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Soft decoding and synchronization of arithmetic codes: Application of image transmission over noisy channels

IEEE TRANSACTIONS ON IMAGE PROCESSING 2003年第12期12卷 1599-1609页

作者： Guionnet, T Guillemot, C INRIA IRISA F-35042 Rennes France

This paper addresses the issue of robust and joint source-channel decoding of arithmetic codes. We first analyze dependencies between the variables involved in arithmetic coding by means of the Bayesian formalism. This provides a suitable framework for designing a soft decoding algorithm that provides high error-resilience. It also provides a natural setting for "soft synchronization," i.e., to introduce anchors favoring the likelihood of "synchronized" paths. In order to maintain the complexity of the estimation within a realistic range, a simple, yet efficient, pruning method is described. The algorithm can be placed in an iterative source-channel decoding structure, in the spirit of serial turbo codes. Models and algorithms are then applied to context-based arithmetic coding widely used in practical systems (e.g., JPEG-2000). Experimentation results with both theoretical sources and with real images code with JPEG-2000 reveal very good error resilience performances.

关键词： arithmetic codes entropy codes error correction image coding joint source-channel coding maximum likelihood decoding sequential decoding soft synchronization

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Performance analysis and design criteria for finite-alphabet source-channel codes

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IEEE TRANSACTIONS ON COMMUNICATIONS 2004年第11期52卷 1872-1879页

作者： Hedayat, A Nosratinia, A Univ Texas Multimedia Commun Lab Richardson TX 75083 USA

Efficient compression of finite-alphabet sources requires variable-length codes. (VLCs). However, in the presence of noisy channels, error propagation in the decoding of VLCs severely degrades performance. To address this problem, redundant entropy codes and iterative source-channel decoding have been suggested, but to date, neither performance bounds nor design criteria for the composite system have been available. We calculate performance bounds for the source-channel system by generalizing techniques originally developed for serial concatenated convolutional codes. Using this analysis, we demonstrate the role of a recursive structure for the inner code and the distance properties of the outer code. We use density evolution to study the convergence of our decoders. Finally, we pose the question: Under a fixed rate and complexity constraint, when should we use source-channel decoding (as opposed to separable decoding)? We offer answers in several specific cases. For our analysis and design rules, we use union bounds that are technically valid only above the cutoff rate, but interestingly, the codes designed with union-bound criteria perform well even in low signal-to-noise ratio regions, as shown by our simulations as well as previous works on concatenated codes.

关键词： concatenated coding iterative decoding joint source-channel coding variable-length codes (VLCs)

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joint source-channel codes for MIMO block-fading channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第1期54卷 116-134页

作者： Gunduz, Deniz Erkip, Elza Polytech Univ Dept Elect & Comp Engn Brooklyn NY 11201 USA Stanford Univ Dept Elect Engn Stanford CA 94305 USA

We consider transmission of a continuous amplitude source over an L-block Rayleigh-fading M-t x M-r, multiple-input multiple-output (MIMO) channel when the channel state information is only available at the receiver. Since the channel is not ergodic, Shannon's source-channel separation theorem becomes obsolete and the optimal performance requires a joint source-channel approach. Our goal is to minimize the expected end-to-end distortion, particularly in the high signal-to-noise ratio (SNR) regime. The figure of merit is the distortion exponent, defined as the exponential decay rate of the expected distortion with increasing SNR. We provide an upper bound and lower bounds for the distortion exponent with respect to the bandwidth ratio among the channel and source bandwidths. For the lower bounds, we analyze three different strategies based on layered source coding concatenated with progressive superposition or hybrid digital/analog transmission. In each case, by adjusting the system parameters we optimize the distortion exponent as a function of the bandwidth ratio. We prove that the distortion exponent upper bound can be achieved when the channel has only one degree of freedom, that is L = 1, and min {M-t, M-r} = 1. When we have more degrees of freedom, our achievable distortion exponents meet the upper bound for only certain ranges of the bandwidth ratio. We demonstrate that our results, which were derived for a complex Gaussian source, can be extended to more general source distributions as well.

关键词： broadcast codes distortion exponent diversity-multiplexing gain tradeoff hybrid digital/analog coding joint source-channel coding multiple-input multiple-output (MIMO) successive refinement

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Reed-Solomon decoding algorithms for digital audio broadcasting in the AM band

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IEEE TRANSACTIONS ON BROADCASTING 2001年第2期47卷 115-122页

作者： Laneman, JN Sundberg, CEW Lucent Technol Bell Labs Multimedia Commun Res Lab Murray Hill NJ 07974 USA

Digital audio broadcasting (DAB) systems for the AM band are being developed to provide higher-quality radio broadcasts, broader coverage, and data services. Transmission is typically done by means of multistreaming with QAM/OFDM in the high bits/sec/Hz regime, in which Reed-Solomon codes, either alone or in concatenation with inner trellis coded modulation (TCM), are natural choices for error control. For the AM DAB application, Reed-Solomon codes with suboptimal decoders of the bounded-distance type offer error correction important for bringing down the error probability, but also offers error detection important for generating block detected-error flags for use in the error concealment, or error mitigation, algorithm in the audio decoder. For multistream systems, the block detected-error flags can also be used to select the component streams retained by the audio decoder. In this paper, we evaluate the performance of Reed-Solomon codes in terms of both detected (flag) and undetected error rates for DAB applications. We provide simulation results for a variety of decoding algorithms, including hard-decision decoding (HDD), successive-erasure decoding (SED), and fixed-erasure decoding (FED), and discuss the channel environments in which each of these algorithms may be appropriate. Among other results, for example, we address the issue of matching the blocklength of the Reed-Solomon code to the audio decoder with its variable frame structure. From our simulation results for HDD, we conclude that the increased error correction capability of longer Reed-Solomon codes more than compensates for the mismatch in terms of error mitigation in the audio decoder. We also observe that SED provides only small improvements for uniform interference channels, while FED offers considerable improvements for some partial-band interference channels. We describe an appealing two-mode adaptive configuration using HDD and FED for mitigating partial-band interference caused by some second

关键词： bounded-distance decoding digital audio broadcasting (DAB) error mitigation generalized minimum-distance decoding joint source-channel coding Reed-Solomon codes

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Power, spatio-temporal bandwidth, and distortion in large sensor networks

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2005年第4期23卷 745-754页

作者： Gastpar, M Vetterli, M Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA Swiss Fed Inst Technol EPFL Inst Commun Syst CH-1015 Lausanne Switzerland

For a class of sensor networks, the task is to monitor an underlying physical phenomenon over space and time through an imperfect observation process. The sensors can communicate back to a central data collector over a noisy channel. The key parameters in such a setting are the fidelity (or distortion) at which the underlying physical phenomenon can be estimated by the data collector, and the cost of operating the sensor network. This is a network joint source-channel communication problem, involving both compression and communication. It is well known that these two tasks may not be addressed separately without sacrificing optimality, and the optimal performance is generally unknown. This paper presents a lower bound on the best achievable end-to-end distortion a's a function of the number of sensors, their total transmit power, the number of degrees of,freedom of the underlying source process, and the spatio-temporal communication bandwidth. Particular coding schemes are studied, and it is shown that in some cases, the lower bound is tight in a scaling-law sense. By contrast, it is shown that the standard practice of separating source from channel coding may incur an exponential penalty in terms of communication resources, as a function of the number of sensors. Hence, such code designs effectively prevent scalability. Finally, it is outlined how the results extend to cases involving missing synchronization and channel fading.

关键词： CEO problem information theory joint source-channel coding sensor networks separation theorem

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To code, or not to code: Lossy source-channel communication revisited

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IEEE TRANSACTIONS ON INFORMATION THEORY 2003年第5期49卷 1147-1158页

作者： Gastpar, M Rimoldi, B Vetterli, M Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA Ecole Polytech Fed Lausanne Inst Commun Syst CH-1015 Lausanne Switzerland

What makes a source-channel communication system optimal? It is shown that in order to achieve an optimal cost-distortion tradeoff, the source and the channel have to be matched in a. probabilistic sense. The match (or lack of it) involves the source distribution, the distortion measure, the channel conditional distribution, and the channel input cost function. Closed-form necessary and sufficient expressions relating the above entities are given. This generalizes both the separation-based approach as well as the two well-known examples of optimal uncoded communication. The condition of probabilistic matching is extended to certain nonergodic and multiuser scenarios. This leads to a result on optimal single-source broadcast communication.

关键词： joint source-channel coding separation theorem single-letter codes single-source broadcast uncoded transmission

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Reliable joint source-channel Cooperative Transmission Over Relay Networks

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IEEE TRANSACTIONS ON INFORMATION THEORY 2013年第4期59卷 2442-2458页

作者： Guenduez, Deniz Erkip, Elza Goldsmith, Andrea Poor, H. Vincent Univ London Imperial Coll Sci Technol & Med Dept Elect & Elect Engn London SW7 2AZ England Polytech Inst New York Univ Dept Elect Engn Brooklyn NY 11201 USA Stanford Univ Dept Elect Engn Stanford CA 94305 USA Princeton Univ Dept Elect Engn Princeton NJ 08544 USA

Reliable transmission of a discrete memoryless source to multiple destinations over a relay network is considered. Motivated by sensor network applications, it is assumed that the relays and the destinations all have access to side information correlated with the underlying source signal. joint source-channel cooperative transmission is studied in which the terminals in the network help the transmission of the source signal to the destinations by using their overheard signals, as in the classical channel cooperation scenario, as well as the available correlated side information. Decode-and-forward-based cooperative transmission is studied in a network of multiple relay terminals and two different achievability schemes are proposed: 1) a regular encoding and sliding-window decoding scheme without explicit source binning at the encoder;and 2) a semiregular encoding and backward decoding scheme with binning based on the side information statistics. It is shown that both of these schemes lead to the same source-channel code rate, which is shown to be the source-channel capacity in the case of 1) a physically degraded relay network with a single destination in which the side information signals are degraded in the same order as the channel;and 2) a relay network with multiple destinations, in which all the terminals want to reconstruct the source reliably, while at most one of them can act as a relay.

关键词： Cooperative transmission decode-and-forward joint source-channel coding network information theory relay network

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Interference channels With Correlated Receiver Side Information

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IEEE TRANSACTIONS ON INFORMATION THEORY 2010年第12期56卷 5984-5998页

作者： Liu, Nan Guenduez, Deniz Goldsmith, Andrea J. Poor, H. Vincent Stanford Univ Dept Elect Engn Stanford CA 94305 USA Princeton Univ Dept Elect Engn Princeton NJ 08544 USA

The problem of joint source-channel coding in transmitting independent sources over interference channels with correlated receiver side information is studied. When each receiver has side information correlated with its own desired source, it is shown that source-channel separation is optimal. When each receiver has side information correlated with the interfering source, sufficient conditions for reliable transmission are provided based on a joint source-channel coding scheme using the superposition encoding and partial decoding idea of Han and Kobayashi. When the receiver side information is a deterministic function of the interfering source, source-channel separation is again shown to be optimal. In addition to these source-channel coding problems, a new channel model that generalizes the classical interference channel is introduced: the interference channel with message side information. Achievable rate regions are given and a single letter characterization of the capacity region for a special class of Z-interference channels is provided. Using this capacity result and the optimality of source-channel separation, we demonstrate that our sufficient conditions for reliable transmission when each receiver has side information correlated with the interfering source are also necessary for some special cases. As a by-product, the capacity region of a class of Z-channels with degraded message sets is also provided.

关键词： Interference channel joint source-channel coding receiver side information source-channel separation theorem

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On Lossy Multi-Connectivity: Finite Blocklength Performance and Second-Order Asymptotics

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2019年第4期37卷 735-748页

作者： Zhou, Lin Wolf, Albrecht Motani, Mehul Natl Univ Singapore Dept Elect & Comp Engn Singapore 117583 Singapore Univ Michigan Dept Elect Engn & Comp Sci Ann Arbor MI 48109 USA Tech Univ Dresden Vodafone Chair Mobile Commun Syst D-01069 Dresden Germany

We consider the lossy transmission of a single source over parallel additive white Gaussian noise channels with independent quasi-static fading, which we term the lossy multi-connectivity problem. We assume that only the decoder has access to the channel state information. Motivated by ultra-reliable and low latency communication requirements, we are interested in the finite blocklength performance of the problem, i.e., the minimal excess-distortion probability of transmitting k source symbols over n channel uses. By generalizing non-asymptotic bounds by Kostina and Verdu for the lossy joint source-channel coding problem, we derive non-asymptotic achievability and converse bounds for the lossy multi-connectivity problem. Using these non-asymptotic bounds and under mild conditions on the fading distribution, we derive approximations for the finite blocklength performance in the spirit of second-order asymptotics for any discrete memoryless source under an arbitrary bounded distortion measure. Furthermore, in the achievability part, we analyze the performance of a universal coding scheme by modifying the universal joint source-channel coding scheme by Csiszar and using a generalized minimum distance decoder. Our results demonstrate that the asymptotic notions of outage probability and outage capacity are in fact reasonable criteria even in the finite blocklength regime. Finally, we illustrate our results via numerical examples.

关键词： Parallel channels dispersion 5G ultra-reliable and low latency communication finite blocklength analysis quasi-static fading joint source-channel coding

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Constellation mappings for two-dimensional signaling of nonuniform sources

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IEEE TRANSACTIONS ON COMMUNICATIONS 2003年第3期51卷 400-408页

作者： Takahara, G Alajaji, F Beaulieu, NC Kuai, HY Queens Univ Dept Math & Stat Kingston ON K7L 3N6 Canada Queens Univ Dept Elect & Comp Engn Kingston ON K7L 3N6 Canada Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2G7 Canada

The design of two-dimensional constellation mappings for the transmission of binary nonuniform memoryless sources over additive white Gaussian noise channels using standard M-ary PSK and QAM modulation schemes is investigated. The main application of this problem is the incorporation of an adaptive mapping assignment in modem devices that employ fixed PSK/QAM modulation schemes for the transmission of heterogenous data (such as multimedia information) containing various levels of nonuniformity. In general, the optimal mapping depends on both the probability distribution of the input signals and the signal-to-noise ratio (SNR) in the channel, in addition to the geometry of the signal constellation. We show that constellation mappings which follow the objective of minimizing the average symbol energy and, given this, maximizing the decoding probability of the most likely signals, can yield symbol-error-rate and bit-error-rate performance that is substantially better than Gray encoding maps. Gains as high as 3.5 dB in SNR E-b/N-o are obtained for highly nonuniform sources. Finally, we note that the mappings techniques result in nonzero mean constellations and briefly consider their performances when they are converted to zero mean constellations by shifting. In this case, we observe that the shifted zero-mean Gray map outperforms our shifted maps for small- to medium-sized constellations (M less than or equal to 32), but not for larger sizes.

关键词： error rate Gray map joint source-channel coding maximum a posteriori (MAP) and maximum-likelihood (ML) decoding nonuniform sources phase-shift keying (PSK) and quadrature amplitude modulation (QAM) signal mapping

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