The Research Of Decoding Algorithms Of LDPC Codes

Achieving reliable communication approaching Shannon`s capacity limit at effective power cost is the ultimate object of modern channel coding technique. The invention and development of low-density parity-check codes (LDPC) narrow the gap between real system performance and channel capacity. Combing the existing theoretic and pratical fruits, researchers focus on the designing of powerful LDPC codes with low coding and decoding complexity. In this dissertation, LDPC codes decoding algorithm are investigated.Firstly, The present situation of the development of error-correcting code and LDPC codes, as well as some problems in this area are pointed out. Secondly, some fundamental theories and the structure of LDPC encoder and decoder are described. According to these, some analyses for the performance of LDPC codes are presented.Thirdly, in order to increase decoding rate without any effect on bit error rate, A difference-based decoding method is put forward which can simplify calculation without negative effect on the performance of algorithm process. Analyse with experiment is given then.Finally, a linear calibration of BP decoding algorithm is put forward which can simplify calculation complexity and make hardware convenient without negative effect on the performance of algorithm process.Although the theory and application of LDPC codes have get along well, there are many problems need to be solved, such as the conflict between simplification and reduced performance of BP decoding algorithm. It must be admitted that LDPC codes have excellent performance. They are another upsurge in error-correctingarea after Turbo codes. They have wide prospect. And LDPC codes are power competitor of Turbo codes in many communications and digital memory systems which require high reliability.