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LP decoding for joint source-channel codes and for the non-ergodic Polya channel

IEEE COMMUNICATIONS LETTERS 2008年第9期12卷 678-680页

作者： Cohen, Adam Alajaji, Fady Kashyap, Navin Takahara, Glen Queens Univ Dept Math & Stat Kingston ON K7L 3N6 Canada

Linear programming (LP) decoding of low-density parity-check codes over discrete memoryless symmetric channels was introduced by Feldman et al in [1]. Here, we extend the LP decoding paradigm by applying it to two additional scenarios: joint source-channel (JSC) coding and decoding over the infinite-memory non-ergodic binary Polya-contagion channel. Simulation results indicate that the JSC LP decoder yields significant gains over the standard LP decoder for non-uniform sources. Simulations also show that the LP decoder for the Polya channel performs moderately well in relation to the epsilon-capacity limit.

关键词： LP decoding joint source-channel coding non-ergodic Polya channel systematic and non-systematic codes

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On the distortion SNR exponent of some layered transmission schemes

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第7期54卷 2943-2958页

作者： Bhattad, Kapil Narayanan, Krishna R. Caire, Giuseppe Qualcomm Inc San Diego CA 92121 USA Texas A&M Univ Dept Elect & Comp Engn College Stn TX 77843 USA Univ So Calif Dept Elect Engn Viterbi Sch Engn Los Angeles CA 90089 USA

We consider the problem of joint source-channel coding for transmitting K samples of a complex Gaussian source over T = bK uses of a block-fading multiple-input multiple-output (MIMO) channel with M transmit and N receive antennas. We consider the case when we are allowed to code over L blocks. The channel gain is assumed to be constant over a block and channel gains for different blocks are assumed to be independent. The performance measure of interest is the rate of decay of the expected mean-squared error with the signal-to-noise ratio (SNR), called the distortion SNR exponent. We first show that using a broadcast strategy similar to that of Gunduz and Erkip, but with a different power and rate allocation policy, the optimal distortion SNR exponent can be achieved for 0 <= b < (vertical bar N - M vertical bar + 1) / min (M, N) and for b > MNL2. This is the first time the optimal exponent is characterized for 1/ min(M, N) < b < (vertical bar N - M vertical bar + 1)/ min(M, N). Then, we propose a digital layered transmission scheme that uses both time layering and superposition. The new scheme is at least as good as currently known schemes for the entire range of bandwidth expansion factors b, whereas at least for some M, N, and b, it is strictly better than the currently known schemes.

关键词： broadcast distortion signal-to-noise ratio (SNR) exponent diversity-multiplexing tradeoff joint source-channel coding layered source-channel coding multiple-input multiple-output (MIMO) successive refinement superposition

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A COVQ-Based image coder for channels with bit errors and erasures

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IEEE TRANSACTIONS ON COMMUNICATIONS 2008年第2期56卷 161-165页

作者： Andersson, Tomas Skoglund, Mikael Royal Inst Technol Sch Elect Engn SE-10044 Stockholm Sweden

We illustrate how channel optimized vector quantization (COVQ) can be used for channels with both bit-errors and bit-erasures. First, a memoryless channel model is presented, and the performance of COVQ's trained for this channel is evaluated for an i.i.d. Gaussian source. Then, the new method is applied in implementing an error-robust sub-band image coder, and we present image results that illustrate the resulting performance. Our experiments show that the new approach is able to outperform a traditional scheme based on separate source and channel coding.

关键词： binary erasure channels binary symmetric channels channel-optimized quantization image coding joint source-channel coding

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Robust and extreme unequal error protection scheme for the transmission of scalable data over OFDM systems

Robust and extreme unequal error protection scheme for the t...

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33rd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Houas, Heykel Fijalkow, Inbar Baras, Cleo Univ Cergy Pontoise ENSEA CNRS ETIS UMR 8051 6 Ave Ponceau F-95014 Cergy Pontoise France Domaine Univ CNRS UMR 5216 GIPSA Lab F-38042 Grenoble France

ISBN: (纸本)9781424414833

Wireless applications are subject to the end-to-end Quality of Service (QoS) requirements. This paper presents a new resources allocation algorithm that allows to transmit scalable multimedia data over a frequency selective channel with partial channel knowledge. The available resources are subject to payload and QoS constraints and the algorithm aims at maximizing the transmission robustness to channel estimation errors. The impact of this technique is evaluated for a MPEG-4 audio application.

关键词： unequal error protection resources allocation OFDM scalable data joint source-channel coding

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joint source-channel mappings for the relay channel

Joint source-channel mappings for the relay channel

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33rd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Karlsson, Johannes Skoglund, Mikael Royal Inst Technol KTH Sch Elect Engn SE-10044 Stockholm Sweden

ISBN: (纸本)9781424414833

The three-node relay channel with a Gaussian source is studied for transmission subject to a low-delay constraint. A joint source-channel coding design algorithm is proposed and numerically evaluated. The designed system is compared to a reference system, based on modular source and channel coding, and the distortion-rate function for the Gaussian source, using known achievable rates on the relay channel. The structure of the source encoder and the relay mapping is visualized and discussed in order to gain understanding of how the system works. The relay mapping gets a structure that resembles a Wyner-Ziv code.

关键词： estimation joint source-channel coding relay channel quantization sensor networks

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A cheap relaying protocol for orthogonal relay channels

A cheap relaying protocol for orthogonal relay channels

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33rd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Djeumou, Brice Lasaulce, Samson Klein, Andrew G. SUPELEC LSS CNRS F-91190 Gif Sur Yvette France

ISBN: (纸本)9781424414833

The proposed relaying scheme, which is an optimized scalar quantize-and-forward (QF) protocol, has at least three attractive features: 1. it is simple;2. it exploits the signal-to-noise ratios (SNR) of the source-relay and relay-destination channels;3. it can be seen as a digital alternative of the conventional (analog) amplify-and-forward (AF) in a digital relay transceiver. The presented QF protocol is optimized in terms of end-to-end distortion, extending the idea of joint source-channel coding. Using this cooperation protocol over orthogonal relay channels, it is shown that the quantization noise introduced by the relay can significantly degrade the receiver performance if the latter uses a maximum ratio combiner (MRC) to combine the two signals from the source and relay. In order for the receiver to compensate for this effect, we propose a maximum likelihood detector (MLD), which is optimum for the QF protocol.

关键词： relay channel quantize-and-forward joint source-channel coding ML detector amplify-and-forward

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Robust image transmission strategies for fading channels

Robust image transmission strategies for fading channels

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3rd International Conference on Information and Communication Technologies

作者： Boeglen, Herve Haeberle, Olivier Chatellier, Christian Olivier, Christian IUT Mulhouse Lab MIPS LABEL 61 Rue Albert Camus F-68093 Mulhouse France UMR CNRS 6172 Lab SIC XLIM F-86962 Futuroscope France

ISBN: (纸本)9781424417513

The aim of this paper is to present a robust still-image transmission scheme and show its performance when used on a frequency flat fading channel. By following a joint source-channel coding approach, it is shown that image transmission with good visual quality is possible even with BER as high as 4%. Furthermore, this scheme only requires 26% redundancy for Error Control coding (ECC). The ECC part can be completed by an original PDE-based restoration algorithm to further improve the visual quality of the image.

关键词： joint source-channel coding image transmission image compression fading channels

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Lattice-Based Precoding And Decoding in MIMO Fading Systems

Lattice-Based Precoding And Decoding in MIMO Fading Systems

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作者： Taherzadeh, Mahmoud University of Waterloo

学位级别：master

In this thesis, different aspects of lattice-based precoding and decoding for the transmission of digital and analog data over MIMO fading channels are investigated:1) Lattice-based precoding in MIMO broadcast systems:A new viewpoint for adopting the lattice reduction in communication over MIMO broadcast channels is introduced. Lattice basis reduction helps us to reduce the average transmitted energy by modifying the region which includes the constellation points. The new viewpoint helps us to generalize the idea of lattice-reduction-aided precoding for the case of unequal-rate transmission, and obtain analytic results for the asymptotic behavior of the symbol-error-rate for the lattice-reduction-aided precoding and the perturbation technique. Also, the outage probability for both cases of fixed-rate users and fixed sum-rate is analyzed. It is shown that the lattice-reduction-aided method, using LLL algorithm, achieves the optimum asymptotic slope of symbol-error-rate (called the precoding diversity).2) Lattice-based decoding in MIMO multiaccess systems and MIMO point-to-point systems:Diversity order and diversity-multiplexing tradeoff are two important measures for the performance of communication systems over MIMO fading channels. For the case of MIMO multiaccess systems (with single-antenna transmitters) or MIMO point-to-point systems with V-BLAST transmission scheme, it is proved that lattice-reduction-aided decoding achieves the maximum receive diversity (which is equal to the number of receive antennas). Also, it is proved that the naive lattice decoding (which discards the out-of-region decoded points) achieves the maximum diversity in V-BLAST systems. On the other hand, the inherent drawbacks of the naive lattice decoding for general MIMO fading systems is investigated. It is shown that using the naive lattice decoding for MIMO systems has considerable deficiencies in terms of the diversity-multiplexing tradeoff. Unlike the case of maximum-likelihood decod

关键词： Lattice decoding Precoding MIMO communications Fading channels joint source-channel coding Lattice-basis reduction LLL algorithm Diversity-multiplexing trade-off Diversity-fidelity trade-off

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Dynamic Rate Allocation with Variable Quantization in Multi-Sensor Wyner-Ziv Video coding Systems

Dynamic Rate Allocation with Variable Quantization in Multi-...

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3rd International Symposium on Communications, Control, and Signal Processing (ISCCSP 2008), vol.1

作者： C. Yaacoub J. Farah B. Pesquet-Popescu Faculty of Sciences and Computer Engineering Holy Spirit University of Kaslik Jounieh Lebanon Department of Signal and Image Processing Ecole Nationale Supérieure des TéIécommunications Paris France

In this paper, we present a novel algorithm for dynamic quantization in distributed Wyner-Ziv video coding. In contrast with previous work where the quantization parameter is fixed and a feedback channel is used, our proposed technique relies on theoretical calculations to jointly determine the number of quantization levels along with a suitable compression rate for each video frame. It employs a cross-layer approach that dynamically allocates unequal transmission rates for different users by taking into account the amount of motion in the captured video scenes on one hand and the transmission conditions for each sensor on the other. The application of this algorithm in a wireless video sensor network shows a significant improvement in the system performance when compared to a traditional system that allocates equal channel resources with a fixed quantization parameter.

关键词： Dynamic quantization joint source-channel coding Rate allocation Wireless video sensor network Wyner-Ziv coding

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Determination of optimal distortion-based protection in progressive image transmission: A heuristic approach

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2008年第9期17卷 1654-1662页

作者： Fresia, Maria Lavagetto, Fabio Princeton Univ Dept Elect Engn Princeton NJ 08544 USA Univ Genoa Dept Commun Comp & Syst Sci I-16100 Genoa Italy

In this paper, we describe a method for fast determination of distortion-based optimal unequal error protection (UEP) of bitstreams generated by embedded image coders and transmitted over memoryless noisy channels. The UEP problem is reduced to the more general problem of finding a path in a graph, where each path of the graph represents a possible protection policy, with the objective of selecting the best path being that one inducing minimal distortion. The problem is combinatorially complex and excludes a brute force approach. The solution is provided by, applying heuristic information from the problem domain to reduce search complexity. In particular, we use graph search procedure A suggested by Hart et al., well known in the field of artificial intelligence, to avoid exhaustive search. Numerical results show that this technique outperforms the method presented by Hamzaoui et al., in terms of Mean Square Error (MSE) distortion and computational complexity. After testing our solution using analytical models of the operational distortion curves proposed by Charfi et al., we implement a transmission architecture that, using the actual distortion values generated by a real embedded coder, computes the optimal protection policy for the considered image, protects the packets, and transmits them over a channel.

关键词： joint source-channel coding progressive transmission unequal error protection (UEP)

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