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: Research Article Joint Source and Channel Decoding for Variable Length Encoded Turbo Codes | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Article ID 149839 7 pages doi 2008 149839 Research Article Joint Source and Channel Decoding for Variable Length Encoded Turbo Codes Jianjun Liu 1 Guofang Tu 1 Can Zhang 2 and Yang Yang1 1 School of Information Science and Engineering Graduate University of Chinese Academy of Sciences Beijing 100049 China 2 State Key Laboratory of Information Security Chinese Academy of Sciences Beijing 100049 China Correspondence should be addressed to Jianjun Liu jjliu@ Received 29 November 2006 Revised 19 April 2007 Accepted 16 September 2007 Recommended by Huaiyu Dai Joint source and channel decoding JSCD has been proved to be an effective technique which can improve decoding performance by exploiting residual source redundancy. Most previous publications on this subject focus on a traditional coding scheme in which the source variable-length coding VLC is serially concatenated with a channel code. In this paper a parallel concatenated coding scheme for the VLC combined with a turbo code is presented. By merging a symbol-level VLC trellis with a convolutional trellis we construct a symbol-level joint trellis with compound states. Also a solution of the symbol-by-symbol a posteriori probability APP decoding algorithm based on this joint trellis is derived which leads to an iterative JSCD approach in the similar way to the classical turbo decoder. The simulation results show that our joint source-channel en decoding system achieves some gains at the cost of increasing decoding complexity when compared to the joint iterative decoding based on the bit-level super trellis for the separate coding system. Copyright 2008 Jianjun Liu et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION .
