Encoding of LDPC codes with an irregular parity check matrix obtained by masking

摘要

There is provided a check-matrix generating method for generating a parity check matrix for LDPC codes. The method includes a quasi-cyclic matrix generating step of generating a regular (weights of a row and a column are uniform) quasi-cyclic matrix in which cyclic permutation matrices are arranged in a row direction and a column direction and specific regularity is given to the cyclic permutation matrices; a mask-matrix generating step of generating a mask matrix for making the regular quasi-cyclic matrix into irregular (weights of a row and a column are nonuniform), the mask matrix capable of supporting a plurality of encoding rates; a masking step of converting a specific cyclic permutation matrix in the regular quasi-cyclic matrix into a zero-matrix using a mask matrix corresponding to a specific encoding rate to generate an irregular masking quasi-cyclic matrix; and a check-matrix generating step of generating an irregular parity check matrix with a low-density generation matrix (LDGM) structure in which the masking quasi-cyclic matrix and a matrix in which the cyclic permutation matrices are arranged in a staircase manner are arranged in a predetermined location.