Multi-Round Joint Belief Propagation Decoding with Perturbation for JSCC System Based on DP-LDPC Codes

In this paper, a multi-round joint belief propagation (BP) decoding with perturbation algorithm is proposed for joint source-channel coding (JSCC) system based on double protograph low-density parity-check (DP-LDPC) codes to improve decoding performance. In the proposed algorithm, the joint BP decoding is concatenated with cyclic redundancy check (CRC). The reliability of each variable node (VN) is evaluated in the joint BP decoding algorithm, and the CRC is used to check the error which is undetected by the joint BP. When error is detected, re-decoding process with perturbation for the unreliable VN is aroused. The simulation results indicate that the proposed method has a better bit error rate (BER) performance in comparison with the traditional joint BP algorithm.