Research Pn Construction Of Structured LDPC Codes Based On Matrix Masking

Low-Density Parity-Check (LDPC) codes are a class of capacity approaching gooderror-correcting codes. By using linear time complexity belief propagation iterativedecoding algorithm, LDPC codes can get near Shannon limit decoding performance withalmost all errors detectable. Due to the advantages of LDPC codes, their applications inreliable communications have received great interests and have become one of mostattractive field in channel coding community. Now, the application of LDPC has been puton the agenda.This dissertation mainly focuses on the construction of structured LDPC codesbased on Finite Field and Euclidean Geometries, and presents some methods forconstructing regular and irregular LDPC codes using matrix masking. Some results areobtained and summarized as follow:1. The basic principle of LDPC codes is illuminated. Two classes of constructionof LDPC codes are introduced. The principles of coding and decoding for low-densityparity-check codes are briefly summarized.2. An analysis of RC-constrained and matrix extention of element in Finite Fieldis made in detail. The special construction methods of structured LDPC codes based onFinite Field are represented. Simulation results show that the array codes can lead togood structure and avoid4-cycle effectively.3. An intensive study of the construction of LDPC codes based on EuclideanGeometries is made, with the principle of decomposition, a good structured LDPCcodes are constructed, Simulation results show that it performs well.4. A construction of regular and irregular LDPC codes using matrix masking isrealized, and its good property of structure is deeply analyzed. The codes constructedabove perform better than Mackay codes with iterative decoding over AWGN channel.