Research On The Iterative Decoding Algorithm Over The Erasure Channel

Low-Density Parity-Check (LDPC) codes are a class of capacity approaching error- correcting codes. By using low complexity sum-product algorithm, LDPC codes can get near Shannon limit decoding performance. For long code lengths, LDPC codes can even outperform Turbo codes. Due to the advantages of LDPC codes, their applications in reliable communications have received great interests and have become one of most attractive field in channel coding community. Now, the application of LDPC has been put on the agenda.Based on an in-depth understanding of LDPC codes'basic encoding and decoding theory, the decoding algorithm of LDCP over the Binary Erasure Channel (BEC) is studied. The main contents and results are as follows:1.Based on Factor Graph model, the classification and features of LDPC codes are illuminated. The principle of Message-Passing algorithm is analyzed, and the Belief Propagate algorithm is expatiated.2. Based on the analysis of the impact of stopping set and circle on LDPC codes'iterative decoding performance, an improved decoding algorithm is presented. The simulation results show that the new algorithm could decrease guess times efficiently, thus the decoding performance is raised.3.The calculation method of LDPC code's threshold over erasure channel with density evolution method is presented, simulation results shows that this calculation method of LDPC code's threshold is correct.