Patent ID: 7516391

Claim:
A method for an encoder by generating a block low density parity check (LDPC), the method comprising the steps of: receiving an information word; and generating a block LDPC code by coding the information word using one of a first parity check matrix and a second parity check matrix depending on a length to be applied when generating the block LDPC code, wherein the second parity check matrix is a parity check matrix defined by varying a size of the first parity check matrix, the first parity check matrix is a parity check matrix generated such that the block LDPC code has a predetermined length and is satisfied with a predetermined coding rate, the first parity check matrix includes a predetermined number of partial blocks, and each of the partial blocks having a predetermined size, when the coding rate is ½, the first parity check matrix is expressed as one of the 5 tables shown in FIGS. 18 , 22 , 23 , 26 and 27 , wherein, in each of the 5 tables, blocks represent the partial blocks, numbers represent exponents of corresponding permutation matrixes, and blocks with no number represent partial blocks to which zero matrixes are mapped.