Study And Simulation On Decoding Algorithm Of LDCP Codes

Low Density Parity Check codes is currently one of the pop research theses in error-correcting coding of communication field, it is the powerful competition in the 4th generation of mobile communication system.This paper presents two major types of decoding algorithm for LDPC codes, they are hard decision and soft decision decoding. Some simulations and performance comparisons on different decoding algorithms are carried out. An improved belief propagation (BP) decoding scheme is put forward to solve the high complexity and low decoding efficiency problems of traditional BP algorithms in LDPC codes. The proposed decoding scheme employs a judging rule based on illegal check number and Log Likelihood Ratio of probability to evaluate every variable node's reliability before each step of iteration, some variable nodes quit iteration cycle when they meet the rule. The decoding operation will stop as all variable nodes quit iteration cycle.All of comprehensive study and simulations on decoding algorithms of LDPC codes are proved that the improved algorithm is employed to obtain less calculation and better decoding performance, so it has higher practical value.