A Novel Hybrid Decoding Algorithm for Convolutional Codes
Yang Fan①; Luo Zhen-dong②; Tian Bao-yu①
①School of Information Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China;②Institute of Communication Standards Research China Academy of Telecommunication Research of Ministry of Information Industy (MII), Beijing 100045, China
Abstract：A concatenated hybrid decoding algorithm for convolutional codes is presented. The algorithm is complemented by using two-stage decoding, where the first stage uses the Belief-Propagation (BP) algorithm, while the second stage uses the Modified Viterbi Decoding (MVD) algorithm. Firstly, the received sequence is pre-decoded by BP, and its outputs are divided into two groups which are reliable Log-Likelihood Ratios (LLRs) and unreliable LLRs. The hard decision symbols corresponding to reliable LLRs and the parts of received symbols corresponding to unreliable LLRs are formed a hybrid sequence, which is further corrected by MVD. Simulation shows that compared with the conventional Viterbi decoding algorithm, the proposed algorithm has a little performance deterioration with much lower average complexity at moderate-to-high signal to noise ratio.
2009, Vol. 31 
