A simple design for large girth LDPC matrix

This paper describes an alternative method for designing regular quasi-cyclic LDPC codes with large girths. The permutation matrix was designed based on the geometric sequence and prime number field. The design starts with a portion of the full-range matrix with column weight of 3. With a decided code rate, elements in the rows are extended by adding a certain column of the same full-range matrix into the designing matrix. Resulted codes can offer relatively good performance compared to the published literatures.