Patent ID: 8171374

Claim:
An LDPC check matrix generation method in a communication system for generating a check matrix H 1 of a code C 1 from a check matrix H 0 of a code C 0 , where the codes C 0 and C 1 are LDPC systematic codes having different encoding ratios in a rate-compatible relationship, and information bit sizes of the systematic codes C 0 and C 1 are K respectively, and parity bit sizes thereof are M 0 and M 1 (M 0 <M 1 , M 1 −M 0 =L) respectively, the method comprising: selecting L number of rows out of the check matrix H 0 ; separating an information bit portion and a parity bit portion constituting each of the selected rows into two respectively, such that each of the separated information bit portions includes one or more non-zero elements which are “elements different from 0”; creating a new first row by coupling one separated information bit portion and one separated parity bit portion and creating a new second row by coupling another separated information bit portion and another separated parity portion; and generating, in a check matrix generator, the check matrix H 1 of the systematic code C 1 by placing the new first and second rows in place of each of the selected L number of rows in the check matrix H 0 .