Construction Of LDPC Codecheck Marix Girth Greater Than Or Equals To 8

Low-density parity check code(LDPC)is a kind of error correction code developed recently,has been used in various communication systems widely,theory research has become more and more mature,using graph theory and method for constructing a parity check matrix and Tanner graph can avoid short ring in code words to optimize LDPC codes,It has been a new field of LDPC code research.This paper mainly focus on the structural problems LDPC check matrix,summarizes the research development status,present a more in-depth look at the construction process of LDPC code check matrix.Use the newest research results in the construction of bipartite graph,generate a bipartite graph which girth greater than or equals to 8,It can be used for the construction of Tanner graph,after some process with a rule for generated matrix,A tanner graph and check matrix that follow the norm of LDPC codes.Combine the basis matrix has been constructed and the construction method of QC-LDPC codes used cyclic shift matrices with good property to form the check matrix with girth greater than or equals to 8 which easy for storage and decoding implementation,and do some simulation to verify the construction method.