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Error Recovery of variable length code over BSC with Arbitrary Crossover Probability

IEEE TRANSACTIONS ON COMMUNICATIONS 2010年第6期58卷 1654-1666页

作者： Zhou, Jiantao Au, Oscar C. Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Hong Kong Hong Kong Peoples R China

The error recovery capability of variable length code (VLC) has been considered as an important performance and design criterion in addition to its coding efficiency. However, almost all of the existing methods for evaluating the error recovery capability of VLC assume that the transmission fault is a random single bit inversion. In this paper, we consider a more generalized problem of precisely evaluating the error recovery capability of VLC in the case that the encoded bit stream is transmitted over a BSC with arbitrary crossover probability. By making use of the Perron-Frobenius Theorem, we derive a very simple expression for the exact mean error propagation rate (MEPR), and show that the variance of error propagation rate (VEPR) is zero. We also prove that in the regime of very low crossover probability, the mean error propagation length (MEPL) derived for single inversion error case approaches a scaled value of the MEPR. Furthermore, we briefly discuss the problem of evaluating the error detection capability of non-exhaustive code over BSC.

关键词： Source coding variable length code synchronization error recovery binary symmetric channel

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A variable length code transmission technique on multicode DS/SS systems

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IEICE TRANSACTIONS ON COMMUNICATIONS 1998年第3期E81B卷 625-636页

作者： Sanada, Y Araki, K Tokyo Inst Technol Fac Engn Tokyo 1528552 Japan

In this paper, a new variable length code transmission technique utilizing multicode DS/SS is proposed. A common problem associated with the use of variable length codes over wireless channels is loss of synchronization due to bit inversion caused by channel noise. The loss of synchronization produces burst errors in the received source symbols. The proposed system assigns multiple spreading codes to a single user to transmit variable length codes. The number of the spreading codes is equal to the maximum bit length of the codewords. All the bits of the codeword are spread and transmitted at one time by utilizing the assigned multiple spreading codes. Therefore no synchronization of the codeword is required. This paper evaluates the performance of the proposed technique over an AWGN channel and a Rayleigh fading channel. Our results show that the proposed technique improves the symbol error rate (SER) performance by 2-3 dB on the AWGN channel and 10-20 dB on the Rayleigh fading channel as compared with a conventional transmission technique. The source-channel coding suitable for the proposed technique improves the performance by another 15 dB on the Rayleigh fading channel. The proposed transmission technique works even in a low Es/No region.

关键词： variable length code multicode DS/SS image transmission

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A variable-length code FOR AN INCREMENTAL DISPLAY SYSTEM

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IEEE TRANSACTIONS ON COMPUTERS 1969年第7期C 18卷 643-&页

作者： HAUSE, AD WELLER, DR IEEE

A compact, simple code for a general-purpose incrementally controlled display system is described. The code consists of three 2-bit incremental bytes, three 4-bit state-control bytes, and a 16-bit data byte which supp... 详细信息

关键词： Cathode Ray Tube Display Incremental Display code Incremental Display System variable length code

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Performance Bounds and Distance Spectra of variable length codes in Turbo/Concatenated Systems

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IEEE TRANSACTIONS ON COMMUNICATIONS 2010年第9期58卷 2537-2548页

作者： Jaspar, Xavier Vandendorpe, Luc Catholic Univ Louvain Lab Telecommun & Teledetect B-1348 Louvain Belgium

variable length codes (VLCs), used in data compression, are very sensitive to error propagation in the presence of noisy channels. Addressing this problem with joint source-channel turbo techniques has been proposed in the literature and looks quite promising. But to date, most code-related conclusions are based on simulations. This paper states and proves several theoretical results about the robustness of prefix VLCs concatenated with linear error correcting codes (ECC), assuming a maximum likelihood decoder. Especially, an approximate and asymptotically tight distance spectrum of the concatenated code (VLC+ECC) is rigorously developed. Together with the union bound, it provides upper bounds on the symbol and frame/packet error rates.

关键词： variable length code turbo code interleaving gain distance spectrum union bound

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Using CSP to model the synchronisation process of variable length codes

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IEE PROCEEDINGS-COMMUNICATIONS 2006年第2期153卷 195-200页

作者： Fong, ACM Simpson, A Nanyang Technol Univ Sch Comp Engn Singapore 639798 Singapore Univ Oxford Comp Lab Oxford OX1 3QD England

variable length codes (VLC) have found widespread use for efficient encoding of symbols with unequal probabilities in many practical situations. However, bit errors can cause a loss of decoder synchronism that often leads to error propagation. Recent advances in the development of VLC that limit the effect of error propagation, Such as reversible VLC and self-synchronising VLC, contribute Further to their popularity. However, it is still important to model the performance of various VLC code sets so that comparisons can be made between different coding schemes and for different applications. Communicating sequential processes (CSP) is a well-established formal description technique that allows one to analyse the behaviour of concurrently evolving processes. It has been successfully applied to industrial-scale problems. The paper describes how CSP can be applied to the modelling of the resync process of VLC. This approach offers three main advantages. First, it complete model comprises processes and events its basic building blocks, making this approach highly scalable. Second, different semantic models provide different level of abstraction. Third, tools are available for automatic generation of sync sequences, which also provide a measure of sync performance. This facilitates comparisons of different VLC schemes in addition to code sets obtained using a given coding scheme.

关键词： probability VLC error propagation decoder synchronism CSP unequal probability abstraction level variable length codes variable length code sequences communicating sequential process automatic generation synchronisation formal description technique Other topics in statistics sync sequence codes symbol encoding synchronisation process semantic model sequential decoding

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Joint Source-Channel codes based on Irregular Turbo codes and variable length codes

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IEEE TRANSACTIONS ON COMMUNICATIONS 2008年第11期56卷 1824-1835页

作者： Jaspar, Xavier Vandendorpe, Luc Catholic Univ Louvain Lab Telecommun & Teledetect B-1348 Louvain Belgium

variable length codes (VLCs), used in data compression, are very sensitive to error propagation in the presence of noisy channels. To address this problem, several joint source-channel turbo techniques have been proposed in the literature. In this paper, we focus on pairs of source/VLC of low redundancy, i.e., when there is a good match between the source statistics and the length distribution of the VLC. It is a case not considered. extensively in the literature so far and the classical concatenation of a VLC and a convolutional code is not satisfying. Through EXIT chart and interleaving gain analysis, we show that the introduction of a repetition code between the VLC and the convolutional code considerably improves global performance. In particular, excellent symbol error rates are obtained with reversible VLCs which are used in recent source codecs.

关键词： variable length code irregular turbo code interleaving gain joint source channel EXIT chart

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Impact of variable length codes on the Interleaving Gain of Turbo Systems: The Concept of Bounded Spectrum

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IEEE TRANSACTIONS ON COMMUNICATIONS 2011年第7期59卷 1796-1806页

作者： Jaspar, Xavier Vandendorpe, Luc Univ Catholique Louvain 2 Commun & Remote Sensing Lab B-1348 Louvain Belgium

When a telecommunication system is constrained in terms of delay and complexity, it is usually wise to allow some cross-layer cooperation between the source and channel layers. In this context, the success of joint source-channel turbo techniques has been attested several times in the literature, in particular to transmit variable length code (VLC) streams which are very sensitive to error propagation. Capitalizing on previously developed performance upper bounds, this paper investigates whether the VLC can contribute to the interleaving gain of concatenated codes just as a convolutional code with non-catastrophic encoder would. To this end, the important concept of bounded VLC spectrum is introduced and is proved to be a sufficient condition for the VLC to contribute indeed to the interleaving gain. This concept is also proved to be closely related to non-catastrophic VLCs and, under certain assumptions, to the well known concept of statistically synchronizable VLCs.

关键词： variable length code linear code interleaving gain bounded VLC spectrum statistically synchronizable VLC

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Using reversible variable length codes for JPEG image transmission in a noisy channel

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ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING 2012年第2期71卷 337-341页

作者： Ashourian, Mohsen Afzal, Amir Moallem, Payman Islamic Azad Univ Majlesi Branch Dept Elect Engn Esfahan Iran Univ Isfahan Fac Engn Dept Elect Engn Esfahan Iran Islamic Azad Univ Majlesi Branch Fac Elect Engn Esfahan Iran Islamic Azad Univ Majlesi Branch Multimedia Network Lab Esfahan Iran Univ Isfahan Fac Elect Engn Esfahan Iran

JPEG coder is still the most attractive compression scheme for still image. Using Huffman coding makes the JPEG coder very sensitive to communication error. In this paper we propose a simple modification to JPEG coder by using reversible variable length code designed for the DC coefficients of each block. The results show great improvement in error resilience in a binary symmetric channel transmission with an average reduction of 5-10% in compression ratio.

关键词： Image coding Huffman JPEG variable length code

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Joint Source and Channel Decoding of variable length codes Based on Pruned VLC-Block Trellis

Joint Source and Channel Decoding of Variable Length Codes B...

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20th IEEE Symposium on Communications and Vehicular Technology in the Benelux (SCVT)

作者： Tu, Guofang Dai, Jing Univ Chinese Acad Sci Sch Elect Elect & Commun Engn Beijing 100049 Peoples R China

ISBN: (纸本)9781479932061

Joint source and channel decoding (JSCD) of variable length codes (VLCs) has been attracting considerable attention in recent years. It is a capacity-approaching technique to decode in an iterative way, or known as iterative source-channel decoding (ISCD) of VLCs. When the side information of both bit length and symbol length of the VLC sequence are available, VLC-block trellis can be constructed, which exploits the knowledge of both lengths. The ISCD based on VLC-block trellis generally performs better than that based on the more widely used Balakirsky trellis. However, the complexity of VLC-block trellis is much higher, and grows exponentially with the sequence size. In this paper we study a sub-optimal solution by pruning some states and branches of the trellis. Simulation results show that this method can adjustably reduce complexity with acceptable performance loss.

关键词： Joint source and channel decoding iterative source-channel decoding variable length code VLC-block trellis BCJR

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Design and performance analysis of joint source-channel turbo schemes with variable length codes

Design and performance analysis of joint source-channel turb...

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IEEE International Conference on Communications (ICC 2005)

作者： Jaspar, X Vandendorpe, L Catholic Univ Louvain Commun & Remote Sensing Lab B-1348 Louvain Belgium

ISBN: (纸本)0780389387

Recently, we proposed in [10] a joint source-channel (JSC) turbo-(de)coder combining a variable length code (VLC) with a turbo-code. The simulation results showed the better performance and the lower decoding complexity of this new scheme,over the previous ones. In this paper, we provide tools for the analysis and the performance prediction of this scheme. The bit, symbol and frame distance spectra are developed for VLCs and for the More general case of VLCs turbo-concatenated with an error correcting code (ECC). These spectra are then used to get the union bounds on the bit, symbol and frame error probabilities, and to shed some light on previous :simulation-based results. These tools are also valid for a wide variety of other similar schemes currently explored in the literature and, hence, can be used to analyze and to compare them.

关键词： variable length code iterative decoding joint source channel bound concatenated codes serial concatenation turbo codes puncturing

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