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Báo cáo hóa học: " Iterative List Decoding of Concatenated Source-Channel Codes"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài:Iterative List Decoding of Concatenated Source-Channel Codes | EURASIP Journal on Applied Signal Processing 2005 6 954-960 2005 Hindawi Publishing Corporation Iterative List Decoding of Concatenated Source-Channel Codes Ahmadreza Hedayat Multimedia Communications Laboratory The University of Texas at Dallas TX 75083-0688 USA Email hedayat@utdallas.edu Aria Nosratinia Multimedia Communications Laboratory The University of Texas at Dallas TX 75083-0688 USA Email aria@utdallas.edu Received 6 October 2003 Revised 17 June 2004 Whenever variable-length entropy codes are used in the presence of a noisy channel any channel errors will propagate and cause significant harm. Despite using channel codes some residual errors always remain whose effect will get magnified by error propagation. Mitigating this undesirable effect is of great practical interest. One approach is to use the residual redundancy of variable-length codes for joint source-channel decoding. In this paper we improve the performance of residual redundancy source-channel decoding via an iterative list decoder made possible by a nonbinary outer CRC code. We show that the list decoding of VLCs is beneficial for entropy codes that contain redundancy. Such codes are used in state-of-the-art video coders for example. The proposed list decoder improves the overall performance significantly in AWGN and fully interleaved Rayleigh fading channels. Keywords and phrases joint source-channel coding variable-length codes list decoding iterative decoding. 1. INTRODUCTION Variable-length codes VLCs for entropy coding are by now a central part of most data compression techniques which are in turn essential for many communications applications including text voice images and video. While VLCs achieve significant compression they also introduce dependencies in the data structure through their variable length thus leading to error propagation in the decoded sequence. One of the techniques that has been used to combat this undesirable effect is joint source-channel decoding. It is known .