Soft source decoding with applications

Bystrom, M.; Kaiser, Susanna; Kopansky, A.

doi:10.1109/76.954497

Cited by 49 publications

(26 citation statements)

References 24 publications

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“…The corresponding complexity is actually not tractable for typical sequence lengths. In order to overcome this complexity hurdle, most authors apply suboptimal estimation methods on this optimal state model such as sequential decoding [14][16] [17].…”

Section: Introductionmentioning

confidence: 99%

Synchronization Recovery and State Model Reduction for Soft Decoding of Variable Length Codes

Malinowski

Guillemot

2007

IEEE Trans. Inform. Theory

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Abstract-Variable length codes (VLCs) exhibit desynchronization problems when transmitted over noisy channels. Trellis decoding techniques based on Maximum A Posteriori (MAP) estimators are often used to minimize the error rate on the estimated sequence. If the number of symbols and/or bits transmitted are known by the decoder, termination constraints can be incorporated in the decoding process. All the paths in the trellis which do not lead to a valid sequence length are suppressed. This paper presents an analytic method to assess the expected error resilience of a VLC when trellis decoding with a sequence length constraint is used. The approach is based on the computation, for a given code, of the amount of information brought by the constraint. It is then shown that this quantity as well as the probability that the VLC decoder does not re-synchronize in a strict sense, are not significantly altered by appropriate trellis states aggregation. This proves that the performance obtained by running a length-constrained Viterbi decoder on aggregated state models approaches the one obtained with the bit/symbol trellis, with a significantly reduced complexity. It is then shown that the complexity can be further decreased by projecting the state model on two state models of reduced size.

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Section: Introductionmentioning

confidence: 99%

Synchronization Recovery and State Model Reduction for Soft Decoding of Variable Length Codes

Malinowski

Guillemot

2007

IEEE Trans. Inform. Theory

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“…It can be evaluated as follows: (6) Given that AC is close to ideal, so that the codeword bits are almost independent and equally likely, we can assume . Consequently, depends only on the a priori probability , which represents the input of the AC SISO decoder.…”

Section: A App Computationmentioning

confidence: 99%

“…The possibility of exploiting the residual redundancy of VLC as a form of implicit error protection has been studied in [4] and [5], where maximum a posteriori (MAP) decoding of Huffman codes in presence of transmission errors is proposed. A code construction technique for VLC with a given Hamming distance is presented in [6], where VLC MAP decoding performance is Manuscript received March 13, 2006; revised February 1, 2007. The associate editor coordinating the review of this manuscript and approving it for publication was Dr. Ricardo L. de Queiroz.…”

Section: Introductionmentioning

confidence: 99%

Iterative Decoding of Serially Concatenated Arithmetic and Channel Codes With JPEG 2000 Applications

Grangetto

Scanavino

Olmo

et al. 2007

IEEE Trans. on Image Process.

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Abstract-In this paper, an innovative joint-source channel coding scheme is presented. The proposed approach enables iterative soft decoding of arithmetic codes by means of a soft-in soft-out decoder based on suboptimal search and pruning of a binary tree. An error-resilient arithmetic coder with a forbidden symbol is used in order to improve the performance of the joint source/channel scheme. The performance in the case of transmission across the AWGN channel is evaluated in terms of word error probability and compared to a traditional separated approach. The interleaver gain, the convergence property of the system, and the optimal source/channel rate allocation are investigated. Finally, the practical relevance of the proposed joint decoding approach is demonstrated within the JPEG 2000 coding standard. In particular, an iterative channel and JPEG 2000 decoder is designed and tested in the case of image transmission across the AWGN channel.

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“…Bystrom et al [1] investigated a scheme for soft decoding of Variable Length Code (VLC) data in MPEG-4 video. In the scheme, the number of bits and the number of codewords in a coded bitstream are transmitted in an error-free side-channel.…”

Section: Introductionmentioning

confidence: 99%