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Proceedings Paper

MAP decoding of variable length codes over noisy channels
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Paper Abstract

In this paper, we discuss the maximum a-posteriori probability (MAP) decoding of variable length codes(VLCs) and propose a novel decoding scheme for the Huffman VLC coded data in the presence of noise. First, we provide some simulation results of VLC MAP decoding and highlight some features that have not been discussed yet in existing work. We will show that the improvement of MAP decoding over the conventional VLC decoding comes mostly from the memory information in the source and give some observations regarding the advantage of soft VLC MAP decoding over hard VLC MAP decoding when AWGN channel is considered. Second, with the recognition that the difficulty in VLC MAP decoding is the lack of synchronization between the symbol sequence and the coded bit sequence, which makes the parsing from the latter to the former extremely complex, we propose a new MAP decoding algorithm by integrating the information of self-synchronization strings (SSSs), one important feature of the codeword structure, into the conventional MAP decoding. A consistent performance improvement and decoding complexity reduction over the conventional VLC MAP decoding can be achieved with the new scheme.

Paper Details

Date Published: 25 October 2005
PDF: 9 pages
Proc. SPIE 6015, Multimedia Systems and Applications VIII, 60150L (25 October 2005); doi: 10.1117/12.630926
Show Author Affiliations
Lei Yao, The Univ. of Mississippi (United States)
Lei Cao, The Univ. of Mississippi (United States)
Chang Wen Chen, Florida Institute of Technology (United States)

Published in SPIE Proceedings Vol. 6015:
Multimedia Systems and Applications VIII
Anthony Vetro; Chang Wen Chen; C.-C. J. Kuo; Tong Zhang; Qi Tian; John R. Smith, Editor(s)

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