Design And Application Of Rate Compatible LDPC Code

Low-Density Parity-Check (LDPC) codes have received a lot of attention because of near-Shannon performance and low decoding computation complexity. As the improvement of Encoding Algorithm and Decoding Algorithm, the implementation of LDPC Codes has become more and more easy. Nowadays, LDPC Codes is been used in DVB-S2,802.16e,802.11n and the CMMB standard. However, the implementation of Rate-compatible LDPC codes is not flexible as that of Turbo Codes, which is an obstacle of the application in Mobile system. Our research is to solve this problem.We focus on the structure of LDPC Codes. By constructing the H Matrix via PEG Algorithm and using the degree distribution optimized by EXIT Charts with an improved structure, we found that it can make the implementation of RC-LDPC Codes more flexible without any loss of performance. The structure can be modified to implement decomposable RC-LDPC (D-RC-LDPC) Codes by farther research. The D-RC-LDPC can be used in an innovational HARQ Scheme to improve the throughput of the system at low SNR. These improvements can promote the application of LDPC Codes in Mobile System.However, how to make the code length and code rate flexible at any code length is still a big challenge. Then, we will focus our research on this problem.