The invention relates to a
low density parity check (LDPC) code check matrix construction method and a corresponding matrix multiply operation device. The method comprises the following steps that: determining the length n*L of a
code word, the size L of a circulating replacement sub-matrix, a
code rate L and number of rows m*L of a check matrix, wherein the size Hb of a basic matrix is m*n, the size H of the check matrix is mL*nL; determining best distribution of the check matrix H; constructing a basic matrix Hb with maximal
loop length; exapdning the obtain basic matrix Hb to a quasi-cyclic-
low density parity check (QC-LDCP) code with the
loop length being maximized by selecting an appropriate movement factor, and determining the entire check matrix H by selecting the movement factor with element of a 1 position in the basic matrix Hb. The device comprises a check parity
generating unit, an information sequence
generating unit, a segmenting unit and a multiply unit. Due to the adoption of the method and the device, the coding complexity is reduced, the LDPC code with an
error check performance being very approximate to a
random structure is obtained, and simultaneously the realization complexity of the LDPC code is reduced.