we describe a couple of key features of channels and radio propagation which are not sufficiently included in current MIMO models.

  17. Channel estimation for MIMO-OFDM systems in mobile wireless channels

    Institute of Scientific and Technical Information of China (English)

    WU Yun; LUO Han-wen; SONG Wen-tao

    2008-01-01

    A channel estimation method is proposed for multiple-input multiple-output orthogonal frequency di-vision multiplexing (MIMO-OFDM) systems in time-varying fading channels. In this method, a decision-direct-ed space-ahernating generalized expectation-maximization (SAGE) algorithm is introduced to the tracking of time-varying fading. In order to improve the estimation performance of the SAGE algorithm, a low rank approxi-mation method is presented by using the signal subspaee of the channel frequency autocorrelation matrix. The study reveals that this method can be incorporated into the SAGE algorithm. Furthermore, a modified fast sub-space tracking algorithm is given to adaptively estimate the signal subspace by utilizing training OFDM blocks sent at regular interval. Simulation results demonstrate the considerable benefits of the proposed channel estima-tion method.

  18. Reducing interferences in wireless communication systems by mobile agents with recurrent neural networks-based adaptive channel equalization

    Science.gov (United States)

    Beritelli, Francesco; Capizzi, Giacomo; Lo Sciuto, Grazia; Napoli, Christian; Tramontana, Emiliano; Woźniak, Marcin

    2015-09-01

    Solving channel equalization problem in communication systems is based on adaptive filtering algorithms. Today, Mobile Agents (MAs) with Recurrent Neural Networks (RNNs) can be also adopted for effective interference reduction in modern wireless communication systems (WCSs). In this paper MAs with RNNs are proposed as novel computing algorithms for reducing interferences in WCSs performing an adaptive channel equalization. The method to provide it is so called MAs-RNNs. We perform the implementation of this new paradigm for interferences reduction. Simulations results and evaluations demonstrates the effectiveness of this approach and as better transmission performance in wireless communication network can be achieved by using the MAs-RNNs based adaptive filtering algorithm.

  19. A 100-channel hermetically sealed implantable device for chronic wireless neurosensing applications.

    Science.gov (United States)

    Yin, Ming; Borton, David A; Aceros, Juan; Patterson, William R; Nurmikko, Arto V

    2013-04-01

    A 100-channel fully implantable wireless broadband neural recording system was developed. It features 100 parallel broadband (0.1 Hz-7.8 kHz) neural recording channels, a medical grade 200 mAh Li-ion battery recharged inductively at 150 kHz , and data telemetry using 3.2 GHz to 3.8 GHz FSK modulated wireless link for 48 Mbps Manchester encoded data. All active electronics are hermetically sealed in a titanium enclosure with a sapphire window for electromagnetic transparency. A custom, high-density configuration of 100 individual hermetic feedthrough pins enable connection to an intracortical neural recording microelectrode array. A 100 MHz bandwidth custom receiver was built to remotely receive the FSK signal and achieved -77.7 dBm sensitivity with 10(-8) BER at 48 Mbps data rate. ESD testing on all the electronic inputs and outputs has proven that the implantable device satisfies the HBM Class-1B ESD Standard. In addition, the evaluation of the worst-case charge density delivered to the tissue from each I/O pin verifies the patient safety of the device in the event of failure. Finally, the functionality and reliability of the complete device has been tested on-bench and further validated chronically in ongoing freely moving swine and monkey animal trials for more than one year to date.

  20. A Schedule-based Multi-channel MAC Protocol for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Ilyoung Chong

    2010-10-01

    Full Text Available Due to the half-duplex property of the sensor radio and the broadcast nature of wireless medium, limited bandwidth remains a pressing issue for wireless sensor networks (WSNs. The design of multi-channel MAC protocols has attracted the interest of many researchers as a cost effective solution to meet the higher bandwidth demand for the limited bandwidth in WSN. In this paper, we present a scheduled-based multi-channel MAC protocol to improve network performance. In our protocol, each receiving node selects (schedules some timeslot(s, in which it may receive data from the intending sender(s. The timeslot selection is done in a conflict free manner, where a node avoids the slots that are already selected by others in its interference range. To minimize the conflicts during timeslot selection, we propose a unique solution by splitting the neighboring nodes into different groups, where nodes of a group may select the slots allocated to that group only. We demonstrate the effectiveness of our approach thorough simulations in terms of performance parameters such as aggregate throughput, packet delivery ratio, end-to-end delay, and energy consumption.

  1. Robust transmission of progressive image bitstreams based on DCT over broadband wireless channels

    Institute of Scientific and Technical Information of China (English)

    WANG Dong-hua; ZHOU Yuan-hua; MA Zeng-dong

    2006-01-01

    A robust progressive image transmission scheme over broadband wireless fading channels is developed for 4th generation wireless communication systems (4G) in this paper. The proposed scheme is based on space-time block coded orthogonal frequency-division multiplexing ( OFDM ) with 4 transmit antennas and 2 receive antennas and uses a simplified minimum mean square error (MMSE) detector instead of maximum likelihood (ML) detectors. Considering DCT is simpler and more widely applied in the industry than wavelet transforms, a progressive image compression method based on DCT called mean-subtract embedded DCT (MSEDCT) is developed, with a simple mean-subtract method for the redundancy of reorganized DC blocks in addition to a structure similar to the embedded zerotree wavelet coding (EZW) method. Then after analyzing and testing bit importance of the progressive MSEDCT bitstreams, the layered unequal error protection method of joint source-channels coding based on Reed-Solomon (RS) codes is used to protect different parts of bitstreams,providing different QoS assurances and good flexibility. Simulation experiments show our proposed scheme can effectively degrade fading effects and obtain better image transmission effects with 10~20 dB average peak-signal-noise-ratio (PSNR) gains at the median Eb/No than those schemes without space-time coded OFDM or equal error protections with space-time coded OFDM.

  2. Impact of Interference in Coexisting Wireless Networks with Applications to Arbitrarily Varying Bidirectional Broadcast Channels

    Directory of Open Access Journals (Sweden)

    Holger Boche

    2012-08-01

    Full Text Available The paradigm shift from an exclusive allocation of frequency bands, one for each system, to a shared use of frequencies comes along with the need of new concepts since interference will be an ubiquitous phenomenon. In this paper, we use the concept of arbitrarily varying channels to model the impact of unknown interference caused by coexisting wireless systems which operate on the same frequencies. Within this framework, capacity can be zero if pre-specified encoders and decoders are used. This necessitates the use of more sophisticated coordination schemes where the choice of encoders and decoders is additionally coordinated based on common randomness. As an application we study the arbitrarily varying bidirectional broadcast channel and derive the capacity regions for different coordination strategies. This problem is motivated by decode-and-forward bidirectional or two-way relaying, where a relay establishes a bidirectional communication between two other nodes while sharing the resources with other coexisting wireless networks.

  3. Channel modeling for fifth generation cellular networks and wireless sensor networks

    Science.gov (United States)

    Torabi, Amir

    In view of exponential growth in data traffic demand, the wireless communications industry has aimed to increase the capacity of existing networks by 1000 times over the next 20 years. A combination of extreme cell densification, more bandwidth, and higher spectral efficiency is needed to support the data traffic requirements for fifth generation (5G) cellular communications. In this research, the potential improvements achieved by using three major 5G enabling technologies (i.e., small cells, millimeter-wave spectrum, and massive MIMO) in rural and urban environments are investigated. This work develops SPM and KA-based ray models to investigate the impact of geometrical parameters on terrain-based multiuser MIMO channel characteristic. Moreover, a new directional 3D channel model is developed for urban millimeter-wave (mmW) small cells. Path-loss, spatial correlation, coverage distance, and coherence length are studied in urban areas. Exploiting physical optics (PO) and geometric optics (GO) solutions, closed form expressions are derived for spatial correlation. Achievable spatial diversity is evaluated using horizontal and vertical linear arrays as well as planar 2D arrays. In another study, a versatile near-ground field prediction model is proposed to facilitate accurate wireless sensor network (WSN) simulations. Monte Carlo simulations are used to investigate the effects of antenna height, frequency of operation, polarization, and terrain dielectric and roughness properties on WSNs performance.

  4. Properties of Channel Interference for Wi-Fi Location Fingerprinting

    OpenAIRE

    Chan, Eddie C. L.; Baciu, George; Mak, S. C.

    2010-01-01

    Localization systems for indoor areas have recently been suggested that make use of existing wireless local area network (WLAN) infrastructure and location fingerprinting approach. However, most existing research work ignores channel interference between wireless infrastructures and this could affect accurate and precise positioning. A better understanding of the properties of channel interference could assist in improving the positioning accuracy while saving significant amounts of resources...

  5. Using the amplitude variation of a reverberation chamber channel to predict the synchronization of a wireless digital communication test system

    NARCIS (Netherlands)

    Tanuhardja, Ray R.; Gonzalez, Luis A.; Wang, Chih-Ming; Young, William F.; Remley, Kate A.; Ladbury, John M.

    2015-01-01

    We discuss the use of a metric based on the amplitude variation of a channel in the signal bandwidth to predict whether or not a digital wireless communication test system receiver will be able to demodulate a test signal. This metric is compared to another method consisting of the correlation calcu

  6. Indoor Climate Quality Assessment -

    DEFF Research Database (Denmark)

    Ansaldi, Roberta; Asadi, Ehsan; Costa, José Joaquim

    This Guidebook gives building professionals useful support in the practical measurements and monitoring of the indoor climate in buildings. It is evident that energy consumption in a building is directly influenced by required and maintained indoor comfort level. Wireless technologies for measure...... for measurement and monitoring have allowed a significantly increased number of possible applications, especially in existing buildings. The Guidebook illustrates several cases with the instrumentation of the monitoring and assessment of indoor climate....

  7. Wireless radio channel for intramuscular electrode implants in the control of upper limb prostheses.

    Science.gov (United States)

    Stango, Antonietta; Yazdandoost, Kamya Yekeh; Farina, Dario

    2015-01-01

    In the last few years the use of implanted devices has been considered also in the field of myoelectric hand prostheses. Wireless implanted EMG (Electromyogram) sensors can improve the functioning of the prosthesis, providing information without the disadvantage of the wires, and the usability by amputees. The solutions proposed in the literature are based on proprietary communication protocols between the implanted devices and the prosthesis controller, using frequency bands that are already assigned to other purposes. This study proposes the use of a standard communication protocol (IEEE 802.15.6), specific for wireless body area networks (WBANs), which assign a specific bandwidth to implanted devices. The propagation losses from in-to-on body were investigated by numerical simulation with a 3D human model and an electromagnetic solver. The channel model resulting from the study represents the first step towards the development of myoelectric prosthetic hands which are driven by signals acquired by implanted sensors. However these results can provide important information to researchers for further developments, and manufacturers, which can decrease the production costs for hand prostheses having a common standard of communication with assigned frequencies of operation.

  8. Fading Characteristics of Wireless Channel on High-Speed Railway in Hilly Terrain Scenario

    Directory of Open Access Journals (Sweden)

    Fengyu Luan

    2013-01-01

    Full Text Available This paper focuses on the fading characteristics of wireless channel on High-Speed Railway (HSR in hilly terrain scenario. Due to the rapid speed, the fading characteristics of HSR channel are highly correlated with time or Transmit-Receive distance and have their own special property. To investigate the fading characteristics, the measurement is conducted on the Guangzhou-Shenzhen passenger-dedicated line in China with the speed of 295 km/h in the data-collection area at 2.4 GHz. From the measured data, the amplitude of each path is estimated by using the Subspace-Alternating Generalized Expectation-Maximization (SAGE algorithm along with other parameters of channel impulse responses. Then the fading parameters, including path loss, shadow fading, and K-factor, are analysed. With the numerical results in the measurement and analysis, the fading characteristics have been revealed and modelled. It is supposed that this work has a promotion for HSR communication system design and improvement.

  9. Channel Equalization in Filter Bank Based Multicarrier Modulation for Wireless Communications

    Directory of Open Access Journals (Sweden)

    Markku Renfors

    2007-01-01

    Full Text Available Channel equalization in filter bank based multicarrier (FBMC modulation is addressed. We utilize an efficient oversampled filter bank concept with 2x-oversampled subcarrier signals that can be equalized independently of each other. Due to Nyquist pulse shaping, consecutive symbol waveforms overlap in time, which calls for special means for equalization. Two alternative linear low-complexity subcarrier equalizer structures are developed together with straightforward channel estimation-based methods to calculate the equalizer coefficients using pointwise equalization within each subband (in a frequency-sampled manner. A novel structure, consisting of a linear-phase FIR amplitude equalizer and an allpass filter as phase equalizer, is found to provide enhanced robustness to timing estimation errors. This allows the receiver to be operated without time synchronization before the filter bank. The coded error-rate performance of FBMC with the studied equalization scheme is compared to a cyclic prefix OFDM reference in wireless mobile channel conditions, taking into account issues like spectral regrowth with practical nonlinear transmitters and sensitivity to frequency offsets. It is further emphasized that FBMC provides flexible means for high-quality frequency selective filtering in the receiver to suppress strong interfering spectral components within or close to the used frequency band.

  10. Channel Equalization in Filter Bank Based Multicarrier Modulation for Wireless Communications

    Science.gov (United States)

    Ihalainen, Tero; Hidalgo Stitz, Tobias; Rinne, Mika; Renfors, Markku

    2006-12-01

    Channel equalization in filter bank based multicarrier (FBMC) modulation is addressed. We utilize an efficient oversampled filter bank concept with 2x-oversampled subcarrier signals that can be equalized independently of each other. Due to Nyquist pulse shaping, consecutive symbol waveforms overlap in time, which calls for special means for equalization. Two alternative linear low-complexity subcarrier equalizer structures are developed together with straightforward channel estimation-based methods to calculate the equalizer coefficients using pointwise equalization within each subband (in a frequency-sampled manner). A novel structure, consisting of a linear-phase FIR amplitude equalizer and an allpass filter as phase equalizer, is found to provide enhanced robustness to timing estimation errors. This allows the receiver to be operated without time synchronization before the filter bank. The coded error-rate performance of FBMC with the studied equalization scheme is compared to a cyclic prefix OFDM reference in wireless mobile channel conditions, taking into account issues like spectral regrowth with practical nonlinear transmitters and sensitivity to frequency offsets. It is further emphasized that FBMC provides flexible means for high-quality frequency selective filtering in the receiver to suppress strong interfering spectral components within or close to the used frequency band.

  11. Statistical mechanical analysis of the Kronecker channel model for MIMO wireless communication

    CERN Document Server

    Hatabu, Atsushi; Kabashima, Yoshiyuki

    2009-01-01

    The Kronecker channel model of wireless communication is analyzed using statistical mechanics methods. In the model, spatial proximities among transmission/reception antennas are taken into account as certain correlation matrices, which generally yield non-trivial dependence among symbols to be estimated. This prevents accurate assessment of the communication performance by naively using a previously developed analytical scheme based on a matrix integration formula. In order to resolve this difficulty, we develop a formalism that can formally handle the correlations in Kronecker models based on the known scheme. Unfortunately, direct application of the developed scheme is, in general, practically difficult. However, the formalism is still useful, indicating that the effect of the correlations generally increase after the fourth order with respect to correlation strength. Therefore, the known analytical scheme offers a good approximation in performance evaluation when the correlation strength is sufficiently s...

  12. Research on diversity receive technology for wireless optical communication using PPM in weak turbulence atmosphere channel

    Science.gov (United States)

    Liu, Yang; Zhang, Guo-an

    2014-09-01

    In order to mitigate atmospheric turbulence, the free space optical (FSO) system model with spatial diversity is analyzed based on intensity detection pulse position modulation (PPM) in the weak turbulence atmosphere. The slot error rate (SER) calculating formula of the system without diversity is derived under pulse position modulation firstly. Then as a benchmark, independent of identical distribution, the average slot error rates of the three linear combining technologies, which are the maximal ratio combining (MRC), equal gain combining (EGC) and selection combining (SelC), are compared. Simulation results show that the performance of system is the best improved by MRC, followed by EGC, and is poor by SelC, but SelC is simpler and more convenient. Spatial diversity is efficient to improve the performance and has strong ability on resistance to atmospheric channel decline. The above scheme is more suitable for optical wireless communication systems.

  13. A MIMO-OFDM Testbed, Channel Measurements, and System Considerations for Outdoor-Indoor WiMAX

    Directory of Open Access Journals (Sweden)

    Torres

    2010-01-01

    Full Text Available The design, implementation, and test of a real-time flexible (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing MIMO-OFDM IEEE 802.16 prototype are presented. For the design, a channel measurement campaign on the 3.5 GHz band has been carried out, focusing on outdoor-indoor scenarios. The analysis of measured channels showed that higher capacity can be achieved in case of obstructed scenarios and that (Channel Distribution Information at the Transmitter CDIT capacity is close to (Channel State Information at the Transmitter CSIT with much lower complexity and requirements in terms of channel estimation and feedback. The baseband prototype used an (Field Programmable Gate Array FPGA where enhanced signal processing algorithms are implemented in order to improve system performance. We have shown that for MIMO-OFDM systems, extra signal processing such as enhanced joint channel and frequency offset estimation is needed to obtain a good performance and approach in practice the theoretical capacity improvements.

  14. A MIMO-OFDM Testbed, Channel Measurements, and System Considerations for Outdoor-Indoor WiMAX

    Directory of Open Access Journals (Sweden)

    Víctor P. Gil Jiménez

    2010-01-01

    Full Text Available The design, implementation, and test of a real-time flexible 2×2 (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing MIMO-OFDM IEEE 802.16 prototype are presented. For the design, a channel measurement campaign on the 3.5 GHz band has been carried out, focusing on outdoor-indoor scenarios. The analysis of measured channels showed that higher capacity can be achieved in case of obstructed scenarios and that (Channel Distribution Information at the Transmitter CDIT capacity is close to (Channel State Information at the Transmitter CSIT with much lower complexity and requirements in terms of channel estimation and feedback. The baseband prototype used an (Field Programmable Gate Array FPGA where enhanced signal processing algorithms are implemented in order to improve system performance. We have shown that for MIMO-OFDM systems, extra signal processing such as enhanced joint channel and frequency offset estimation is needed to obtain a good performance and approach in practice the theoretical capacity improvements.

  15. Outage performance analysis of underlay cognitive RF and FSO wireless channels

    KAUST Repository

    Ansari, Imran Shafique

    2014-09-01

    In this work, the outage performance analysis of a dual-hop transmission system composed of asymmetric radio frequency (RF) channel cascaded with a free-space optical (FSO) link is presented. For the RF link, an underlay cognitive network is considered where the secondary users share the spectrum with licensed primary users. Indoor femtocells act as a practical example for such networks. More specifically, it is assumed that the RF link applies power control to maintain the interference at the primary network below a predetermined threshold. While the RF channel is modeled by the Rayleigh fading distribution, the FSO link is modeled by a unified Gamma-Gamma turbulence distribution. The FSO link accounts for pointing errors and both types of detection techniques (i.e. heterodyne detection as well as intensity modulation/direct detection (IM/DD)). With this model, a new exact closed-form expression is derived for the outage probability of the end-To-end signal-To-noise ratio of these systems in terms of the Meijer\\'s G function and the Fox\\'s H functions under fixed amplify-and-forward relay scheme. All new analytical results are verified via computer-based Monte-Carlo simulations and are illustrated by some selected numerical results.

  16. Indoor accurate localization algorithm based on wireless sensor networks%基于无线传感器网络的室内精确定位算法

    Institute of Scientific and Technical Information of China (English)

    孙妍; 陶正苏; 陈德富

    2009-01-01

    An indoor localization algorithm based on wireless sensor networks is brought up to fulfill the requirement of accuracy. It is the premises of all to obtain environmental parameters with least square method and choose appropriate leakage model. A brand new method is designed for indoor environment, which is filtering the reliable nodes and dealing with the received signal strength indicator(RSSI) with Gauss model. The accuracy will be further improved after optimization. Experiment data show that this algorithm boasted itself with high accuracy and simple hardware requirements, compared with the result of improved Euclidean algorithm. It is practical to utilize indoors.%提出了一种基于无线传感器网络的用于室内的高精度定位算法.采用最小二乘法对测量地区的环境参数进行拟合,获得适用的损耗模型.并根据室内的实际情况提出了筛选可靠节点和使用高斯模型处理数据的方法,从而挑选出更为合适的接收信号强度指示器(RSSI)值进行定位计算.最后,对计算结果进行优化,进一步提高定位精度.实验表明:和现有的改进Euclidean算法相比,该算法定位精度高,且设备要求低,对于室内定位具有一定实用价值.

  17. Spatio-temporal measurement of indoor particulate matter concentrations using a wireless network of low-cost sensors in households using solid fuels.

    Science.gov (United States)

    Patel, Sameer; Li, Jiayu; Pandey, Apoorva; Pervez, Shamsh; Chakrabarty, Rajan K; Biswas, Pratim

    2017-01-01

    Many households use solid fuels for cooking and heating purposes. There is currently a knowledge gap in our understanding of the variations in indoor air quality throughout the household as most of the studies focus on the areas in the close proximity of the cookstove. A low-cost wireless particulate matter (PM) sensor network was developed and deployed in households in Raipur, India to establish the spatio-temporal variation of PM concentrations. The data from multiple sensors were acquired in real-time with a wireless system. Data collected from the sensors agreed well (R(2) =0.713) with the reference data collected from a commercially available instrument. Low spatial variability was observed within the kitchen due to its small size and poor ventilation - a common feature of most rural Indian kitchens. Due to insufficient ventilation from open doors and windows, high PM concentrations similar to those found in the kitchen were also found in the adjoining rooms. The same household showed significantly different post-extinguished cookstove PM concentration decay rates (0.26mg/m(3)-min and 0.87mg/m(3)-min) on different days, owing to varying natural air exchange rates (7.68m(3)/min and 37.40m(3)/min).

  18. Non-cooperative Feedback Rate Control Game for Channel State Information in Wireless Networks

    CERN Document Server

    Song, Lingyang; Zhang, Zhongshan; Jiao, Bingli

    2011-01-01

    It has been well recognized that channel state information (CSI) feedback is of great importance for dowlink transmissions of closed-loop wireless networks. However, the existing work typically researched the CSI feedback problem for each individual mobile station (MS), and thus, cannot efficiently model the interactions among self-interested mobile users in the network level. To this end, in this paper, we propose an alternative approach to investigate the CSI feedback rate control problem in the analytical setting of a game theoretic framework, in which a multiple-antenna base station (BS) communicates with a number of co-channel MSs through linear precoder. Specifically, we first present a non-cooperative feedback-rate control game (NFC), in which each MS selects the feedback rate to maximize its performance in a distributed way. To improve efficiency from a social optimum point of view, we then introduce pricing, called the non-cooperative feedback-rate control game with price (NFCP). The game utility is ...

  19. Parity-Check Network Coding for Multiple Access Relay Channel in Wireless Sensor Cooperative Communications

    Directory of Open Access Journals (Sweden)

    Du Bing

    2010-01-01

    Full Text Available A recently developed theory suggests that network coding is a generalization of source coding and channel coding and thus yields a significant performance improvement in terms of throughput and spatial diversity. This paper proposes a cooperative design of a parity-check network coding scheme in the context of a two-source multiple access relay channel (MARC model, a common compact model in hierarchical wireless sensor networks (WSNs. The scheme uses Low-Density Parity-Check (LDPC as the surrogate to build up a layered structure which encapsulates the multiple constituent LDPC codes in the source and relay nodes. Specifically, the relay node decodes the messages from two sources, which are used to generate extra parity-check bits by a random network coding procedure to fill up the rate gap between Source-Relay and Source-Destination transmissions. Then, we derived the key algebraic relationships among multidimensional LDPC constituent codes as one of the constraints for code profile optimization. These extra check bits are sent to the destination to realize a cooperative diversity as well as to approach MARC decode-and-forward (DF capacity.

  20. Enhanced protocol for real-time transmission of echocardiograms over wireless channels.

    Science.gov (United States)

    Cavero, Eva; Alesanco, Alvaro; García, Jose

    2012-11-01

    This paper presents a methodology to transmit clinical video over wireless networks in real-time. A 3-D set partitioning in hierarchical trees compression prior to transmission is proposed. In order to guarantee the clinical quality of the compressed video, a clinical evaluation specific to each video modality has to be made. This evaluation indicates the minimal transmission rate necessary for an accurate diagnosis. However, the channel conditions produce errors and distort the video. A reliable application protocol is therefore proposed using a hybrid solution in which either retransmission or retransmission combined with forward error correction (FEC) techniques are used, depending on the channel conditions. In order to analyze the proposed methodology, the 2-D mode of an echocardiogram has been assessed. A bandwidth of 200 kbps is necessary to guarantee its clinical quality. The transmission using the proposed solution and retransmission and FEC techniques working separately have been simulated and compared in high-speed uplink packet access (HSUPA) and worldwide interoperability for microwave access (WiMAX) networks. The proposed protocol achieves guaranteed clinical quality for bit error rates higher than with the other protocols, being for a mobile speed of 60 km/h up to 3.3 times higher for HSUPA and 10 times for WiMAX.

  1. An Optimal Transmission Strategy for Joint Wireless Information and Energy Transfer in MIMO Relay Channels

    Directory of Open Access Journals (Sweden)

    Dingcheng Yang

    2015-01-01

    Full Text Available An optimal resource allocation strategy for MIMO relay system is considered in simultaneous wireless information and energy transfer network, where two users with multiple antennas communicate with each other assisted by an energy harvesting MIMO relay that gathers energy from the received signal by applying time switching scheme and forwards the received signal by using the harvesting energy. It is focused on the precoder design and resource allocation strategies for the system to allocate the resources among the nodes in decode-and-forward (DF mode. Specifically, optimal precoder design and energy transfer strategy in MIMO relay channel are firstly proposed. Then, we formulate the resource allocation optimization problem. The closed-form solutions for the time and power allocation are derived. It is revealed that the solution can flexibly allocate the resource for the MIMO relay channel to maximize the sum rate of the system. Simulation results demonstrated that the performance of the proposed algorithm outperforms the traditional fixed method.

  2. Indoor Climate Quality Assessment -

    DEFF Research Database (Denmark)

    Ansaldi, Roberta; Asadi, Ehsan; Costa, José Joaquim

    This Guidebook gives building professionals useful support in the practical measurements and monitoring of the indoor climate in buildings. It is evident that energy consumption in a building is directly influenced by required and maintained indoor comfort level. Wireless technologies for measure......This Guidebook gives building professionals useful support in the practical measurements and monitoring of the indoor climate in buildings. It is evident that energy consumption in a building is directly influenced by required and maintained indoor comfort level. Wireless technologies...... for measurement and monitoring have allowed a significantly increased number of possible applications, especially in existing buildings. The Guidebook illustrates several cases with the instrumentation of the monitoring and assessment of indoor climate....

  3. Effects of the Wireless Channel, Signal Compression and Network Architecture on Speech Quality in Voip Networks

    Science.gov (United States)

    2007-06-01

    the connection. [11] With the advances of wireless communications and the increasing use of WiFi (Wireless Fidelity) and satellite networks, there...802.11, “Wireless LAN Medium Access Control (MAC) and Physical Layer Specifications,” ISO/IEC 802-11-1999, 1999. [38] S. McClure et al, Hacking

  4. Machine-Learning Based Channel Quality and Stability Estimation for Stream-Based Multichannel Wireless Sensor Networks

    Science.gov (United States)

    Rehan, Waqas; Fischer, Stefan; Rehan, Maaz

    2016-01-01

    Wireless sensor networks (WSNs) have become more and more diversified and are today able to also support high data rate applications, such as multimedia. In this case, per-packet channel handshaking/switching may result in inducing additional overheads, such as energy consumption, delays and, therefore, data loss. One of the solutions is to perform stream-based channel allocation where channel handshaking is performed once before transmitting the whole data stream. Deciding stream-based channel allocation is more critical in case of multichannel WSNs where channels of different quality/stability are available and the wish for high performance requires sensor nodes to switch to the best among the available channels. In this work, we will focus on devising mechanisms that perform channel quality/stability estimation in order to improve the accommodation of stream-based communication in multichannel wireless sensor networks. For performing channel quality assessment, we have formulated a composite metric, which we call channel rank measurement (CRM), that can demarcate channels into good, intermediate and bad quality on the basis of the standard deviation of the received signal strength indicator (RSSI) and the average of the link quality indicator (LQI) of the received packets. CRM is then used to generate a data set for training a supervised machine learning-based algorithm (which we call Normal Equation based Channel quality prediction (NEC) algorithm) in such a way that it may perform instantaneous channel rank estimation of any channel. Subsequently, two robust extensions of the NEC algorithm are proposed (which we call Normal Equation based Weighted Moving Average Channel quality prediction (NEWMAC) algorithm and Normal Equation based Aggregate Maturity Criteria with Beta Tracking based Channel weight prediction (NEAMCBTC) algorithm), that can perform channel quality estimation on the basis of both current and past values of channel rank estimation. In the end

  5. Machine-Learning Based Channel Quality and Stability Estimation for Stream-Based Multichannel Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Waqas Rehan

    2016-09-01

    Full Text Available Wireless sensor networks (WSNs have become more and more diversified and are today able to also support high data rate applications, such as multimedia. In this case, per-packet channel handshaking/switching may result in inducing additional overheads, such as energy consumption, delays and, therefore, data loss. One of the solutions is to perform stream-based channel allocation where channel handshaking is performed once before transmitting the whole data stream. Deciding stream-based channel allocation is more critical in case of multichannel WSNs where channels of different quality/stability are available and the wish for high performance requires sensor nodes to switch to the best among the available channels. In this work, we will focus on devising mechanisms that perform channel quality/stability estimation in order to improve the accommodation of stream-based communication in multichannel wireless sensor networks. For performing channel quality assessment, we have formulated a composite metric, which we call channel rank measurement (CRM, that can demarcate channels into good, intermediate and bad quality on the basis of the standard deviation of the received signal strength indicator (RSSI and the average of the link quality indicator (LQI of the received packets. CRM is then used to generate a data set for training a supervised machine learning-based algorithm (which we call Normal Equation based Channel quality prediction (NEC algorithm in such a way that it may perform instantaneous channel rank estimation of any channel. Subsequently, two robust extensions of the NEC algorithm are proposed (which we call Normal Equation based Weighted Moving Average Channel quality prediction (NEWMAC algorithm and Normal Equation based Aggregate Maturity Criteria with Beta Tracking based Channel weight prediction (NEAMCBTC algorithm, that can perform channel quality estimation on the basis of both current and past values of channel rank estimation

  6. Machine-Learning Based Channel Quality and Stability Estimation for Stream-Based Multichannel Wireless Sensor Networks.

    Science.gov (United States)

    Rehan, Waqas; Fischer, Stefan; Rehan, Maaz

    2016-09-12

    Wireless sensor networks (WSNs) have become more and more diversified and are today able to also support high data rate applications, such as multimedia. In this case, per-packet channel handshaking/switching may result in inducing additional overheads, such as energy consumption, delays and, therefore, data loss. One of the solutions is to perform stream-based channel allocation where channel handshaking is performed once before transmitting the whole data stream. Deciding stream-based channel allocation is more critical in case of multichannel WSNs where channels of different quality/stability are available and the wish for high performance requires sensor nodes to switch to the best among the available channels. In this work, we will focus on devising mechanisms that perform channel quality/stability estimation in order to improve the accommodation of stream-based communication in multichannel wireless sensor networks. For performing channel quality assessment, we have formulated a composite metric, which we call channel rank measurement (CRM), that can demarcate channels into good, intermediate and bad quality on the basis of the standard deviation of the received signal strength indicator (RSSI) and the average of the link quality indicator (LQI) of the received packets. CRM is then used to generate a data set for training a supervised machine learning-based algorithm (which we call Normal Equation based Channel quality prediction (NEC) algorithm) in such a way that it may perform instantaneous channel rank estimation of any channel. Subsequently, two robust extensions of the NEC algorithm are proposed (which we call Normal Equation based Weighted Moving Average Channel quality prediction (NEWMAC) algorithm and Normal Equation based Aggregate Maturity Criteria with Beta Tracking based Channel weight prediction (NEAMCBTC) algorithm), that can perform channel quality estimation on the basis of both current and past values of channel rank estimation. In the end

  7. Test-retest reliability of a single-channel, wireless EEG system.

    Science.gov (United States)

    Rogers, Jeffrey M; Johnstone, Stuart J; Aminov, Anna; Donnelly, James; Wilson, Peter H

    2016-08-01

    Recording systems to acquire electroencephalogram (EEG) data are traditionally lab-based. However, there are shortcomings to this method, and the ease of use and portability of emerging wireless EEG technologies offer a promising alternative. A previous validity study demonstrated data derived from a single-channel, wireless system (NeuroSky ThinkGear, San Jose, California) is comparable to EEG recorded from conventional lab-based equipment. The current study evaluated the reliability of this portable system using test-retest and reliable change analyses. Relative power (RP) of delta, theta, alpha, and beta frequency bands was derived from EEG data obtained from a single electrode over FP1 in 19 healthy youth (10-17years old), 21 healthy adults (18-28years old), and 19 healthy older adults (55-79years old), during eyes-open, eyes-closed, auditory oddball, and visual n-back conditions. Intra-class correlations (ICCs) and Coefficients of Repeatability (CRs) were calculated from RP data re-collected one-day, one-week, and one-month later. Participants' levels of mood and attention were consistent across sessions. Eyes-closed resting EEG measurements using the portable device were reproducible (ICCs 0.76-0.85) at short and longer retest intervals in all three participant age groups. While still of at least fair reliability (ICCs 0.57-0.85), EEG obtained during eyes-open paradigms was less stable, and any change observed over time during these testing conditions can be interpreted utilizing the CR values provided. Combined with existing validity data, these findings encourage application of the portable EEG system for the study of brain function.

  8. Channel capacity of TDD-OFDM-MIMO for multiple access points in a wireless single-frequency-network

    DEFF Research Database (Denmark)

    Takatori, Y.; Fitzek, Frank; Tsunekawa, K.

    2005-01-01

    The multiple-input-multiple-output (MIMO) technique is the most attractive candidate to improve the spectrum efficiency in the next generation wireless communication systems. However, the efficiency of MIMO techniques reduces in the line of sight (LOS) environments. In this paper, we propose a new...... MIMO data transmission scheme, which combines Single-Frequency-Network (SFN) with TDD-OFDM-MIMO applied for wireless LAN networks. In our proposal, we advocate to use SFN for multiple access points (MAP) MIMO data transmission. The goal of this approach is to achieve very high channel capacity in both...... LOS and non line of sight (NLOS) environments. The channel capacity of the proposed method is derived for the direct path environments and it confirms the effectiveness of the proposed scheme in the LOS scenario. Moreover, solid computer simulation results confirm the effectiveness of the proposed...

  9. On the power and offset allocation for rate adaptation of spatial multiplexing in optical wireless MIMO channels

    KAUST Repository

    Park, Kihong

    2011-07-01

    Visible light communication (VLC) using optical sources which can be simultaneously utilized for illumination and communication is currently an attractive option for wireless personal area network. Improving the data rate in optical wireless communication system is challenging due to the limited bandwidth of the optical sources. In this paper, we design the singular value decomposition (SVD)- based multiplexing multiple-input multiple-output (MIMO) system to support two data streams in optical wireless channels. Noting that the conventional allocation method in radio frequency (RF) MIMO channels cannot be applied directly to the optical intensity channels, we propose a novel method to allocate the optical power, the offset value and the modulation size for maximum sum rate under the constraints of the nonnegativity of the modulated signals, the aggregate optical power and the bit error rate (BER) requirement. The simulation results show that the proposed allocation method gives the better performance than the method to allocate the optical power equally for each data stream. © 2011 IEEE.

  10. MIMO wireless networks channels, techniques and standards for multi-antenna, multi-user and multi-cell systems

    CERN Document Server

    Clerckx, Bruno

    2013-01-01

    This book is unique in presenting channels, techniques and standards for the next generation of MIMO wireless networks. Through a unified framework, it emphasizes how propagation mechanisms impact the system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time signal processing, the book progressively derives innovative designs for space-time coding and precoding as well as multi-user and multi-cell techniques, taking into consideration that MIMO channels are often far from ideal. Reflecting developments

  11. Energy Efficient and Performance Analysis of Multihop Wireless Communication Over Nakagami-m Fading Channel

    KAUST Repository

    Randrianantenaina, Itsikiantsoa

    2015-06-01

    The concept of multihop communications (where the source communicates with the destination via many intermediate nodes) has been revisited and adapted to mitigate wireless channel impairments and ensure broader coverage. It has been shown in the literature that, in addition to extending coverage, overcoming shadowing and reducing the transmit power, multihop communications can increase the capacity of the network at a low additional cost. On the other hand, the problem of energy efficiency is one of the current biggest challenges towards green radio communications. Morevover, electromagnetic radiation is at its limit in many contexts, while for battery-powered devices, transmit and circuit energy consumption has to be minimized for better battery lifetime and performance. In this work, the performance of multihop communication over Nakagami-m fading is investigated for both cases without and with diversity combining. Closed form expressions of the average ergodic capacity are derived for each of these cases. Then, an expression of the outage probability is obtained using the inverse of Laplace transform and the average bit error rate is bounded using the Moment-Generating-Function approach. The energy efficiency is analyzed using the "consumption factor" as a metric, and it is derived in closed-form. And based on the obtained expressions, we propose a power allocation strategy maximizing this consumption factor.

  12. Optimizing Channel Access for Event-Driven Wireless Sensor Networks: Analysis and Enhancements

    CERN Document Server

    Shakya, Rajeev K; Verma, Nishchal K

    2012-01-01

    We study the problem of medium access control in domain of event-driven wireless sensor networks (WSN). In this kind of WSN, sensor nodes send data to sink node only when an event occurs in the monitoring area. The nodes in this kind of WSN encounter correlated traffic as a subset of nodes start sending data by sensing a common event simultaneously. We wish to rethink of medium access control (MAC) for this type of traffic characteristics. For WSN, many existing MAC protocols utilize the basic CSMA strategies like 802.11 that uses Binary Exponential Backoff (BEB) algorithm to handle the collisions among packets when more than one node want to access the channel. We show that this BEB algorithm does not work well without incurring access delay or performance degradation due to increased number of collisions and retransmissions when nodes encounter correlated traffic. In this paper, we investigate on how to minimize the access delay and improve throughput by setting contention window (CW) size adaptively accord...

  13. A digital phase locked loop based signal and symbol recovery system for wireless channel

    CERN Document Server

    Purkayastha, Basab Bijoy

    2015-01-01

    The book reports two approaches of implementation of the essential components of a Digital Phase Locked Loop based system for dealing with wireless channels showing Nakagami-m fading. It is mostly observed in mobile communication. In the first approach, the structure of a Digital phase locked loop (DPLL) based on Zero Crossing (ZC) algorithm is proposed. In a modified form, the structure of a DPLL based systems for dealing with Nakagami-m fading based on Least Square Polynomial Fitting Filter is proposed, which operates at moderate sampling frequencies. A sixth order Least Square Polynomial Fitting (LSPF) block and Roots Approximator (RA) for better phase-frequency detection has been implemented as a replacement of Phase Frequency Detector (PFD) and Loop Filter (LF) of a traditional DPLL, which has helped to attain optimum performance of DPLL. The results of simulation of the proposed DPLL with Nakagami-m fading and QPSK modulation is discussed in detail which shows that the proposed method provides better pe...

  14. Wireless Channel Characterization: Modeling the 5 GHz Microwave Landing System Extension Band for Future Airport Surface Communications

    Science.gov (United States)

    Matolak, D. W.; Apaza, Rafael; Foore, Lawrence R.

    2006-01-01

    We describe a recently completed wideband wireless channel characterization project for the 5 GHz Microwave Landing System (MLS) extension band, for airport surface areas. This work included mobile measurements at large and small airports, and fixed point-to-point measurements. Mobile measurements were made via transmission from the air traffic control tower (ATCT), or from an airport field site (AFS), to a receiving ground vehicle on the airport surface. The point-to-point measurements were between ATCT and AFSs. Detailed statistical channel models were developed from all these measurements. Measured quantities include propagation path loss and power delay profiles, from which we obtain delay spreads, frequency domain correlation (coherence bandwidths), fading amplitude statistics, and channel parameter correlations. In this paper we review the project motivation, measurement coordination, and illustrate measurement results. Example channel modeling results for several propagation conditions are also provided, highlighting new findings.

  15. Wireless Indoor Distribution System and Construction Application Plan%无线室内分布系统及其施工应用方案

    Institute of Scientific and Technical Information of China (English)

    邓武锵

    2015-01-01

    针对当前4G尤其是TD-LTE和FDD-LTE2种移动通信网络建设的需要,分析了4G网络与GSM网络分布系统的差异,指出了室内分布覆盖技术在4G网络建设中存在的主要问题,分别从性能和应用方面简要介绍了适用于4G网络分布覆盖建设的无线光纤分布覆盖系统。同时,介绍了无线光纤分布覆盖系统在移动通信网络建设中的几个典型试点应用案例。经过相关分析可知,无线光纤分布覆盖系统特别适用于大型建筑物,比如火车站、停车场、医院等的分布覆盖,其在性能方面和工程实施中的优势以及分布覆盖应用的适应能力会在我国移动通信网络覆盖建设中发挥重要的作用。%In view of the current TD-LTE 4G in particular and FDD-LTE2 kinds of mobile communication network construction needs, analyze the difference between 4G networks and GSM network distribution system, the distribution of the main problems of indoor coverage technology presence in the construction of 4G networks, respectively, from the performance and application introduces the applicable distribution network covering the construction of 4G wireless fiber distribution coverage system. Meanwhile, the introduction of wireless fiber distribution system covering a few typical cases of pilot applications in the mobile communication network construction. After correlation analysis, covering wireless fiber distribution system is particularly suitable for large buildings, such as the distribution of covering the railway station, parking lots, hospitals, etc., as well as its ability to adapt to the distribution of the advantages of covering applications in terms of performance and project implementation will be in our country mobile telephone network coverage construction plays an important role.

  16. Multi-channel multi-radio using 802.11 based media access for sink nodes in wireless sensor networks.

    Science.gov (United States)

    Campbell, Carlene E-A; Khan, Shafiullah; Singh, Dhananjay; Loo, Kok-Keong

    2011-01-01

    The next generation surveillance and multimedia systems will become increasingly deployed as wireless sensor networks in order to monitor parks, public places and for business usage. The convergence of data and telecommunication over IP-based networks has paved the way for wireless networks. Functions are becoming more intertwined by the compelling force of innovation and technology. For example, many closed-circuit TV premises surveillance systems now rely on transmitting their images and data over IP networks instead of standalone video circuits. These systems will increase their reliability in the future on wireless networks and on IEEE 802.11 networks. However, due to limited non-overlapping channels, delay, and congestion there will be problems at sink nodes. In this paper we provide necessary conditions to verify the feasibility of round robin technique in these networks at the sink nodes by using a technique to regulate multi-radio multichannel assignment. We demonstrate through simulations that dynamic channel assignment scheme using multi-radio, and multichannel configuration at a single sink node can perform close to optimal on the average while multiple sink node assignment also performs well. The methods proposed in this paper can be a valuable tool for network designers in planning network deployment and for optimizing different performance objectives.

  17. Multi-Channel Multi-Radio Using 802.11 Based Media Access for Sink Nodes in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Kok-Keong Loo

    2011-05-01

    Full Text Available The next generation surveillance and multimedia systems will become increasingly deployed as wireless sensor networks in order to monitor parks, public places and for business usage. The convergence of data and telecommunication over IP-based networks has paved the way for wireless networks. Functions are becoming more intertwined by the compelling force of innovation and technology. For example, many closed-circuit TV premises surveillance systems now rely on transmitting their images and data over IP networks instead of standalone video circuits. These systems will increase their reliability in the future on wireless networks and on IEEE 802.11 networks. However, due to limited non-overlapping channels, delay, and congestion there will be problems at sink nodes. In this paper we provide necessary conditions to verify the feasibility of round robin technique in these networks at the sink nodes by using a technique to regulate multi-radio multichannel assignment. We demonstrate through simulations that dynamic channel assignment scheme using multi-radio, and multichannel configuration at a single sink node can perform close to optimal on the average while multiple sink node assignment also performs well. The methods proposed in this paper can be a valuable tool for network designers in planning network deployment and for optimizing different performance objectives.

  18. Performance analysis and comparison of m x n zero forcing and MMSE equalizer based receiver for mimo wireless channel

    Directory of Open Access Journals (Sweden)

    N. Sathish Kumar

    2011-06-01

    Full Text Available Wireless transmission is affected by fading and interference effects which can be combated with equalizer.The useof MIMO system promises good improvement in terms of spectral efficency,link relaibility andSignal to Noise Ratio (SNR.The effect of fading and interference always causes an issue for signal recovery in wireless communication. Equalizationcompensates for Intersymbol Interference (ISI created by multipath within time dispersive channels. This paper analyses theperformance of Zeroforcing and MMSE equalizer for MIMO wireless chaneels. The simulation results are obtained usingMatLab tool box version 7.0 at RF signal processing lab.The Bit Error Rate (BER characteristics for the various transmittingand receiveing antennna is simulated in matlab tool box and many advantages and disdvantagesof the system is descrbed.The simulation results show that the equalizer based zero forcing receiver is good for noise free channel and is successfulin remving ISI,but MMSE is a better choice than ZF in terms of BER charateristics and under Noise performance.

  19. A Novel Technique for Transmission of M-Ary Signal through Wireless Fading Channel Using Wavelet Denoising

    Directory of Open Access Journals (Sweden)

    Md. Zahangir Alam

    2011-01-01

    Full Text Available The paper proposes a novel technique for reducing noise in M-ary signal transmission through wireless fading channel using wavelet denoising that play the key role. The paper also explains that the conventional threshold-based technique is not capable of denoising M-ary quadrature amplitude modulated (M-QAM signals having multilevel wavelet coefficients through wireless fading channels. A detailed step by step wavelet decomposition and reconstruction processes are discussed here to transform a signal function into wavelet coefficients using simulation software like MATLAB. A 16-QAM modulated symbol through a Rician fading channel is weighted by a control variable of complex form to force the mean of each detail coefficient except low frequency component to zero to enhance noiseless property. The bit error rate (BER performance of the simulation results are furnished to show the effectiveness of the proposed technique. The root mean square of the deviation of the reconstruct signal from the original signal is used to express the effectiveness of the proposed technique. The traditional denoising provides very high value (above 90% of the percentage root mean square difference (PDR and the proposed technique provides only 10% PDR value for the symbol through a noisy channel. The result of the simulation study reveals that the BER performance can be increased using an appropriate control variable to force the mean of each detail coefficient to zero.

  20. Combined Rate and Power Allocation with Link Scheduling in Wireless Data Packet Relay Networks with Fading Channels

    Directory of Open Access Journals (Sweden)

    Subhrakanti Dey

    2007-08-01

    Full Text Available We consider a joint rate and power control problem in a wireless data traffic relay network with fading channels. The optimization problem is formulated in terms of power and rate selection, and link transmission scheduling. The objective is to seek high aggregate utility of the relay node when taking into account buffer load management and power constraints. The optimal solution for a single transmitting source is computed by a two-layer dynamic programming algorithm which leads to optimal power, rate, and transmission time allocation at the wireless links. We further consider an optimal power allocation problem for multiple transmitting sources in the same framework. Performances of the resource allocation algorithms including the effect of buffer load control are illustrated via extensive simulation studies.

  1. Combined Rate and Power Allocation with Link Scheduling in Wireless Data Packet Relay Networks with Fading Channels

    Directory of Open Access Journals (Sweden)

    Dey Subhrakanti

    2007-01-01

    Full Text Available We consider a joint rate and power control problem in a wireless data traffic relay network with fading channels. The optimization problem is formulated in terms of power and rate selection, and link transmission scheduling. The objective is to seek high aggregate utility of the relay node when taking into account buffer load management and power constraints. The optimal solution for a single transmitting source is computed by a two-layer dynamic programming algorithm which leads to optimal power, rate, and transmission time allocation at the wireless links. We further consider an optimal power allocation problem for multiple transmitting sources in the same framework. Performances of the resource allocation algorithms including the effect of buffer load control are illustrated via extensive simulation studies.

  2. Decentralized Estimation over Orthogonal Multiple-access Fading Channels in Wireless Sensor Networks - Optimal and Suboptimal Estimators

    CERN Document Server

    Wang, Xin

    2010-01-01

    Optimal and suboptimal decentralized estimators in wireless sensor networks (WSNs) over orthogonal multiple-access fading channels are studied in this paper. Considering multiple-bit quantization before digital transmission, we develop maximum likelihood estimators (MLEs) with both known and unknown channel state information (CSI). When training symbols are available, we derive a MLE that is a special case of the MLE with unknown CSI. It implicitly uses the training symbols to estimate the channel coefficients and exploits the estimated CSI in an optimal way. To reduce the computational complexity, we propose suboptimal estimators. These estimators exploit both signal and data level redundant information to improve the estimation performance. The proposed MLEs reduce to traditional fusion based or diversity based estimators when communications or observations are perfect. By introducing a general message function, the proposed estimators can be applied when various analog or digital transmission schemes are u...

  3. A Self-Sustained Wireless Multi-Sensor Platform Integrated with Printable Organic Sensors for Indoor Environmental Monitoring

    Directory of Open Access Journals (Sweden)

    Chun-Chang Wu

    2017-03-01

    Full Text Available A self-sustained multi-sensor platform for indoor environmental monitoring is proposed in this paper. To reduce the cost and power consumption of the sensing platform, in the developed platform, organic materials of PEDOT:PSS and PEDOT:PSS/EB-PANI are used as the sensing films for humidity and CO2 detection, respectively. Different from traditional gas sensors, these organic sensing films can operate at room temperature without heating processes or infrared transceivers so that the power consumption of the developed humidity and the CO2 sensors can be as low as 10 μW and 5 μW, respectively. To cooperate with these low-power sensors, a Complementary Metal-Oxide-Semiconductor (CMOS system-on-chip (SoC is designed to amplify and to read out multiple sensor signals with low power consumption. The developed SoC includes an analog-front-end interface circuit (AFE, an analog-to-digital convertor (ADC, a digital controller and a power management unit (PMU. Scheduled by the digital controller, the sensing circuits are power gated with a small duty-cycle to reduce the average power consumption to 3.2 μW. The designed PMU converts the power scavenged from a dye sensitized solar cell (DSSC module into required supply voltages for SoC circuits operation under typical indoor illuminance conditions. To our knowledge, this is the first multiple environmental parameters (Temperature/CO2/Humidity sensing platform that demonstrates a true self-powering functionality for long-term operations.

  4. The Performance Analysis of Smartphone-Based Pedestrian Dead Reckoning and Wireless Locating Technology for Indoor Navigation Application

    Directory of Open Access Journals (Sweden)

    Jhen-Kai Liao

    2016-12-01

    Full Text Available Recent developments in smartphone technology have increased user demand for indoors applications. The Global Navigation Satellite System (GNSS and the Inertial Navigation System (INS are the two advanced systems for navigation technology. However, it is still difficult for GNSS to provide an accurate and practical navigation solution, especially in environments with little or no signal availability. These failings should be easy to overcome; because of their portability and multiple embedded hardware sensors, smartphones seem well positioned to make pedestrian navigation easy and convenient in any environment. Pedestrian Dead Reckoning (PDR is one of the most commonly used technologies used for pedestrian navigation, but it is not always accurate because its positioning errors tend to accumulate over time. Therefore, this research introduces a new tool to overcome this failing; a Bluetooth Low-Energy (BLE beacon can maintain and improve the accuracy of PDR. Moreover, a BLE beacon can be initialized from any user position in an indoor environment. The random and unpredictable positions of pedestrians inevitably result in the degradation of navigation guidance systems’ data. To rectify this problem, we have implemented activity recognition technology to notify the proposed system so as to provide a more accurate heading estimate. This study proposes a Personal Navigation System (PNS based on this technology; it can estimate navigation solutions in real time and combines the advantages of PDR and Bluetooth positioning technology. A series of experiments were conducted to evaluate the accuracy of the system and the efficacy of our proposed algorithms. Preliminary results show the average relative precision of PDR to be about 2.5%, when using a mobile hand-held device. The error of initial position from 2-D beacon positioning is less than two meters. The proposed system works well without post-processing, and the multi-sensor activity recognition

  5. A multi-channel low-power system-on-chip for single-unit recording and narrowband wireless transmission of neural signal.

    Science.gov (United States)

    Bonfanti, A; Ceravolo, M; Zambra, G; Gusmeroli, R; Spinelli, A S; Lacaita, A L; Angotzi, G N; Baranauskas, G; Fadiga, L

    2010-01-01

    This paper reports a multi-channel neural recording system-on-chip (SoC) with digital data compression and wireless telemetry. The circuit consists of a 16 amplifiers, an analog time division multiplexer, an 8-bit SAR AD converter, a digital signal processor (DSP) and a wireless narrowband 400-MHz binary FSK transmitter. Even though only 16 amplifiers are present in our current die version, the whole system is designed to work with 64 channels demonstrating the feasibility of a digital processing and narrowband wireless transmission of 64 neural recording channels. A digital data compression, based on the detection of action potentials and storage of correspondent waveforms, allows the use of a 1.25-Mbit/s binary FSK wireless transmission. This moderate bit-rate and a low frequency deviation, Manchester-coded modulation are crucial for exploiting a narrowband wireless link and an efficient embeddable antenna. The chip is realized in a 0.35- εm CMOS process with a power consumption of 105 εW per channel (269 εW per channel with an extended transmission range of 4 m) and an area of 3.1 × 2.7 mm(2). The transmitted signal is captured by a digital TV tuner and demodulated by a wideband phase-locked loop (PLL), and then sent to a PC via an FPGA module. The system has been tested for electrical specifications and its functionality verified in in-vivo neural recording experiments.

  6. Near-Infrared Wireless Optical Communication with Particulates In-Suspension over the Underwater Channel

    KAUST Repository

    Lee, It Ee

    2017-05-08

    We demonstrate a gigabit near-infrared-based underwater wireless optical communication link using an 808-nm laser diode to mitigate the particle scattering effect in turbid medium. An improvement in the error performance is observed with increasing concentrations.

  7. Optimal Performance Monitoring of Hybrid Mid-Infrared Wavelength MIMO Free Space Optical and RF Wireless Networks in Fading Channels

    Science.gov (United States)

    Schmidt, Barnet Michael

    An optimal performance monitoring metric for a hybrid free space optical and radio-frequency (RF) wireless network, the Outage Capacity Objective Function, is analytically developed and studied. Current and traditional methods of performance monitoring of both optical and RF wireless networks are centered on measurement of physical layer parameters, the most common being signal-to-noise ratio, error rate, Q factor, and eye diagrams, occasionally combined with link-layer measurements such as data throughput, retransmission rate, and/or lost packet rate. Network management systems frequently attempt to predict or forestall network failures by observing degradations of these parameters and to attempt mitigation (such as offloading traffic, increasing transmitter power, reducing the data rate, or combinations thereof) prior to the failure. These methods are limited by the frequent low sensitivity of the physical layer parameters to the atmospheric optical conditions (measured by optical signal-to-noise ratio) and the radio frequency fading channel conditions (measured by signal-to-interference ratio). As a result of low sensitivity, measurements of this type frequently are unable to predict impending failures sufficiently in advance for the network management system to take corrective action prior to the failure. We derive and apply an optimal measure of hybrid network performance based on the outage capacity of the hybrid optical and RF channel, the outage capacity objective function. The objective function provides high sensitivity and reliable failure prediction, and considers both the effects of atmospheric optical impairments on the performance of the free space optical segment as well as the effect of RF channel impairments on the radio frequency segment. The radio frequency segment analysis considers the three most common RF channel fading statistics: Rayleigh, Ricean, and Nakagami-m. The novel application of information theory to the underlying physics of the

  8. Outage Performance Analysis of Relay Selection Schemes in Wireless Energy Harvesting Cooperative Networks over Non-Identical Rayleigh Fading Channels.

    Science.gov (United States)

    Do, Nhu Tri; Bao, Vo Nguyen Quoc; An, Beongku

    2016-02-26

    In this paper, we study relay selection in decode-and-forward wireless energy harvesting cooperative networks. In contrast to conventional cooperative networks, the relays harvest energy from the source's radio-frequency radiation and then use that energy to forward the source information. Considering power splitting receiver architecture used at relays to harvest energy, we are concerned with the performance of two popular relay selection schemes, namely, partial relay selection (PRS) scheme and optimal relay selection (ORS) scheme. In particular, we analyze the system performance in terms of outage probability (OP) over independent and non-identical (i.n.i.d.) Rayleigh fading channels. We derive the closed-form approximations for the system outage probabilities of both schemes and validate the analysis by the Monte-Carlo simulation. The numerical results provide comprehensive performance comparison between the PRS and ORS schemes and reveal the effect of wireless energy harvesting on the outage performances of both schemes. Additionally, we also show the advantages and drawbacks of the wireless energy harvesting cooperative networks and compare to the conventional cooperative networks.

  9. Design Criteria for Hierarchical Exclusive Code with Parameter-Invariant Decision Regions for Wireless 2-Way Relay Channel

    Directory of Open Access Journals (Sweden)

    Tomas Uricar

    2010-01-01

    Full Text Available The unavoidable parametrization of the wireless link represents a major problem of the network-coded modulation synthesis in a 2-way relay channel. Composite (hierarchical codeword received at the relay is generally parametrized by the channel gain, forcing any processing on the relay to be dependent on channel parameters. In this paper, we introduce the codebook design criteria, which ensure that all permissible hierarchical codewords have decision regions invariant to the channel parameters (as seen by the relay. We utilize the criterion for parameter-invariant constellation space boundary to obtain the codebooks with channel parameter-invariant decision regions at the relay. Since the requirements on such codebooks are relatively strict, the construction of higher-order codebooks will require a slightly simplified design criteria. We will show that the construction algorithm based on these relaxed criteria provides a feasible way to the design of codebooks with arbitrary cardinality. The promising performance benefits of the example codebooks (compared to a classical linear modulation alphabets will be exemplified on the minimum distance analysis.

  10. Robust transmission of packet-based H.264/AVC video with data partitioning over DS-CDMA wireless channels

    Science.gov (United States)

    Mantravadi, Anand V. S.; Bansal, Manu; Kondi, Lisimachos P.

    2006-01-01

    In this paper, we address the problem of robust transmission of packet based H.264/AVC video over direct sequence-code division multiple access (DS-CDMA) channels. H.264 based data partitioning is used to produce video packets of unequal importance with regards to their need in terms of the decoded video quality. In the proposed transmission system, the data partitioned video packets are packetized as per IP/UDP/RTP protocol stack and are sorted into different levels for giving unequal error protection (UEP) using Rate Compatible Punctured Convolutional (RCPC) codes. Constant size framing is done at the link layer and Cyclic Redundancy Check header (CRC) is attached for error detection. Link layer buffering and packet interleaving schemes are proposed to improve the efficiency of the system. A multipath Rayleigh fading channel with Additive White Gaussian Noise (AWGN) and interference from other users is considered at the physical layer. The link layer frames are channel encoded, spread and transmitted over the channel. The received data is despread/demodulated using the Auxiliary Vector (AV) filter or RAKE matched filter (RAKE-MF) receiver and subsequently channel and source decoded. Our experimental results show the effectiveness of using data partitioning for wireless transmissions when compared to the system not using data partitioning. Also the superior interference mitigation capabilities of AV receiver is shown in comparison to the RAKE-MF receiver.

  11. Queuing Theory Based Co-Channel Interference Analysis Approach for High-Density Wireless Local Area Networks

    Science.gov (United States)

    Zhang, Jie; Han, Guangjie; Qian, Yujie

    2016-01-01

    Increased co-channel interference (CCI) in wireless local area networks (WLANs) is bringing serious resource constraints to today’s high-density wireless environments. CCI in IEEE 802.11-based networks is inevitable due to the nature of the carrier sensing mechanism however can be reduced by resource optimization approaches. That means the CCI analysis is basic, but also crucial for an efficient resource management. In this article, we present a novel CCI analysis approach based on the queuing theory, which considers the randomness of end users’ behavior and the irregularity and complexity of network traffic in high-density WLANs that adopts the M/M/c queuing model for CCI analysis. Most of the CCIs occur when multiple networks overlap and trigger channel contentions; therefore, we use the ratio of signal-overlapped areas to signal coverage as a probabilistic factor to the queuing model to analyze the CCI impacts in highly overlapped WLANs. With the queuing model, we perform simulations to see how the CCI influences the quality of service (QoS) in high-density WLANs. PMID:27563896

  12. Queuing Theory Based Co-Channel Interference Analysis Approach for High-Density Wireless Local Area Networks.

    Science.gov (United States)

    Zhang, Jie; Han, Guangjie; Qian, Yujie

    2016-08-23

    Increased co-channel interference (CCI) in wireless local area networks (WLANs) is bringing serious resource constraints to today's high-density wireless environments. CCI in IEEE 802.11-based networks is inevitable due to the nature of the carrier sensing mechanism however can be reduced by resource optimization approaches. That means the CCI analysis is basic, but also crucial for an efficient resource management. In this article, we present a novel CCI analysis approach based on the queuing theory, which considers the randomness of end users' behavior and the irregularity and complexity of network traffic in high-density WLANs that adopts the M/M/c queuing model for CCI analysis. Most of the CCIs occur when multiple networks overlap and trigger channel contentions; therefore, we use the ratio of signal-overlapped areas to signal coverage as a probabilistic factor to the queuing model to analyze the CCI impacts in highly overlapped WLANs. With the queuing model, we perform simulations to see how the CCI influences the quality of service (QoS) in high-density WLANs.

  13. A Fast Channel Assignment Scheme for Emergency Handling in Wireless Body Area Networks

    Science.gov (United States)

    Nepal, Sabita; Pudasani, Amod; Shin, Seokjoo

    2017-01-01

    Ubiquitous healthcare is a promising technology that has attracted significant attention in recent years; this has led to the realization of wireless body area networks (WBANs). For designing a robust WBAN system, the WBAN has to solve the drawbacks of wireless technology. Also, a WBAN has to support immediate, reliable data transmission for medical services during emergencies. Hence, this study proposes a new MAC superframe structure that can handle emergencies by delivering strongly correlated regular data to a caretaker, within a certain time threshold. Simulation results demonstrate that the proposed MAC protocol achieves low latency and high throughput. PMID:28264455

  14. Multi-Channel Scheduling for Fast Convergecast in Wireless Sensor Networks

    NARCIS (Netherlands)

    Durmaz, O.; Ghosh, A.; Krishnamachari, B.; Chintalapudi, K.

    We explore the following fundamental question - how fast can information be collected from a wireless sensor network? We consider a number of design parameters such as, power control, time and frequency scheduling, and routing. There are essentially two factors that hinder efficient data collection

  15. Broadcast Approach and Oblivious Cooperative Strategies for the Wireless Relay Channel - Part I: Sequential Decode-and-Forward (SDF)

    CERN Document Server

    Braginskiy, Evgeniy; Shamai, Shlomo

    2010-01-01

    In this two part paper we consider a wireless network in which a source terminal communicates with a destination and a relay terminal is occasionally present in close proximity to the source without source's knowledge, suggesting oblivious protocols. The source-relay channel is assumed to be a fixed gain AWGN due to the proximity while the source-destination and the relay-destination channels are subject to a block flat Rayleigh fading. A perfect CSI at the respective receivers only is assumed. With the average throughput as a performance measure, we incorporate a two-layer broadcast approach into two cooperative strategies based on the decode-and-forward scheme - Sequential Decoded-and Forward (SDF) in part I and the Block-Markov (BM) in part II. The broadcast approach splits the transmitted rate into superimposed layers corresponding to a "bad" and a "good" channel states, allowing better adaptation to the actual channel conditions In part I, the achievable rate expressions for the SDF strategy are derived ...

  16. On limits of Wireless Communications in a Fading Environment: a General Parameterization Quantifying Performance in Fading Channel

    Directory of Open Access Journals (Sweden)

    Amit Grover

    2014-08-01

    Full Text Available The reliable services along with high throughput can be achieved by using wireless communication systems. These systems also provides a wide coverage because of their features, no doubt MIMO Communication System [1] is one among them. Features provided by these systems ensure the improved system coverage and increased data transmission rate by considering multiple numbers of transmitter and receiver antennas. In this article, the concept of equalization has been considered and finally the performance of the MIMO Systems in Rician flat fading [5] channel is compared with the Rayleigh flat fading channel. It has also been observed that the performance of these Systems in Rician Flat Fading Channel is the best as compare to the Rayleigh Flat Fading Channel [10]. It has been concluded that the successive interference methods provide better performance as compare to others, but their complexity is high. Simulation results shows that ML provides the better performance in comparison to other equalizers but Sphere decoder provides the best performance.

  17. A Multi-Channel MAC Protocol For Wireless Hospital Sensor Networks

    CERN Document Server

    Slimane, Jamila Ben; Frikha, Mounir; Koubâa, Anis

    2008-01-01

    Both IEEE 802.15.4 and 802.15.4a standards allow for dynamic channel allocation and use of multiple channels available at their physical layers but its MAC protocols are designed only for single channel. Also, sensor's transceivers such as CC2420 provide multiple channels and channel switch latency of CC2420 transceiver is very short just about 200 micro seconds. In order to enhance both energy efficiency and to shorten end to end delay, we propose, in this report, a new MAC protocol allowing multi-channel allocation for 802.15.4a compliant devices.

  18. A multiple channel assignment algorithm and routing protocol base on wireless mesh networks

    Science.gov (United States)

    Shi, Xiaochuan; Li, Nan

    2011-10-01

    In this paper, a hybrid routing protocol TOIRP and a distributed channel assignment algorithm CLBCA of WMN in the multi-channel environment are proposed. The tree base protocol and the traditional AODV routing protocol are integrated together to reduce delay in the routing protocol, which is proposed by HWMP. A new routing metric CETTI is used in this routing protocol, which uses a new method to quantify the interference of communication. It divided interference into two parts: inter-flow interference and intra- flow interference, and it integrate the considerations of hop- count and delay. This improves the throughput of WMN. The channel assignment algorithm is divided into two parts: radio- neighbor binding and channel-radio binding. This algorithm is based on the channel load and avoids the channel-dependency problem which is common in the multi-channel environment. In the same time, it increases the utilization of each channel.

  19. Optical wireless transmission of 405 nm, 1.45 Gbit/s optical IM/DD-OFDM signals through a 4.8 m underwater channel.

    Science.gov (United States)

    Nakamura, Kazuhiko; Mizukoshi, Izumi; Hanawa, Masanori

    2015-01-26

    In this paper, we experimentally demonstrate wireless transmission of optical intensity modulation/direct detection-orthogonal frequency division multiplexing (IM/DD-OFDM) signals in an underwater channel using a field programmable gate array based real-time transmitter. The real-time transmission of a 405 nm 1.45 Gbit/s optical OFDM signal through a 4.8 m underwater channel with an error vector magnitude of approximately 10% was successfully achieved.

  20. Sparse Variational Bayesian SAGE Algorithm With Application to the Estimation of Multipath Wireless Channels

    DEFF Research Database (Denmark)

    Shutin, Dmitriy; Fleury, Bernard Henri

    2011-01-01

    channels. The application context of the algorithm considered in this contribution is parameter estimation from channel sounding measurements for radio channel modeling purpose. The new sparse VB-SAGE algorithm extends the classical SAGE algorithm in two respects: i) by monotonically minimizing...... scattering, calibration and discretization errors, allowing for a robust extraction of the relevant multipath components. The performance of the sparse VB-SAGE algorithm and its advantages over conventional channel estimation methods are demonstrated in synthetic single-input-multiple-output (SIMO) time......-invariant channels. The algorithm is also applied to real measurement data in a multiple-input-multiple-output (MIMO) time-invariant context....

  1. Fiber-wireless links supporting high-capacity W-band channels

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2013-01-01

    , is seeding the need to use bands located at the millimeter-wave region (30-300 GHz), mainly because of its inherent broadband nature. In our lab, we have conducted extensive research on high-speed photonic-wireless links in the V-band (50-75GHz) and the W-band (75-110GHz). In this paper, we will present our...

  2. Response time analysis of slotted WiDom in noisy wireless channels

    OpenAIRE

    Vahabi, Maryam; Tennina, Stefano; Tovar, Eduardo; Andersson, Björn

    2012-01-01

    International Conference on Emerging Technologies and Factory Automation (ETFA 2015), Industrial Communication Technologies and Systems, Luxembourg, Luxembourg. Timely delivery of critical traffic is a major challenge in industrial applications. The Wireless Dominance (WiDOM) medium access control protocol offers a very large number of priority levels to suit time sensitive application requirements. In particular, assuming that its overhead is properly modeled, WiDOM enables an accurate ev...

  3. Indoor Navigation Signal Channel Model Research%室内卫星导航定位信号模型研究

    Institute of Scientific and Technical Information of China (English)

    秦长路; 吕晶; 常江; 李罡

    2012-01-01

    首先总结了一些室内信道模型研究成果,这些模型或方式都没有给出广义的与室内场景特征有关的信号参数分布,或者仅仅表明了信号参数随着室内场景特征变化的趋势,同时不能反映卫星导航室内信道的动态特性。在前人的信号模型研究基础上,重点分析了室内导航信号衰落特征,提出用卫星陆地移动通信系统中的Lutz模型描述室内导航衰落信道,根据室内环境特征给出模型中各参数的取值,并且对三种典型的室内场景做了仿真。仿真结果表明,这种模型能够很好地描述室内多径和衰落特性。%Lots of study results about indoor channel model were summarized.These models or manners didn't present the generalized relationship between the signal parameter and indoor scenario characteristic,or just gave the trend of signal parameter as indoor character changed.And they couldn't reflect the channel's dynamic character.On the basis of some researcher's results,the indoor signal fading character was taken into analysis,and then it was put forward using the Lutz model,which was used to characterize the terrestrial satellite mobile communication system channel,to simulate it.According to the distributing of the indoor environments,the value of the parameters in every scenario was given.Finally,the simulation results of three typical scenarios indicate that this model is capable of characterizing the indoor multipath and fading characteristic.

  4. A novel unified expression for the capacity and bit error probability of wireless communication systems over generalized fading channels

    KAUST Repository

    Yilmaz, Ferkan

    2012-07-01

    Analysis of the average binary error probabilities (ABEP) and average capacity (AC) of wireless communications systems over generalized fading channels have been considered separately in past years. This paper introduces a novel moment generating function (MGF)-based unified expression for the ABEP and AC of single and multiple link communications with maximal ratio combining. In addition, this paper proposes the hyper-Fox\\'s H fading model as a unified fading distribution of a majority of the well-known generalized fading environments. As such, the authors offer a generic unified performance expression that can be easily calculated, and that is applicable to a wide variety of fading scenarios. The mathematical formulism is illustrated with some selected numerical examples that validate the correctness of the authors\\' newly derived results. © 1972-2012 IEEE.

  5. Wireless Powered Relaying Networks Under Imperfect Channel State Information: System Performance and Optimal Policy for Instantaneous Rate

    Directory of Open Access Journals (Sweden)

    D. T. Do

    2017-09-01

    Full Text Available In this investigation, we consider wireless powered relaying systems, where energy is scavenged by a relay via radio frequency (RF signals. We explore hybrid time switching-based and power splitting-based relaying protocol (HTPSR and compare performance of Amplify-and-Forward (AF with Decode-and-Forward (DF scheme under imperfect channel state information (CSI. Most importantly, the instantaneous rate, achievable bit error rate (BER are determined in the closed-form expressions under the impact of imperfect CSI. Through numerical analysis, we evaluate system insights via different parameters such as power splitting (PS and time switching (TS ratio of the considered HTPSR which affect outage performance and BER. It is noted that DF relaying networks outperform AF relaying networks. Besides that, the numerical results are given to prove the optimization problems of PS and TS ratio to obtain optimal instantaneous rate.

  6. 3-lead acquisition using single channel ECG device developed on AD8232 analog front end for wireless ECG application

    Science.gov (United States)

    Agung, Mochammad Anugrah; Basari

    2017-02-01

    Electrocardiogram (ECG) devices measure electrical activity of the heart muscle to determine heart conditions. ECG signal quality is the key factor in determining the diseases of the heart. This paper presents the design of 3-lead acquistion on single channel wireless ECG device developed on AD8232 chip platform using microcontroller. To make the system different from others, monopole antenna 2.4 GHz is used in order to send and receive ECG signal. The results show that the system still can receive ECG signal up to 15 meters by line of sight (LOS) condition. The shape of ECG signals is precisely similar with the expected signal, although some delays occur between two consecutive pulses. For further step, the system will be applied with on-body antenna in order to investigate body to body communication that will give variation in connectivity from the others.

  7. Optimized Hybrid Resource Allocation in Wireless Cellular Networks with and without Channel Reassignment

    Directory of Open Access Journals (Sweden)

    Xin Wu

    2010-01-01

    Full Text Available In cellular networks, it is important to determine an optimal channel assignment scheme so that the available channels, which are considered as “limited” resources in cellular networks, are used as efficiently as possible. The objective of the channel assignment scheme is to minimize the call-blocking and the call-dropping probabilities. In this paper, we present two efficient integer linear programming (ILP formulations, for optimally allocating a channel (from a pool of available channels to an incoming call such that both “hard” and “soft” constraints are satisfied. Our first formulation, ILP1, does not allow channel reassignment of the existing calls, while our second formulation, ILP2, allows such reassignment. Both formulations can handle hard constraints, which includes co-site and adjacent channel constraints, in addition to the standard co-channel constraints. The simplified problem (with only co-channel constraints can be treated as a special case of our formulation. In addition to the hard constraints, we also consider soft constraints, such as, the packing condition, resonance condition, and limiting rearrangements, to further improve the network performance. We present the simulation results on a benchmark 49 cell environment with 70 channels that validate the performance of our approach.

  8. TIME-FREQUENCY 2-D LMS BASED LONG-RANGE CHANNEL PREDICTION FOR WIRELESS OFDM SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Adaptive modulation can optimize the spectrum efficiency and system performance with the channel state information achieved by the long-range channel prediction. To avoid re-estimating channel correlation function as the channel stationarity varies and to track the channel adaptively,LMS (Least-Mean-Square) based long-range channel prediction is discussed in the existing literature,but it needs long observation interval to reach the convergence. Given that all OFDM (Orthogonal Frequency Division Multiplexing) subcarriers have the identical time-domain correlation and stationarity during the same time interval, this paper proposed a 2-D LMS based predictor which updates the filter weights in both time and frequency domain. The proposed scheme can effectively decrease the observation intervals and significantly speed up the convergence than the conventional LMS and Parallel LMS (PLMS). Complexity analysis and simulation results prove that the proposed scheme can improve the BER (Bit Error Rate) performance and spectrum efficiency with negligible complexity increase.

  9. Analysis of Channel-aware Multichannel ALOHA in OFDMA Wireless Networks

    Institute of Scientific and Technical Information of China (English)

    Zhang Yumei; Sheng Yu

    2009-01-01

    Orthogonal frequency division multiple access (OFDMA) systems provide multiple channels that can be accessed via random access schemes. In this paper a channel-aware multichannel random access, based on local channel state information (CSI), was investigated and a multichannel slotted ALOHA scheme was proposed accordingly. Also an analytical investigation of total system throughput and the queue state evolution of generic node in the network were present by assuming the channel has been modeled by means of a two state Markov chain. Through the theoretical model and simulation results, we confirm that the proposed algorithm has the advantage of high throughput and low access delay.

  10. Utility Optimal Coding for Packet Transmission over Wireless Networks - Part II: Networks of Packet Erasure Channels

    CERN Document Server

    Karumbu, Premkumar; Leith, Douglas J

    2011-01-01

    We define a class of multi--hop erasure networks that approximates a wireless multi--hop network. The network carries unicast flows for multiple users, and each information packet within a flow is required to be decoded at the flow destination within a specified delay deadline. The allocation of coding rates amongst flows/users is constrained by network capacity. We propose a proportional fair transmission scheme that maximises the sum utility of flow throughputs. This is achieved by {\\em jointly optimising the packet coding rates and the allocation of bits of coded packets across transmission slots.}

  11. A Fast-CSMA Algorithm for Deadline-Constrained Scheduling over Wireless Fading Channels

    CERN Document Server

    Li, Bin

    2012-01-01

    Recently, low-complexity and distributed Carrier Sense Multiple Access (CSMA)-based scheduling algorithms have attracted extensive interest due to their throughput-optimal characteristics in general network topologies. However, these algorithms are not well-suited for serving real-time traffic under time-varying channel conditions for two reasons: (1) the mixing time of the underlying CSMA Markov Chain grows with the size of the network, which, for large networks, generates unacceptable delay for deadline-constrained traffic; (2) since the dynamic CSMA parameters are influenced by the arrival and channel state processes, the underlying CSMA Markov Chain may not converge to a steady-state under strict deadline constraints and fading channel conditions. In this paper, we attack the problem of distributed scheduling for serving real-time traffic over time-varying channels. Specifically, we consider fully-connected topologies with independently fading channels (which can model cellular networks) in which flows wi...

  12. Optical wireless communications an emerging technology

    CERN Document Server

    Capsoni, Carlo; Ghassemlooy, Zabih; Boucouvalas, Anthony; Udvary, Eszter

    2016-01-01

    This book focuses on optical wireless communications (OWC), an emerging technology with huge potential for the provision of pervasive and reliable next-generation communications networks. It shows how the development of novel and efficient wireless technologies can contribute to a range of transmission links essential for the heterogeneous networks of the future to support various communications services and traffic patterns with ever-increasing demands for higher data-transfer rates. The book starts with a chapter reviewing the OWC field, which explains different sub-technologies (visible-light, ultraviolet (UV) and infrared (IR) communications) and introduces the spectrum of application areas (indoor, vehicular, terrestrial, underwater, intersatellite, deep space, etc.). This provides readers with the necessary background information to understand the specialist material in the main body of the book, which is in four parts. The first of these deals with propagation modelling and channel characterization of ...

  13. Personal Navigation Algorithms Based on Wireless Networks and Inertial Sensors

    Science.gov (United States)

    Kaňa, Zdenek; Bradáč, Zdenek; Fiedler, Petr

    2014-08-01

    The work aims at a development of positioning algorithm suitable for low-cost indoor or urban pedestrian navigation application. The sensor fusion was applied to increase the localization accuracy. Due to required low application cost only low grade inertial sensors and wireless network based ranging were taken into account. The wireless network was assumed to be preinstalled due to other required functionality (for example: building control) therefore only received signal strength (RSS) range measurement technique was considered. Wireless channel loss mapping method was proposed to overcome the natural uncertainties and restrictions in the RSS range measurements The available sensor and environment models are summarized first and the most appropriate ones are selected secondly. Their effective and novel application in the navigation task, and favorable fusion (Particle filtering) of all available information are the main objectives of this thesis.

  14. Measurement-based Channel Characterization for 5G Wireless Communications on Campus Scenario

    DEFF Research Database (Denmark)

    Mi, Yang; He, Ruisi; Ai, Bo

    2017-01-01

    The fifth generation (5G) communication has been a hotspot of research in recent years, and both research institutions and industrial enterprises put a lot of interests for 5G communication at some new frequency bands. In this paper, we investigate the radio channels of 5G communications below 6...... GHz according to the requirements and scenarios of 5G communication. Channel measurements were conducted on campus of Beijing Jiaotong University, China at two key optional frequency bands below 6 GHz. By using the measured data, we analyzed key channel parameters at 460MHz and 3.5GHz, such as power...

  15. INDOOR LOCALIZATION SOLUTION FOR GPS

    OpenAIRE

    Shreyanka B. Chougule; Dr.Sayed Abdulhayan

    2017-01-01

    GPS technology is used for positioning application and it is highly reliable and accurate when used outdoor. Due to multipath propagation, signal attenuation and blockage its performance is limited in indoor and dense urban environment. As a solution, technologies like Apple’s iBeacon, Radio-frequency identification (RFID), Ultrasonic and Wireless Fidelity (Wi-Fi) access points are used to improve performance in Indoor environment. We are having a look at all these technologies which are mean...

  16. On Topological Properties of Wireless Sensor Networks under the q-Composite Key Predistribution Scheme with On/Off Channels

    CERN Document Server

    Zhao, Jun; Gligor, Virgil

    2014-01-01

    The q-composite key predistribution scheme [1] is used prevalently for secure communications in large-scale wireless sensor networks (WSNs). Prior work [2]-[4] explores topological properties of WSNs employing the q-composite scheme for q = 1 with unreliable communication links modeled as independent on/off channels. In this paper, we investigate topological properties related to the node degree in WSNs operating under the q-composite scheme and the on/off channel model. Our results apply to general q and are stronger than those reported for the node degree in prior work even for the case of q being 1. Specifically, we show that the number of nodes with certain degree asymptotically converges in distribution to a Poisson random variable, present the asymptotic probability distribution for the minimum degree of the network, and establish the asymptotically exact probability for the property that the minimum degree is at least an arbitrary value. Numerical experiments confirm the validity of our analytical find...

  17. On the power and offset allocation for rate adaptation of spatial multiplexing in optical wireless MIMO channels

    KAUST Repository

    Park, Kihong

    2013-04-01

    In this paper, we consider resource allocation method in the visible light communication. It is challenging to achieve high data rate due to the limited bandwidth of the optical sources. In order to increase the spectral efficiency, we design a suitable multiple-input multiple-output (MIMO) system utilizing spatial multiplexing based on singular value decomposition and adaptive modulation. More specifically, after explaining why the conventional allocation method in radio frequency MIMO channels cannot be applied directly to the optical intensity channels, we theoretically derive a power allocation method for an arbitrary number of transmit and receive antennas for optical wireless MIMO systems. Based on three key constraints: the nonnegativity of the intensity-modulated signal, the aggregate optical power budget, and the bit error rate requirement, we propose a novel method to allocate the optical power, the offset value, and the modulation size. Based on some selected simulation results, we show that our proposed allocation method gives a better spectral efficiency at the expense of an increased computational complexity in comparison to a simple method that allocates the optical power equally among all the data streams. © 2013 IEEE.

  18. 基于温度传感器和FPGA室内温度智能无线控制设计%Design of indoor temperature intelligent wireless control based on temperature sensor and FPGA

    Institute of Scientific and Technical Information of China (English)

    丛子林

    2016-01-01

    In order to prolong the indoor temperature control range,and attain the goal of mobile phone wireless control and intelligent temperature adjustment,a intelligent wireless indoor temperature control system was designed based on the tem⁃perature sensor and FPGA. A mobile phone application program was written in the Android Studio integrated development envi⁃ronment. Reading of the indoor temperature,open/close state of windows,temperature adjustment and setting of maximum warning temperature were realized. The wireless temperature measuring network is composed of the temperature acquisition sensor and a serial port WIFI module. Main serial WIFI module working in AP mode communicates with FPGA through RS232 serial port. The FPGA as the main control center processes the data,sends the data to the mobile phone terminal and infrared control air conditioner,and control the curtains and windows through motors. The testing result indicates that the system runs smoothly, and has simple operation and high promotion value.%为了提高室内温度控制距离、实现手机无线控制以及温度智能调节,基于温度传感器和FPGA设计一个室内温度智能无线控制系统。通过Android Studio集成开发环境,编写手机应用程序,程序实现读取室内温度和窗子开关状态,同时还实现温度调节和最高预警温度设置的功能。通过温度传感器采集温度与串口WiFi模块组成无线温度测量网络,工作在AP模式的主串口WiFi模块通过RS 232串口与FPGA无线通信,FPGA作为主控中心处理数据并发送数据给手机终端和红外控制空调,并且通过电机控制窗帘和窗子。经测试,该系统运行稳定,操作简单、方便而且推广价值较高。

  19. Optimal Training for Time-Selective Wireless Fading Channels Using Cutoff Rate

    Directory of Open Access Journals (Sweden)

    Tong Lang

    2006-01-01

    Full Text Available We consider the optimal allocation of resources—power and bandwidth—between training and data transmissions for single-user time-selective Rayleigh flat-fading channels under the cutoff rate criterion. The transmitter exploits statistical channel state information (CSI in the form of the channel Doppler spectrum to embed pilot symbols into the transmission stream. At the receiver, instantaneous, though imperfect, CSI is acquired through minimum mean-square estimation of the channel based on some set of pilot observations. We compute the ergodic cutoff rate for this scenario. Assuming estimator-based interleaving and -PSK inputs, we study two special cases in-depth. First, we derive the optimal resource allocation for the Gauss-Markov correlation model. Next, we validate and refine these insights by studying resource allocation for the Jakes model.

  20. Robust Distributed Kalman Filter for Wireless Sensor Networks with Uncertain Communication Channels

    Directory of Open Access Journals (Sweden)

    Du Yong Kim

    2012-01-01

    Full Text Available We address a state estimation problem over a large-scale sensor network with uncertain communication channel. Consensus protocol is usually used to adapt a large-scale sensor network. However, when certain parts of communication channels are broken down, the accuracy performance is seriously degraded. Specifically, outliers in the channel or temporal disconnection are avoided via proposed method for the practical implementation of the distributed estimation over large-scale sensor networks. We handle this practical challenge by using adaptive channel status estimator and robust L1-norm Kalman filter in design of the processor of the individual sensor node. Then, they are incorporated into the consensus algorithm in order to achieve the robust distributed state estimation. The robust property of the proposed algorithm enables the sensor network to selectively weight sensors of normal conditions so that the filter can be practically useful.

  1. On the Performance of Optical Wireless Links over Random Foggy Channels

    KAUST Repository

    Esmail, Maged

    2017-02-17

    Fog and dust are used to be considered as major performance degrading factors for free space optic (FSO) communication links. Despite the number of field measurements, performed in foggy environments during the last decades, most of the proposed channel attenuation models are deterministic, i.e., assumed the channel attenuation constant over time. Stochastic behavior of the channel is still understudied. In this work, we investigate the probabilistic behavior of the FSO channel in fog and develop a new statistical model for the signal attenuation. Moreover, we derive a probability distribution function (PDF) for the channel state. Using this PDF, we study the FSO system performance considering various metrics including average signal-to-noise ratio, average bit error rate, channel capacity, and probability of outage. Closed form expressions are derived for the average SNR and outage probability. We found acceptable performance with moderate and light fog. However, under thick and dense fog, the system performance poorly deteriorates. Finally, we derived closed form expressions for the average attenuation-distance product and the link availability that will potentially be very helpful for network design and planning.

  2. Indoor Intelligent Mobile Robot Based on ZigBee Wireless Location%室内智能移动机器人ZigBee无线网络定位技术

    Institute of Scientific and Technical Information of China (English)

    邹宜成; 梁红

    2012-01-01

    Traditional localization for indoor robot cannot reach expected positioning accuracy in a complex and wide environment. Based on the received signal strength indicator,a method that uses a ZigBee wireless network was proposed. A ZigBee wireless network indoor positioning system was built up. It provides the coordinates of the robot for the main controller to schedule the pathway of robot. Parameters in positioning system were demarcated and (actors that affect the positioning accuracy were analyzed. The experimental results show that the system can locate the robot under a complex indoor environment. If there are no obstacles, the accuracy can reach 0.25 m. It can meet the requirements of indoor positioning accuracy. The localization scope can be extended according to actual demands.%针对目前室内机器人定位方法不能同时满足定位精度、定位范围和复杂环境条件下定位的情况,提出了一种利用ZigBee无线网络、基于接收到信号强度测距的定位方法.研究通过搭建一个ZigBee无线网络室内定位系统,实时提供机器人的位置坐标,为机器人实现路径规划提供保障.通过实验对定位系统中的各项参数进行标定,并分析了影响定位精度的因素.实验结果表明,ZigBee无线网络定位系统在室内复杂环境下可实现定位,在无障碍物的条件下精度可达到0.25m,可以满足室内机器人的定位精度要求,定位范围可根据实际需求进行扩展.

  3. Light Fidelity (Li-Fi) Based Indoor Communication System

    OpenAIRE

    Farooq Aftab; Muhammad Nafees Ulfat khan; Shahzad Ali

    2016-01-01

    Indoor wireless communication is an essential part of next generation wireless communication system.For an indoor communication number of users and their device are increasing very rapidly so as a result capacity of frequency spectrum to accommodate further users in future is limited and also it would be difficult for service providers to provide more user reliable and high speed communication so this short come can be solve in future by using Li-Fi based indoor communication syst...

  4. Measurement-based Channel Characterization for 5G Wireless Communications on Campus Scenario

    DEFF Research Database (Denmark)

    Mi, Yang; He, Ruisi; Ai, Bo

    2017-01-01

    The fifth generation (5G) communication has been a hotspot of research in recent years, and both research institutions and industrial enterprises put a lot of interests for 5G communication at some new frequency bands. In this paper, we investigate the radio channels of 5G communications below 6...... GHz according to the requirements and scenarios of 5G communication. Channel measurements were conducted on campus of Beijing Jiaotong University, China at two key optional frequency bands below 6 GHz. By using the measured data, we analyzed key channel parameters at 460MHz and 3.5GHz, such as power...... delay profile, path loss exponent, shadow fading, and delay spread. The results are helpful for the 5G communication system design....

  5. Tree-Structured Random Vector Quantization for Limited-Feedback Wireless Channel

    CERN Document Server

    Santipach, Wiroonsak

    2011-01-01

    We consider quantizing transmit beamforming vector in a multiantenna channel and signature vector in code division multiple access (CDMA). Assuming perfect channel knowledge, receiver selects for a transmitter the vector that maximizes the performance from a random vector quantization (RVQ) codebook, which consists of independent isotropically distributed unit-norm vectors. The quantized vector is then relayed to the transmitter via a rate-limited feedback channel. The RVQ codebook requires exhaustive search to locate the selected entry. To reduce the search complexity, we apply generalized Lloyd or $k$-dimensional (kd)-tree algorithms to organize RVQ entries into a tree. In examples shown, the search complexity of tree-structured (TS) RVQ can be a few orders of magnitude less than that of the unstructured RVQ for the same performance. We also derive the performance approximation for TS-RVQ in a large system limit, which predicts the performance of moderate-size systems very well.

  6. BLIND CHANNEL AND SYMBOL JOINT ESTIMATION IN COOPERATIVE MIMO FOR WIRELESS SENSOR NETWORK

    Institute of Scientific and Technical Information of China (English)

    Yan Zhenya; Zheng Baoyu

    2008-01-01

    In this paper, application of Sequential Quasi Monte Carlo (SQMC) to blind channel and symbol joint estimation in cooperative Multiple-Input Multiple-Output (MIMO) system is proposed, which does not need to transmit training symbol and can save the power and channel bandwidth. Additionally, an improved version of SQMC algorithm by taking advantage of current received signal is discussed. Simulation results show that the SQMC method outperforms the Sequential Monte Carlo (SMC) methods, and the incorporation of current received signal improves the performance of the SQMC obviously.

  7. Wireless data transmission through in-band on-channel digital audio broadcasting

    Science.gov (United States)

    Vigil, A. J.

    1995-12-01

    USA Digital Radio (USADR) is finalizing the development of new state-of-the-art formats for in-band on-channel (IBOC) delivery of digital audio broadcasting (DAB). USADR's IBOC DAB systems are designed for top-notch digital audio delivery as well as enhanced ancillary data transmission capabilities. USADR's AM and FM IBOC DAB systems employ MUSICAMR source encoding as well as innovative modulation techniques which address the various radio channel impairments characteristic of AM and FM band propagation. The USADR IBOC DAB systems are designed to be backwards compatible with conventional AM and FM broadcasting for a seamless and cost-effective transition to DAB.

  8. A MIMO-OFDM Testbed for Wireless Local Area Networks

    Directory of Open Access Journals (Sweden)

    Conrat Jean-Marc

    2006-01-01

    Full Text Available We describe the design steps and final implementation of a MIMO OFDM prototype platform developed to enhance the performance of wireless LAN standards such as HiperLAN/2 and 802.11, using multiple transmit and multiple receive antennas. We first describe the channel measurement campaign used to characterize the indoor operational propagation environment, and analyze the influence of the channel on code design through a ray-tracing channel simulator. We also comment on some antenna and RF issues which are of importance for the final realization of the testbed. Multiple coding, decoding, and channel estimation strategies are discussed and their respective performance-complexity trade-offs are evaluated over the realistic channel obtained from the propagation studies. Finally, we present the design methodology, including cross-validation of the Matlab, C++, and VHDL components, and the final demonstrator architecture. We highlight the increased measured performance of the MIMO testbed over the single-antenna system.

  9. A MIMO-OFDM Testbed for Wireless Local Area Networks

    Science.gov (United States)

    Fàbregas, Albert Guilléni; Guillaud, Maxime; Slock, Dirk TM; Caire, Giuseppe; Gosse, Karine; Rouquette, Stéphanie; Dias, Alexandre Ribeiro; Bernardin, Philippe; Miet, Xavier; Conrat, Jean-Marc; Toutain, Yann; Peden, Alain; Li, Zaiqing

    2006-12-01

    We describe the design steps and final implementation of a MIMO OFDM prototype platform developed to enhance the performance of wireless LAN standards such as HiperLAN/2 and 802.11, using multiple transmit and multiple receive antennas. We first describe the channel measurement campaign used to characterize the indoor operational propagation environment, and analyze the influence of the channel on code design through a ray-tracing channel simulator. We also comment on some antenna and RF issues which are of importance for the final realization of the testbed. Multiple coding, decoding, and channel estimation strategies are discussed and their respective performance-complexity trade-offs are evaluated over the realistic channel obtained from the propagation studies. Finally, we present the design methodology, including cross-validation of the Matlab, C++, and VHDL components, and the final demonstrator architecture. We highlight the increased measured performance of the MIMO testbed over the single-antenna system.

  10. Autonomous transmission power adaptation for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2008-09-01

    Full Text Available Multi-Radio Multi-Channel (MRMC) systems are key to power control problems in WMNs. Previous studies have emphasized throughput maximization in such systems as the main design challenge and transmission power control treated as a secondary issue...

  11. Autonomous transmission power adaptation for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2009-09-01

    Full Text Available Multi-Radio Multi-Channel (MRMC) systems are key to power control problems in WMNs. Previous studies have emphasized through- put maximization in such systems as the main design challenge and transmission power control treated as a secondary issue...

  12. Modeling and Simulation of MIMO Mobile-to-Mobile Wireless Fading Channels

    Directory of Open Access Journals (Sweden)

    Gholamreza Bakhshi

    2012-01-01

    Full Text Available Analysis and design of multielement antenna systems in mobile fading channels require a model for the space-time cross-correlation among the links of the underlying multipleinput multiple-output (MIMO Mobile-to-Mobile (M-to-M communication channels. In this paper, we propose the modified geometrical two-ring model, a MIMO channel reference model for M-to-M communication systems. This model is based on the extension of single-bounce two-ring scattering model for flat fading channel under the assumption that the transmitter and the receiver are moving. Assuming single-bounce scattering model in both isotropic and nonisotropic environment, a closed-form expression for the space-time cross-correlation function (CCF between any two subchannels is derived. The proposed model provides an important framework in M-to-M system design, where includes many existing correlation models as special cases. Also, two realizable statistical simulation models are proposed for simulating both isotropic and nonisotropic reference model. The realizable simulation models are based on Sum-of-Sinusoids (SoS simulation model. Finally, the correctness of the proposed simulation models is shown via different simulation scenarios.

  13. Microfluidic channel-based wireless charging and communication platform for microsensors with miniaturized onboard antenna

    Science.gov (United States)

    Duan, G.; Zhao, X.; Seren, H. R.; Chen, C.; Li, A.; Zhang, X.

    2016-12-01

    A double layer spiral antenna with side length of 380 μm was fabricated by a multi-step electroplating process, and integrated with a commercialized passive RFID chip to realize the RF power harvesting and communication functions of a microsensor. To power up and communicate with the microchips, a single layer spiral reader antenna was fabricated on top of a glass substrate with side length of 1 mm. The microchips and the reader antenna were both optimized at the frequency of 915 MHz. Due to the small size of the reader antenna, the strength of the magnetic field decreased dramatically along the axial direction of the reader antenna, which limited the working distance to within 1 mm. To enclose the microchips within the reading range, a three-layer microfluidic channel was designed and fabricated. The channel and cover layers were fabricated by laser cutting of acrylic sheets, and bonded with the glass substrate to form the channel. To operate multiple microchips simultaneously, separation and focusing function units were also designed. Low loss pump oil was used to transport the microchips flowing inside the channel. Within the reading area, the microchips were powered up, and their ID information was retrieved and displayed on the computer interface successfully.

  14. Results of attenuation measurements for optical wireless channels under dense fog conditions regarding different wavelengths

    Science.gov (United States)

    Flecker, B.; Gebhart, M.; Leitgeb, E.; Sheikh Muhammad, S.; Chlestil, C.

    2006-08-01

    Free Space Optics (FSO) has gained considerable importance in this decade of demand for high bandwidth transmission capabilities. FSO can provide the last mile solution, but the availability and reliability issues concerned with it can not be ignored, and requires thorough investigations. In this work, we present our results about light attenuation at 950 and 850 nm wavelengths in continental city fog conditions with peak values up to 130 dB/km and compare them with attenuation under dense maritime conditions with peak values up to 480 dB/km. Dense fog is the most severe limiting factor in terrestrial optical wireless applications and light propagation in fog has properties in the spatial, spectral and the time domain, which are of importance to free-space optic data communication. In 2004 (within a short term scientific mission of COST 270) measurements of very dense maritime fog and low clouds were made in the mountains of La Turbie, close to the coast of southern France. Using the same equipment, the measurements were continued for the conditions of the continental city of Graz, Austria. This campaign was done in the winter months from 2004 to 2005 and 2005 to 2006 and allows us to compare fog properties for different environments, and the impact of snow fall. We provide detail analysis of a fog and a snow event for better understanding of their attenuation behavior.

  15. A Wireless Channel Encryption Method with γ Mean Square Error%γ约束均方误差下的无线信道加密方法

    Institute of Scientific and Technical Information of China (English)

    罗文宇; 金梁; 黄开枝; 钟州

    2012-01-01

    The design of secure wireless communication suffers a great challenge for openness of wireless channel and the broadcast nature of radio signals. The security problem introduced by wireless channel may be solved adequately by wireless channel itself. The space redundancy is often used in existing physical-layer security method to enhance security. So the concept of / mean square error is proposed in the paper, which is used to introduce redundancy for pre-coding weight. The concrete analysis and corresponding formal derivations are also given in the paper. Based on these, a novel physical-layer encryption method is proposed according to short-term reciprocity,rapid Decorrelation of wireless channel. Simulation results show that the proposed method guarantees wireless transmission in the authorized receiver and reduces the probability of interception.%无线信道的开放性和电磁信号的广播特性对无线通信系统的安全提出了极大挑战.无线信道引入的安全问题还需要从无线信道本身加以根本解决.现有基于无线信道的物理层安全方法大多利用了多天线带来的空间冗余,无法应用于单天线点对点的场景.为此,本文首先提出了γ约束均方误差的概念,通过放宽授权用户的最佳线性接收条件在发送端引入预编码权值的冗余.在此基础上将物理层安全问题转变为发送信号随机化问题,并给出了具体分析和相应的理论推导.然后利用无线信道特征的短期可逆性、快速去相关性提出一种全新的物理层加密方法.分析和仿真结果表明,该方法在保证授权用户无条件正常接收的同时大大降低了信号被非法用户截获的概率.

  16. Decentralized power control for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2010-09-01

    Full Text Available for their operations in such applications. Furthermore, due to the scarce skilled manpower, regular network maintenances and battery replacements in remote places are seldom. Typical topography of remote areas requires that mesh networks deliver packets over long... deviation. The contribution of the paper lies on how such metrics from neighbouring orthogonal channels can effectively be coordinated to yield optimal power levels for each transmitter. This scalability naturally suits the WMN applications...

  17. Channel access delay and buffer distribution of two-user opportunistic scheduling schemes in wireless networks

    KAUST Repository

    Hossain, Md Jahangir

    2010-07-01

    In our earlier works, we proposed rate adaptive hierarchical modulation-assisted two-best user opportunistic scheduling (TBS) and hybrid two-user scheduling (HTS) schemes. The proposed schemes are innovative in the sense that they include a second user in the transmission opportunistically using hierarchical modulations. As such the frequency of information access of the users increases without any degradation of the system spectral efficiency (SSE) compared to the classical opportunistic scheduling scheme. In this paper, we analyze channel access delay of an incoming packet at the base station (BS) buffer when our proposed TBS and HTS schemes are employed at the BS. Specifically, using a queuing analytic model we derive channel access delay as well as buffer distribution of the packets that wait at BS buffer for down-link (DL) transmission. We compare performance of the TBS and HTS schemes with that of the classical single user opportunistic schemes namely, absolute carrier-to-noise ratio (CNR)-based single user scheduling (ASS) and normalized CNR-based single user scheduling (NSS). For an independent and identically distributed (i.i.d.) fading environment, our proposed scheme can improve packet\\'s access delay performance compared to the ASS. Selected numerical results in an independent but non-identically distributed (i.n.d.) fading environment show that our proposed HTS achieves overall good channel access delay performance. © 2010 IEEE.

  18. Statistics of α-μ Random Variables and Their Applications inWireless Multihop Relaying and Multiple Scattering Channels

    KAUST Repository

    Wang, Kezhi

    2015-06-01

    Exact results for the probability density function (PDF) and cumulative distribution function (CDF) of the sum of ratios of products (SRP) and the sum of products (SP) of independent α-μ random variables (RVs) are derived. They are in the form of 1-D integral based on the existing works on the products and ratios of α-μ RVs. In the derivation, generalized Gamma (GG) ratio approximation (GGRA) is proposed to approximate SRP. Gamma ratio approximation (GRA) is proposed to approximate SRP and the ratio of sums of products (RSP). GG approximation (GGA) and Gamma approximation (GA) are used to approximate SP. The proposed results of the SRP can be used to calculate the outage probability (OP) for wireless multihop relaying systems or multiple scattering channels with interference. The proposed results of the SP can be used to calculate the OP for these systems without interference. In addition, the proposed approximate result of the RSP can be used to calculate the OP of the signal-To-interference ratio (SIR) in a multiple scattering system with interference. © 1967-2012 IEEE.

  19. Compressive sensing-based channel bandwidth improvement in optical wireless orthogonal frequency division multiplexing link using visible light emitting diode.

    Science.gov (United States)

    Won, Yong-Yuk; Yoon, Sang Min

    2014-08-25

    A new technique, which can compensate for the lack of channel bandwidth in an optical wireless orthogonal frequency division multiplexing (OFDM) link based on a light emitting diode (LED), is proposed. It uses an adaptive sampling and an inverse discrete cosine transform in order to convert an OFDM signal into a sparse waveform so that not only is the important data obtained efficiently but the redundancy one is removed. In compressive sensing (CS), a sparse signal that is sampled below the Nyquist/Shannon limit can be reconstructed successively with enough measurement. This means that the CS technique can increase the data rate of visible light communication (VLC) systems based on LEDs. It is observed that the data rate of the proposed CS-based VLC-OFDM link can be made 1.7 times greater than a conventional VLC-OFDM link (from 30.72 Mb/s to 51.2 Mb/s). We see that the error vector magnitude (EVM) of the quadrature phase shift keying (QPSK) symbol is 31% (FEC limit: EVM of 32%) at a compression ratio of 40%.

  20. Design of a low power 10 bit 300 ksps multi-channel SAR ADC for wireless sensor network applications

    Science.gov (United States)

    Hui, Hong; Shiliang, Li; Tao, Zhou

    2015-04-01

    This paper presents a low power 10 bit 300 ksps successive approximation register analog-to-digital converter (SAR ADC) which is applied in wireless sensor network (WSN) applications. A single ended energy-saving split capacitor DAC array and a latch comparator with a rail to rail input stage are utilized to implement the ADC, which can reduce power dissipation while expanding the full scale input range and improve the signal-to-noise ratio (SNR). For power optimization the supply voltage of the SAR ADC is designed to be as low as 2 V. Four analog input channels are designed which make the ADC more suitable for WSN applications. The prototype circuit is fabricated using 3.3 V, 0.35 μm 2P4M CMOS technology and occupies an active chip area of 1.23 mm2. The test results show that the power dissipation is only 200 μW at a 2 V power supply and a sampling rate of 166 ksps. The calculated SNR is 58.25 dB, the ENOB is 9.38 bit and the FOM is 4.95 pJ/conversion-step. Project supported by the National Natural Science Foundation of China (No. 61107025) and the Key Innovation Team Project of Zhejiang Province (No. 2010R50010).

  1. Statistical mechanical analysis of the Kronecker channel model for multiple-input multiple-output wireless communication.

    Science.gov (United States)

    Hatabu, Atsushi; Takeda, Koujin; Kabashima, Yoshiyuki

    2009-12-01

    The Kronecker channel model of wireless communication is analyzed using statistical mechanics methods. In the model, spatial proximities among transmission/reception antennas are taken into account as certain correlation matrices, which generally yield nontrivial dependence among symbols to be estimated. This prevents accurate assessment of the communication performance by naively using a previously developed analytical scheme based on a matrix integration formula. In order to resolve this difficulty, we develop a formalism that can formally handle the correlations in Kronecker models based on the known scheme. Unfortunately, direct application of the developed scheme is, in general, practically difficult. However, the formalism is still useful, indicating that the effect of the correlations generally increase after the fourth order with respect to correlation strength. Therefore, the known analytical scheme offers a good approximation in performance evaluation when the correlation strength is sufficiently small. For a class of specific correlation, we show that the performance analysis can be mapped to the problem of one-dimensional spin systems in random fields, which can be investigated without approximation by the belief propagation algorithm.

  2. Low noise multi-channel biopotential wireless data acquisition system for dry electrodes

    Science.gov (United States)

    Pandian, P. S.; Whitchurch, Ashwin K.; Abraham, Jose K.; Bhusan Baskey, Himanshu; Radhakrishnan, J. K.; Varadan, Vijay K.; Padaki, V. C.; Bhasker Rao, K. U.; Harbaugh, R. E.

    2008-03-01

    and transmitted wirelessly to a remote monitoring station.

  3. A Direct Radiative Transfer Equation Solver for Path Loss Calculation of Underwater Optical Wireless Channels

    KAUST Repository

    Li, Changping

    2014-11-10

    In this report, we propose a fast numerical solution for the steady state radiative transfer equation in order to calculate the path loss due to light absorption and scattering in various type of underwater channels. In the proposed scheme, we apply a direct non-uniform method to discretize the angular space and an upwind type finite difference method to discretize the spatial space. A Gauss-Seidel iterative method is then applied to solve the fully discretized system of linear equations. The accuracy and efficiency of the proposed scheme is validated by Monte Carlo simulations.

  4. Indoor radio channel modeling and mitigation of fading effects using linear and circular polarized antennas in combination for smart home system at 868 MHz

    Science.gov (United States)

    Wunderlich, S.; Welpot, M.; Gaspard, I.

    2014-11-01

    The markets for smart home products and services are expected to grow over the next years, driven by the increasing demands of homeowners considering energy monitoring, management, environmental controls and security. Many of these new systems will be installed in existing homes and offices and therefore using radio based systems for cost reduction. A drawback of radio based systems in indoor environments are fading effects which lead to a high variance of the received signal strength and thereby to a difficult predictability of the encountered path loss of the various communication links. For that reason it is necessary to derive a statistical path loss model which can be used to plan a reliable and cost effective radio network. This paper presents the results of a measurement campaign, which was performed in six buildings to deduce realistic radio channel models for a high variety of indoor radio propagation scenarios in the short range devices (SRD) band at 868 MHz. Furthermore, a potential concept to reduce the variance of the received signal strength using a circular polarized (CP) patch antenna in combination with a linear polarized antenna in an one-to-one communication link is presented.

  5. Utility Optimal Coding for Packet Transmission over Wireless Networks - Part I: Networks of Binary Symmetric Channels

    CERN Document Server

    Karumbu, Premkumar; Leith, Douglas J

    2011-01-01

    We consider multi--hop networks comprising Binary Symmetric Channels ($\\mathsf{BSC}$s). The network carries unicast flows for multiple users. The utility of the network is the sum of the utilities of the flows, where the utility of each flow is a concave function of its throughput. Given that the network capacity is shared by the flows, there is a contention for network resources like coding rate (at the physical layer), scheduling time (at the MAC layer), etc., among the flows. We propose a proportional fair transmission scheme that maximises the sum utility of flow throughputs subject to the rate and the scheduling constraints. This is achieved by {\\em jointly optimising the packet coding rates of all the flows through the network}.

  6. Feedback Power Control Strategies inWireless Sensor Networks with Joint Channel Decoding

    Directory of Open Access Journals (Sweden)

    Fabio Perna

    2009-11-01

    Full Text Available In this paper, we derive feedback power control strategies for block-faded multiple access schemes with correlated sources and joint channel decoding (JCD. In particular, upon the derivation of the feasible signal-to-noise ratio (SNR region for the considered multiple access schemes, i.e., the multidimensional SNR region where error-free communications are, in principle, possible, two feedback power control strategies are proposed: (i a classical feedback power control strategy, which aims at equalizing all link SNRs at the access point (AP, and (ii an innovative optimized feedback power control strategy, which tries to make the network operational point fall in the feasible SNR region at the lowest overall transmit energy consumption. These strategies will be referred to as “balanced SNR” and “unbalanced SNR,” respectively. While they require, in principle, an unlimited power control range at the sources, we also propose practical versions with a limited power control range. We preliminary consider a scenario with orthogonal links and ideal feedback. Then, we analyze the robustness of the proposed power control strategies to possible non-idealities, in terms of residual multiple access interference and noisy feedback channels. Finally, we successfully apply the proposed feedback power control strategies to a limiting case of the class of considered multiple access schemes, namely a central estimating officer (CEO scenario, where the sensors observe noisy versions of a common binary information sequence and the AP’s goal is to estimate this sequence by properly fusing the soft-output information output by the JCD algorithm.

  7. Analysis of electromagnetic field emitted from home plug power line used for indoor high-speed broadband communication

    Institute of Scientific and Technical Information of China (English)

    Yong XU; Yinghua LV; Biao YANG; Hongxin ZHANG

    2009-01-01

    High-speed broadband power line communication (BPL) is a novel and practicable technique for NetatHome or home area local area networking (LAN).Because of the characteristics of BPL, the electromagnetic wave emitted from the BPL transmission media will influence the indoor electromagnetic environment, which would also affect the performance of other wireless communications. Based on the analysis of the communication channel characteristic, network impedance and attenuation characteristic of the BPL, this paper proposes a novel model for calculating the BPL radiation and the computer simulation model, which are proved by the coherence of the simulation and the test data. The interferences from the high-speed BPL to indoor wireless communications are analyzed to stipulate the standards of high-speed BPL in the future.

  8. Spectral and spatial characterization of perfluorinated graded-index polymer optical fibers for the distribution of optical wireless communication cells.

    Science.gov (United States)

    Hajjar, Hani Al; Montero, David S; Lallana, Pedro C; Vázquez, Carmen; Fracasso, Bruno

    2015-02-10

    In this paper, the characterization of a perfluorinated graded-index polymer optical fiber (PF-GIPOF) for a high-bitrate indoor optical wireless system is reported. PF-GIPOF is used here to interconnect different optical wireless access points that distribute optical free-space high-bitrate wireless communication cells. The PF-GIPOF channel is first studied in terms of transmission attenuation and frequency response and, in a second step, the spatial power profile distribution at the fiber output is analyzed. Both characterizations are performed under varying restricted mode launch conditions, enabling us to assess the transmission channel performance subject to potential connectorization errors within an environment where the end users may intervene by themselves on the home network infrastructure.

  9. IMPROVING THE PERFORMANCE AND REDUCING BIT ERROR RATE ON WIRELESS DEEP FADING ENVIRONMENT RECEIVERS

    Directory of Open Access Journals (Sweden)

    K. Jayanthi

    2014-01-01

    Full Text Available One of the major challenges in wireless communication system is increasing complexity and reducing performance in detecting the received digital information in indoor and outdoor Environments. Consequently to overcome this problem we analyze the delay performance of a multiuser with perfect channel state information transmitting data on deep fading environment. In this proposed system, the Wireless Deep Fading Environment (WDFE creation for causing a Nakagami Multipath Fading Channel of fading figure ‘m’ is used to rectify the delay performance over the existing Rayleigh fading channel. In this WDFE receivers received coherent, synchronized, secured and improved signal strength of information using a Multiuser Coherent Joint Diversity (MCJD with Multi Carrier-Code Division Multiple Access (MC-CDMA. The MCJD in ‘M’ branch of antennas are used to reduce the Bit Error Rate (BER and MC-CDMA method is used to improve the performance. Therefore, in this proposed system we accompany with MCJD and MC-CDMA is very good transceiver for next generation wireless system of an existing 3G wireless system. Overall, this experimental results show improved performance in different multiuser wireless systems under different multipath fading conditions.

  10. 水下无线传感器网络信道研究%Research on Wireless Sensor Networks Channel in Underwater

    Institute of Scientific and Technical Information of China (English)

    顾相平; 金鹰

    2011-01-01

    水下无线传感器网络通信信道是一种环境噪声高、传播时延长、误比特率高、多径干扰、多普勒效应严重的时、频、空变复杂的随机信道.水下声信道的复杂性和多变性严重限制了水下声通信的性能.本文使用Matlab软件研究、仿真分析了上述因素对水下无线传感器网络通信性能的影响,为更好地设计无线传感器网络信道模型、合理的水下无线传感器网络拓扑结构以及低功耗、高性能的路由协议提供一定的参考依据.%Underwater wireless sensor networks is a high environment noise, large transmission delay, high bit error rate, multi-path propagation, Doppler effect, time-frequency-space stochastic channel. The complexity and variability of an underwater a-coustic channel severely limit the performance of underwater acoustic communication. Using Matlab, the paper analyzes the influence of these factors on the underwater wireless sensor network communication performance, and provides a reference basis for designing feasible channel model of underwater wireless sensor networks, underwater reasonable topology and low-power, high-performance routing protocol.

  11. 基于STM32的智能家居无线激光报警系统%Intelligent indoor wireless laser alarm system based on STM32

    Institute of Scientific and Technical Information of China (English)

    李娜; 牛晓飞; 许海峰; 汪材印; 唐永刚

    2013-01-01

    This thesis has designed an intelligent indoor wireless laser alarm system which takes Micro controller Unit STM 32F103 as the core .The system consists of Micro controller Unit ,GSM wireless transceiver ,matrix keyboard ,sound and light alarm and pyroelectric laser sensors .Pyroelectric laser sensor receives infrared signal which would be analysed by STM 32F103 .Alarm signal would be send out by the sound and light alarm module .In the meantime GSM would transmit short message to the mobile of user through mobile network to reflect the circumstances of the alarm location .Because of the wide mobile network , the system is unnecessary to set up special network and maintain it .Therefore ,it has unique advantages compared with the traditional monitor systems .%以STM32为核心,设计了智能家居无线激光报警系统。该系统由单片机控制模块、GSM无线发送接收模块、矩阵键盘模块、声光报警模块、热释电激光传感器模块组成。通过热释电激光传感器采集相关信号,单片机STM32经过处理后控制声光报警模块发出报警信号,并将报警信号通过GSM短信模块发送至用户手机上,实时反馈报警地点的情况。该系统利用广泛的移动网络,不需要组建专用网络和维护网络,较传统的监控系统有着独特的优势。

  12. Wired and wireless convergent extended-reach optical access network using direct-detection of all-optical OFDM super-channel signal.

    Science.gov (United States)

    Chow, C W; Yeh, C H; Sung, J Y; Hsu, C W

    2014-12-15

    We propose and demonstrate the feasibility of using all-optical orthogonal frequency division multiplexing (AO-OFDM) for the convergent optical wired and wireless access networks. AO-OFDM relies on all-optically generated orthogonal subcarriers; hence, high data rate (> 100 Gb/s) can be easily achieved without hitting the speed limit of electronic digital-to-analog and analog-to-digital converters (DAC/ADC). A proof-of-concept convergent access network using AO-OFDM super-channel (SC) is demonstrated supporting 40 - 100 Gb/s wired and gigabit/s 100 GHz millimeter-wave (MMW) ROF transmissions.

  13. Adaptive Denoising and Equalization of Infrared Wireless CDMA System

    Directory of Open Access Journals (Sweden)

    Fernando Xavier N.

    2005-01-01

    Full Text Available Infrared has abundant, unregulated bandwidth enabling rapid deployment at low cost. However, safety limits on power emission levels (IEC825, large noise due to ambient lighting, and multipath dispersion remain as hurdles in diffused indoor environments. Especially, the high-frequency periodic interference produced by fluorescent lights is a major concern. Spread spectrum techniques enable low-power operation and noise rejection, at the expense of large processing gain. In this paper, we quantify the noise received and propose an adaptive FIR filter to jointly cancel the multipath dispersion and the fluorescent light noise in an infrared CDMA system. From analytical and simulation results, the adaptive filter significantly enhances the noise rejection capability of the CDMA system and tracks well the quasistationary indoor wireless channel. Our results show tenfold improvement in the BER for a given SNR and processing gain due to the adaptive filter. The filter also performs well in the multiuser environment.

  14. Outage Performance Analysis of Relay Selection Schemes in Wireless Energy Harvesting Cooperative Networks over Non-Identical Rayleigh Fading Channels

    Science.gov (United States)

    Do, Nhu Tri; Bao, Vo Nguyen Quoc; An, Beongku

    2016-01-01

    In this paper, we study relay selection in decode-and-forward wireless energy harvesting cooperative networks. In contrast to conventional cooperative networks, the relays harvest energy from the source’s radio-frequency radiation and then use that energy to forward the source information. Considering power splitting receiver architecture used at relays to harvest energy, we are concerned with the performance of two popular relay selection schemes, namely, partial relay selection (PRS) scheme and optimal relay selection (ORS) scheme. In particular, we analyze the system performance in terms of outage probability (OP) over independent and non-identical (i.n.i.d.) Rayleigh fading channels. We derive the closed-form approximations for the system outage probabilities of both schemes and validate the analysis by the Monte-Carlo simulation. The numerical results provide comprehensive performance comparison between the PRS and ORS schemes and reveal the effect of wireless energy harvesting on the outage performances of both schemes. Additionally, we also show the advantages and drawbacks of the wireless energy harvesting cooperative networks and compare to the conventional cooperative networks. PMID:26927119

  15. Optimization of wireless sensor communication channel based on adaptive noise cancellation%基于自适应噪声抵消的无线传感网络信道优化

    Institute of Scientific and Technical Information of China (English)

    龙清; 胡光波

    2016-01-01

    Wireless sensor network communication technology is widely applied in the field of Internet of things near field communication, underwater acoustic communication. The wireless sensor network communication channel often encounter the multi⁃path interference, which lead to an imbalance of channel. Based on the aboved, the paper develops the channel equalization model design. Proposed a wireless sensor communication channel based on adaptive noise cancellation optimization technique. Firstly, build the channel model of wireless sensor network communication. The wireless sensor network communication channel in the process of decay signal loss and various paths of the reorganization, the adaptive noise cancellation algorithm for channel multipath interference filter, combined with the least square ( RLS) criterion algorithm for wireless sensor communications channel equalization design. Simulation results show that using the communication channel equalization technique can effectively improve the quality of the wireless sensor network communication channel, reduce the communication transmission distortion and bit error rate, realize the adaptive channel equalization, therefore improve the anti⁃interference ability of communication.%无线传感器网络通信技术广泛应用在物联网近场通信、水声通信等领域。无线传感网络通信信道受到多途干扰,导致信道失衡,需要进行信道均衡模型设计。提出一种基于自适应噪声抵消的无线传感器网络通信信道优化技术,首先构建了无线传感器网络通信的信道模型,对无线传感器网络信道传播过程中衰减损失和各条路径的信号进行重组,采用自适应噪声抵消算法进行信道的多途干扰滤波,结合最小二乘( RLS)准则算法进行无线传感器网络通信信道均衡设计。仿真结果表明,采用该通信信道均衡技术能有效提高无线传感器网络通信的信道质量,降低通信传

  16. Wireless communication with chaos.

    Science.gov (United States)

    Ren, Hai-Peng; Baptista, Murilo S; Grebogi, Celso

    2013-05-03

    The modern world fully relies on wireless communication. Because of intrinsic physical constraints of the wireless physical media (multipath, damping, and filtering), signals carrying information are strongly modified, preventing information from being transmitted with a high bit rate. We show that, though a chaotic signal is strongly modified by the wireless physical media, its Lyapunov exponents remain unaltered, suggesting that the information transmitted is not modified by the channel. For some particular chaotic signals, we have indeed proved that the dynamic description of both the transmitted and the received signals is identical and shown that the capacity of the chaos-based wireless channel is unaffected by the multipath propagation of the physical media. These physical properties of chaotic signals warrant an effective chaos-based wireless communication system.

  17. Accuracy of depolarization and delay spread predictions using advanced ray-based modeling in indoor scenarios

    Directory of Open Access Journals (Sweden)

    Mani Francesco

    2011-01-01

    Full Text Available Abstract This article investigates the prediction accuracy of an advanced deterministic propagation model in terms of channel depolarization and frequency selectivity for indoor wireless propagation. In addition to specular reflection and diffraction, the developed ray tracing tool considers penetration through dielectric blocks and/or diffuse scattering mechanisms. The sensitivity and prediction accuracy analysis is based on two measurement campaigns carried out in a warehouse and an office building. It is shown that the implementation of diffuse scattering into RT significantly increases the accuracy of the cross-polar discrimination prediction, whereas the delay-spread prediction is only marginally improved.

  18. Wi-Fi Wireless Networks and Technology

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Most agree that wireless networking represent the future of computer and Internet connectivity worldwide.Wi-Fi continues to be the pre-eminent technology for building general-purpose wireless networks. 1 What is Wireless Networking? Wireless networks utilize radio waves and/or microwaves to maintain communication channels between computers.Wireless net- working is a more modern alternative to wired networking that relies on copper and/or fiber optic cabling between network devices.

  19. Toward a Gigabit Wireless Communications System

    CERN Document Server

    Rakotondrainibe, Lahatra; Zaharia, Gheorghe; Zein, Ghaïs El

    2009-01-01

    This paper presents the design and the realization of a hybrid wireless Gigabit Ethernet indoor communications system operating at 60 GHz. As the 60 GHz radio link operates only in a single-room configuration, an additional Radio over Fiber (RoF) link is used to ensure the communications within all the rooms of a residential environment. The system uses low complexity baseband processing modules. A byte synchronization technique is designed to provide a high value of the preamble detection probability and a very small value of the false detection probability. Conventional RS (255, 239) encoder and decoder are used for channel forward error correction (FEC). The FEC parameters are determined by the tradeoff between higher coding gain and hardware complexity. The results of bit error rate measurements at 875 Mbps are presented for various antennas configurations.

  20. A SIMO Fiber Aided Wireless Network Architecture

    OpenAIRE

    Ray, Siddharth; Medard, Muriel; Zheng, Lizhong

    2006-01-01

    The concept of a fiber aided wireless network architecture (FAWNA) is introduced in [Ray et al., Allerton Conference 2005], which allows high-speed mobile connectivity by leveraging the speed of optical networks. In this paper, we consider a single-input, multiple-output (SIMO) FAWNA, which consists of a SIMO wireless channel and an optical fiber channel, connected through wireless-optical interfaces. We propose a scheme where the received wireless signal at each interface is quantized and se...

  1. Ultra-Wideband Indoor Channel Modelling Using Ray-Tracing Software for through-the-Wall Imaging Radar

    Directory of Open Access Journals (Sweden)

    Christophe Lièbe

    2010-01-01

    Full Text Available This paper presents a new software for design of through-the-wall imaging radars. The first part describes the evolution of a ray tracing simulator, originally designed for propagation of narrowband signals, and then for ultra-wideband signals. This simulator allows to obtain temporal channel response to a wide-band emitter (3 GHz to 10 GHz. An experimental method is also described to identify the propagation paths. Simulation results are compared to propagation experiments under the same conditions. Different configurations are tested and then discussed. Finally, a configuration of through-the-wall imaging radar is proposed, with different antennas patterns and different targets. Simulated images will be helpful for understanding the experiment obtained images.

  2. Multi-channel selection algorithm in wireless monitoring networks%无线监测网络中多信道优化选择算法

    Institute of Scientific and Technical Information of China (English)

    丁胜; 蒋建国; 夏娜; 王佩佩

    2016-01-01

    无线监测网络中多电台监测节点通过捕捉和分析无线用户的通信数据 ,可以达到监测网络行为、诊断网络故障和管理网络资源的目的 ,而为多电台监测节点优化选择工作信道、最大化捕获数据量、获得最佳网络监测质量(quality of monitoring ,QoM )是一个关键问题.文章研究了一种基于同步微扰随机近似(SPSA )的信道选择算法.该算法在迭代过程中以随机扰动策略得到目标函数的近似梯度 ,引导搜索过程逐步逼近最优解 ;适合于复杂的多维优化问题求解 ,收敛速度快、复杂度低.实验结果表明 ,该算法可以实现无线监测网络中多电台监测节点的信道优化选择 ,并且性能优良.%In wireless monitoring networks ,multi-radio wireless sniffers are distributed for capturing and analyzing user activities in order to realize network monitoring ,fault diagnosis ,resource manage-ment and so on .Therefore ,it is a key topic to optimize the channel selection for sniffers to maximize the information collected ,so as to maximize the quality of monitoring(QoM ) .In this paper ,a simul-taneous perturbation stochastic approximation (SPSA )-based solution is proposed in order to realize optimal channel selection .During iteration process ,the random perturbation strategy is used to com-pute the approximate gradient of the objective function ,which can lead the searching to the optimal solution .The algorithm is fast in convergence and low in complexity .The results of comparison ex-periments demonstrate that the proposed algorithm can realize the multi-channel selection in wireless monitoring networks with high QoM .

  3. Localization Technologies for Indoor Human Tracking

    CERN Document Server

    Zhang, Da; Yang, Zhuo; Yao, Lin; Zhao, Wenhong

    2010-01-01

    The proliferation of wireless localization technologies provides a promising future for serving human beings in indoor scenarios. Their applications include real-time tracking, activity recognition, health care, navigation, emergence detection, and target-of-interest monitoring, among others. Additionally, indoor localization technologies address the inefficiency of GPS (Global Positioning System) inside buildings. Since people spend most of their time in indoor environments, indoor tracking service is in great public demand. Based on this observation, this paper aims to provide a better understanding of state-of-the-art technologies and stimulate new research efforts in this field. For these purposes, existing localization technologies that can be used for tracking individuals in indoor environments are reviewed, along with some further discussions.

  4. 基于 iBuildNet 的室内无线网络优化%Optimization of Indoor Wireless Network Based on iBuildNet

    Institute of Scientific and Technical Information of China (English)

    王宇飞; 秦政坤; 马欣竹; 崔壮; 李爽

    2016-01-01

    With the development of society , the demand of telecommuter service is increasing and current telecommuter network is not satisfied any more .Therefore,optimization of wireless communication networks is particularly important.In this paper,the communication system could be adjusted by using the 7th teaching building in Jilin Normal University as an example .The model could be established according to the existing communications network ,the communication quality of the system could be simulated hence it could improved such as the network coverage,signal strength,signal to noise ratio,etc.By modifying some parameters,it could optimized the whole system and provided a reference for the communication network construction of school buildings.%随着社会的发展,对通信业务的要求越来越高,原有的通信网络无法满足日益增长的通信需要,因此对无线通信网络的优化工作就显得尤为重要。以吉林师范大学的第七教学楼为研究对象,对楼内的通信系统进行调整优化,根据现有的通信网络,建立相关模型,通过仿真规划模拟出系统的通信质量,并针对一些参数进行修改调整,使其在网络覆盖率、信号强度、信噪比等方面有一定的提高,达到对系统优化的目的,为教学楼的通信网络建设提供一定的参考。

  5. Indoor aerosols

    DEFF Research Database (Denmark)

    Morawska, L.; Afshari, Alireza; N. Bae, G.

    2013-01-01

    Motivated by growing considerations of the scale, severity, and risks associated with human exposure to indoor particulate matter, this work reviewed existing literature to: (i) identify state-of-the-art experimental techniques used for personal exposure assessment; (ii) compare exposure levels...... reported for domestic/school settings in different countries (excluding exposure to environmental tobacco smoke and particulate matter from biomass cooking in developing countries); (iii) assess the contribution of outdoor background vs indoor sources to personal exposure; and (iv) examine scientific...... understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident...

  6. Smartphone-Based Indoor Localization with Bluetooth Low Energy Beacons.

    Science.gov (United States)

    Zhuang, Yuan; Yang, Jun; Li, You; Qi, Longning; El-Sheimy, Naser

    2016-04-26

    Indoor wireless localization using Bluetooth Low Energy (BLE) beacons has attracted considerable attention after the release of the BLE protocol. In this paper, we propose an algorithm that uses the combination of channel-separate polynomial regression model (PRM), channel-separate fingerprinting (FP), outlier detection and extended Kalman filtering (EKF) for smartphone-based indoor localization with BLE beacons. The proposed algorithm uses FP and PRM to estimate the target's location and the distances between the target and BLE beacons respectively. We compare the performance of distance estimation that uses separate PRM for three advertisement channels (i.e., the separate strategy) with that use an aggregate PRM generated through the combination of information from all channels (i.e., the aggregate strategy). The performance of FP-based location estimation results of the separate strategy and the aggregate strategy are also compared. It was found that the separate strategy can provide higher accuracy; thus, it is preferred to adopt PRM and FP for each BLE advertisement channel separately. Furthermore, to enhance the robustness of the algorithm, a two-level outlier detection mechanism is designed. Distance and location estimates obtained from PRM and FP are passed to the first outlier detection to generate improved distance estimates for the EKF. After the EKF process, the second outlier detection algorithm based on statistical testing is further performed to remove the outliers. The proposed algorithm was evaluated by various field experiments. Results show that the proposed algorithm achieved the accuracy of localization accuracy in environments with sparse beacon deployment.

  7. Wireless Computing Architecture III

    Science.gov (United States)

    2013-09-01

    Strider: automatic rate adaptation and collision handling. In ACM SIGCOMM 2011. [7] K . Lin el al. Random access heterogeneous MIMO networks. In ACM...Noncooperative cellular wireless with unlimited numbers of base station antennas. IEEE Trans. Wireless Commun., 9(11):3590–3600, 2010. [10] K . Tan el al...communication. Cambridge Univ Pr, 2005. [12] J. Van de Beek, O. Edfors , M. Sandell, S. Wilson, and P. Borjesson. On channel estimation in OFDM systems

  8. Indoor Location Fingerprinting with Heterogeneous Clients

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun

    2011-01-01

    Heterogeneous wireless clients measure signal strength differently. This is a fundamental problem for indoor location fingerprinting, and it has a high impact on the positioning accuracy. Mapping-based solutions have been presented that require manual and error-prone calibration for each new client...

  9. Block Iterative/Adaptive Frequency-Domain Channel Estimation for Cyclic-Prefixed Single-Carrier Broadband Wireless Systems

    Directory of Open Access Journals (Sweden)

    Jong-Seob Baek

    2008-01-01

    Full Text Available This paper presents a new block iterative/adaptive frequency-domain channel estimation scheme, in which a channel frequency response (CFR is estimated iteratively by the proposed weighted element-wise block adaptive frequency-domain channel estimation (WEB-CE scheme using the soft information obtained by a soft-input soft-output (SISO decoder. In the WEB-CE, an equalizer coefficient is calculated by minimizing a weighted conditional squared-norm of the a posteriori error vector with respect to its correction term. Simulation results verify the superiority of the WEB-CE in a time-varying typical urban (TU channel.

  10. Wireless communications algorithmic techniques

    CERN Document Server

    Vitetta, Giorgio; Colavolpe, Giulio; Pancaldi, Fabrizio; Martin, Philippa A

    2013-01-01

    This book introduces the theoretical elements at the basis of various classes of algorithms commonly employed in the physical layer (and, in part, in MAC layer) of wireless communications systems. It focuses on single user systems, so ignoring multiple access techniques. Moreover, emphasis is put on single-input single-output (SISO) systems, although some relevant topics about multiple-input multiple-output (MIMO) systems are also illustrated.Comprehensive wireless specific guide to algorithmic techniquesProvides a detailed analysis of channel equalization and channel coding for wi

  11. Indoor aerosols

    DEFF Research Database (Denmark)

    Morawska, L.; Afshari, Alireza; N. Bae, G.;

    2013-01-01

    reported for domestic/school settings in different countries (excluding exposure to environmental tobacco smoke and particulate matter from biomass cooking in developing countries); (iii) assess the contribution of outdoor background vs indoor sources to personal exposure; and (iv) examine scientific......Motivated by growing considerations of the scale, severity, and risks associated with human exposure to indoor particulate matter, this work reviewed existing literature to: (i) identify state-of-the-art experimental techniques used for personal exposure assessment; (ii) compare exposure levels...... are likely to be a dominant environmental factor affecting human health. However, due to challenges associated with conducting epidemiological assessments, the role of indoor-generated particles has not been fully acknowledged, and improved exposure/risk assessment methods are still needed, together...

  12. 无线信号工作面传播定律及信道模型%Transmission Law and Channel Model of Wireless Signal in Coal Face

    Institute of Scientific and Technical Information of China (English)

    赵端; 丁恩杰; 俞啸

    2013-01-01

    工作面环境是由三面金属挡板,一面煤壁组成的异质封闭空间.与有线通信相比,无线通信在工作面内有着无法比拟的优越性.该文提出了采煤工作面射线传播定律,给出了在异质空间环境中多径信号多次反射后能量计算的具体方法,并以此为基础建立了工作面内冲激响应的信道模型.该文最后,利用计算机仿真了工作面内冲激响应和不同的载频的不同的时延特性,并深入分析了其中原因.%The coal face is the closed space with different dielectric which consists of four walls, threes are metal baffle plates and the residual is the coal wall. Compared with the wire communication system, wireless communications has the great advantages in the coal face. We proposed the radio wave propagation law in the coal face, provided a method of calculating the reflectivity of radio wave propagating in the coal face, established the model of coal face wireless channel impulse response .We simulated the coal face response of impulse, the characteristic of time delay with different carrier frequency and explained that.

  13. Wireless wearable network and wireless body-centric network for future wearable computer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The wireless wearable network and wireless body-centric network can assistant to the user anywhere at anytime communicating with wireless components seamlessly. In this paper, the wireless wearable network and wireless body-centric network have been discussed, and the frequency band and human body effect has been estimated. The bluetooth and UWB technology can be used to construct the narrow band and the broad band wireless wearable network and wireless body-centric network separately. Further, the narrow band wireless wearable network and wireless body-centric network based on bluetooth technology has been constructed by integrated planar inverted-F antenna and the communication channel character has been studied by measurement. The results can provide the possibility of producing a prototype radio system that can be integrated with the wearable computers by suitable wireless technologies developed and applied to facilitate a reliable and continuous connectivity between the system units.

  14. Development and experimental validation of downlink multiuser MIMO-OFDM in gigabit wireless LAN systems

    Science.gov (United States)

    Ishihara, Koichi; Asai, Yusuke; Kudo, Riichi; Ichikawa, Takeo; Takatori, Yasushi; Mizoguchi, Masato

    2013-12-01

    Multiuser multiple-input multiple-output (MU-MIMO) has been proposed as a means to improve spectrum efficiency for various future wireless communication systems. This paper reports indoor experimental results obtained for a newly developed and implemented downlink (DL) MU-MIMO orthogonal frequency division multiplexing (OFDM) transceiver for gigabit wireless local area network systems in the microwave band. In the transceiver, the channel state information (CSI) is estimated at each user and fed back to an access point (AP) on a real-time basis. At the AP, the estimated CSI is used to calculate the transmit beamforming weight for DL MU-MIMO transmission. This paper also proposes a recursive inverse matrix computation scheme for computing the transmit weight in real time. Experiments with the developed transceiver demonstrate its feasibility in a number of indoor scenarios. The experimental results clarify that DL MU-MIMO-OFDM transmission can achieve a 972-Mbit/s transmission data rate with simple digital signal processing of single-antenna users in an indoor environment.

  15. Performance analysis of dual-hop optical wireless communication systems over k-distribution turbulence channel with pointing error

    Science.gov (United States)

    Mishra, Neha; Sriram Kumar, D.; Jha, Pranav Kumar

    2017-06-01

    In this paper, we investigate the performance of the dual-hop free space optical (FSO) communication systems under the effect of strong atmospheric turbulence together with misalignment effects (pointing error). We consider a relay assisted link using decode and forward (DF) relaying protocol between source and destination with the assumption that Channel State Information is available at both transmitting and receiving terminals. The atmospheric turbulence channels are modeled by k-distribution with pointing error impairment. The exact closed form expression is derived for outage probability and bit error rate and illustrated through numerical plots. Further BER results are compared for the different modulation schemes.

  16. Monitoring devices and systems for monitoring frequency hopping wireless communications, and related methods

    Energy Technology Data Exchange (ETDEWEB)

    Derr, Kurt W.; Richardson, John G.

    2017-05-02

    Monitoring devices and systems comprise a plurality of data channel modules coupled to processing circuitry. Each data channel module of the plurality of data channel modules is configured to capture wireless communications for a selected frequency channel. The processing circuitry is configured to receive captured wireless communications from the plurality of data channel modules and to organize received wireless communications according to at least one parameter. Related methods of monitoring wireless communications are also disclosed.

  17. Designing Interference-Robust Wireless Mesh Networks Using a Defender-Attacker-Defender Model

    Science.gov (United States)

    2015-02-01

    THIS PAGE INTENTIONALLY LEFT BLANK 1 I. INTRODUCTION Wireless mesh networks (WMNs) are interconnected systems of wireless access points (APs...2004). Channel surfing and spatial retreats: defenses against wireless denial of service. Proceedings of 3rd ACM Workshop on Wireless Security, 80...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA DESIGNING INTERFERENCE-ROBUST WIRELESS MESH NETWORKS USING A DEFENDER-ATTACKER-DEFENDER MODEL

  18. Fingerprint Indoor Position System Based

    Directory of Open Access Journals (Sweden)

    José Antonio Gómez Martin

    2013-01-01

    Full Text Available This paper presents a research and a development of a fingerprint-indoor-positioning system using the Received Signal Strength Indication (RSSI of a Wireless Sensor Network (WSN. The WSN implementation is based on two different protocol stacks: BitCloud and OpenMAC, a certified ZigBee Compliant Platform (ZCP and an IEEE 802.15.4 embedded software implementation respectively, both from Atmel, and the system uses two different fingerprint algorithms, Simple and Centroid. A comparative analysis of both algorithms using both protocol stacks implementations have been performed to ascertain the best WSN protocol stack and the best algorithm for positioning purposes.

  19. On the performance of free-space optical wireless communication systems over double generalized gamma fading channels

    KAUST Repository

    Al-Quwaiee, Hessa

    2014-03-01

    Starting with the double generalized Gamma (GG) model that was proposed in [1] to describe turbulence-induced fading in free-space optical (FSO) systems, we propose a new unified model which accounts for the impact of pointing errors and type of receiver detector. Based on this new unified model, we study the performance of FSO links operating over these kind of channels. All our analytical results are verified using computer based Monte-Carlo simulations. © 2014 IEEE.

  20. A New Scaling Law on Throughput and Delay Performance of Wireless Mobile Relay Networks over Parallel Fading Channels

    CERN Document Server

    Wang, Rui; Huang, Kaibin

    2009-01-01

    In this paper, utilizing the relay buffers, we propose an opportunistic decode-wait-and-forward relay scheme for a point-to-point communication system with a half-duplexing relay network to better exploit the time diversity and relay mobility. For instance, we analyze the asymptotic throughput-delay tradeoffs in a dense relay network for two scenarios: (1) fixed relays with \\textit{microscopic fading} channels (multipath channels), and (2) mobile relays with \\textit{macroscopic fading} channels (path loss). In the first scenario, the proposed scheme can better exploit the \\textit{multi-relay diversity} in the sense that with $K$ fixed relays and a cost of $\\mathcal{O}(K)$ average end-to-end packet delay, it could achieve the same optimal asymptotic average throughput as the existing designs (such as regular decode-and-forward relay schemes) with $K^2$ fixed relays. In the second scenario, the proposed scheme achieves the maximum throughput of $\\Theta(\\log K)$ at a cost of $\\mathcal{O}(K/q)$ average end-to-end...

  1. A New Signaling Architecture THREP with Autonomous Radio-Link Control for Wireless Communications Systems

    Science.gov (United States)

    Hirono, Masahiko; Nojima, Toshio

    This paper presents a new signaling architecture for radio-access control in wireless communications systems. Called THREP (for THREe-phase link set-up Process), it enables systems with low-cost configurations to provide tetherless access and wide-ranging mobility by using autonomous radio-link controls for fast cell searching and distributed call management. A signaling architecture generally consists of a radio-access part and a service-entity-access part. In THREP, the latter part is divided into two steps: preparing a communication channel, and sustaining it. Access control in THREP is thus composed of three separated parts, or protocol phases. The specifications of each phase are determined independently according to system requirements. In the proposed architecture, the first phase uses autonomous radio-link control because we want to construct low-power indoor wireless communications systems. Evaluation of channel usage efficiency and hand-over loss probability in the personal handy-phone system (PHS) shows that THREP makes the radio-access sub-system operations in a practical application model highly efficient, and the results of a field experiment show that THREP provides sufficient protection against severe fast CNR degradation in practical indoor propagation environments.

  2. CDMA室内分布系统LTE改造方案研究%Research on LTE Transformation of CDMA Indoor Distribution System

    Institute of Scientific and Technical Information of China (English)

    方丹

    2016-01-01

    主要研究电信室内无线网络向4 G网络的转型改造,即现网室内分布系统如何进行LT E改造的问题,首先介绍了LT E室内覆盖时需要考虑的几个方面,然后结合工作中的实际经验分析了几类改造,包括普通分布系统改造、分布系统双流改造,最后总结了实际工程建设中需注意的几个问题。%This paper mainly studied the 4G transformation of telecommunication indoor wireless network, which is the issue of LTE transformation of the current network indoor distribution system. First, it introduced several aspects of the LTE indoor coverage that need to be considered. Then several types of transformation were presented and analyzed based on actual working experience, including typical indoor distribution system and dual-channel indoor distribution system. Finally it drew attention to several issues of the actual construction process.

  3. Correlated shadowing and fading characterization of MIMO off-body channels by means of multiple autonomous on-body nodes

    OpenAIRE

    Van Torre, Patrick; Vanveerdeghem, Peter; Rogier, Hendrik

    2014-01-01

    In off-body communication systems low-cost and compact transceivers are important for realistic applications. An autonomous off-body wireless node was designed and integrated onto a textile antenna. Channel measurements were performed for an indoor non line-off-sight 4x2 MIMO (Multiple-Input Multiple-Output) link using four off-body transmitting nodes and two similar fixed receiving nodes. The channel behavior is characterized as Rayleigh fading with lognormal shadowing and is fitted to a mod...

  4. Performance analysis of a random ARQ initialized cooperative communication protocol in shadowed Nakagami-m wireless channel

    Institute of Scientific and Technical Information of China (English)

    AHMED Irfan; PENG MuGen; WANG WenBo; SHAH Syed Ismail

    2009-01-01

    In this paper, we develop and analyze an energy efficient ARQ (automatic repeat request) initialized transmit diversity protocol for cooperative communications. Medium access control (MAC) layer packet retransmission limit (similar to aShortRetryLimit or aLongRetryLimit [802.11-1997]) has been used as an actuator for transmit cooperative diversity initialization. We take the channel state information (CSI) as a function of retransmission tries and the number of retransmission tries is modeled as a random variable. Relays close to the source node are chosen for the transmit cooperation. Closed form expressions are obtained for symbol error rate (SER), outage capacity and outage probability for the proposed scheme in shadowed fading channels. This cooperative scheme achieves lower signal-to-noise ratio (SNR), stumpy outage probability, higher bandwidth, and transmit energy efficiencies for desired average symbol error rate (ASER) than the preceding ARQ based cooperative protocols. Finally, the results of computer simulations are included to demonstrate the efficacy of the proposed scheme and to verify the accuracy of the analytical expressions.

  5. Interleaving Gains for Receive Diversity Schemes of Distributed Turbo Codes in Wireless Half–Duplex Relay Channels

    Directory of Open Access Journals (Sweden)

    Tamer H. M. Soliman

    2015-06-01

    Full Text Available This paper proposes the interleaving gain in two different distributed turbo-coding schemes: Distributed Turbo Codes (DTC and Distributed Multiple Turbo Codes (DMTC for half-duplex relay system as an extension of our previous work on turbo coding interleaver design for direct communication channel. For these schemes with half-duplex constraint, the source node transmits its information with the parity bit sequence(s to both the relay and the destination nodes during the first phase. The relay received the data from the source and process it by using decode and forward protocol. For the second transmission period, the decoded systematic data at relay is interleaved and re-encoded by a Recursive Systematic Convolutional (RSC encoder and forwarded to the destination. At destination node, the signals received from the source and relay are processed by using turbo log-MAP iterative decoding for retrieving the original information bits. We demonstrate via simulations that the interleaving gain has a large effect with DTC scheme when we use only one RSC encoder at both the source and relay with best performance when using Modified Matched S-Random (MMSR interleaver. Furthermore, by designing a Chaotic Pseudo Random Interleaver (CPRI as an outer interleaver at the source node instead of classical interleavers, our scheme can add more secure channel conditions.

  6. Improving HSDPA Indoor Coverage and Throughput by Repeater and Dedicated Indoor System

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available The target of the paper is to provide guidelines for indoor planning and optimization using an outdoor-to-indoor repeater or a dedicated indoor system. The paper provides practical information for enhancing the performance of high-speed downlink packet access (HSDPA in an indoor environment. The capabilities of an outdoor-to-indoor analog WCDMA repeater are set against a dedicated indoor system and, furthermore, compared to indoor coverage of a nearby macrocellular base station. An extensive measurement campaign with varying system configurations was arranged in different indoor environments. The results show that compared to dedicated indoor systems, similar HSDPA performance can be provided by extending macrocellular coverage inside buildings using an outdoor-to-indoor repeater. According to the measurements, the pilot coverage planning threshold of about −80 dBm ensures a 2500 kbps throughput for shared HSDPA connections. Improving the coverage above −80 dBm seems to provide only small advantage in HSDPA throughput. Of course, the pilot planning thresholds may change if different channel power allocations are used. In addition, network performance can be further improved by increasing the antenna density in the serving distributed antenna system. Finally, good performance of repeater implementation needs careful repeater gain setting and donor antenna siting.

  7. Improving HSDPA Indoor Coverage and Throughput by Repeater and Dedicated Indoor System

    Directory of Open Access Journals (Sweden)

    Isotalo Tero

    2008-01-01

    Full Text Available Abstract The target of the paper is to provide guidelines for indoor planning and optimization using an outdoor-to-indoor repeater or a dedicated indoor system. The paper provides practical information for enhancing the performance of high-speed downlink packet access (HSDPA in an indoor environment. The capabilities of an outdoor-to-indoor analog WCDMA repeater are set against a dedicated indoor system and, furthermore, compared to indoor coverage of a nearby macrocellular base station. An extensive measurement campaign with varying system configurations was arranged in different indoor environments. The results show that compared to dedicated indoor systems, similar HSDPA performance can be provided by extending macrocellular coverage inside buildings using an outdoor-to-indoor repeater. According to the measurements, the pilot coverage planning threshold of about −80 dBm ensures a 2500 kbps throughput for shared HSDPA connections. Improving the coverage above −80 dBm seems to provide only small advantage in HSDPA throughput. Of course, the pilot planning thresholds may change if different channel power allocations are used. In addition, network performance can be further improved by increasing the antenna density in the serving distributed antenna system. Finally, good performance of repeater implementation needs careful repeater gain setting and donor antenna siting.

  8. Securing underwater wireless communication networks

    OpenAIRE

    Domingo Aladrén, Mari Carmen

    2011-01-01

    Underwater wireless communication networks are particularly vulnerable to malicious attacks due to the high bit error rates, large and variable propagation delays, and low bandwidth of acoustic channels. The unique characteristics of the underwater acoustic communication channel, and the differences between underwater sensor networks and their ground-based counterparts require the development of efficient and reliable security mechanisms. In this article, a compl...

  9. Evaluation of wireless data communications at KSC

    Science.gov (United States)

    Gejji, Raghvendra R.

    1995-01-01

    This project is motivated by the need for temporary or emergency provisioning of LAN service at KSC. The main goal of the project was to evaluate existing wireless bridge equipment in the KSC environment. Wireless bridge equipment can be used to make a wireless connection between two remotely located LAN segments. This report describes the experimental setup used to evaluate the equipment, including antenna connections, workstation connections, bridge software and workstation software The rangefinder program on the bridge was used to gather data about how the RF propagation environment at KSC affects the performance of the wireless bridge. Data was gathered for indoor as well as outdoor propagation. The report concludes with recommendations on how to take into account the particular terrain and building structures at KSC to design future applications of wireless bridges.

  10. Censored cooperative positioning for dense wireless networks

    NARCIS (Netherlands)

    Das, Kallol; Wymeersch, Henk

    Cooperative positioning is an emerging topic in wireless sensor networks and navigation. It can improve the positioning accuracy and coverage in GPS-challenged conditions such as inside tunnels, in urban canyons, and indoors. Different algorithms have been proposed relying on iteratively exchanging

  11. 多通道高精度无线温度记录仪设计%Design of Multi-Channel High-Precision Wireless Temperature Recorder

    Institute of Scientific and Technical Information of China (English)

    赵晨; 何君燕; 刘刚

    2014-01-01

    本文介绍一种用于超高温度环境下的高精度温度采集记录仪,主要分析硬件的组成技术方案和软件接口协议。温度传感器采用高精度的DS1626U,微控制器为AT91SAM7S32-AU,设计接口有无线接口和USB转串接口,供用户进行选择,采用高分辨率的AD7794BRU对热电偶的输入信号直接进行采集转换,可同时对12个通道的信号进行采集并处理,还具有智能检测温度异常并给出预警提示功能。%A high-precision temperature collection recorder used in ultra-high temperature environments is introduced,mainly analyzes the composition technology solutions of hardware and interface protocol of software.Temperature sensor accuracy is DS1626U, microcontroller is AT91SAM7S32-AU, interface are wireless interface and a USB-to-serial interface for users to choose, high-resolution AD7794BRU collect conversion the input signal of thermocouple, while collecting and processing the 12-channel signal, further comprising detecting abnormal temperature and gives a smart warning prompts.

  12. Wireless physical layer security

    Science.gov (United States)

    Poor, H. Vincent; Schaefer, Rafael F.

    2017-01-01

    Security in wireless networks has traditionally been considered to be an issue to be addressed separately from the physical radio transmission aspects of wireless systems. However, with the emergence of new networking architectures that are not amenable to traditional methods of secure communication such as data encryption, there has been an increase in interest in the potential of the physical properties of the radio channel itself to provide communications security. Information theory provides a natural framework for the study of this issue, and there has been considerable recent research devoted to using this framework to develop a greater understanding of the fundamental ability of the so-called physical layer to provide security in wireless networks. Moreover, this approach is also suggestive in many cases of coding techniques that can approach fundamental limits in practice and of techniques for other security tasks such as authentication. This paper provides an overview of these developments.

  13. Wireless communications resource management

    CERN Document Server

    Lee, B; Seo, H

    2009-01-01

    Wireless technologies continue to evolve to address the insatiable demand for faster response times, larger bandwidth, and reliable transmission. Yet as the industry moves toward the development of post 3G systems, engineers have consumed all the affordable physical layer technologies discovered to date. This has necessitated more intelligent and optimized utilization of available wireless resources. Wireless Communications Resource Managem ent, Lee, Park, and Seo cover all aspects of this critical topic, from the preliminary concepts and mathematical tools to detailed descriptions of all the resource management techniques. Readers will be able to more effectively leverage limited spectrum and maximize device battery power, as well as address channel loss, shadowing, and multipath fading phenomena.

  14. 分布式多天线信道时变特征参数的联合估计for distributed multi-antenna wireless channel%Joint estimation of time-variant characteristic parameters for distributed multi-antenna wireless channel

    Institute of Scientific and Technical Information of China (English)

    张静

    2013-01-01

      针对分布式多天线信道随机时变特征参数的获取问题,通过参数化建模方法建立信道时变参数的自回归模型,将由频率偏置和复信道衰落构成的强非线性观测方程在估计值处展开成泰勒级数进而线性化观测方程后,运用扩展卡尔曼滤波算法联合估计未知参数。仿真结果表明,该方法可在序贯的观测值下对信道时变参数进行联合估计和跟踪,能获得逼近克拉默—拉奥下界的估计精度。%In order to estimate random time-varying wireless channel characteristic parameters of distributed multi-input multi-output (MIMO) communication systems, autoregressive models of unknown parameters were established according to statistical models of MIMO channel. By linearization of observation equation composed of multiple frequency offset and complex channel fading at estimate values, it applied extended Kalman filter to jointly obtain the parameters. Simula-tion results show that the method can estimate and track time-varying parameters under sequential observation. It can ob-tain the estimate accuracy close to Cramer-Rao lower bound.

  15. A proposed UAV for indoor patient care.

    Science.gov (United States)

    Todd, Catherine; Watfa, Mohamed; El Mouden, Yassine; Sahir, Sana; Ali, Afrah; Niavarani, Ali; Lutfi, Aoun; Copiaco, Abigail; Agarwal, Vaibhavi; Afsari, Kiyan; Johnathon, Chris; Okafor, Onyeka; Ayad, Marina

    2015-09-10

    Indoor flight, obstacle avoidance and client-server communication of an Unmanned Aerial Vehicle (UAV) raises several unique research challenges. This paper examines current methods and associated technologies adapted within the literature toward autonomous UAV flight, for consideration in a proposed system for indoor healthcare administration with a quadcopter. We introduce Healthbuddy, a unique research initiative towards overcoming challenges associated with indoor navigation, collision detection and avoidance, stability, wireless drone-server communications and automated decision support for patient care in a GPS-denied environment. To address the identified research deficits, a drone-based solution is presented. The solution is preliminary as we develop and refine the suggested algorithms and hardware system to achieve the research objectives.

  16. Indoor Positioning with Radio Location Fingerprinting

    CERN Document Server

    Kjærgaard, Mikkel Baun

    2010-01-01

    An increasingly important requirement for many novel applications is sensing the positions of people, equipment, etc. GPS technology has proven itself as a successfull technology for positioning in outdoor environments but indoor no technology has yet gained a similar wide-scale adoption. A promising indoor positioning technique is radio-based location fingerprinting, having the major advantage of exploiting already existing radio infrastructures, like IEEE 802.11, which avoids extra deployment costs and effort. The research goal of this thesis is to address the limitations of current indoor location fingerprinting systems. In particular the aim is to advance location fingerprinting techniques for the challenges of handling heterogeneous clients, scalability to many clients, and interference between communication and positioning. The wireless clients used for location fingerprinting are heterogeneous even when only considering clients for the same technology. Heterogeneity is a challenge for location fingerpr...

  17. 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.

  18. 集中式信道分配算法在WSN移动节点中的应用研究%Study on Centralized Channel Assignment Algorithm for Mobile Nodes in Wireless Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    赵军; 陈祥光; 刘春涛; 余向明; 岳彬

    2011-01-01

    为提高油料保障系统中信息采集的实时性和能量的高效性,使网关及时检测到移动设备的状态,降低无线网络间的干扰,提高网络的容量.以军用机场加油车为研究对象,提出了适用于快速移动节点的集中式信道分配算法和功率分级的能量控制方法.在无线网络节点上安装两个工作在不同频道上的网络接口,通过控制协商动态的切换数据信道,平衡网络负载,以增加总的带宽.实验结果表明,采用3条数据信道便可实现信道的集中式分配和发送功率的分级控制,有效地扩展了网络的容量和提高能量的高效性.%By investigating the working process of tanker trucks in a military airport, this paper proposes a centralized channel assignment algorithm and a power rating control method for fast-moving nodes to improve the real-time property and energy efficiency of the information collection, detect the state of mobile devices promptly, reduce interference between wireless networks and to increase network capacity in oil security systems. Considering the fact that IEEE 802. 11 wireless LAN standard defines a number of non-overlapping channels which could be used at the same time, two wireless network interfaces operating on different channels could be installed to every node. Through the negotiation on the control channel and switching the data channel dynamically, the balance of network loads could be fulfilled so as to increase the total bandwidth. Simulation and application results demonstrate that, only three data channels is needed to realize the centralized channel assignment and the power rating control, and the network capacity and energy efficiency could be improved effectively.

  19. Wireless Networks

    OpenAIRE

    Samaka, Mohammed; Khan, Khaled M.D.

    2007-01-01

    Wireless communication is the fastest-growing field in the telecommunication industry. Wireless networks have grown significantly as an important segment of the communications industry. They have become popular networks with the potential to provide high-speed, high-quality information exchange between two or more portable devices without any wire or conductors. Wireless networks can simply be characterized as the technology that provides seamless access to information, anywhere, anyplace, an...

  20. Introduction to Ultra Wideband for Wireless Communications

    DEFF Research Database (Denmark)

    Nikookar, Homayoun; Prasad, Ramjee

    wireless channels, interference, signal processing as well as applications and standardization activities are addressed. Introduction to Ultra Wideband for Wireless Communications provides easy-to-understand material to (graduate) students and researchers working in the field of commercial UWB wireless......Ultra Wideband (UWB) Technology is the cutting edge technology for wireless communications with a wide range of applications. In Introduction to Ultra Wideband for Wireless Communications UWB principles and technologies for wireless communications are explained clearly. Key issues such as UWB...... communications. Due to tutorial nature of the book it can also be adopted as a textbook on the subject in the Telecommunications Engineering curriculum. Problems at the end of each chapter extend the reader's understanding of the subject. Introduction to Ultra Wideband for Wireless Communications will aslo...

  1. Wireless virtualization

    CERN Document Server

    Wen, Heming; Le-Ngoc, Tho

    2013-01-01

    This SpringerBriefs is an overview of the emerging field of wireless access and mobile network virtualization. It provides a clear and relevant picture of the current virtualization trends in wireless technologies by summarizing and comparing different architectures, techniques and technologies applicable to a future virtualized wireless network infrastructure. The readers are exposed to a short walkthrough of the future Internet initiative and network virtualization technologies in order to understand the potential role of wireless virtualization in the broader context of next-generation ubiq

  2. Analysis and Description of HOLTIN Service Provision for AECG monitoring in Complex Indoor Environments

    Directory of Open Access Journals (Sweden)

    Francisco Falcone

    2013-04-01

    Full Text Available In this work, a novel ambulatory ECG monitoring device developed in-house called HOLTIN is analyzed when operating in complex indoor scenarios. The HOLTIN system is described, from the technological platform level to its functional model. In addition, by using in-house 3D ray launching simulation code, the wireless channel behavior, which enables ubiquitous operation, is performed. The effect of human body presence is taken into account by a novel simplified model embedded within the 3D Ray Launching code. Simulation as well as measurement results are presented, showing good agreement. These results may aid in the adequate deployment of this novel device to automate conventional medical processes, increasing the coverage radius and optimizing energy consumption.

  3. Optimizing the Positioning of MIMO and SISO Systems in Indoor Environments

    Science.gov (United States)

    Bechet, P.; Bouleanu, I.; Neagu, A.; Helbet, R.; Hangan, A.

    The adoption of multiple-input multiple-output (MIMO) technologies for the air interface of new wireless communication systems promises to meet the increasing data rate demands of future applications within a reasonable radio bandwidth. MIMO can provide increased spectrum efficiency by exploiting the spatial dimension of the radio wave propagation. The aim of this chapter is to analyze the data transfer capacity in an indoor environment which is relevant for MIMO technology due to its pronounced dispersive character. The performances of individual single-input single-output (SISO), single-input multiple-output (SIMO), multiple-input single-output (MISO), and MIMO communication channels in various scenarios are emphasized in order to identify the optimum positioning of the system components.

  4. Smartphone-Based Indoor Localization with Bluetooth Low Energy Beacons

    Directory of Open Access Journals (Sweden)

    Yuan Zhuang

    2016-04-01

    Full Text Available Indoor wireless localization using Bluetooth Low Energy (BLE beacons has attracted considerable attention after the release of the BLE protocol. In this paper, we propose an algorithm that uses the combination of channel-separate polynomial regression model (PRM, channel-separate fingerprinting (FP, outlier detection and extended Kalman filtering (EKF for smartphone-based indoor localization with BLE beacons. The proposed algorithm uses FP and PRM to estimate the target’s location and the distances between the target and BLE beacons respectively. We compare the performance of distance estimation that uses separate PRM for three advertisement channels (i.e., the separate strategy with that use an aggregate PRM generated through the combination of information from all channels (i.e., the aggregate strategy. The performance of FP-based location estimation results of the separate strategy and the aggregate strategy are also compared. It was found that the separate strategy can provide higher accuracy; thus, it is preferred to adopt PRM and FP for each BLE advertisement channel separately. Furthermore, to enhance the robustness of the algorithm, a two-level outlier detection mechanism is designed. Distance and location estimates obtained from PRM and FP are passed to the first outlier detection to generate improved distance estimates for the EKF. After the EKF process, the second outlier detection algorithm based on statistical testing is further performed to remove the outliers. The proposed algorithm was evaluated by various field experiments. Results show that the proposed algorithm achieved the accuracy of <2.56 m at 90% of the time with dense deployment of BLE beacons (1 beacon per 9 m, which performs 35.82% better than <3.99 m from the Propagation Model (PM + EKF algorithm and 15.77% more accurate than <3.04 m from the FP + EKF algorithm. With sparse deployment (1 beacon per 18 m, the proposed algorithm achieves the accuracies of <3.88 m at

  5. Wireless Acoustic Measurement System

    Science.gov (United States)

    Anderson, Paul D.; Dorland, Wade D.; Jolly, Ronald L.

    2007-01-01

    A prototype wireless acoustic measurement system (WAMS) is one of two main subsystems of the Acoustic Prediction/ Measurement Tool, which comprises software, acoustic instrumentation, and electronic hardware combined to afford integrated capabilities for predicting and measuring noise emitted by rocket and jet engines. The other main subsystem is described in the article on page 8. The WAMS includes analog acoustic measurement instrumentation and analog and digital electronic circuitry combined with computer wireless local-area networking to enable (1) measurement of sound-pressure levels at multiple locations in the sound field of an engine under test and (2) recording and processing of the measurement data. At each field location, the measurements are taken by a portable unit, denoted a field station. There are ten field stations, each of which can take two channels of measurements. Each field station is equipped with two instrumentation microphones, a micro- ATX computer, a wireless network adapter, an environmental enclosure, a directional radio antenna, and a battery power supply. The environmental enclosure shields the computer from weather and from extreme acoustically induced vibrations. The power supply is based on a marine-service lead-acid storage battery that has enough capacity to support operation for as long as 10 hours. A desktop computer serves as a control server for the WAMS. The server is connected to a wireless router for communication with the field stations via a wireless local-area network that complies with wireless-network standard 802.11b of the Institute of Electrical and Electronics Engineers. The router and the wireless network adapters are controlled by use of Linux-compatible driver software. The server runs custom Linux software for synchronizing the recording of measurement data in the field stations. The software includes a module that provides an intuitive graphical user interface through which an operator at the control server

  6. Wireless Internet

    NARCIS (Netherlands)

    el Zarki, M.; Heijenk, Geert; Lee, Kenneth S.; Bidgoli, H.

    This chapter addresses the topic of wireless Internet, the extension of the wireline Internet architecture to the wireless domain. As such the chapter introduces the reader to the dominant characteristics of the Internet, from its structure to the protocols that control the forwarding of data and

  7. OFDM systems for wireless communications

    CERN Document Server

    Narasimhamurthy, Adarsh

    2010-01-01

    Orthogonal Frequency Division Multiplexing (OFDM) systems are widely used in the standards for digital audio/video broadcasting, WiFi and WiMax. Being a frequency-domain approach to communications, OFDM has important advantages in dealing with the frequency-selective nature of high data rate wireless communication channels. As the needs for operating with higher data rates become more pressing, OFDM systems have emerged as an effective physical-layer solution.This short monograph is intended as a tutorial which highlights the deleterious aspects of the wireless channel and presents why OFDM is

  8. 无线传感器网络中一种抗无线局域网干扰的信道分配机制%A Channel Allocation Scheme to Mitigate Wifi Interference for Wireless Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    张招亮; 陈海明; 黄庭培; 崔莉; 赵泽

    2012-01-01

    Wireless sensor networks will suffer severe performance degradation in communication reliability and throughput when interfered by co-located Wifi devices. When multiple sensor networks with different priority are interfered by Wifi devices, it is of great significance to allocate channels according to their priority as well as take into consideration the overall communication reliability and throughput. To address this problem, a channel allocation scheme to mitigate Wifi interference, called EasiCAP (Channel Allocation for wireless sensor networks with Priority) , is presented. The scheme employs an external interference model, which is based on interference signal strength and activity ratio, to measure Wifi interference in each channel of sensor networks. In addition, a receiver-centric interference model is used to gauge internal interference amongst different sensor networks. Based on the measurements of external interference and internal interference, each sensor network independently selects its working channel in real time via alocalized greedy algorithm in order to assign channels according to priority and also reduce the overall interference of all sensor networks as much as possible. Then, the sensor network performs one of the three operations, I. E. , channel keeping, channel swapping, and channel preempting, based on the channel selection decision. Testbed experiments and simulations are conducted to verify the effectiveness of the proposed scheme. The experimental results demonstrate that EasiCAP can provide differentiated communication reliability and throughput corresponding to the network priority. Also, it has higher average communication reliability and throughput than existing schemes. Furthermore, it does not introduce significant overhead.%无线传感器网络(WSN)易受到与其共享信道的无线局域网(Wifi)干扰,造成通信可靠性及吞吐量下降. 当具有不同优先级的多个WSN受到Wifi干扰时,如何按优先级分

  9. Impact of High Power Interference Sources in Planning and Deployment of Wireless Sensor Networks and Devices in the 2.4 GHz Frequency Band in Heterogeneous Environments

    Directory of Open Access Journals (Sweden)

    Francisco Falcone

    2012-11-01

    Full Text Available In this work, the impact of radiofrequency radiation leakage from microwave ovens and its effect on 802.15.4 ZigBee-compliant wireless sensor networks operating in the 2.4 GHz Industrial Scientific Medical (ISM band is analyzed. By means of a novel radioplanning approach, based on electromagnetic field simulation of a microwave oven and determination of equivalent radiation sources applied to an in-house developed 3D ray launching algorithm, estimation of the microwave oven’s power leakage is obtained for the complete volume of an indoor scenario. The magnitude and the variable nature of the interference is analyzed and the impact in the radio link quality in operating wireless sensors is estimated and compared with radio channel measurements as well as packet measurements. The measurement results reveal the importance of selecting an adequate 802.15.4 channel, as well as the Wireless Sensor Network deployment strategy within this type of environment, in order to optimize energy consumption and increase the overall network performance. The proposed method enables one to estimate potential interference effects in devices operating within the 2.4 GHz band in the complete scenario, prior to wireless sensor network deployment, which can aid in achieving the most optimal network topology.

  10. Study on the Measurement and Control System Based on Multi-channel Wireless Sensing Network%多路通道无线传感网络测控系统的研究

    Institute of Scientific and Technical Information of China (English)

    赵双萍; 邢敬宏; 何辉

    2012-01-01

    针对现有无线测控系统功耗大、传输通道单一、实时性不强等问题,研究设计了基于多路通道的无线传感网络测控系统.利用无线传感网络的感知技术和嵌入式网关的传输技术,通过WiFi、GPRS、3G、IP中的任意一种连接方式,实现了嵌入式网关与Intemet服务器的通信;应用HTML5和RTMP技术,研发了基于Web的HMI软件,实现了手机个人数字助理(PDA)等移动终端的访问.运行结果表明,该系统保证了数据传输的可靠性和实时性,具有一定的实际参考价值.%Aiming at the disadvantages of currently existing wireless measurement and control systems, such as large power consumption, single transmission channel and poor real-time performance; the measurement and control system based on multi-channel wireless sensing network is researched and designed. By adopting sensation technology of wireless sensing network and transmission technology of embedded gateway, the communication between embedded gateway and Internet server through any connection method of WiFi, GPRS, 3G or IP, is implemented. Hie technologies of HTML5 and RTMP are applied to research and develop the Web-based HMI software, the access of mobile terminal such as cell phone personal digital assistant (PDA) is implemented. The running result shows that the system guarantees the reliability and real-time performance of data transmission, and possesses certain reference value.

  11. New Methods and Models in Wireless Networks: Multigraphs--Games--Mechanism Design

    Science.gov (United States)

    Tran, Dung Trung

    2010-01-01

    The recent evolution of wireless technology makes wireless devices ever more powerful and intelligent. One trend is that wireless devices are becoming more inexpensive and more diverse. As a result, new technologies make it possible to equip wireless nodes with several radio transmitters/receivers. Each radio may support multiple channels which…

  12. New Methods and Models in Wireless Networks: Multigraphs--Games--Mechanism Design

    Science.gov (United States)

    Tran, Dung Trung

    2010-01-01

    The recent evolution of wireless technology makes wireless devices ever more powerful and intelligent. One trend is that wireless devices are becoming more inexpensive and more diverse. As a result, new technologies make it possible to equip wireless nodes with several radio transmitters/receivers. Each radio may support multiple channels which…

  13. Interoperable Communications for Hierarchical Heterogeneous Wireless Networks

    Science.gov (United States)

    2016-04-01

    signatures of various wireless devices (cellular, WiFi , bluetooth, etc.) are captured using USRP2 and GNUradio platform, and the traces are available on a...action. The algorithm acquires the channel occupancy matrix from the SU channel sensing results and the actual channel occupancy determined by the PUs...true channel status Ma- trix, A (Dc). In the algorithm the values of the estimated matrix and the true channel status matrix are compared to determine

  14. Design and implementation of a wireless (Bluetooth) four channel bio-instrumentation amplifier and digital data acquisition device with user-selectable gain, frequency, and driven reference.

    Science.gov (United States)

    Cosmanescu, Alin; Miller, Benjamin; Magno, Terence; Ahmed, Assad; Kremenic, Ian

    2006-01-01

    A portable, multi-purpose Bio-instrumentation Amplifier and Data AcQuisition device (BADAQ) capable of measuring and transmitting EMG and EKG signals wirelessly via Bluetooth is designed and implemented. Common topologies for instrumentation amplifiers and filters are used and realized with commercially available, low-voltage, high precision operational amplifiers. An 8-bit PIC microcontroller performs 10-bit analog-to-digital conversion of the amplified and filtered signals and controls a Bluetooth transceiver capable of wirelessly transmitting the data to any Bluetooth enabled device. Electrical isolation between patient/subject, circuitry, and ancillary equipment is achieved by optocoupling components. The design focuses on simplicity, portability, and affordability.

  15. Security method of wireless physical layer security based on multipath channel random delay%基于多径信道随机延时的物理层全算法

    Institute of Scientific and Technical Information of China (English)

    庞宏伟; 王雪明; 吉江; 李翔宇; 金梁

    2012-01-01

    For the wire-tapping in wireless communication system, this paper presented an encrypting method based on channel multipath delay-time information to ensure the security of physical layer in wireless communication system. In this method, the transmitter made the time to transmit symbol random with channel multipath delay-time information that estimated, and made the received signal of legitimate receiver stronger at the synchronization location. So the legitimate could receive the information normally. While the received signal of eavesdropper turned random for different channel information, such as phase and range. Then the eavesdropper couldn' t recover the information with the random received signal, and the error probability was high,which increased the security of legitimate receiver. The simulations show that the method can keep the eavesdropper' s error probability at a high level, so as to increase the system security. Finally, it comes to the conclusion that this method can ensure the security of physical layer in wireless communication system with channel multipath.%针对无线通信遇到的第三方窃听问题,利用无线通信系统信道多径延时丰富的特征,提出了一种保证物理层安全传输的加密算法.该算法中,数据发送用户根据估计的多径延时信息随机提前符号发送时间,使授权用户的同步位置有较强的多径信号到达,授权接收用户在保持同步状态不变的情况下可以正常接收信息.而窃听用户具有不同的信道多径延时特征,接收到的信号幅度和相位会随机变化,难以进行同步跟踪,因此接收到的符号会产生大量的误码,从而提高授权用户之间的安全传输性能.仿真结果表明,该算法能有效提高窃听方的误码率,提高授权用户通信的安全性,从而可在多径环境中有效保证物理层通信安全.

  16. INDOOR AIR QUALITY ANALYSIS

    OpenAIRE

    Wang, Xin

    2010-01-01

    With the development of modern architecture, one of the building's interior decoration, furnishings, appliances and equipment have become increasingly demanding, making construction of the indoor environment of increasing pollution, increasing pollution, indoor environmental pollution hazards to human is also a growing the greater. This thesis summarizes the major indoor air pollution sources and major pollutants. Indoor air pollutants are formaldehyde, radon, ammonia, total volatile org...

  17. Indoor air quality

    DEFF Research Database (Denmark)

    Jensen, Trine Susanne; Recevska, Ieva

     The objective of the 35th specific agreement is to provide support to the EEA activities in Environment and Health (E&H) on the topic of indoor air quality. The specific objectives have been to provide an overview of indoor air related projects in EU and indoor air related policies as well...... as idenfiying "good practices" to reduce health impact of indoor air exposure and suggest areas for future improvements....

  18. Indoor air quality

    DEFF Research Database (Denmark)

    Jensen, Trine Susanne; Recevska, Ieva

     The objective of the 35th specific agreement is to provide support to the EEA activities in Environment and Health (E&H) on the topic of indoor air quality. The specific objectives have been to provide an overview of indoor air related projects in EU and indoor air related policies as well...... as idenfiying "good practices" to reduce health impact of indoor air exposure and suggest areas for future improvements....

  19. Wireless Security

    CERN Document Server

    Osterhage, Wolfgang

    2011-01-01

    In the wake of the growing use of wireless communications, new types of security risks have evolved. Wireless Security covers the major topic of wireless communications with relevance both to organizations and private users. The technological background of these applications and protocols is laid out and presented in detail. Special emphasis is placed on the IEEE 802.11x-Standards that have been introduced for WLAN technology. Other technologies covered besides WLAN include: mobile phones, bluetooth and infrared. In each chapter a major part is devoted to security risks and provisions includin

  20. Indoor multipath mitigation

    DEFF Research Database (Denmark)

    Dragünas, Kostas; Borre, Kai

    2010-01-01

    There are many applications that require continuous positioning in combined outdoor urban and indoor environments. GNSS has been used for a long time in outdoor environments, while indoor positioning is still a challenging task. One of the major degradations that GNSS receivers experience indoors...

  1. 大赫兹频段下的无线通信系统信道配准技术%Technology of Wireless Communication System Channel Registration Under Large Hz Band

    Institute of Scientific and Technical Information of China (English)

    朱祥贤

    2015-01-01

    在大赫兹频段下,混合MIMO移动无线通信系统受到强干扰,导致通信系统信道难以配准.传统方法采用自干扰盲辨识刚发实现对大赫兹频段下的无线通信系统信道配准,信道均衡性能不好.提出一种基于自适应滤波功率谱估计的大赫兹频段下的无线通信系统信道配准算法,首先构建大赫兹频段下的无线通信系统,采用传播损失的概念来描述信号的通信传输过程中的能量损失,各阵元中的多径信号实现了同时刻同相位叠加,将多径波的强度、传播时间以及发射信号带宽等的进行耦合,得到功率方法电路系统的耦合约束条件,实现了多径信号的时间压缩又获得了聚焦增益,通过滤波器进行干扰抑制,得到的空间谱瞬时值,通过傅里叶变换求得功率谱密度函数,实现信道配准.仿真结果表明,该算法具有较好的信道配准和均衡性能,提高了功率谱空间增益,改善大赫兹频段下的无线通信质量.%In large Hz band, mixed MIMO mobile radio communication system under strong interference, resulting in a channel of the communication system to registration. The traditional method is using the self interference blind identifica-tion just sent to realize wireless communication system channel registration on Hz frequency band. The equilibrium perfor-mance of the channel is not good. An adaptive filter based on power spectrum estimation under large Hz band channel regis-tration algorithm firstly constructs the wireless communication system, wireless communication system Hz frequency band. We get the coupling constraints of power method of circuit system, realized the multipath signal time compression and won the focusing gain and interference suppression filter is obtained by the spatial spectrum, instantaneous value, through the Fourier transform to obtain the power spectral density function, realize channel registration. The simulation results show that the algorithm has

  2. A Novel Physical Layer Assisted Authentication Scheme for Mobile Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Qiuhua Wang

    2017-02-01

    Full Text Available Physical-layer authentication can address physical layer vulnerabilities and security threats in wireless sensor networks, and has been considered as an effective complementary enhancement to existing upper-layer authentication mechanisms. In this paper, to advance the existing research and improve the authentication performance, we propose a novel physical layer assisted authentication scheme for mobile wireless sensor networks. In our proposed scheme, we explore the reciprocity and spatial uncorrelation of the wireless channel to verify the identities of involved transmitting users and decide whether all data frames are from the same sender. In our proposed scheme, a new method is developed for the legitimate users to compare their received signal strength (RSS records, which avoids the information from being disclosed to the adversary. Our proposed scheme can detect the spoofing attack even in a high dynamic environment. We evaluate our scheme through experiments under indoor and outdoor environments. Experiment results show that our proposed scheme is more efficient and achieves a higher detection rate as well as keeping a lower false alarm rate.

  3. Radio Characterization for ISM 2.4 GHz Wireless Sensor Networks for Judo Monitoring Applications

    Directory of Open Access Journals (Sweden)

    Peio Lopez-Iturri

    2014-12-01

    Full Text Available In this work, the characterization of the radio channel for ISM 2.4GHz Wireless Sensor Networks (WSNs for judo applications is presented. The environments where judo activity is held are usually complex indoor scenarios in terms of radiopropagation due to their morphology, the presence of humans and the electromagnetic interference generated by personal portable devices, wireless microphones and other wireless systems used by the media. For the assessment of the impact that the topology and the morphology of these environments have on electromagnetic propagation, an in-house developed 3D ray-launching software has been used in this study. Time domain results as well as estimations of received power level have been obtained for the complete volume of a training venue of a local judo club’s facilities with a contest area with the dimensions specified by the International Judo Federation (IJF for international competitions. The obtained simulation results have been compared with measurements, which have been carried out deploying ZigBee-compliant XBee Pro modules at presented scenario, using approved Judogis (jacket, trousers and belt. The analysis is completed with the inclusion of an in-house human body computational model. Such analysis has allowed the design and development of an in house application devoted to monitor the practice of judo, in order to aid referee activities, training routines and to enhance spectator experience.

  4. A Novel Physical Layer Assisted Authentication Scheme for Mobile Wireless Sensor Networks.

    Science.gov (United States)

    Wang, Qiuhua

    2017-02-04

    Physical-layer authentication can address physical layer vulnerabilities and security threats in wireless sensor networks, and has been considered as an effective complementary enhancement to existing upper-layer authentication mechanisms. In this paper, to advance the existing research and improve the authentication performance, we propose a novel physical layer assisted authentication scheme for mobile wireless sensor networks. In our proposed scheme, we explore the reciprocity and spatial uncorrelation of the wireless channel to verify the identities of involved transmitting users and decide whether all data frames are from the same sender. In our proposed scheme, a new method is developed for the legitimate users to compare their received signal strength (RSS) records, which avoids the information from being disclosed to the adversary. Our proposed scheme can detect the spoofing attack even in a high dynamic environment. We evaluate our scheme through experiments under indoor and outdoor environments. Experiment results show that our proposed scheme is more efficient and achieves a higher detection rate as well as keeping a lower false alarm rate.

  5. Energy efficient error-correcting coding for wireless systems

    NARCIS (Netherlands)

    Shao, Xiaoying

    2010-01-01

    The wireless channel is a hostile environment. The transmitted signal does not only suffers multi-path fading but also noise and interference from other users of the wireless channel. That causes unreliable communications. To achieve high-quality communications, error correcting coding is required t

  6. RF Localization in Indoor Environment

    Directory of Open Access Journals (Sweden)

    M. Stella

    2012-06-01

    Full Text Available In this paper indoor localization system based on the RF power measurements of the Received Signal Strength (RSS in WLAN environment is presented. Today, the most viable solution for localization is the RSS fingerprinting based approach, where in order to establish a relationship between RSS values and location, different machine learning approaches are used. The advantage of this approach based on WLAN technology is that it does not need new infrastructure (it reuses already and widely deployed equipment, and the RSS measurement is part of the normal operating mode of wireless equipment. We derive the Cramer-Rao Lower Bound (CRLB of localization accuracy for RSS measurements. In analysis of the bound we give insight in localization performance and deployment issues of a localization system, which could help designing an efficient localization system. To compare different machine learning approaches we developed a localization system based on an artificial neural network, k-nearest neighbors, probabilistic method based on the Gaussian kernel and the histogram method. We tested the developed system in real world WLAN indoor environment, where realistic RSS measurements were collected. Experimental comparison of the results has been investigated and average location estimation error of around 2 meters was obtained.

  7. An Indoor Pedestrian Positioning Method Using HMM with a Fuzzy Pattern Recognition Algorithm in a WLAN Fingerprint System

    OpenAIRE

    Yepeng Ni; Jianbo Liu; Shan Liu; Yaxin Bai

    2016-01-01

    With the rapid development of smartphones and wireless networks, indoor location-based services have become more and more prevalent. Due to the sophisticated propagation of radio signals, the Received Signal Strength Indicator (RSSI) shows a significant variation during pedestrian walking, which introduces critical errors in deterministic indoor positioning. To solve this problem, we present a novel method to improve the indoor pedestrian positioning accuracy by embedding a fuzzy pattern reco...

  8. WSN based indoor air quality monitoring in classrooms

    Science.gov (United States)

    Wang, S. K.; Chew, S. P.; Jusoh, M. T.; Khairunissa, A.; Leong, K. Y.; Azid, A. A.

    2017-03-01

    Indoor air quality monitoring is essential as the human health is directly affected by indoor air quality. This paper presents the investigations of the impact of undergraduate students' concentration during lecture due to the indoor air quality in classroom. Three environmental parameters such as temperature, relative humidity and concentration of carbon dioxide are measured using wireless sensor network based air quality monitoring system. This simple yet reliable system is incorporated with DHT-11 and MG-811 sensors. Two classrooms were selected to install the monitoring system. The level of indoor air quality were measured and students' concentration was assessed using intelligent test during normal lecturing section. The test showed significant correlation between the collected environmental parameters and the students' level of performances in their study.

  9. Energy-harvesting in cooperative AF relaying networks over log-normal fading channels

    KAUST Repository

    Rabie, Khaled M.

    2016-07-26

    Energy-harvesting (EH) and wireless power transfer are increasingly becoming a promising source of power in future wireless networks and have recently attracted a considerable amount of research, particularly on cooperative two-hop relay networks in Rayleigh fading channels. In contrast, this paper investigates the performance of wireless power transfer based two-hop cooperative relaying systems in indoor channels characterized by log-normal fading. Specifically, two EH protocols are considered here, namely, time switching relaying (TSR) and power splitting relaying (PSR). Our findings include accurate analytical expressions for the ergodic capacity and ergodic outage probability for the two aforementioned protocols. Monte Carlo simulations are used throughout to confirm the accuracy of our analysis. The results show that increasing the channel variance will always provide better ergodic capacity performance. It is also shown that a good selection of the EH time in the TSR protocol, and the power splitting factor in the PTS protocol, is the key to achieve the best system performance. © 2016 IEEE.

  10. AAU-DLR 2010 Indoor Measurement Campaign

    DEFF Research Database (Denmark)

    Steinböck, Gerhard; Pedersen, Troels; Wang, Wei

    2011-01-01

    A measurement campaign, not part of the WHERE2 project, with the focus on indoor multilink and reverberant in-room channels was conducted by DLR and AAU. The measurement data is used from both parties within the WHERE2 project and can be shared upon request. The measurement campaign has two main...

  11. 融合信道分配的无线Mes h网络多目标网关部署%Multi-Objective Channel Assignment and Gateway Deployment Optimizer for Wireless Mesh Network

    Institute of Scientific and Technical Information of China (English)

    赵传信; 陈付龙; 王汝传; 赵诚; 罗永龙

    2015-01-01

    信道分配和网关部署是无线M esh网络规划面临的重要挑战,作为影响网络性能的关键问题,传统上针对它们的研究都是独立的。为了有效结合二者规划网络,提升网络性能,提出了一种无线M esh网络联合信道分配和网关部署策略,综合考虑了最小化链路冲突量和网关部署代价,在部署网关过程中有效地分配信道以消减无线链路间干扰。利用链路冲突量衡量网关附近节点流量聚集的特征,使用基于多目标粒子群算法来优化信道分配和选择部署网关,在信道分配和网关选择已定的情况下构建了负载均衡的转发树。仿真结果表明,相对于基于平面网络的均衡信道分配网关部署算法,该算法可以有效降低网络干扰、优化网络性能、减少节点路径长度,实现了网关间的负载均衡。%Gateway deployment and channel assignment are important for the wireless mesh network planning because they influence the network quality of service directly . Traditionally , the two problems are studied separately .In this paper ,a comprehensive strategy is proposed to minimize both the link collision and the cost of gateway deployment for wireless mesh network .In addition ,the load balance is also considered in the planning stage and characteristics of the aggregation of flow traffic near the gateway in wireless mesh network are reflected by the degree of link collision . For the gateway deployment ,it has been proved to be NP‐hard .Here a novel multi‐objective particle swarm algorithm is proposed to optimize both channel assignment and gateway deployment .The route of nodes is built through creating a tree algorithm after the channel are assigned and gateway are selected .Thus ,the two problems are decoupled .The channel assignment and gateway deployment are then obtained in polynomial time for wireless mesh network planning .Comparing with the existing algorithms based on

  12. Caching in Wireless Networks

    CERN Document Server

    Niesen, Urs; Wornell, Gregory

    2009-01-01

    We consider the problem of delivering content cached in a wireless network of $n$ nodes randomly located on a square of area $n$. In the most general form, this can be analyzed by considering the $2^n\\times n$-dimensional caching capacity region of the wireless network. We provide an inner bound on this caching capacity region and, in the high path-loss regime, a matching (in the scaling sense) outer bound. For large path-loss exponent, this provides an information-theoretic scaling characterization of the entire caching capacity region. Moreover, the proposed communication scheme achieving the inner bound shows that the problem of cache selection and channel coding can be solved separately without loss of order-optimality.

  13. Combinatiorial Algorithms for Wireless Information Flow

    CERN Document Server

    Ebrahimi, Javad

    2009-01-01

    A long-standing open question in information theory is to characterize the unicast capacity of a wireless relay network. The difficulty arises due to the complex signal interactions induced in the network, since the wireless channel inherently broadcasts the signals and there is interference among transmissions. Recently, Avestimehr, Diggavi and Tse proposed a linear deterministic model that takes into account the shared nature of wireless channels, focusing on the signal interactions rather than the background noise. They generalized the min-cut max-flow theorem for graphs to networks of deterministic channels and proved that the capacity can be achieved using information theoretical tools. They showed that the value of the minimum cut is in this case the minimum rank of all the adjacency matrices describing source-destination cuts. In this paper, we develop a polynomial time algorithm that discovers the relay encoding strategy to achieve the min-cut value in linear deterministic (wireless) networks, for the...

  14. Detection Performance of Polarization and Spatial Diversities for Indoor GNSS Applications

    Directory of Open Access Journals (Sweden)

    Mohammadreza Zaheri

    2012-01-01

    Full Text Available Multipath fading in the form of signal power fluctuation poses a formidable challenge to GNSS signal detection in harsh multipath environments such as indoors. Antenna diversity techniques such as polarization and spatial diversities can be used to combat multipath fading in wireless propagation channels. This paper studies and compares GPS signal detection performance enhancements arising from the spatial and polarization diversity techniques. Performance enhancements are quantified from a theoretical perspective and later verified based on several test measurements in various indoor environments. Enhancement is quantified based on measuring the correlation coefficient values between diversity branches, SNR levels, and computing the level crossing rate and average fade duration. In addition, the processing gain is quantified and the performance of each individual diversity system is evaluated. Experimental results show that, for a given target detection performance in terms of the probability of false alarm and the probability of detection, the required input SNR level to meet the target detection performance can be significantly reduced utilizing the diversity system.

  15. A modeling method of sea surface microwave wireless channels based on stochastic bridge%基于随机桥理论的海面微波信道建模方法

    Institute of Scientific and Technical Information of China (English)

    曹小东; 汪小君; 姜弢

    2015-01-01

    According to the wireless wave propagation and microwave channel modeling in typical sea con⁃ditions, a microwave wireless channel model on two dimensional sea surface in a random environment is es⁃tablished in this paper based on the modeling theory of stochastic bridge for fixed communication environ⁃ment simulation. Firstly, based on the P-M spectrum of the sea surface wave, electromagnetic simulation models in sea conditions ranging from 0 to 6 grade have been established. Then, by analyzing the random ray sample data collected under different sea conditions, the digital characteristics of key parameters of sto⁃chastic bridge processes are determined, and the microwave band stochastic multi-path channel model on sea surface is constructed. Finally, the analysis of radio wave propagation characteristics is conducted us⁃ing the proposed channel model. The simulation and laboratory experimental data show that the characteris⁃tics of the proposed channel model are in agreement with tested results. In brief, this paper provides a valid theoretical method and technique proposal for the modeling and simulation of the received waveform of key electronic equipment on ship in complicated electromagnetic environment.%针对典型海况下的海面无线电波传播及微波信道建模问题,基于陆地多径传播环境下的随机桥过程建模理论,提出一种二维海面微波无线随机信道建模方法。首先,基于P-M海浪谱理论建立典型海况下的海浪电磁仿真模型;然后,采用不同的海况模型进行计算,得到随机电波射线样本数据,分析样本数据并确定随机信道模型参量的数字特征,建立海面微波波段随机多径信道模型;最后,将仿真数据、实验室测试数据和外场测试数据进行对比。结果显示,所建立的随机信道模型有效,可为复杂电磁环境中船用电子设备接收波形的建模与仿真提供有效的理论手段和技术方案。

  16. Optical wireless communications: Theory and applications

    Science.gov (United States)

    Aminikashani, Mohammadreza

    on the potentials of currently used FSO systems. Furthermore, utilizing this new statistical channel model, closed-form expressions for the diversity gain and the error rate performance of FSO links with spatial diversity are derived. In addition to addressing ways to improve outdoor FSO communication sys- tems, this dissertation addresses some major challenges in indoor visible light communication (VLC). VLC is an advantageous technique that is proposed for wireless indoor communications. In VLC systems, the existence of multiple paths between the transmitter and receiver causes multipath distortion, particularly in links using non-directional transmitters and receivers, or in links relying upon non-line of-sight propagation. This multipath distortion can lead to intersymbol interference (ISI) at high bit rates. Multicarrier modulation usually implemented by orthogonal frequency division multiplexing (OFDM) can be used to mitigate ISI and multipath dispersion. Nevertheless, the performance of VLC systems employing OFDM modulation is significantly affected by nonlinear characteristic of light-emitting diode (LED) due to the large peak-to-average power ratio (PAPR) of OFDM signal. In other words, signal amplitudes below the LED turn-on-voltage and above the LED saturation point are clipped. This dissertation targets these important issues and successfully addresses them by developing some techniques to reduce high PAPR of optical OFDM signal and determining the optimum operating characteristics of LEDs for combined lighting and communications applications. VLC can also provide a practical solution for indoor positioning as global po- sitioning system (GPS) does not provide an accurate and rapid indoor positioning since GPS radio signals are attenuated and scattered by walls of large buildings and other objects. A practical VLC system would be likely to deploy the same configuration for both positioning and communication purposes where high speed data rates are desired

  17. 长距离无线数字通信中的信道编码设计%Design of Channel Coding on Long-Distance Wireless Digital Communication

    Institute of Scientific and Technical Information of China (English)

    赵青

    2014-01-01

    This paper introduces a method of designing the channel coding on long-distance wireless digital communication, in order to enhance the quality of communication,(255,233)RS code and(2,1,7)convolu-tion code are cascaded by (8,255) inter-leaver. The MATLAB simulation result shows that cascaded code will be widely used in wireless digital communication region because of its low error rate.%介绍了一种长距离无线数字通信中的信道编码设计方案。为改善通信质量,采用了(255,233)RS编码+(8,255)交织+(2,1,7)卷积编码这一信道编码方式。MATLAB仿真结果表明,该级联码能有效降低数字通信系统的误码率,在无线数字通信领域中有着很好的应用前景。

  18. Improved Wireless Security through Physical Layer Protocol Manipulation and Radio Frequency Fingerprinting

    Science.gov (United States)

    2014-09-18

    FINGERPRINTING I. Introduction Modern wireless communications networks have revolutionized the ways in which information is shared. Inexpensive low-rate wireless ... Wireless Intrusion Detection and Device Fingerprinting through PHY Manipulation 2.1 Introduction Properly securing low-rate LR-WPANs is challenging due... wireless interference or are completely uninterpretable by the receiver. Influence of wireless noise is mitigated by operating on IEEE 802.15.4 channel

  19. Curvature of Indoor Sensor Network: Clustering Coefficient

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available We investigate the geometric properties of the communication graph in realistic low-power wireless networks. In particular, we explore the concept of the curvature of a wireless network via the clustering coefficient. Clustering coefficient analysis is a computationally simplified, semilocal approach, which nevertheless captures such a large-scale feature as congestion in the underlying network. The clustering coefficient concept is applied to three cases of indoor sensor networks, under varying thresholds on the link packet reception rate (PRR. A transition from positive curvature (“meshed” network to negative curvature (“core concentric” network is observed by increasing the threshold. Even though this paper deals with network curvature per se, we nevertheless expand on the underlying congestion motivation, propose several new concepts (network inertia and centroid, and finally we argue that greedy routing on a virtual positively curved network achieves load balancing on the physical network.

  20. Automated alignment system for optical wireless communication systems using image recognition.

    Science.gov (United States)

    Brandl, Paul; Weiss, Alexander; Zimmermann, Horst

    2014-07-01

    In this Letter, we describe the realization of a tracked line-of-sight optical wireless communication system for indoor data distribution. We built a laser-based transmitter with adaptive focus and ray steering by a microelectromechanical systems mirror. To execute the alignment procedure, we used a CMOS image sensor at the transmitter side and developed an algorithm for image recognition to localize the receiver's position. The receiver is based on a self-developed optoelectronic integrated chip with low requirements on the receiver optics to make the system economically attractive. With this system, we were able to set up the communication link automatically without any back channel and to perform error-free (bit error rate <10⁻⁹) data transmission over a distance of 3.5 m with a data rate of 3 Gbit/s.

  1. Is organic photovoltaics promising for indoor applications?

    Science.gov (United States)

    Lee, Harrison K. H.; Li, Zhe; Durrant, James R.; Tsoi, Wing C.

    2016-06-01

    This work utilizes organic photovoltaics (OPV) for indoor applications, such as powering small electronic devices or wireless connected Internet of Things. Three representative polymer-based OPV systems, namely, poly(3-hexylthiophene-2,5-diyl), poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)], and poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  2. Monitoring Indoor Air Quality for Enhanced Occupational Health.

    Science.gov (United States)

    Pitarma, Rui; Marques, Gonçalo; Ferreira, Bárbara Roque

    2017-02-01

    Indoor environments are characterized by several pollutant sources. Because people spend more than 90% of their time in indoor environments, several studies have pointed out the impact of indoor air quality on the etiopathogenesis of a wide number of non-specific symptoms which characterizes the "Sick Building Syndrome", involving the skin, the upper and lower respiratory tract, the eyes and the nervous system, as well as many building related diseases. Thus, indoor air quality (IAQ) is recognized as an important factor to be controlled for the occupants' health and comfort. The majority of the monitoring systems presently available is very expensive and only allow to collect random samples. This work describes the system (iAQ), a low-cost indoor air quality monitoring wireless sensor network system, developed using Arduino, XBee modules and micro sensors, for storage and availability of monitoring data on a web portal in real time. Five micro sensors of environmental parameters (air temperature, humidity, carbon monoxide, carbon dioxide and luminosity) were used. Other sensors can be added for monitoring specific pollutants. The results reveal that the system can provide an effective indoor air quality assessment to prevent exposure risk. In fact, the indoor air quality may be extremely different compared to what is expected for a quality living environment. Systems like this would have benefit as public health interventions to reduce the burden of symptoms and diseases related to "sick buildings".

  3. Wireless Power Transfer in Cooperative DF Relaying Networks with Log-Normal Fading

    KAUST Repository

    Rabie, Khaled M.

    2017-02-07

    Energy-harvesting (EH) and wireless power transfer in cooperative relaying networks have recently attracted a considerable amount of research attention. Most of the existing work on this topic however focuses on Rayleigh fading channels which represents outdoor environments. Unlike these studies, in this paper we analyze the performance of wireless power transfer in two-hop decode-and- forward (DF) cooperative relaying systems in indoor channels characterized by log-normal fading. Three well-known EH protocols are considered in our evaluations: a) time switching relaying (TSR), b) power splitting relaying (PSR) and c) ideal relaying receiver (IRR). The performance is evaluated in terms of the ergodic outage probability for which we derive accurate analytical expressions for the three systems under consideration. Results reveal that careful selection of the EH time and power splitting factors in the TSR- and PSR-based system are important to optimize performance. It is also presented that the optimized PSR system has near- ideal performance and that increasing the source transmit power and/or the energy harvester efficiency can further improve performance.

  4. Mobile radio channels

    CERN Document Server

    Pätzold, Matthias

    2011-01-01

    Providing a comprehensive overview of the modelling, analysis and simulation of mobile radio channels, this book gives a detailed understanding of fundamental issues and examines state-of-the-art techniques in mobile radio channel modelling. It analyses several mobile fading channels, including terrestrial and satellite flat-fading channels, various types of wideband channels and advanced MIMO channels, providing a fundamental understanding of the issues currently being investigated in the field. Important classes of narrowband, wideband, and space-time wireless channels are explored in deta

  5. SMF/MMF Based In-building Gigabit Wireless Access Systems Using Simplified 60-GHz Transceivers

    DEFF Research Database (Denmark)

    Pham, Tien Thang; Lebedev, Alexander; Beltrán, M.

    2011-01-01

    Hybrid fiber-wireless transmission of 2-Gbps signals in 60-GHz band over a composite channel (10-km SMF/1-km MMF/6.5-m wireless) is experimentally demonstrated for gigabit inbuilding wireless access using simple direct modulation, optical upconversion and envelope detection.......Hybrid fiber-wireless transmission of 2-Gbps signals in 60-GHz band over a composite channel (10-km SMF/1-km MMF/6.5-m wireless) is experimentally demonstrated for gigabit inbuilding wireless access using simple direct modulation, optical upconversion and envelope detection....

  6. Performance and accuracy test of a WiFi indoor positioning system

    Science.gov (United States)

    Retscher, Guenther; Moser, Eva; Vredeveld, Dennis; Heberling, Dirk; Pamp, Joerg

    2007-09-01

    Location based-services and personal navigation require the location determination of a user not only in outdoor environments but also indoor. For indoor location already established wireless infrastructure such as WiFi (Wireless Fidelity) or WLAN (Wireless Local Area Networks) can be employed. This approach has the advantage that no costly hardware installations are necessary inside a building if WiFi is already available. The IMST GmbH has developed a software framework called "ipos" for indoor positioning technologies. The principle of the developed platform and the performance of the location determination using WiFi in a localization testbed of IMST GmbH are presented in this paper.

  7. Indoor bioaerosol dynamics.

    Science.gov (United States)

    Nazaroff, William W

    2016-02-01

    Inhaling indoor air is the primary means by which humans are exposed to bioaerosols. Considering bacteria, fungi, and viruses, this study reviews the dynamic processes that govern indoor concentrations and fates of biological particulate material. Bioaerosol behavior is strongly coupled to particle size; this study emphasizes the range 0.1-10 μm in aerodynamic diameter. The principle of material balance allows concentrations to be determined from knowledge of important source and removal processes. Sources reviewed here include outdoor air introduced by air exchange plus indoor emission from occupants, occupant activities, and moldy materials. Important mechanisms that remove bioaerosols from indoor air include air exchange, deposition onto indoor surfaces, and active filtration. The review summarizes knowledge about size-dependent particle deposition in different regions of the respiratory tract, techniques for measuring indoor bioaerosols, and evidence for diseases caused by airborne exposure to bioaerosols. Future research challenges and opportunities are highlighted.

  8. 无线光纤分布系统实现室内信号覆盖方案探讨%Discussion on the Implementation of Indoor Signal Coverage in Wireless Optical Fiber Distribution System

    Institute of Scientific and Technical Information of China (English)

    张岭

    2015-01-01

    论文在提出传统同轴室内分布系统存在问题的基础上,简要介绍了一种无线光纤分布系统WFDS(Wireless Fiber Distribution system)的原理、组网模式.通过实际工程项目案例,从方案设计、工程实施、系统维护的角度与同轴分布系统作了对比分析,同时也对2G、3G室内分布改造作了简要的分析说明.

  9. Wireless distributed computing for cyclostationary feature detection

    Directory of Open Access Journals (Sweden)

    Mohammed I.M. Alfaqawi

    2016-02-01

    Full Text Available Recently, wireless distributed computing (WDC concept has emerged promising manifolds improvements to current wireless technologies. Despite the various expected benefits of this concept, significant drawbacks were addressed in the open literature. One of WDC key challenges is the impact of wireless channel quality on the load of distributed computations. Therefore, this research investigates the wireless channel impact on WDC performance when the latter is applied to spectrum sensing in cognitive radio (CR technology. However, a trade-off is found between accuracy and computational complexity in spectrum sensing approaches. Increasing these approaches accuracy is accompanied by an increase in computational complexity. This results in greater power consumption and processing time. A novel WDC scheme for cyclostationary feature detection spectrum sensing approach is proposed in this paper and thoroughly investigated. The benefits of the proposed scheme are firstly presented. Then, the impact of the wireless channel of the proposed scheme is addressed considering two scenarios. In the first scenario, workload matrices are distributed over the wireless channel. Then, a fusion center combines these matrices in order to make a decision. Meanwhile, in the second scenario, local decisions are made by CRs, then, only a binary flag is sent to the fusion center.

  10. Channel Measurements and Characteristics for Cooperative Positioning Applications

    DEFF Research Database (Denmark)

    Wang, Wei; Steinböck, Gerhard; Jost, Thomas

    2012-01-01

    We have conducted an indoor channel measurement campaign to characterize the propagation channel for the development of cooperative positioning algorithms. The campaign focused particularly on the characteristics of multi-link channels with applications to positioning. In this contribution we...

  11. WIPP: Wi-Fi Compass for Indoor Passive Positioning with Decimeter Accuracy

    Directory of Open Access Journals (Sweden)

    Zhenyuan Zhang

    2016-04-01

    Full Text Available In recent decades, the proliferation of smart phones, tablets, and wireless networks has fostered a growing interest in indoor passive positioning. The Wi-Fi-based passive positioning systems can provide Location-Based Services (LBSs to the third party such as market and security departments. Most of the existing systems are based on the Receive Signal Strength Indication (RSSI information, which are generally time-consuming and susceptible to environmental change. To overcome this problem, we propose the Wi-Fi compass for indoor passive positioning system (WIPP, an Angle of Arrival (AOA based passive positioning system using the existing commodity Wi-Fi network. In this paper, we first propose a new algorithm for the joint estimation of AOA and Time of Arrival (TOA measurements based on the fine-grained Channel State Information (CSI, which is collected by an off-the-shelf Wi-Fi device equipped with only three antennas. Second, we use the affinity propagation clustering algorithm to identify the direct signal path from the target to each Wi-Fi Access Point (AP. Finally, we deploy the WIPP in an actual indoor environment to conduct the performance comparison with the well-known radio-frequency (RF based system for locating and tracking users inside buildings (RADAR, as well as the conventional passive positioning system using the AOA solely. The experimental results show that the WIPP is able to achieve the median positioning error 0.7 m, which is much lower than the ones by the RADAR system and the conventional system using the AOA solely.

  12. Indoor multipath mitigation

    DEFF Research Database (Denmark)

    Dragünas, Kostas

    2010-01-01

    There are many applications that require continuous positioning in combined outdoor urban and indoor environments. GNSS has been used for a long time in outdoor environments, while indoor positioning is still a challenging task. One of the major degradations that GNSS receivers experience indoors...... is the presence of multipath. The current paper analyzes several available multipath mitigation techniques which would be suitable for indoor applications. A few deconvolution based techniques such as the Projection Onto Convex Sets and the Deconvolution Approach are selected for closer investigation...

  13. Pushing the Limits of Indoor Localization in Today’s Wi-Fi Networks

    OpenAIRE

    XIONG, J.

    2015-01-01

    Wireless networks are ubiquitous nowadays and play an increasingly important role in our everyday lives. Many emerging applications including augmented reality, indoor navigation and human tracking, rely heavily on Wi-Fi, thus requiring an even more sophisticated network. One key component for the success of these applications is accurate localization. While we have GPS in the outdoor environment, indoor localization at a sub-meter granularity remains challenging due to a number of factors, i...

  14. Introduction to Indoor Air Quality

    Science.gov (United States)

    ... United States Environmental Protection Agency Search Search Indoor Air Quality (IAQ) Contact Us Share Introduction to Indoor Air Quality Health Effects Primary Causes Identifying Problems Improving IAQ ...

  15. Analysis of Secret Key Randomness Exploiting the Radio Channel Variability

    Directory of Open Access Journals (Sweden)

    Taghrid Mazloum

    2015-01-01

    Full Text Available A few years ago, physical layer based techniques have started to be considered as a way to improve security in wireless communications. A well known problem is the management of ciphering keys, both regarding the generation and distribution of these keys. A way to alleviate such difficulties is to use a common source of randomness for the legitimate terminals, not accessible to an eavesdropper. This is the case of the fading propagation channel, when exact or approximate reciprocity applies. Although this principle has been known for long, not so many works have evaluated the effect of radio channel properties in practical environments on the degree of randomness of the generated keys. To this end, we here investigate indoor radio channel measurements in different environments and settings at either 2.4625 GHz or 5.4 GHz band, of particular interest for WIFI related standards. Key bits are extracted by quantizing the complex channel coefficients and their randomness is evaluated using the NIST test suite. We then look at the impact of the carrier frequency, the channel variability in the space, time, and frequency degrees of freedom used to construct a long secret key, in relation to the nature of the radio environment such as the LOS/NLOS character.

  16. Wireless communication for hearing aid system

    DEFF Research Database (Denmark)

    Nour, Baqer

    This thesis focuses on the wireless coupling between hearing aids close to a human head. Hearing aids constitute devices withadvanced technology and the wireless communication enables the introduction of a range of completely new functionalities. Such devices are small and the available power...... the ear-to-ear wireless communication channel by understanding the mechanisms that control the propagations of the signals and the losses. The second objective isto investigate the properties of magneto-dielectric materials and their potential in antenna miniaturization. There are three approaches...... understanding of the ear-to-ear wireless communication channel. A circular patch antenna was used to study the properties of the magneto-dielectric materials. In the thesis, we focused on three properties; efficiency, quality factor and bandwidth of the antenna. An analytical method is used to calculatethe...

  17. Advanced Signal Processing for Wireless Multimedia Communications

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2000-01-01

    Full Text Available There is at present a worldwide effort to develop next-generation wireless communication systems. It is envisioned that many of the future wireless systems will incorporate considerable signal-processing intelligence in order to provide advanced services such as multimedia transmission. In general, wireless channels can be very hostile media through which to communicate, due to substantial physical impediments, primarily radio-frequency interference and time-arying nature of the channel. The need of providing universal wireless access at high data-rate (which is the aim of many merging wireless applications presents a major technical challenge, and meeting this challenge necessitates the development of advanced signal processing techniques for multiple-access communications in non-stationary interference-rich environments. In this paper, we present some key advanced signal processing methodologies that have been developed in recent years for interference suppression in wireless networks. We will focus primarily on the problem of jointly suppressing multiple-access interference (MAI and intersymbol interference (ISI, which are the limiting sources of interference for the high data-rate wireless systems being proposed for many emerging application areas, such as wireless multimedia. We first present a signal subspace approach to blind joint suppression of MAI and ISI. We then discuss a powerful iterative technique for joint interference suppression and decoding, so-called Turbo multiuser detection, that is especially useful for wireless multimedia packet communications. We also discuss space-time processing methods that employ multiple antennas for interference rejection and signal enhancement. Finally, we touch briefly on the problems of suppressing narrowband interference and impulsive ambient noise, two other sources of radio-frequency interference present in wireless multimedia networks.

  18. 一种提高无线实时低传输率下传输图像质量的方法%Effective Method to Improve Image Impression in Real-time Low-capability Wireless Channel

    Institute of Scientific and Technical Information of China (English)

    白旭; 张中兆; 张佳岩; 马琳

    2007-01-01

    Aiming to improve the visual appearance without increasing the data rate, a real-time field skipping image transmission system, based MJPEG2000 format in wireless channel, is proposed, ADV212 is used for field skipping, image compression and decompression, field interpolation operated in FPGA. In channel capability limited conditions, a good performance can be got for the transmission image.%设计并实现了一种提高无线信道中传输基于MJPEG2000格式的实时图像质量的方法,图像的压缩与解压缩采用专用硬件ADV212实现,通过配置ADV212芯片自身的寄存器实现跳场,利用FPGA实现补场,在信道速率较低的情况下,能够有效地提高传输后图像显示的质量.

  19. Your Indoor Spaces

    Science.gov (United States)

    Exchange: The Early Childhood Leaders' Magazine Since 1978, 2007

    2007-01-01

    In the July 24, 2007 edition of "ExchangeEveryday", readers were asked to submit great indoor space elements from their early childhood programs. Readers sent photographs and brief descriptions of creative elements of their indoor environments. A sampling of ideas are shown on this article.

  20. Multi-channel Dual Clocks three-dimensional probability Random Multiple Access protocol for Wireless Public Bus Networks based on RTS/CTS mechanism

    Directory of Open Access Journals (Sweden)

    Zhou Sheng Jie

    2016-01-01

    Full Text Available A MAC protocol for public bus networks, called Bus MAC protocol, designed to provide high quality Internet service for bus passengers. The paper proposed a multi-channel dual clocks three-demission probability random multiple access protocol based on RTS/CTS mechanism, decreasing collisions caused by multiple access from multiple passengers. Use the RTS/CTS mechanism increases the reliability and stability of the system, reducing the collision possibility of the information packets to a certain extent, improves the channel utilization; use the multi-channel mechanism, not only enables the channel load balancing, but also solves the problem of the hidden terminal and exposed terminal. Use the dual clocks mechanism, reducing the system idle time. At last, the different selection of the three-dimensional probabilities can make the system throughput adapt to the network load which could realize the maximum of the system throughput.

  1. Fading and interference mitigation in wireless communications

    CERN Document Server

    Panic, Stefan; Anastasov, Jelena; Spalevic, Petar

    2013-01-01

    The rapid advancement of various wireless communication system services has created the need to analyze the possibility of their performance improvement. Introducing the basic principles of digital communications performance analysis and its mathematical formalization, Fading and Interference Mitigation in Wireless Communications will help you stay up to date with recent developments in the performance analysis of space diversity reception over fading channels in the presence of cochannel interference.The book presents a unified method for computing the performance of digital communication sys

  2. Bandwidth-Efficient Wireless Multimedia Communications

    OpenAIRE

    Hanzo, L.

    1998-01-01

    Commencing with the brief history of mobile communications and the portrayal of the basic concept of wireless multimedia communications, the implications of Shannon’s theorems regarding joint source and channel coding for wireless communications are addressed. Following a brief introduction to speech, video, and graphical source coding as well as the cellular concept, a rudimentary overview of exible, reconfigurable, mobile radio schemes is provided. We then summarize the fundamental concepts...

  3. Routing Security Issues in Wireless Sensor Networks: Attacks and Defenses

    CERN Document Server

    Sen, Jaydip

    2011-01-01

    Wireless Sensor Networks (WSNs) are rapidly emerging as an important new area in wireless and mobile computing research. Applications of WSNs are numerous and growing, and range from indoor deployment scenarios in the home and office to outdoor deployment scenarios in adversary's territory in a tactical battleground (Akyildiz et al., 2002). For military environment, dispersal of WSNs into an adversary's territory enables the detection and tracking of enemy soldiers and vehicles. For home/office environments, indoor sensor networks offer the ability to monitor the health of the elderly and to detect intruders via a wireless home security system. In each of these scenarios, lives and livelihoods may depend on the timeliness and correctness of the sensor data obtained from dispersed sensor nodes. As a result, such WSNs must be secured to prevent an intruder from obstructing the delivery of correct sensor data and from forging sensor data. To address the latter problem, end-to-end data integrity checksums and pos...

  4. Cooperative communications hardware, channel and PHY

    CERN Document Server

    Dohler, Mischa

    2010-01-01

    Facilitating Cooperation for Wireless Systems Cooperative Communications: Hardware, Channel & PHY focuses on issues pertaining to the PHY layer of wireless communication networks, offering a rigorous taxonomy of this dispersed field, along with a range of application scenarios for cooperative and distributed schemes, demonstrating how these techniques can be employed. The authors discuss hardware, complexity and power consumption issues, which are vital for understanding what can be realized at the PHY layer, showing how wireless channel models differ from more traditional

  5. Voice over IP in Wireless Heterogeneous Networks

    DEFF Research Database (Denmark)

    Fathi, Hanane; Chakraborty, Shyam; Prasad, Ramjee

    The convergence of different types of traffic has preceded the convergence of systems and services in a wireless heterogeneous network. Voice and data traffic are usually treated separate in both 2G and 2.5G wireless networks. With advances in packet switching technology and especially......IP communications are difficult to achieve in a time-varying environment due to channel errors and traffic congestion and across different systems. The provision of VoIP in wireless heterogeneous networks requires a set of time-efficient control mechanisms to support a VoIP session with acceptable quality...

  6. 基于路由树的多信道多跳无线传感器网络资源分配算法%Routing Based Resource Assignment for Multi-Channel Multi-Hop Wireless Sensor Network

    Institute of Scientific and Technical Information of China (English)

    杨彦红; 张晓彤; 张学颖

    2014-01-01

    Using multi-channel resource assignment increases the stability of wireless network and throughput. A resource assignment algorithm is proposed for static and dynamic large scale wireless sensor networks. According the policy to reusing link, links are assigned to nodes based on routing information. In the simulations, it improves the throughput by 35.7% and 18.4% in different communication ranges compared to packets in pipe ( PIP) . In dynamic networks, network traffic generated to restore traffic is related to the number of nodes. The proportion of new traffic to total traffic for networking is less than the proportion of network nodes change.%采用有效的多信道资源分配算法可以增强网络的稳定性,提高网络的通信效率。因此提出一种适用于大规模网络的资源分配算法,既可用于静态网络,也可用于动态网络。首先根据路由树的关系,依据提出的时隙复用规则,给出节点间的时隙分配。仿真与管载数据包算法比较,在不同的通信距离下网络的吞吐率分别提高35郾7%和18郾4%。在动态网络中,恢复网络通信产生的通信量和节点个数的变化有关,与总通信量的比例要小于网络节点变化的比例。

  7. A 0.5 cm(3) four-channel 1.1 mW wireless biosignal interface with 20 m range.

    Science.gov (United States)

    Morrison, Tim; Nagaraju, Manohar; Winslow, Brent; Bernard, Amy; Otis, Brian P

    2014-02-01

    This paper presents a self-contained, single-chip biosignal monitoring system with wireless programmability and telemetry interface suitable for mainstream healthcare applications. The system consists of low-noise front end amplifiers, ADC, MICS/ISM transmitter and infrared programming capability to configure the state of the chip. An on-chip packetizer ensures easy pairing with standard off-the-shelf receivers. The chip is realized in the IBM 130 nm CMOS process with an area of 2×2 mm(2). The entire system consumes 1.07 mW from a 1.2 V supply. It weighs 0.6 g including a zinc-air battery. The system has been extensively tested in in vivo biological experiments and requires minimal human interaction or calibration.

  8. Feedback-based Intra Refresh Scheme for Wireless Video Transmission

    Institute of Scientific and Technical Information of China (English)

    FENGXiubo; XIEJianying

    2004-01-01

    This paper investigates the intra refresh techniques for video transmission in wireless scenario. Twostate Markov model is proposed to simulate the fading wireless channel. Taking feedback information into account, we analyze the channel distortion due to the burst errors. An improved intra refresh scheme is then proposed for optimal selection of coding mode for each Macroblock (MB) in rate-distortion framework. The propo sedscheme can stop error propagation and reduce channel distortion effectively. Simulations using TMN10 show that our scheme obtains improved performance with respect to error resilience for wireless video communication.

  9. Fundamentals of Wireless Networks: Connectivity and Capacity

    Science.gov (United States)

    2010-06-09

    awake every k-th clock cycle. A more detailed explanation of wake-node bands and their variation with parameters is given in the next section. Inspection...which both decoders can decode both messages. The considered channel becomes a compound multiaccess ( MAC ) channel consisting of two MAC channels, one to...organization and energy efficient tdma mac protocol by wake up for wireless sensor networks. In Proceedings of IEEE SECON ’04, pages 335–341, 2004. [9] M. H

  10. Rate Adaptation, Power Control, and Diversity Combining in Wireless Systems

    OpenAIRE

    Gjendemsjø, Anders Milde

    2007-01-01

    The present dissertation consists of a collection of six papers preceded byan introduction. The papers investigate the design and performance analysis of communication systems operating over wireless fading channels.Wireless communication systems carry great expectations for future services. They are expected to give users both reliable high data rate transmission and the freedom of mobility. However, due to the limited available spectral resources and the random nature of the wireless channe...

  11. Indoor Positioning System Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Hamid Mehmood

    2010-01-01

    Full Text Available Problem statement: Location knowledge in indoor environment using Indoor Positioning Systems (IPS has become very useful and popular in recent years. A number of Location Based Services (LBS have been developed, which are based on IPS, these LBS include asset tracking, inventory management and security based applications. Many next-generation LBS applications such as social networking, local search, advertising and geo-tagging are expected to be used in urban and indoor environments where GNSS either underperforms in terms of fix times or accuracy, or fails altogether. To develop an IPS based on Wi-Fi Received Signal Strength (RSS using Artificial Neural Networks (ANN, which should use already available Wi-Fi infrastructure in a heterogeneous environment. Approach: This study discussed the use of ANN for IPS using RSS in an indoor wireless facility which has varying human activity, material of walls and type of Wireless Access Points (WAP, hence simulating a heterogeneous environment. The proposed system used backpropogation method with 4 input neurons, 2 output neurons and 4 hidden layers. The model was trained with three different types of training data. The accuracy assessment for each training data was performed by computing the distance error and average distance error. Results: The results of the experiments showed that using ANN with the proposed method of collecting training data, maximum accuracy of 0.7 m can be achieved, with 30% of the distance error less than 1 m and 60% of the distance error within the range of 1-2 m. Whereas maximum accuracy of 1.01 can be achieved with the commonly used method of collecting training data. The proposed model also showed 67% more accuracy as compared to a probabilistic model. Conclusion: The results indicated that ANN based IPS can provide accuracy and precision which is quite adequate for the development of indoor LBS while using the already available Wi-Fi infrastructure, also the proposed method

  12. A Wireless Grid in Ubiquitous Broadband Wireless Services for Mega-Event Scenario and its Distributed Power Control

    Directory of Open Access Journals (Sweden)

    Liu Yanjun

    2013-12-01

    Full Text Available Wireless grid can provide consumers ubiquitous broadband wireless services with convenience, robustness and mobility, which is one of the most promising alternatives of fixed wireless access networks. As the deployment of Wide City has accelerated quickly, this study focuses on the key technologies of wireless grid in ubiquitous broadband wireless services, such as antennas, MAC design, channel assignment and interface scheduling. A novel hierarchical wireless network based on WiMax-WiFi grid is proposed for mega-event. As a key enabling technology for wireless grid, a distributed power control algorithm for WiFi AP is proposed in this study to achieve the load balancing and the improvement of network performance.

  13. Space subdivision for indoor applications

    NARCIS (Netherlands)

    Zlatanova, S.; Liu, L.; Sithole, G.; Zhao, J.; Mortari, F.

    2014-01-01

    This report makes an overview of 2D, 2,5D and 3D approaches for indoor space subdivision for the purpose of indoor navigation. The report starts with a conceptual framework for indoor space utilisation. We introduce and elaborate on the concepts of indoor space (navigable and non-navigable), agent,

  14. Space subdivision for indoor applications

    NARCIS (Netherlands)

    Zlatanova, S.; Liu, L.; Sithole, G.; Zhao, J.; Mortari, F.

    2014-01-01

    This report makes an overview of 2D, 2,5D and 3D approaches for indoor space subdivision for the purpose of indoor navigation. The report starts with a conceptual framework for indoor space utilisation. We introduce and elaborate on the concepts of indoor space (navigable and non-navigable), agent,

  15. [Wireless human body communication technology].

    Science.gov (United States)

    Sun, Lei; Zhang, Xiaojuan

    2014-12-01

    The Wireless Body Area Network (WBAN) is a key part of the wearable monitoring technologies, which has many communication technologies to choose from, like Bluetooth, ZigBee, Ultra Wideband, and Wireless Human Body Communication (WHBC). As for the WHBC developed in recent years, it is worthy to be further studied. The WHBC has a strong momentum of growth and a natural advantage in the formation of WBAN. In this paper, we first briefly describe the technical background of WHBC, then introduce theoretical model of human-channel communication and digital transmission machine based on human channel. And finally we analyze various of the interference of the WHBC and show the AFH (Adaptive Frequency Hopping) technology which can effectively deal with the interference.

  16. Wireless Network Information Flow: A Deterministic Approach

    CERN Document Server

    Avestimehr, Salman; Tse, David

    2009-01-01

    In contrast to wireline networks, not much is known about the flow of information over wireless networks. The main barrier is the complexity of the signal interaction in wireless channels in addition to the noise in the channel. A widely accepted model is the the additive Gaussian channel model, and for this model, the capacity of even a network with a single relay node is open for 30 years. In this paper, we present a deterministic approach to this problem by focusing on the signal interaction rather than the noise. To this end, we propose a deterministic channel model which is analytically simpler than the Gaussian model but still captures two key wireless channel properties of broadcast and superposition. We consider a model for a wireless relay network with nodes connected by such deterministic channels, and present an exact characterization of the end-to-end capacity when there is a single source and one or more destinations (all interested in the same information) and an arbitrary number of relay nodes....

  17. The Degraded Poisson Wiretap Channel

    OpenAIRE

    Laourine, Amine; Wagner, Aaron B.

    2010-01-01

    Providing security guarantees for wireless communication is critically important for today's applications. While previous work in this area has concentrated on radio frequency (RF) channels, providing security guarantees for RF channels is inherently difficult because they are prone to rapid variations due small scale fading. Wireless optical communication, on the other hand, is inherently more secure than RF communication due to the intrinsic aspects of the signal propagation in the optical ...

  18. Theoretical Foundations of Wireless Networks

    Science.gov (United States)

    2015-07-22

    wireless networks. The interesting aspect of imperfect CSI in a networked setting is that different terminals are likely to have different perceptions ...Regarding asymptotic behaviors, observe that agents’ stage payoffs capture the kind of trade-off exemplified by the Keynesian beauty contest: each...imperfect CSI in a networked setting is that different terminals are likely to have different perceptions on the values of different channels. In

  19. Power Control and Coding Formulation for State Estimation with Wireless Sensors

    DEFF Research Database (Denmark)

    Quevedo, Daniel; Østergaard, Jan; Ahlen, Anders

    2014-01-01

    Technological advances made wireless sensors cheap and reliable enough to be brought into industrial use. A major challenge arises from the fact that wireless channels introduce random packet dropouts. Power control and coding are key enabling technologies in wireless communications to ensure eff...

  20. Performance of MMSE Receiver based Multi Input Multi Output-Interleave Division Multiple-Access System with Multi-user Detection over Frequency Selective Wireless Communication Channel

    Directory of Open Access Journals (Sweden)

    Kuttathatti S. Vishvaksenan

    2011-01-01

    Full Text Available Problem statement: This study presents the performance analysis of turbo assisted Interleave Division Multiple-Access (IDMA system with Multi Input Multi Output (MIMO support for multi user scenario over correlated frequency selective and uncorrelated frequency selective channel. Approach: The key principle of IDMA is that interleaver unique which distinguishes the users in contrast to spreading sequence in Code Division Multiple Access System (CDMA. Results: In this work, we assume that Interleavers are generated independently and randomly. At the receiver, we employed Ordered SIC (OSIC technique using ZF and MMSE criterion to combat Inter Antenna Interference (IAI and Multi User Interference (MUI problem along with iterative decoding to improve the performance in terms of BER. The performance of system has been discussed for different channel conditions with realistic channel model using extensive simulation runs based on Monte Carlo simulation trials. We have exhibited the flexibility and robustness provided by MIMO-IDMA. Conclusion/Recommendations: It has been proved from the results that IDMA principle can be applied to realize many potential performance gains highlighted by information theory, including coding gain multiplexing gain and multiuser gain. Simulation results presented to demonstrate the benefits of IDMA with MUD and iterative decoding. It is discerned that IDMA performs better than CDMA in frequency selective channel for high load conditions which is assessed through computer simulation results.

  1. Practical Performance Analysis for Multiple Information Fusion Based Scalable Localization System Using Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yubin Zhao

    2016-08-01

    Full Text Available In practical localization system design, researchers need to consider several aspects to make the positioning efficiently and effectively, e.g., the available auxiliary information, sensing devices, equipment deployment and the environment. Then, these practical concerns turn out to be the technical problems, e.g., the sequential position state propagation, the target-anchor geometry effect, the Non-line-of-sight (NLOS identification and the related prior information. It is necessary to construct an efficient framework that can exploit multiple available information and guide the system design. In this paper, we propose a scalable method to analyze system performance based on the Cramér–Rao lower bound (CRLB, which can fuse all of the information adaptively. Firstly, we use an abstract function to represent all of the wireless localization system model. Then, the unknown vector of the CRLB consists of two parts: the first part is the estimated vector, and the second part is the auxiliary vector, which helps improve the estimation accuracy. Accordingly, the Fisher information matrix is divided into two parts: the state matrix and the auxiliary matrix. Unlike the theoretical analysis, our CRLB can be a practical fundamental limit to denote the system that fuses multiple information in the complicated environment, e.g., recursive Bayesian estimation based on the hidden Markov model, the map matching method and the NLOS identification and mitigation methods. Thus, the theoretical results are approaching the real case more. In addition, our method is more adaptable than other CRLBs when considering more unknown important factors. We use the proposed method to analyze the wireless sensor network-based indoor localization system. The influence of the hybrid LOS/NLOS channels, the building layout information and the relative height differences between the target and anchors are analyzed. It is demonstrated that our method exploits all of the

  2. Practical Performance Analysis for Multiple Information Fusion Based Scalable Localization System Using Wireless Sensor Networks.

    Science.gov (United States)

    Zhao, Yubin; Li, Xiaofan; Zhang, Sha; Meng, Tianhui; Zhang, Yiwen

    2016-08-23

    In practical localization system design, researchers need to consider several aspects to make the positioning efficiently and effectively, e.g., the available auxiliary information, sensing devices, equipment deployment and the environment. Then, these practical concerns turn out to be the technical problems, e.g., the sequential position state propagation, the target-anchor geometry effect, the Non-line-of-sight (NLOS) identification and the related prior information. It is necessary to construct an efficient framework that can exploit multiple available information and guide the system design. In this paper, we propose a scalable method to analyze system performance based on the Cramér-Rao lower bound (CRLB), which can fuse all of the information adaptively. Firstly, we use an abstract function to represent all of the wireless localization system model. Then, the unknown vector of the CRLB consists of two parts: the first part is the estimated vector, and the second part is the auxiliary vector, which helps improve the estimation accuracy. Accordingly, the Fisher information matrix is divided into two parts: the state matrix and the auxiliary matrix. Unlike the theoretical analysis, our CRLB can be a practical fundamental limit to denote the system that fuses multiple information in the complicated environment, e.g., recursive Bayesian estimation based on the hidden Markov model, the map matching method and the NLOS identification and mitigation methods. Thus, the theoretical results are approaching the real case more. In addition, our method is more adaptable than other CRLBs when considering more unknown important factors. We use the proposed method to analyze the wireless sensor network-based indoor localization system. The influence of the hybrid LOS/NLOS channels, the building layout information and the relative height differences between the target and anchors are analyzed. It is demonstrated that our method exploits all of the available information for

  3. Practical Performance Analysis for Multiple Information Fusion Based Scalable Localization System Using Wireless Sensor Networks

    Science.gov (United States)

    Zhao, Yubin; Li, Xiaofan; Zhang, Sha; Meng, Tianhui; Zhang, Yiwen

    2016-01-01

    In practical localization system design, researchers need to consider several aspects to make the positioning efficiently and effectively, e.g., the available auxiliary information, sensing devices, equipment deployment and the environment. Then, these practical concerns turn out to be the technical problems, e.g., the sequential position state propagation, the target-anchor geometry effect, the Non-line-of-sight (NLOS) identification and the related prior information. It is necessary to construct an efficient framework that can exploit multiple available information and guide the system design. In this paper, we propose a scalable method to analyze system performance based on the Cramér–Rao lower bound (CRLB), which can fuse all of the information adaptively. Firstly, we use an abstract function to represent all of the wireless localization system model. Then, the unknown vector of the CRLB consists of two parts: the first part is the estimated vector, and the second part is the auxiliary vector, which helps improve the estimation accuracy. Accordingly, the Fisher information matrix is divided into two parts: the state matrix and the auxiliary matrix. Unlike the theoretical analysis, our CRLB can be a practical fundamental limit to denote the system that fuses multiple information in the complicated environment, e.g., recursive Bayesian estimation based on the hidden Markov model, the map matching method and the NLOS identification and mitigation methods. Thus, the theoretical results are approaching the real case more. In addition, our method is more adaptable than other CRLBs when considering more unknown important factors. We use the proposed method to analyze the wireless sensor network-based indoor localization system. The influence of the hybrid LOS/NLOS channels, the building layout information and the relative height differences between the target and anchors are analyzed. It is demonstrated that our method exploits all of the available information for

  4. Fading and Shadowing in Wireless Systems

    CERN Document Server

    Shankar, P Mohana

    2012-01-01

    In recent decades, growth in the field of wireless communications has led to an exponential rise in the number of journals catering to the research community. Still unmet, however, is the need to fully and comprehensively understand the effects of channel degradation brought on by the statistical fluctuations in the channel. These fluctuations mainly manifest as variations in signal power observed in the channel generally modeled using a variety of probability distributions, both in straight forms as well as in compound forms. While the former might explain some of the effects, it is the latter, namely, the compound models, which incorporate both short term and long term power fluctuations in the channel, explain the much more complex nature of the signals in these channels. Fading and Shadowing in Wireless Systems offers a pedagogical approach to the topic, with insight into the modeling and analysis of fading and shadowing. Beginning with statistical background and digital communications, the book is formul...

  5. Towards Mobile Information Systems for Indoor Space

    Directory of Open Access Journals (Sweden)

    Xiaoxiang Zhang

    2016-01-01

    Full Text Available With the rapid development of Internet of things (IOT and indoor positioning technologies such as Wi-Fi and RFID, indoor mobile information systems have become a new research hotspot. Based on the unique features of indoor space and urgent needs on indoor mobile applications, in this paper we analyze some key issues in indoor mobile information systems, including positioning technologies in indoor environments, representation models for indoor spaces, query processing techniques for indoor moving objects, and index structures for indoor mobile applications. Then, we present an indoor mobile information management system named IndoorDB. Finally, we give some future research topics about indoor mobile information systems.

  6. Indoor environmental health

    CSIR Research Space (South Africa)

    Parsons, SA

    2010-04-01

    Full Text Available Indoor Environmental Health (IEH) is a comprehensive term that includes the effects of quantity of air, light and noise in a space and the physical, physiological and psychological aspects from colours, aesthetics, services, outdoor climate...

  7. Indoor climate seminar. Sisaeilmastoseminaari

    Energy Technology Data Exchange (ETDEWEB)

    Seppaenen, O. (ed.) (Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Heating, Ventilation and Air Conditioning)

    1990-01-01

    The national energy research programme LVIS-2000: Future Building Services is concerned with the control of energy use and indoor climate in buildings of the future. The projects were presented at a one day seminar arranged by the Laboratory of Heating and Ventilation of the Technical Research Centre in Finland which is coordinating the programme. The topics presented at the seminar were: The effect of indoor air on health in office buildings, The effect of air temperature on performance of office work, Emissions from building and interior materials, Experiences of odour panels in indoor climate research, Mould spores and bacteries in the indoor air of rural houses, Ventilation systems in future buildings, Demonstration project of ventilation systems in a block of flats.

  8. Indoor climate seminar; Sisaeilmastoseminaari

    Energy Technology Data Exchange (ETDEWEB)

    Seppaenen, O. [ed.] [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Heating, Ventilation and Air Conditioning

    1990-12-31

    The national energy research programme LVIS-2000: Future Building Services is concerned with the control of energy use and indoor climate in buildings of the future. The projects were presented at a one day seminar arranged by the Laboratory of Heating and Ventilation of the Technical Research Centre in Finland which is coordinating the programme. The topics presented at the seminar were: The effect of indoor air on health in office buildings, The effect of air temperature on performance of office work, Emissions from building and interior materials, Experiences of odour panels in indoor climate research, Mould spores and bacteries in the indoor air of rural houses, Ventilation systems in future buildings, Demonstration project of ventilation systems in a block of flats.

  9. Indoor environmental health

    CSIR Research Space (South Africa)

    Parsons, S

    2010-01-01

    Full Text Available Indoor Environmental Health (IEH) is a comprehensive term that includes the effects of quantity of air, light and noise in a space and the physical, physiological and psychological aspects from colours, aesthetics, services, outdoor climate...

  10. Great Indoors Awards 2007

    Index Scriptorium Estoniae

    2007-01-01

    Hollandis Maastrichtis jagati 17. XI esimest korda rahvusvahelist auhinda The Great Indoors Award. Aasta sisekujundusfirmaks valiti Masamichi Katayama asutatud Wonderwall. Auhinna said veel Zaha Hadid, Heatherwick Studio, Ryui Nakamura Architects ja Item Idem

  11. Indoor Air Pollution

    Science.gov (United States)

    We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include Mold and pollen Tobacco smoke Household products ...

  12. Image Based Indoor Navigation

    OpenAIRE

    Noreikis, Marius

    2014-01-01

    Over the last years researchers proposed numerous indoor localisation and navigation systems. However, solutions that use WiFi or Radio Frequency Identification require infrastructure to be deployed in the navigation area and infrastructureless techniques, e.g. the ones based on mobile cell ID or dead reckoning suffer from large accuracy errors. In this Thesis, we present a novel approach of infrastructure-less indoor navigation system based on computer vision Structure from Motion techniques...

  13. 47 CFR 74.870 - Wireless video assist devices.

    Science.gov (United States)

    2010-10-01

    ... non-interference basis on VHF and UHF television channels to assist with production activities. (a... electronic news gathering purposes. (c) Wireless video assist devices may operate with a bandwidth not to exceed 6 MHz on frequencies in the bands 180-210 MHz (TV channels 8-12) and 470-698 MHz (TV channels...

  14. Performance analysis of 802.11 DCF broadcast channel access in wireless multi-hop networks%无线多跳网络中802.11 DCF广播信道接入性能分析

    Institute of Scientific and Technical Information of China (English)

    张三峰; 刘铮; 吉逸

    2014-01-01

    分析了采用网络编码和机会路由方法的无线多跳网络中存在的信道接入问题,建模描述了802.11 DCF广播信道接入过程,并对影响无线多跳网络的吞吐率、延迟、信道资源分配等性能指标的因素进行了定量分析.利用M/M/1/K队列和离散时间的二维Markov链,建模描述具有相异报文到达速率的多个节点竞争信道时各个节点上的报文到达、排队、信道接入和发送过程.通过求解该模型,得到各节点的实际发送速率、报文平均服务时间和系统总吞吐率等指标的计算公式.将模型计算结果和基于NS-2网络模拟平台得到的实验结果进行对比.结果表明,该模型能够有效地预测各种传输负载组合情况下的报文平均服务时间和信道资源分配的公平性等网络性能指标.%Channel access problems in wireless multi-hop networks adopting network coding and op-portunistic forwarding technologies are analyzed.A model for an 802.1 1 distributed coordination function (DCF)broadcast channel access process is built to quantitatively analyze the factors that af-fect the performance including the throughput,delay and fairness in wireless multi-hop networks. Behaviors of nodes such as packet arriving,queuing,channel access and sending are modeled based on an M/M/1/K queue and a two-dimensional discrete-time Markov chain when these nodes have different packet arriving rates.By solving the model,equations are obtained to calculate several per-formance indices such as the actual transmission rate and packet service time on each node and the total throughput of the system.Results generated by the model are compared with experimental re-sults from a simulation based on the NS-2 platform.It is shown that the model can effectively predict transmission performance indices including average packet service time and fairness of channel re-source allocation under various traffic load combinations.

  15. Capacity Bounds for the Gaussian IM-DD Optical Multiple-Access Channel

    KAUST Repository

    Chaaban, Anas

    2017-03-18

    Optical wireless communications (OWC) is a promising technology for closing the mismatch between the growing number of connected devices and the limited wireless network capabilities. Similar to downlink, uplink can also benefit from OWC for establishing connectivity between such devices and an optical access point. In this context, the incoherent intensitymodulation and direct-detection (IM-DD) scheme is desirable in practice. Hence, it is important to understand the fundamental limits of communication rates over an OWC uplink employing IM-DD, i.e., the channel capacity. This uplink, modeled as a Gaussian multiple-access channel (MAC) for indoors OWC, is studied in this paper, under the IM-DD constraints which form the main difference with the standard Gaussian MAC commonly studied in the radio-frequency context. Capacity region outer and inner bounds for this channel are derived. The bounds are fairly close at high signal-to-noise ratio (SNR), where a truncated- Gaussian input distribution achieves the capacity region within a constant gap. Furthermore, the bounds coincide at low SNR showing the optimality of on-off keying combined with successive cancellation decoding in this regime. At moderate SNR, an optimized uniformly-spaced discrete input distribution achieves fairly good performance.

  16. Joint routing, scheduling, and power control for multichannel wireless sensor networks with physical interference

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Reliability and real-time requirements bring new challenges to the energy-constrained wireless sensor networks, especially to the industrial wireless sensor networks. Meanwhile, the capacity of wireless sensor networks can be substantially increased by operating on multiple nonoverlapping channels. In this context, new routing, scheduling, and power control algorithms are required to achieve reliable and real-time communications and to fully utilize the increased bandwidth in multichannel wireless sensor ne...

  17. Turning the Tables: Using Wireless Communication Against an Attacker

    Science.gov (United States)

    Martinovic, Ivan; Schmitt, Jens B.

    In this paper, we propose a system leveraging the peculiarities of the wireless medium, such as the broadcast nature of wireless communication and the unpredictability of indoor signal propagation to achieve effective protection against attacks based on the injection of fake data in wireless sensor networks (WSNs). Using a real-world WSN deployment and a realistic implementation of an attacker, we analyze this protection scheme and demonstrate that neither position change, transmission power manipulation, nor complete knowledge of wireless parameters can help an attacker to successfully attack the network. As a result, this work demonstrates how the chaotic nature of radio communication, which is often considered a disadvantage in regard to security objectives, can be exploited to enhance protection and support implementation of lightweight security mechanisms.

  18. Towards Ultrahigh Speed Impulse Radio THz Wireless Communications

    DEFF Research Database (Denmark)

    Yu, Xianbin; Galili, Michael; Morioka, Toshio

    2015-01-01

    THz impulse radio technologies promise a new paradigm of fast wireless access with simplified wireless reception. However, huge loss of propagating broad bandwidth THz impulse radio signals limits THz wireless transmission distance and reduces the achievable link data rates. In this paper, we...... evaluate the realistic throughput and accessible wireless range of a THz impulse radio communication link based on a uni-travelling photodiode (UTC-PD) as THz emitter and a photoconductive antenna (PCA) as THz receiver. The impact of highly frequency-selective THz channel and the noise in the system...

  19. Channel allo cation game algorithm based on lifetime mo del in wireless sensor network%基于生命期模型的无线传感器网络信道分配博弈算法∗

    Institute of Scientific and Technical Information of China (English)

    郝晓辰; 姚宁; 汝小月; 刘伟静; 辛敏洁

    2015-01-01

    针对无线传感器网络中节点因干扰过大导致重传能耗增加,进而节点过早失效、网络生命期缩短的问题,根据网络拓扑信息和路由信息设计节点的负载模型,从而构建了节点的生命期模型。然后利用博弈论将路径增益、交叉干扰和节点生命期等性能参数融入到效益函数中,构建信道分配博弈模型。理论分析证明该博弈模型存在纳什均衡。进而运用最佳回应策略,在所构建的信道分配博弈模型的基础上,设计了一种优化网络生命期的抗干扰信道分配算法。该算法使节点在选择信道时避免与网络中交叉干扰较大的节点和生命期较小的节点使用相同信道,实现干扰小、能耗低且均衡的信道选择。理论分析与仿真结果证明该算法最终能够快速地收敛到纳什均衡,且具有较小的信息复杂度,从而减小算法本身的通信能耗。同时,该算法具有良好的抗干扰性和信道均衡性,能够有效地延长网络生命期。%In wireless sensor network, the lager interference makes the data transmission failed, thus leading to data retrans-mission of nodes. This situation exacerbates the energy consumption of retransmission. As a result, some nodes will prematurely fail to work, thus reducing the network lifetime. In order to deal with the above issue, this paper takes full advantage of the topology and route information to design a novel load model of nodes. Then, a lifetime model of each node is constructed based on the load model. Subsequently, the path gain, intersecting interference and node lifetime are integrated into a utility function to construct a channel allocation game model called channel allocation based-game (CABG) by taking advantage of the game theory. The theoretical analysis proves the existence of the Nash Equilibrium of CABG. And then, using the best response dynamics, a channel allocation game algorithm for anti

  20. Experimental Demonstration of 5-Gb/s Polarization-Multiplexed Fiber-Wireless MIMO Systems

    DEFF Research Database (Denmark)

    Zhao, Ying; Pang, Xiaodan; Deng, Lei;

    2011-01-01

    We experimentally demonstrate a 5-Gb/s fiber-wireless transmission system combining optical polarization-division-multiplexing (PDM) and wireless multiple-input, multiple-output (MIMO) spatial multiplexing technologies. The optical-wireless channel throughput is enhanced by achieving a 4b...... advantageous to the MIMO wireless system due to the inter-channel delay insensitivity. The hybrid transmission performance of 26km fiber and up to 2m wireless MIMO is investigated......./s/Hz spectral efficiency. Based on the implementation of constant modulus algorithm (CMA), the 2×2 MIMO wireless channel is characterized and adaptively equalized for signal demodulation. The performance of the CMA-based channel adaptation is studied and it is revealed that the algorithm is particularly...