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IEEE International Conference on Image Processing

作者： J. Chou S.S. Pradhan L. El Ghaoui K. Ramchandran University of California Berkeley Berkeley CA USA

ISBN: (纸本)0780362977

Inspired by a previously proposed constructive framework for the distributed source coding problem. We propose a powerful constructive approach to the watermarking problem, emphasizing the dual rules of distributed source coding with side information at the decoder and channel coding with side information at the encoder. In our framework, we explore various source and channel codes to close the gap on the achievable capacity of watermarking systems. We propose two methods of solution, one which is based on optimal rate-distortion quantizers and the other based on robust optimization and convex programming. The resulting watermarking schemes, when subjected to additive white gaussian noise (AWGN) attacks, achieve results which are comparable to or better than the best watermarking schemes in the literature.

关键词： Watermarking source coding Decoding AWGN Channel coding Additive white noise Data encapsulation Rate-distortion Noise robustness Electronic mail

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Tradeoffs of source coding, channel coding and spreading in CDMA systems

Tradeoffs of source coding, channel coding and spreading in ...

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MILCOM, Military Communications Conference

作者： Qinghua Zhao P. Cosman L.B. Milstein Department of Electrical and Computer Engineering University of California San Diego USA

ISBN: (纸本)0780365216

We consider a CDMA system consisting of an image source coder, a convolutional channel coder, an interleaver, and a direct sequence spreading module. With different allocations of bandwidth to source coding, channel coding and spreading, the system is analyzed over a frequency selective Rayleigh fading channel. The performance of the system is evaluated using the cumulative distribution function of peak signal-to-noise ratio. We show that, among other things, given a fixed channel coding rate, allocating more bandwidth to source coding allows higher maximum image quality. At the same time, the probability of achieving this high quality is small. Allocating more bandwidth to spreading decreases the number of source information bits transmitted, thus limiting the achievable image quality, but the probability of achieving this maximum quality is high.

关键词： source coding Channel coding Multiaccess communication Bandwidth Image quality Convolutional codes Convolution Radio spectrum management Fading Distribution functions

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Wide-band CDMA for the UMTS/IMT-2000 satellite component

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2002年第2期51卷 306-331页

作者： Boudreau, D Caire, G Corazza, GE De Gaudenzi, R Gallinaro, G Luglio, M Lyons, R Romero-García, J Vernucci, A Widmer, H Commun Res Ctr Ottawa ON K2H 8S2 Canada Politecn Torino I-10129 Turin Italy Univ Roma Tor Vergata Dept Elect Engn I-00133 Rome Italy European Space Agcy Estec TOS ETC NL-2200 AG Noordwijk Netherlands Space Engn SPA I-00155 Rome Italy Sq Peg Commun Inc Kanata ON K2K 2A3 Canada European Space Agcy F-75738 Paris France Ascom Syst AG Technol Unit CH-5506 Magenwil Switzerland

This paper describes the main aspects relevant to the development of a third-generation radio transmission technology (RTT) concept identified as satellite wide-band CDMA (SW-CDMA), which has been accepted [1] by the International Telecommunications Union (ITU) as one of the possible RTTs for the satellite component of International Mobile Telecommunications-2000 (IMT-2000). The main outcomes of the extensive system engineering effort that has led to the above ITU RTT are described. In particular, we address propagation channel characteristics, satellite diversity, power control, pilot channel, code acquisition, digital modulation and spreading format, interference mitigation, and resource allocation. Due to its similarity with respect to the terrestrial W-CDMA proposal from which it is derived, the SW-CDMA open air interface solution is described briefly, with emphasis only on the major adaptation required to best cope with the satellite environment. Quantitative results concerning the physical-layer performance over realistic channel conditions, for both forward and reverse link, are reported. A system capacity study case for a low-earth-orbit constellation is also provided.

关键词： code division multiaccess fading channels power control satellite mobile source coding

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Channel-optimized soft trellis waveform coding

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2002年第9期50卷 2306-2318页

作者： Haddad, T Yongaçoglu, A Zarlink Semicond Ottawa ON K2K 3H4 Canada Univ Ottawa Sch Informat Technol & Engn Ottawa ON K1N 6N5 Canada

In this paper, we provide a new fuzzy relaxation trellis codebook search algorithm over noisy channels. The new algorithm solves the problems associated with the LBG algorithm in the sense of delivering relatively lower distortion configurations using short training sequences. Furthermore, the new approach is significantly less sensitive to the initialization process. The algorithm minimizes a weighted distortion measure averaged over both the source and the channel statistics. The weights are soft distortion-related reliability information, which are delivered by a soft trellis vector quantization algorithm (STVQ). The concept of soft compression is introduced by Haddad and Yongaqoklu in another paper, using the forward-backward symbol-MAP algorithm. The work introduced in this paper is an extension of the work established for the noiseless channel case by Haddad and Yongacoglu in yet another paper. Testing is performed using first- and second-order Gauss-Markov sources over several trellis structures, vector dimensions, and compression rates. Moreover, the robustness of the optimal configurations is tested under channel-mismatch conditions and compared with tandem coding systems.

关键词： channel optimized compression data compression fuzzy systems source coding trellis codes

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An improvement to multiple description transform coding

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2002年第11期50卷 2843-2854页

作者： Wang, Y Reibman, AR Orchard, MT Jafarkhani, H Polytech Univ Brooklyn NY 11201 USA AT&T Labs Res Florham Pk NJ 07932 USA Rice Univ Dept Elect & Comp Engn Houston TX 77005 USA Univ Calif Irvine Dept Elect & Comp Engn Ctr Pervas Commun Irvine CA USA

A multiple description transform coding (MDTC) method has been reported previously. The redundancy rate distortion (RRD) performance of this coding scheme for the independent and identically distributed (i.i.d.) two-dimensional (2-D) Gaussian source has been analyzed using mean squared error (MSE) as the distortion measure. At the small redundancy region, the MDTC scheme can achieve excellent RRD performance because a small increase in redundancy can reduce the single description distortion at a rate faster than exponential, but the performance of MDTC becomes increasingly poor at larger redundancies. This paper describes a generalization of the MDTC (GMDTC) scheme, which introduces redundancy both by transform and through correcting the error resulting from a single description. Its RRD performance is closer to the theoretical bound in the entire range of redundancy. Analysis both for a single pair of variables and for multiple variables is presented.

关键词： error resilience multiple description coding source coding

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Design and performance of VQ-based hybrid digital-analog joint source-channel codes

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IEEE TRANSACTIONS ON INFORMATION THEORY 2002年第3期48卷 708-720页

作者： Skoglund, M Phamdo, N Alajaji, F Royal Inst Technol Dept Signals Sensors & Syst SE-10044 Stockholm Sweden SUNY Stony Brook Dept Elect & Comp Engn Stony Brook NY 11794 USA Queens Univ Dept Math & Stat Kingston ON K7L 3N6 Canada Queens Univ Dept Elect & Comp Engn Kingston ON K7L 3N6 Canada

A joint source-channel hybrid digital-analog (HDA) vector quantization (VQ) system is presented. The main advantage of the new VQ-based HDA system is that it achieves excellent rate-distortion-capacity performance at the design signal-to-noise ratio (SNR) while maintaining a "graceful improvement" characteristic at higher SNRs. It is demonstrated that, within the HDA framework, the parameters of the system can be optimized using an iterative procedure similar to that of channel-optimized vector quantizer design. Comparisons are made with three purely digital systems and one purely analog system. It is found that, at high SNRs, the VQ-based HDA system is superior to the other investigated systems. At low SNRs, the performance of the new scheme can be improved using the optimization procedure and using soft decoding in the digital part of the system. These results demonstrate that the introduced scheme provides an attractive method for terrestrial broadcasting applications.

关键词： broadcasting hybrid digital-analog coding joint source-channel coding robust transmission source coding vector quantization (VQ)

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Optimal bit allocation for source/channel coding in joint trellis coded quantization/modulation

Optimal bit allocation for source/channel coding in joint tr...

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IEEE Wireless Communications and Networking Conference

作者： Usevitch, B Venkatraman, G Univ Texas Dept Elect & Comp Engn El Paso TX 79968 USA

ISBN: (纸本)0780365968

Shannon showed that the problems of source and channel coding could be considered separately, without loss of performance, if complexity Is not an issue. Recent investigations have shown performance gain for more practical problems where channel and source coding have been jointly designed. This paper investigates the joint source/channel coding problem when using trellis coded quantization (TCQ). TCQ has shown to offer improved source coding performance (when compared to Lloyd-Max quantization) while additionally offering some error immunity, When using TCQ in practical transmission systems, the question arises as to the number of bits that should be allocated to source and channel coding for overall best performance, Results here show that for binary symmetric channels with medium SNR's, better overall mean square error (MSE) performance results from taking bits from the source coder and allocating them to the channel coder. However, for high and low SNR's better MSE results from allocating all bits to source coder.

关键词： Channel coding source coding ENCODER Trellis codes binary symmetric channel allocation Transmission systems coding

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Performances analysis of a transmission system for H263 compressed and turbo-coded video sequences over a UMTS/TDD downlink

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ANNALS OF TELECOMMUNICATIONS 2002年第11-12期57卷 1149-1170页

作者： Farah, J Marx, F Arndt, M France Telecom R&D DIH F-38243 Meylan France

The aim of this paper is to present a comparative study of the performances, in terms of the mean PSNR (Peak Signal to Noise Ratio), of a UMTS/TDD transmission system for H263 compressed and turbo-coded video sequences. Several parameters are emphasized, among them : the rate of occurrence of Intra coded frames, the video compression level and the Bit Error Rate of the transmission channel. We also present a methodology for determining the best repartition scheme of the global channel bandwidth between source and channel coding, in order to minimize the global distortion on the transmitted sequences.

关键词： mobile radiocommunication UNITS code division multiple access physical layer multipath propagation fading adaptive filtering turbo code picture coding moving image error propagation picture quality source coding channel coding

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On the rate-distortion region for multiple descriptions

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IEEE TRANSACTIONS ON INFORMATION THEORY 2002年第7期48卷 2012-2021页

作者： Fu, FW Yeung, RW Natl Univ Singapore Temasek Labs Singapore 119260 Singapore Chinese Univ Hong Kong Dept Informat Engn Shatin Hong Kong Peoples R China

In this paper, we study the problem of source coding with multiple descriptions, which is described as follows. Let X be a discrete memoryless source. There are two encoders, Encoders 1 and 2, and three decoders, Decoders 0, 1, and 2. Encoders 1 and 2 describe the source X at respective rates R-1 and R-2. Decoder 1 receives the output of Encoder 1 only, and it can recover X with distortion D-1. Decoder 2 receives the output of Encoder 2 only, and it can recover X with distortion D-2. Decoder 0 receives the outputs of both Encoders 1 and 2, and it can recover X with distortion D-0. We show that if Decoder 2 (or Decoder 1) is required to recover a function of the source X perfectly in the usual Shannon sense, the El Gamal-Cover inner bound on the rate distortion region is tight. This finding subsumes the Rimoldi rate-distortion region for successive refinement of information, the Kaspi rate-distortion function when side information may be present at the decoder, and the El Gamal-Cover achievable rate region for multiple descriptions with deterministic distortion measures. We have also obtained a new outer bound on the rate-distortion region which enhances the outer bound due to Witsenhausen and Wyner. This new outer bound implies some interesting facts regarding the achievable rate-distortion vectors. Finally, we pose a multilevel diversity source coding problem for further study.

关键词： multilevel diversity coding multiple descriptions rate-distortion function source coding successive refinement

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Huffman code based error screening and channel code optimization for error concealment in Perceptual Audio coding (PAC) algorithms

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IEEE TRANSACTIONS ON BROADCASTING 2002年第3期48卷 193-206页

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

The class of Perceptual Audio coding (PAC) algorithms yields efficient and high-quality stereo digital audio bitstreams at bit rates from 16 kb/sec to 128 kb/sec (and even higher bit rates). To avoid "pops and clicks" in the decoded audio signals due to erasure or undetected errors from transmission over unreliable channels, e.g., in the context of digital audio broadcasting (DAB), channel error detection combined with source error concealment, or source error mitigation, techniques are preferred to pure channel error correction. One simple and efficient way to perform channel error detection is to employ a high-rate block code;for example, the preferred solution for hybrid in-band on-channel (HIBOC) DAB in the FM band employs a cyclic redundancy check (CRC) code. Several joint, source-channel coding issues arise in this framework because PAC contains a fixed-to-variable source coding component in the form of Huffman codes, so that the output audio packets are of varying length. We explore two such issues in this paper. First, we develop methods for screening for undetected channel errors in the audio decoder by looking for inconsistencies between the number of bits decoded by the Huffman decoder and the number of bits in the packet as specified by control information within the bitstream. We evaluate this scheme by means of simulations of Bernouli sources and real audio data encoded by PAC, both exposed to random bit errors as well as errors that pass undetected through a CRC decoder. Considerable reduction in undetected errors is obtained with little extra processing in the receiver and with little or no increase in the transmitted bit rate. Second, we consider several configurations for the channel error detection codes, in particular CRC codes, by means of representative simulations and informal listening tests, for several audio coder bit rates of interest in DAB. One configuration employs a fixed-rate, fixed-blocklength code of optimized length outside the PAC

关键词： conformance testing digital audio broadcasting error detection coding Huffman codes source coding

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