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Power Optimized DSTBC Assisted DMF Relaying in Wireless Sensor Networks with Redundant Super Nodes

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2013年第2期12卷 636-645页

作者： Razi, Abolfazl Afghah, Fatemeh Abedi, Ali Univ Maine Dept Elect & Comp Engn Wireless Sensor Networks Lab WiSe Net Orono ME 04469 USA

In conventional two-tiered Wireless Sensor Networks (WSN), sensors in each cluster transmit observed data to a fusion center via an intermediate supernode. This structure is vulnerable to supernode failure. A double supernode system model with a new coding scheme is proposed to monitor a binary data source. A distributed Joint Source Channel Code (D-JSCC) is proposed for sensors inside a cluster that provides two advantages of low complexity transmitters and scalability to a large number of sensors. In order to setup a robust communication channel from sensors to the data fusion center, distributed Space-Time Block coding (D-STBC) is employed at two supernodes prior to relaying that results in additional diversity gain. DeModulate and Forward (DMF) relaying mode is chosen to enable packet reformatting at the supernodes, which is not possible in widely used Amplify and Forward (AF) mode. The optimum power allocation for the two-hop multiple DMF relaying is calculated to minimize the system Bit Error Rate (BER). An upper bound is derived for the system end-to-end BER by analyzing a basic decoder operation over the system model. The simulation results validate this upper bound and also demonstrate considerable improvement in the system BER for the proposed coding scheme.

关键词： distributed coding demodulate and forward relaying distributed space-time block codes power optimization

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distributed Serially Concatenated Codes for Multi-Source Cooperative Relay Networks

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2011年第1期10卷 253-263页

作者： Youssef, Roua Graell i Amat, Alexandre Inst TELECOM TELECOM Bretagne Dept Elect F-29238 Brest 3 France

In this paper, we propose a distributed turbo-like coding scheme for a multi-source relay scenario where multiple sources communicate with a destination with the help of a common relay, which uses the decode-and-forward strategy and operates in half-duplex mode. The proposed distributed code can be viewed as a serially concatenated code (SCC). Thus, at the destination decoding is performed in an iterative fashion which resembles the decoding of a classic SCC. We consider the two scenarios where the sources transmit over orthogonal channels and where they do not. For the latter, interleave-division multiple-access is used for multiuser detection. For both scenarios we optimize the transmission time allocated to the sources and to the relay and compute the achievable rates. The proposed scheme achieves very low error rates and offers significant performance gains with respect to non-cooperation, even for a very large number of sources. Furthermore, it provides a high flexibility in terms of code rate, number of sources, overall system rate and error protection.

关键词： Achievable rates cooperative communications distributed coding relay channel serially concatenated codes turbo codes

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Feedback-based adaptive network coded cooperation for wireless networks

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2011年第1期2011卷 1页

作者： Zhang, Kaibin Yin, Liuguo Lu, Jianhua Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China Tsinghua Univ Sch Aerosp Beijing 100084 Peoples R China

A novel feedback-based adaptive network coded cooperation (FANCC) scheme is proposed for wireless networks that comprise a number of terminals transmitting data to a common destination. The proposed FANCC exploits network coding and matches code-on-graph with network-on-graph, which is a substantial extension of adaptive network coded cooperation (ANCC). In the relay phase of FANCC, the terminal will be active when its channel fading coefficient magnitude vertical bar h vertical bar is larger than the threshold T-th and the broadcast-packet of one terminal will be possibly selected for check-sum when vertical bar h vertical bar is less than the threshold R-th. In the indication phase, the destination broadcasts above message at cost of 2 bits per terminal. Therefore, distributed fountain codes are generated at the destination. Both achievable rates and outage probabilities are evaluated for FANCC and closed-form expressions are derived when the network size approaches infinity. Moreover, compared with ANCC, analysis results demonstrate that FANCC achieves 1-2 dB performance improvement at the outage probability of 10(-6) and 1-2 dB gain at the same achievable rate and the simulation results shows that FANCC has better Frame error ratio (FER) performance.

关键词： cooperative wireless network network coding fountain codes distributed coding

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On Zero-Delay Source-Channel coding

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IEEE TRANSACTIONS ON INFORMATION THEORY 2014年第12期60卷 7473-7489页

作者： Akyol, Emrah Viswanatha, Kumar B. Rose, Kenneth Ramstad, Tor A. Univ Calif Santa Barbara Dept Elect & Comp Engn Santa Barbara CA 93106 USA Norwegian Univ Sci & Technol Dept Elect & Telecommun N-7491 Trondheim Norway

This paper studies the zero-delay source-channel coding problem, and specifically the problem of obtaining the vector transformations that optimally map between the m-dimensional source space and k-dimensional channel space, under a given transmission power constraint and for the mean square error distortion. The functional properties of the cost are studied and the necessary conditions for the optimality of the encoder and decoder mappings are derived. An optimization algorithm that imposes these conditions iteratively, in conjunction with the noisy channel relaxation method to mitigate poor local minima, is proposed. The numerical results show strict improvement over prior methods. The numerical approach is extended to the scenario of source-channel coding with decoder side information. The resulting encoding mappings are shown to be continuous relatives of, and in fact subsume as special case, the Wyner-Ziv mappings encountered in digital distributed source coding systems. A well-known result in information theory pertains to the linearity of optimal encoding and decoding mappings in the scalar Gaussian source and channel setting, at all channel signal-to-noise ratios (CSNRs). In this paper, the linearity of optimal coding, beyond the Gaussian source and channel, is considered and the necessary and sufficient condition for linearity of optimal mappings, given a noise (or source) distribution, and a specified a total power constraint are derived. It is shown that the Gaussian source-channel pair is unique in the sense that it is the only source-channel pair for which the optimal mappings are linear at more than one CSNR values. Moreover, the asymptotic linearity of optimal mappings is shown for low CSNR if the channel is Gaussian regardless of the source and, at the other extreme, for high CSNR if the source is Gaussian, regardless of the channel. The extension to the vector settings is also considered where besides the conditions inherited from the scalar case, a

关键词： Joint source channel coding analog communications estimation distributed coding

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distributed Orthogonal and Quasi-Orthogonal Space-Time Block Code with Embedded AAF/DAF Matrix Elements in Wireless Relay Networks with Four Relays

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WIRELESS PERSONAL COMMUNICATIONS 2014年第2期75卷 1187-1198页

作者： Tseng, Shu-Ming Liao, Che-Ying Natl Taipei Univ Technol Dept Elect Engn Taipei 106 Taiwan

We consider cooperative networks of one source, four relays, and one destination. Each of them has a single antenna. The four relays use a proposed full rate distributed quasi orthogonal space time block code (DQOSTBC) scheme. If the channel state between the source and a relay is above a threshold, we select the elements of the DQOSTBC matrix to be the decode-and-forward (DAF) type;if it is below the threshold, the corresponding elements are the amplify-and-forward (AAF) type. Thus the proposed scheme is a DQOSTBC matrix with embedded adaptive DAF/AAF elements. The bit error rate (BER) simulation results show that the proposed DQOSTBC is approximately 7 dB better than the traditional DQOSTBC (all matrix elements are fixed as DAF type) at a BER of because traditional DQOSTBC loses full diversity due to errors in the information received. The proposed DQOSTBC is about 3 dB better than the rate 1/2 DOSTBC also proposed with adaptive DAF/AAF matrix elements at a BER of at the same spectral efficiency of 2 bits/s/Hz.

关键词： Cooperative networks distributed coding Information receiving error

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Spatially-Coupled LDPC Codes for Decode-and-Forward Relaying of Two Correlated Sources over the BEC

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IEEE TRANSACTIONS ON COMMUNICATIONS 2014年第4期62卷 1324-1337页

作者： Schwandter, Stefan Graell i Amat, Alexandre Matz, Gerald Ametek Inc Grabner Instruments A-1220 Vienna Austria Chalmers Univ Technol Dept Signals & Syst SE-41296 Gothenburg Sweden Vienna Univ Technol Inst Telecommun A-1040 Vienna Austria

We present a decode-and-forward transmission scheme based on spatially-coupled low-density parity-check (SC-LDPC) codes for a network consisting of two (possibly correlated) sources, one relay, and one destination. The links between the nodes are modeled as binary erasure channels. Joint source-channel coding with joint channel decoding is used to exploit the correlation. The relay performs network coding. We derive analytical bounds on the achievable rates for the binary erasure time-division multiple-access relay channel with correlated sources. We then design bilayer SC-LDPC codes and analyze their asymptotic performance for this scenario. We prove analytically that the proposed coding scheme achieves the theoretical limit for symmetric channel conditions and uncorrelated sources. Using density evolution, we furthermore demonstrate that our scheme approaches the theoretical limit also for non-symmetric channel conditions and when the sources are correlated, and we observe the threshold saturation effect that is typical for spatially-coupled systems. Finally, we give simulation results for large block lengths, which validate the DE analysis.

关键词： Binary erasure channel cooperative communications correlated sources decode-and-forward distributed coding relay channel spatially-coupled low-density parity-check codes threshold saturation

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Design of optimized distributed Goppa codes and joint decoding at the destination

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TELECOMMUNICATION SYSTEMS 2022年第3期81卷 341-355页

作者： Waweru, Daniel Kariuki Yang, Fengfan Zhao, Chunli Paul, Lawrence Muthama Xu, Hongjun Nanjing Univ Aeronaut & Astronaut Coll Elect & Informat Engn Nanjing 210016 Jiangsu Peoples R China Univ KwaZulu Natal Sch Engn George V Ave ZA-4041 Durban South Africa

In this paper, we propose a Goppa coded-cooperative (GCC) diversity scheme for a single-relay setting where a source communicates with a destination with the help of a relay in a two-time-slot transmission. Two Goppa codes are distributed over the source and the relay terminals in order to construct a jointly designed channel code at the destination. In the multiple access phase, we consider an optimization design criterion at the relay, which is shown to greatly enhance the Bit Error Rate (BER) performance of the cooperative system. In this way, the source and the relay codes jointly contribute to building the best possible optimized code at the destination. To get the maximum coding gains from this joint construction, a joint decoding scheme is employed at the destination. We investigate the BER performance of the GCC diversity scheme for both the cooperative and non-cooperative schemes over the Rayleigh fading channel. Monte-Carlo simulations show that the proposed GCC scheme significantly outperforms the non-cooperation scheme.

关键词： Goppa codes distributed coding Optimized relay channel Joint decoding

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distributed Irregular Codes Relying on Decode-and-Forward Relays as Code Components

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2015年第10期64卷 4579-4588页

作者： Ng, Soon Xin Li, Yonghui Vucetic, Branka Hanzo, Lajos Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England Univ Sydney Sch Elect & Informat Engn Sydney NSW 2006 Australia

A near-capacity distributed coding scheme is conceived by incorporating multiple relay nodes (RNs) for constructing a virtual irregular convolutional code (IRCC). We first compute the relay channel's capacity and then design IRCCs for the source and relay nodes. Extrinsic information transfer (EXIT) charts are utilized to design the codes for approaching the achievable capacity of the relay channels. Additionally, we improve the transmit power efficiency of the overall system by invoking both power allocation and relay selection. We found that even a low-complexity repetition code or a unit-memory convolutional code is capable of forming a near-capacity virtual IRCC. The performance of the proposed distributed IRCC (DIRCC) scheme is shown to be perfectly consistent with that predicted from the EXIT chart. More specifically, the DIRCC scheme is capable of operating within 0.68 dB from the corresponding lower bound of the relay channel capacity, despite the fact that each RN is exposed to realistic decoding errors due to communicating over imperfect source-relay channels.

关键词： Cooperative communications cooperative diversity distributed coding irregular convolutional codes (IRCCs) relay selection

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Communication constraints for decentralized stabilizability with time-invariant policies

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 2007年第6期52卷 1060-1066页

作者： Yuksel, Serdar Basar, Tamer Univ Illinois Coordinated Sci Lab Urbana IL 61801 USA

In this note, we study communication requirements for decentralized control schemes when sensors and controllers are connected via noiseless digital channels and system noises are bounded. Under various information structures, and within the class of time-invariant encoding and control policies, we quantify achievable rates, and obtain fixed-rate and delayless encoders and decoders that achieve boundedness in the state estimation errors at the controllers. We use distributed coding theoretic approaches to show that when the sensors do not collaborate, it is sufficient for the controllers to share information amongst themselves but not with the sensors. Sensor collaboration, however, leads to improvement in rate performance.

关键词： control under communication constraints decentralized control distributed coding multi-agent systems quantization

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The neural code of reward anticipation in human orbitofrontal cortex

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2010年第13期107卷 6010-6015页

作者： Kahnt, Thorsten Heinzle, Jakob Park, Soyoung Q. Haynes, John-Dylan Charite Univ Med Berlin Bernstein Ctr Computat Neurosci D-10115 Berlin Germany Max Planck Inst Human Cognit & Brain Sci D-04303 Leipzig Germany Humboldt Univ Berlin Sch Mind & Brain D-10099 Berlin Germany Free Univ Berlin D-14195 Berlin Germany Otto Von Guericke Univ Dept Neurol D-39120 Magdeburg Germany

An optimal choice among alternative behavioral options requires precise anticipatory representations of their possible outcomes. A fundamental question is how such anticipated outcomes are represented in the brain. Reward coding at the level of single cells in the orbitofrontal cortex (OFC) follows a more heterogeneous coding scheme than suggested by studies using functional MRI (fMRI) in humans. Using a combination of multivariate pattern classification and fMRI we show that the reward value of sensory cues can be decoded from distributed fMRI patterns in the OFC. This distributed representation is compatible with previous reports from animal electrophysiology that show that reward is encoded by different neural populations with opposing coding schemes. Importantly, the fMRI patterns representing specific values during anticipation are similar to those that emerge during the receipt of reward. Furthermore, we show that the degree of this coding similarity is related to subjects' ability to use value information to guide behavior. These findings narrow the gap between reward coding in humans and animals and corroborate the notion that value representations in OFC are independent of whether reward is anticipated or actually received.

关键词： expected reward value functional MRI multivariate decoding distributed coding decision making

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