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SparseCast: Hybrid Digital-Analog Wireless Image Transmission Exploiting Frequency-Domain Sparsity

IEEE COMMUNICATIONS LETTERS 2018年第12期22卷 2451-2454页

作者： Tung, Tze-Yang Gunduz, Deniz Univ Southern Calif Viterbi Sch Engn Los Angeles CA 90089 USA Imperial Coll London Dept Elect & Elect Engn London SW7 2AZ England

A hybrid digital-analog wireless image transmission scheme, called SparseCast, is introduced, which provides graceful degradation with channel quality. SparseCast achieves improved end-to-end reconstruction quality while reducing the bandwidth requirement by exploiting frequency-domain sparsity through compressed sensing. The proposed algorithm produces a linear relationship between the channel signal-to-noise ratio and peak signal-to-noise ratio (PSNR) without requiring the channel state knowledge at the transmitter. This is particularly attractive when transmitting to multiple receivers or over unknown time-varying channels, as the receiver PSNR depends on the experienced channel quality and is not bottlenecked by the worst channel. SparseCast is benchmarked against two alternative algorithms: SoftCast and block CS-smooth projected Landweber (BCS-SPL). Our findings show that the proposed algorithm outperforms SoftCast by approximately 3.5 dB and BCS-SPL by 15.2 dB.

关键词： joint source-channel coding analog transmission compressed sensing

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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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source-adaptive power allocation for digital modulation

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IEEE COMMUNICATIONS LETTERS 2003年第12期7卷 569-571页

作者： Görtz, N Bresch, E Tech Univ Munich Inst Commun Engn D-80290 Munich Germany

A novel joint source channel-coding technique called source-adaptive power allocation is introduced for the transmission of continuous-amplitude waveform source samples over a noisy channel. Starting from a binary or quaternary digital Modulation scheme we apply a power control, which depends on the uniquantized source samples, to the modulation signal points before they are transmitted over the channel. The resulting system shows strongly superior performance compared with conventional schemes.

关键词： joint source-channel coding power allocation source-adaptive modulation

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Near-Optimal Nonbinary Index Assignment for Equiprobable Lattice Quantizers

IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY

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IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY 2023年 4卷 1350-1370页

作者： Yao, Yunxiang Mow, Wai Ho Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Hong Kong Peoples R China

Index assignment (IA) is a low-complexity joint source-channel coding technique that has the potential for use in low-latency and low-power applications, such as wireless sensor networks (WSNs). Though binary IA has been extensively studied for assigning binary indices to quantized codewords (or symbols) under the assumption of binary symmetric channels (BSCs), real-world scenarios often use M-ary modulations. Directly applying binary IAs designed for BSCs to M-ary modulations results in suboptimal performance. In this paper, we investigate the M-ary IA, which assigns M-ary labels to quantized codewords (or symbols), assuming the use of a equiprobable lattice quantizer. For such a system, we derive a tight performance bound and propose a near-optimal IA scheme based on a two-step design. In addition, we propose explicit IA constructions for practical modulation schemes, including PAM, QAM, and PSK. Our proposed IA design is rigorously proven to be optimal for 3-PSK and QPSK, whereas for larger modulation orders, the proposed IA constructions approach the bounds within small gaps. Our simulations show that the constructed IA scheme can achieve significant energy savings compared to the conventional binary IA scheme. Specifically, in some WSN scenarios, the proposed IA for 16-QAM is shown to achieve significant reductions in energy consumption relative to the conventional binary counterpart.

关键词： Discrete memoryless channel index assignment joint source-channel coding quantization

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A joint source-channel speech coder using hybrid digital-analog (HDA) modulation

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IEEE TRANSACTIONS ON SPEECH AND AUDIO PROCESSING 2002年第4期10卷 222-231页

作者： Phamdo, N Mittal, U SUNY Stony Brook Dept Elect & Comp Engn Stony Brook NY 11794 USA

A joint source-channel coding system for transmitting speech on a bandlimited additive white Gaussian noise (AWGN) channel is presented. The proposed method uses a hybrid of digital and analog modulation techniques. The digital part of the system consists of a Federal Standard 1016 Code-Excited Linear Predictive (FS 1016 CELP) speech coder followed by a rate-3/5 parallel concatenated (turbo) error correcting code. The analog part, which transmits the quantization error due to the FS 1016 CELP coder, consists of a linear encoder and decoder. The advantage of the proposed system is that it achieves excellent rate-distortion/capacity performance that is common in digital systems while maintaining a "graceful degradation" characteristic that is common in analog systems. Comparisons are made with three purely digital systems and an analog system-with all systems operating at the same overall rate. A formal listening test shows that, at high channel SNR, the improved performance of the proposed hybrid system (versus the purely digital systems) is noticeable to the average listener. Finally, an informal listening test indicates that at low channel SNR (where the error correcting code breaks down) the decoded speech of the hybrid system is still intelligible.

关键词： joint source-channel coding robustness speech coding

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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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COVQ for MAP Hard-Decision Demodulated channels

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IEEE COMMUNICATIONS LETTERS 2009年第1期13卷 28-30页

作者： Saffar, Hamidreza Ebrahimzadeh Alajaji, Fady Linder, Tamas Queens Univ Dept Math & Stat Kingston ON K7L 3N6 Canada

We design a channel optimized vector quantizer (COVQ) for symbol-by-symbol maximum a posteriori (MAP) hard-decision demodulated channels. The main objective is to exploit the non-uniformity of the indices representing the quantized source via the MAP decoder and iteratively optimize the overall discrete channel (at the symbol level) jointly with the quantizer. We consider memoryless Gaussian and Gauss-Markov sources transmitted over a binary phase-shift keying modulated Rayleigh fading channel. Our scheme has less encoding computational and storage complexity (particularly for noisy channel conditions) than both conventional and soft-decision COVQ systems, which use hard-decision and soft-decision maximum likelihood demodulation, respectively. Furthermore, it provides a notable signal-to-distortion ratio gain over the former system, and in some cases it matches or outperforms the latter one.

关键词： joint source-channel coding channel optimized vector quantization MAP decoding encoding computational and storage complexity hard and soft-decision demodulation

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A type-aware coding approach for unequal message protection

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PHYSICAL COMMUNICATION 2022年第0期53卷

作者： Yao, Xinyuanmeng Wan, Hai Ma, Xiao Sun Yat Sen Univ Sch Comp Sci & Engn Guangzhou 510006 Guangdong Peoples R China Guangdong Key Lab Informat Secur Technol Guangzhou 510006 Guangdong Peoples R China

In this paper, to achieve an unequal message protection (UMP), we propose a type-aware coding approach. The proposed approach can be used to construct a UMP code with multiple classes of messages, and can also be employed as a finite-length joint source-channel coding (JSCC) where the source statistics is not required at the transmitter. At the transmitter, an information bit sequence is first encoded using a fixed-to-fixed-length type-aware description and then encoded by a given linear block code along with a "free-ride "approach. At the receiver, a type-search decoding algorithm is employed. Numerical results show that, 1) As a UMP coding, the type-aware coding can provide more protection for biased binary sequences;2) As a finite-length JSCC, the type-aware coding can improve the average error performance for biased sources over the distribution-aware decoding. (c) 2022 Elsevier B.V. All rights reserved.

关键词： Fixed-to-fixed-length type-aware description Free-ride approach joint source-channel coding Type-aware coding approach Unequal message protection

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Layered Unequal Loss Protection with Pre-Interleaving for Fast Progressive Image Transmission Over Packet-Loss channels

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ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS 2005年第4期1卷 338-353页

作者： Cai, Jianfei Li, Xiangjun Chen, Chang Wen Nanyang Technol Univ Ctr Multimedia & Network Technol Sch Comp Engn Singapore 639798 Singapore Florida Inst Technol Dept Elect & Comp Engn Melbourne FL 32901 USA

Most existing unequal loss protection (ULP) schemes do not consider the minimum quality requirement and usually have high computation complexity. In this research, we propose a layered ULP (L-ULP) scheme to solve these problems. In particular, we use the rate-based optimal solution with a local search to find the average forward error correction (FEC) allocation and use the gradient search to find the FEC solution for each layer. Experimental results show that the executing time of L-ULP is much faster than the traditional ULP scheme but the average distortion is worse. Therefore, we further propose to combine the L-ULP with the pre-interleaving to have an improved L-ULP (IL-ULP) system. By using the pre-interleaving, we are able to delay the occurrence of the first unrecoverable loss in the source bitstream and thus improve the loss resilience performance. With the better loss resilience performance in the source bitstream, our proposed IL-ULP scheme is allowed to have a weaker FEC protection and allocate more bits to the source coding which leads to the improvement of overall performance. Experimental results show that our proposed IL-ULP scheme even outperforms the global optimal result obtained by any traditional ULP scheme while the complexity of IL-ULP is almost the same as L-ULP.

关键词： Algorithms Progressive image transmission unequal loss protection joint source-channel coding forward error correction packet loss

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Robust transmission of progressive image bitstreams based on DCT over broadband wireless channels

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Journal of Harbin Institute of Technology(New Series) 2006年第2期13卷 219-225页

作者：王东华周源华马曾栋 Institute of Image Communication & Information Processing Shanghai Jiaotong University Shanghai 200030 China Research Institute of Communication Technology Harbin Institute of Technology Harbin 150001 China

A robust progressive image transmission scheme over broadband wireless fading channels is developed for 4th generation wireless communication systems （4G） in this paper. The proposed scheme is based on space-time block coded orthogonal frequency-division multiplexing （OFDM） with 4 transmit antennas and 2 receive antennas and uses a simplified minimum mean square error （MMSE） detector instead of maximum likelihood （ML） detectors. Considering DCT is simpler and more widely applied in the industry than wavelet transforms, a progressive image compression method based on DCT called mean-subtract embedded DCT （MSEDCT） is developed, with a simple mean-subtract method for the redundancy of reorganized DC blocks in addition to a structure similar to the embedded zerotree wavelet coding （EZW） method. Then after analyzing and testing bit importance of the progressive MSEDCT bitstreams, the layered unequal error protection method of joint source-channels coding based on Reed-Solomon （RS） codes is used to protect different parts of bitstreams, providing different QoS assurances and good flexibility. Simulation experiments show our proposed scheme can effectively degrade fading effects and obtain better image transmission effects with 10 -20 dB average peak-sig- nal-noise-ratio （PSNR） gains at the median Eb/No than those schemes without space-time coded OFDM or equal error protections with space-time coded OFDM.

关键词： broadband communication embedded source coding image transmission joint source-channel coding

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