Research on LDPC Code Decoding Algorithm Based on Scheduling Strategy

With the rapid development of the channel coding technology, low density parity check(LDPC) code has been widely concerned by researchers all of the world as an approaching code to Shannon limit. Error floor is an important issue in the theory of LDPC codes and the research of iterative decoding algorithms. Based on the decoding of LDPC codes, a new improved decoding algorithm, Group Belief Propagation (GBP) based on variable nodes is proposed for the different scheduling strategies of the LDPC codes. According to the difference between the messages and the hard decision values, the variable nodes are divided into reliable nodes and unreliable nodes. And the unreliable nodes are priority to update. Further, the effect of threshold for judging the group on GBP strategy is analyzed. Simulation results show that the proposed algorithm can achieve better convergence and decoding performances compared to three classical scheduling algorithms. Meanwhile, it can overcome the error floor phenomenon caused by the trapping set effectively.