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Robust decoding of variable-length encoded Markov sources using a three-dimensional trellis

IEEE COMMUNICATIONS LETTERS 2003年第7期7卷 320-322页

作者： Thobaben, R Kliewer, J Univ Kiel Fac Engn Inst Circuits & Syst Theory D-24143 Kiel Germany

In this letter, we present an improved index-based a-posteriori probability (APP) decoding approach for the error-resilient transmission of packetized variable-length encoded Markov sources. The proposed algorithm is based on a novel two-dimensional (2-D) state representation which leads to a three-dimensional trellis with unique state transitions. APP decoding on this trellis is realized by employing a 2-D version of the BCJR algorithm where all available source statistics can be fully exploited in the source decoder. For an additional use of channel codes the proposed approach leads to an increased error-correction performance compared to a one-dimensional state representation.

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

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Utilization of multi-dimensional source correlation in multi-dimensional single parity check codes

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TELECOMMUNICATION SYSTEMS 2016年第4期62卷 735-745页

作者： Izhar, Mohd Azri Mohd Zhou, Xiaobo Matsumoto, Tad Univ Teknol Malaysia Wireless Commun Ctr Skudai 81310 Johor Malaysia Tianjin Univ Sch Comp Sci & Technol Weijin Rd 92 Tianjin 300072 Peoples R China Japan Adv Inst Sci & Technol 1-1 Asahidai Nomi Ishikawa 9231292 Japan

This paper proposes a joint source-channel coding (JSCC) technique that well utilizes multi-dimensional (MD) source correlation using MD single parity check codes (MD-SPCCs). The source is assumed to be described by the coupling of multiple first-order binary Markov processes. The knowledge about the source correlation is utilized in the channel decoding process where each component decoder utilizes a single dimension correlation of the MD source. To enhance performance and reduce the error floor, a rate-1 recursive systematic convolutional code is serially concatenated to the MD-SPCC via a random interleaver. Two decoding techniques are proposed for each component decoder, and the selection of the decoding technique depends on the strength of the source correlation, which may further enhance the performance of the proposed JSCC technique. Simulation results reveal that a significant performance gain can be achieved by exploiting the MD source correlation with the proposed JSCC technique compared with the case in which the source correlation is not utilized;more significant gains can be achieved with stronger source correlation, and with a larger dimensionality source correlation as well.

关键词： joint source-channel coding Single parity check codes Multi-dimensional source correlation Turbo coding

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Tree-structured oversampled filterbanks as joint source-channel codes: Application to image transmission over erasure channels

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2004年第9期52卷 2584-2599页

作者： Motwani, R Guillemot, C Data Storage Inst Singapore Singapore Natl Univ Singapore Singapore 117548 Singapore INRIA IRISA F-35042 Rennes France

This paper studies oversampled filterbanks for robust transmission of multimedia signals over erasure channels. Oversampled filterbanks implement frame expansions of signals in l(2)(Z). The dependencies between the expansion coefficients introduced by the oversampled filterbank are first characterized both in the z-domain and in the time-domain. Conditions for recovery of some typical erasure patterns like bursty erasure patterns are derived. The analysis leads to the design of two erasure recovery algorithms that are first studied without quantization noise. The reconstruction algorithm derived from the time-domain analysis exploits the fact that an oversampled filterbank represents signals with more than one set of basis functions. The erased samples are first reconstructed from the received ones, and then, signal space projection is applied. The effect of quantization noise on the reconstructed signal is studied for both algorithms. Using image signals, the theoretical results are validated for a number of erasure patterns, considering unequal error protection enabled tree-structured decompositions.

关键词： erasure resilient coding frames joint source-channel coding multiple description coding oversampled filterbanks

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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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Packet video transmission over wireless channels with adaptive channel rate allocation

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2005年第4-5期16卷 475-498页

作者： Kung, WY Kim, CS Kuo, CCJ Univ So Calif Dept Elect Engn Integrated Media Syst Ctr Los Angeles CA 90089 USA Chinese Univ Hong Kong Dept Informat Engn Shatin Hong Kong Peoples R China

A robust video communication system based on layered coding and unequal error protection is developed in this work. We consider two video communication scenarios. First, for pre-compressed video bitstreams, a channel code rate allocation scheme is proposed to minimize the expected mean square error subject to a constraint on the overall bit budget. Second, for real-time video transmission, we jointly optimize the quantization parameters and the channel coding rates according to channel conditions. To this end, we develop a simple rate-distortion model for general video coders using DCT and motion compensation, so that the rate and the distortion can be estimated without an expensive encoding procedure. Simulation results Show that the proposed algorithms provide acceptable image quality even in high bit error rate environments. (c) 2005 Elsevier Inc. All rights reserved.

关键词： packet video wireless video robust video transmission joint source-channel coding unequal error protection

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Two-Way Semantic Communications Without Feedback

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2024年第6期73卷 9077-9082页

作者： Yu, Kaiwen He, Qi Wu, Gang Univ Elect Sci & Technol China Natl Key Lab Wireless Commun Chengdu 611731 Peoples R China

Semantic communications can significantly improve transmission efficiency, especially in the low signal-to-noise (SNR) regime. However, two-way semantic communications still remain an unexplored topic, which is a critical issue in many machine communication scenarios. Simply extending existing semantic communication systems to the two-way situation requires bidirectional information feedback during the training process, resulting in significant communication overhead. To fill this gap, we investigate a two-way semantic communication (TW-SC) system, where the information feedback can be omitted by exploiting the weight reciprocity in the transceiver. Particularly, the channel simulator and semantic transceiver are implemented on both TW-SC nodes and the channel distribution is modeled by a conditional generative adversarial network. Simulation results demonstrate that the proposed TW-SC system performs closing to the state-of-the-art one-way semantic communication systems but requiring no feedback between the transceiver in training process.

关键词： Semantics Training Transmitters Receivers Wireless communication Generators Artificial neural networks Semantic communications deep learning joint source-channel coding

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Multi-Way Relay Networks: Orthogonal Uplink, source-channel Separation and Code Design

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IEEE TRANSACTIONS ON COMMUNICATIONS 2013年第2期61卷 753-768页

作者： Timo, Roy Lechner, Gottfried Ong, Lawrence Johnson, Sarah Univ S Australia Inst Telecommun Res Adelaide SA 5001 Australia Univ Newcastle Sch Elect Engn & Comp Sci Callaghan NSW 2308 Australia

We consider a multi-way relay network with an orthogonal uplink and correlated sources, and we characterise reliable communication (in the usual Shannon sense) with a single-letter expression. The characterisation is obtained using a joint source-channel random-coding argument, which is based on a combination of Wyner et al.'s Cascaded Slepian-Wolf source coding and Tuncel's Slepian-Wolf coding over Broadcast channels. We prove a separation theorem for the special case of two nodes;that is, we show that a modular code architecture with separate source and channel coding functions is (asymptotically) optimal. Finally, we propose a practical coding scheme based on low-density parity-check codes, and we analyse its performance using multi-edge density evolution.

关键词： joint source-channel coding two-way relay network source-channel separation

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Cache-Aided K-User Broadcast channels With State Information at Receivers

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IEEE TRANSACTIONS ON INFORMATION THEORY 2024年第4期70卷 2518-2537页

作者： Reisizadeh, Hadi Maddah-Ali, Mohammad Ali Mohajer, Soheil Univ Minnesota Twin Cities Dept Elect & Comp Engn Minneapolis MN 55455 USA

We study a K-user coded-caching broadcast problem in a joint source-channel coding framework. The transmitter observes a database of files that are being generated at a certain rate per channel use, and each user has a cache, which can store a fixed fraction of the generated symbols. In the delivery phase, the transmitter broadcasts a message so that the users can decode their desired files using the received signal and their cache content. The communication between the transmitter and the receivers happens over a (deterministic) time-varying erasure broadcast channel, and the channel state information is only available to the users. We characterize the maximum achievable source rate for the 2-user and the degraded K -user problems. We provide an upper bound for any caching strategy's achievable source rates. Finally, we present a linear programming formulation to show that the upper bound is not a sharp characterization. Closing the gap between the achievable rate and the optimum rate remains open.

关键词： Coded caching joint source-channel coding broadcast channel wireless networks

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Computation Over Gaussian Networks With Orthogonal Components

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IEEE TRANSACTIONS ON INFORMATION THEORY 2014年第12期60卷 7841-7861页

作者： Jeon, Sang-Woon Wang, Chien-Yi Gastpar, Michael Andong Natl Univ Dept Informat & Commun Engn Andong 760749 South Korea Ecole Polytech Fed Lausanne Sch Comp & Commun Sci CH-1015 Lausanne Switzerland Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA

Function computation over Gaussian networks with orthogonal components is studied for arbitrarily correlated discrete memoryless sources. Two classes of functions are considered: 1) the arithmetic sum function and 2) the type function. The arithmetic sum function in this paper is defined as a set of multiple weighted arithmetic sums, which includes averaging of the sources and estimating each of the sources as special cases. The type or frequency histogram function counts the number of occurrences of each argument, which yields various fundamental statistics, such as mean, variance, maximum, minimum, median, and so on. The proposed computation coding first abstracts Gaussian networks into the corresponding modulo sum multiple-access channels via nested lattice codes and linear network coding and then computes the desired function using linear Slepian-Wolf source coding. For orthogonal Gaussian networks (with no broadcast and multiple-access components), the computation capacity is characterized for a class of networks. For Gaussian networks with multiple-access components (but no broadcast), an approximate computation capacity is characterized for a class of networks.

关键词： Distributed averaging function computation joint source-channel coding lattice codes linear source coding network coding sensor networks

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Optimal and robust communication for a uniform source

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IET COMMUNICATIONS 2012年第6期6卷 577-586页

作者： Nguyen, H. T. Ramstad, T. A. Balasingham, I. Norwegian Univ Sci & Technol NTNU Dept Elect & Telecommun NO-7491 Trondheim Norway NTNU Dept Elect & Telecommun NO-7491 Trondheim Norway Oslo Univ Hosp Intervent Ctr NO-0027 Oslo Norway Univ Oslo Inst Clin Med NO-0317 Oslo Norway

A communication system based on the joint source-channel coding principle is proposed, where a fixed-rate source encoder is used to avoid the error propagation effect as experienced when variable length coding is used and thus gain system robustness. An explicit expression of the mean square error (MSE) distortion of the system for a uniform source is derived. We provide an algorithm to achieve the optimal solution by investigating the Karush-Kuhn-Tucker (KKT) condition. The numerical results show that the overall performance of the proposed system is close to the performance of the entropy coded scalar quantiser (ECSQ) system established by A. Gyorgy and T. Under for almost all rate region. A 0.176-bits-per-sample performance loss is found for the worst case by comparing our considered system and ECSQ system. An observation resembling the finding by V. Goya1 et al. is that in the low rate region, there exist certain regimes in which the proposed system outperforms the ECSQ system. Finally, the proposed system outperforms the equal rate system with a large margin.

关键词： joint source-channel coding entropy codes error propagation effect Interpolation and function approximation (numerical analysis) entropy coded scalar quantiser combined source-channel coding variable length codes KKT condition fixed-rate source encoder optimal communication ECSQ system mean square error methods MSE distortion mean square error distortion variable length coding robust communication Karush-Kuhn-Tucker condition Codes

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