A modified decoding algorithm involving priori characteristics bits for LDPC

The initial condition of BP decoding algorithm for Low-Density Parity-Check code(LDPC)which is based on the knowledge of channel has greatly affected the performance of the algorithm. In ultra-high-speed optical transmission systems, the probability of correction of each bit transmitted will have shown some relativity. In this paper, we introduce a new method which can be used to estimate the state of the channel by using prior information of some watermark bits. The simulation results show that the performance of the modified decoding algorithm can be improved and the complexity can be reduced effectively.