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On the distortion SNR exponent of hybrid digital-analog space-time coding

IEEE TRANSACTIONS ON INFORMATION THEORY 2007年第8期53卷 2867-2878页

作者： Caire, Giuseppe Narayanan, Krishna Univ So Calif Dept Elect Engn Viterbi Sch Engn Los Angeles CA 90089 USA Texas A&M Univ Dept Elect Engn College Stn TX 77840 USA

We consider the transmission of a real independent and identically distributed(i.i.d.) "analog" source over a quasi-static M-input N-output multiple-input multiple-output (MIMO) block-fading channel. The relevant performance criterion is end-to-end average quadratic distortion D versus channel signal-to-noise ratio (SNR), for given spectral efficiency eta, defined as the ratio of the source bandwidth over the channel bandwidth. In the limit of high SNR, we define the distortion SNR exponent a*(eta) as the largest a such that D = snr(-alpha), over all possible source-channel coding schemes of spectral efficiency eta. We find a simple upper bound on a*(eta), an achievable lower bound a(sep) (eta) achievable by separated (tandem) source-channel coding, and a tighter lower bound a(hybrid)(eta)achievablebynew hybrid digital analog space-time coding schemes. As a corollary, we have that a* (eta) is completely determined for the scalar case M = N = 1 and for the "bandwidth compression" case eta >= 2 min {M, N}. Explicit and simple construction of hybrid space-time codes achieving a(hybrid)(eta) are also given.

关键词： block-fading channels distortion exponent hybrid digital analog coding joint source-channel coding multiplexing-diversity tradeoff space-time coding outage probability

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Quality enhancement of printed-and-scanned images using distributed coding

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SIGNAL PROCESSING 2007年第6期87卷 1301-1313页

作者： Voloshynovskiy, S. Koval, O. Deguillaume, F. Pun, T. Univ Geneva CUI CH-1211 Geneva 4 Switzerland

In this paper we address visual communications via print-and-scan channels from an information-theoretic point of view as communications with side information that targets quality enhancement of visual data at the output of this type of channels. The solution to this problem addresses important aspects of multimedia data processing and management. A practical approach to side information communications for printed documents based on Wyner-Ziv and Gray setups is analyzed in the paper that assumes two separated communications channels where an appropriate distributed coding should be elaborated. The printing channel is considered to be a direct visual channel for images ("analog" channel with degradations). The "digital channel" is considered to be an appropriate auxiliary channel exploited to communicate the information exploited for quality enhancement of printed-and-scanned image. We demonstrate both theoretically and practically how one can benefit from this sort of "distributed paper communications". (c) 2006 Elsevier B.V. All rights reserved.

关键词： data-hiding printed-and-scanned documents communications with side-information bar codes distributed coding joint source-channel coding Gel'fand-Pinsker problem Wyner-Ziv coding gray coding image enhancement

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coding problems for channels with partial state information at the transmitter

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IEEE TRANSACTIONS ON INFORMATION THEORY 2007年第12期53卷 4521-4536页

作者： Cemal, Yakup Steinberg, Yossef AudioCodes Ltd IL-70151 Lod Israel Technion Israel Inst Technol Dept Elect Engn IL-32000 Haifa Israel

channel coding for single-user channels with rate-limited, coded, partial channel state information at the transmitter and full side information (SI) at the receiver is studied. In the first part of the current work, we consider joint source-channel state channel coding. In particular, we deal with lossy transmission of a source, over a cost-constrained state controlled channel where the receiver gets full SI and the transmitter receive coded partial SI. We derive a single-letter characterization of the achievable distortion-cost triples. From this characterization, a separation principle follows for both, coding of the main source and the transmitter SI. In the second part, we consider channel coding when the transmitter receives multiple partial, rate-limited descriptions of the state, and the receiver gets full SI. Two rate-limited descriptions of the state sequence are generated and conveyed to the transmitter, where each description can be lost independently during this transmission. For three different possible partial SI at the transmitter, we explore a channel coding strategy with three different forward channel rates. Inner and outer bounds are derived on the set of achievable partial description and forward channel rates. Furthermore, special cases where the inner bound is tight are studied. Similarities between coding of SI as multiple partial descriptions and the multiple description problem of source coding theory are pointed out.

关键词： coded side information (SI) excess rate hierarchical coding joint source-channel coding multiple description state-controlled channels successive refinement

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Packet-by-packet adaptive scheme for video coding and transmission over wireless IP networks using rate-compatible punctured turbo (RCPT) codes

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WIRELESS PERSONAL COMMUNICATIONS 2007年第4期43卷 1675-1687页

作者： Pei, Yong Arnbetkar, Viraj S. Wright State Univ Dept Comp Sci & Engn Dayton OH 45435 USA

In this paper, we consider real-time video coding and transmission over packet-switched wireless IP networks, such as WLAN, using RCPT codes and joint source-channel coding (JSCC) with concentration on a packet-by-packet adaptive scheme. We present a systematic design methodology to enable the applicability of JSCC techniques. The performance of H.263+ video coding and transmission over wireless channel modeled as slow Rician fading channels using this approach is studied. Results indicate that a packet-by-packet adaptive RCPT-JSCC approach is of significant advantage for real-time video applications and leads to more acceptable video delivery quality over interference-limited and time-varying wireless networks.

关键词： video transmission RTP-H.263+ RCPT codes joint source-channel coding Rician fading

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Rate and power allocation for layered transmission with superposition coding

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IEEE SIGNAL PROCESSING LETTERS 2007年第11期14卷 773-776页

作者： Etemadi, Farzad Jafarkhani, Hamid Univ Calif Irvine Ctr Pervasive Communicat & Comp Dept Elect Engn & Comp Sci Irvine CA 92697 USA

We consider layered transmission of a Gaussian source over a quasi-static fading channel. A broadcast strategy is used in which multiple layers of source data are superimposed, and each layer is allocated a different power and transmission rate. For a multiple-antenna system where either the transmitter or the receiver has a single antenna, we propose a low-complexity algorithm for minimizing the expected end-to-end distortion of the received signal. Numerical results for a Rayleigh fading channel are presented, and the performance gain over a time-sharing strategy is quantified. It is numerically shown that for a wide range of operating conditions, equal rate allocation is as good as unequal rate allocation.

关键词： joint source-channel coding resource allocation superposition coding

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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, vol.2

作者： Herve BOEGLEN Olivier HAEBERLE Christian CHATELLIER Christian OLIVIER Laboratoire MIPS LABEL IUT de Mulhouse Mulhouse Cedex France Laboratoire SIC XLIM UMR CNRS 6172 Futuroscope Cedex France

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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Efficient algorithms for optimal uneven protection of single and multiple scalable code streams against packet erasures

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IEEE TRANSACTIONS ON MULTIMEDIA 2007年第7期9卷 1466-1474页

作者： Dumitrescu, Sorina wu, Xiaolin Wang, Zhe McMaster Univ Dept Elect & Comp Engn Hamilton ON L8S 4K1 Canada

We study algorithmic approaches for rate-fidelity optimal packetization of a single and multiple scalable source code streams with uneven erasure protection (UEP). A new algorithm is developed to obtain the globally optimal solution for scalable source codes of convex rate-fidelity function and for a wide class of erasure channels, including channels for which the probability of losing n packets is monotonically nonincreasing in n, and independent erasure channels with packet erasure rate smaller than 0.5. This is achieved at linear space complexity and near-linear time complexity in the transmission budget, representing significant improvement over the known globally optimal algorithm. When applied to SPIHT compressed images, the results of the proposed algorithm are virtually the same as the global optima. The above success is also extended to UEP packetization of multiple scalable code streams. We improve the existing algorithms in both speed and performance.

关键词： joint source-channel coding Monge property multimedia streaming rate-distortion optimization uneven erasure protection

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joint source-channel-authentication resource allocation and unequal authenticity protection for multimedia over wireless networks

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IEEE TRANSACTIONS ON MULTIMEDIA 2007年第4期9卷 837-850页

作者： Li, Zhi Sun, Qibin Lian, Yong Chen, Chang Wen Natl Univ Singapore Dept Elect & Comp Engn Singapore 117548 Singapore ASTAR Inst Infocomm Res Singapore 119613 Singapore Florida Inst Technol Dept Elect & Comp Engn Melbourne FL 32901 USA

There have been increasing concerns about the security issues of wireless transmission of multimedia in recent years. Wireless networks, by their nature, are more vulnerable to external intrusions than wired ones. Many applications demand authenticating the integrity of multimedia content delivered wirelessly. In this work, we describe a framework for jointly coding and authenticating multimedia to be delivered over heterogeneous wireless networks. We firstly introduce a novel concept called unequal authenticity protection (UAP), which unequally allocate resources to achieve an optimal authentication result. We then consider integrating UAP with specific source and channel-coding models, to obtain optimal end-to-end quality by the means of joint source-channel-authentication analysis. Lastly, we present an implementation of the proposed joint coding and authentication system on a progressive JPEG coder. Experimental results demonstrate that the proposed approach is indeed able to achieve the desired authentication of multimedia over wireless networks.

关键词： authentication digital signatures joint source-channel coding rate-distortion optimization unequal authenticity protection

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An end-to-end embedded approach for multicast/broadcast of scalable video over multiuser CDMA wireless networks

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IEEE TRANSACTIONS ON MULTIMEDIA 2007年第3期9卷 655-667页

作者： Chan, Yee Sin Modestino, James W. Qu, Qi Fan, Xingzhe Univ Miami Dept Elect & Comp Engn Coral Gables FL 33124 USA Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

We investigate an embedded multicast/broadcast approach for transport of digital video over spread-spectrum code-division multiple access (CDMA) cellular networks. Previous work has shown that the incorporation of a scalable source coding scheme with multiresolution modulation provides a promising design paradigm for the practical realization of the information-theoretic performance predictions originally developed by Cover [1], which demonstrated that optimal multicast/broadcast performance could be achieved by an embedded transmission scheme. Hence, the major technical challenge associated with the design of an end-to-end embedded multicast/broadcast system is how to match an embedded modulation constellation with a scalable source coding scheme. In this work, taking into consideration both the interference-limited and bandwidth-limited characteristics of a CDMA system, we provide a cross-layer approach incorporating adaptive power allocation and channel coding strategies and effectively match a discrete cosine transform based scalable motion-compensated video encoder to an embedded multiresolution modulation scheme to simultaneously deliver a basic quality-of-service (QoS) to less capable receivers while maximizing both the QoS for more capable receivers and the system capacity. We demonstrate the efficacy of this approach using the ITU-T H.263+ video scalable hybrid coder, although the approach is generally extensible to other scalable coding schemes as well.

关键词： adaptive modulation and coding code-division multiple access (CDMA) cross-layer drift control embedded transmission H.263+ joint source-channel coding joint source coding-power control multicast/broadcast turbo codes wireless video

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Error resilient LZ'77 data compression: Algorithms, analysis, and experiments

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IEEE TRANSACTIONS ON INFORMATION THEORY 2007年第5期53卷 1799-1813页

作者： Lonardi, Stefano Szpankowski, Wojciech Ward, Mark Daniel Univ Calif Riverside Dept Comp Sci & Engn Riverside CA 92521 USA Purdue Univ Dept Comp Sci W Lafayette IN 47907 USA Univ Penn Dept Math Philadelphia PA 19104 USA

We propose a joint source-channel coding algorithm capable of correcting some errors in the popular Lempel-Ziv'77 (LZ'77)scheme without introducing any measurable degradation in the compression performance. This can be achieved because the LZ'77 encoder does not completely eliminate the redundancy present in the input sequence. One source of redundancy can be observed when an LZ'77 phrase has multiple matches. In this case, LZ'77 can issue a pointer to any of those matches, and a particular choice carries some additional bits of information. We call a scheme with embedded redundant information the LZS'77 algorithm. We analyze the number of longest matches in such a scheme and prove that it follows the logarithmic series distribution with mean 1/h (plus some fluctuations), where h is the source entropy. Thus, the distribution associated with the number of redundant bits is well concentrated around its mean, a highly desirable property for error correction. These analytic results are proved by a combination of combinatorial, probabilistic, and analytic methods (e.g., Mellin transform, depoissonization, combinatorics on words). In fact, we analyze LZRS'77 by studying the multiplicity matching parameter in a suffix tree, which in turn is analyzed via comparison to its independent version, called trie. Finally, we present an algorithm in which a channel coder (e.g., Reed-Solomon (RS) coder) succinctly uses the inherent additional redundancy left by the LZS'77 encoder to detect and correct a limited number of errors. We call such a scheme the LZS'77 algorithm. LZRS'77 is perfectly backward-compatible with LZ'77, that is, a file compressed with our error-resistant LZRS'77 can still be decompressed by a generic LZ'77 decoder.

关键词： autocorrelation polynomial combinatorics on words depoissonization joint source-channel coding Lempel-Ziv'77 (LZ'77) scheme Mellin transform multiple matches pattern matching Reed-Solomon (RS) code suffix trees tries

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