Research On Construction Of Rate Compatible Low Density Parity Check Codes And Their Applications

Recently, regarded as one of the key symbols of rapid development on communication technology, channel coding has gained its splendid progress in both theoretical and practical fields. Low density parity check (LDPC) codes, which are recognized as the most significant breakthrough after Turbo codes, draws increasing attention from all over the world. Thanks to its excellent performance, LDPC codes have been widely considered as next-generation error-correcting codes for telecommunication and magnetic storage. The work in this thesis mainly focuses on the rate-compatible LDPC codes. A novel strategy to construct RC-LDPC codes is proposed. Based on it, several construction algorithms and hardware schemes are presented. A novel type II hybrid ARQ scheme by using RC-LDPC codes is also proposed.In this thesis, the background of channel coding and the development of LDPC codes are first introduced. Then after summarizing and analyzing the classic algorithms of decoding and encoding, some important conclusions are found to direct the construction of LDPC codes. Based on them, the representatives of both random construction by computer search and mathematical construction are analyzed.The theory of finite geometries and construction approaches of QC-LDPC codes based on them are introduced in this thesis. Because QC-LDPC codes can be encoded in the linear time, they are important and helpful to the complexity-limited systems. Extended and shortened QC-LDPC codes are investigated to produce the new codes at different rate codes.It is innovative to present a brand-new strategy and several novel algorithms based on it to construct RC-LDPC codes. Using the new algorithms, a sequence of RC-LDPC codes across a range of rates can be decoded by a single decoder. A novel scheme to encode the constructed RC-LDPC codes in the linear time is also proposed.QC-LDPC codes and RC-LDPC codes, two practical channel coding techniques can be combined by using presented new strategy creatively. The encoding schemes to implement quasi-cyclic RC-LDPC codes are investigated in detail.As a useful application in the practical commutation systems, a novel scheme for type-II hybrid ARQ protocols using RC-LDPC codes are proposed as well in this thesis.