On the existence of a class of QC-LDPC codes with girth at least six
Guohua Zhang, Xinmei Wang · Journal of Xidian University · 2011
For QC-LDPC codes with column weights of three and four,and girth of at least six,M.Hagiwara et al recently investigated the smallest value of the dimension p of the cyclic permutation matrix,and remarked that for m greater than or equal to 50,the existence of QC-LDPC codes with column weight of four,row weight of 6m+3,dimension of 6m+3 and girth of at least six,remains open.By the method of matrix combination,it is proved in this paper that there exist infinite values of m which enable such codes to exist.