Patent ID: 7882414

Claim:
A method for transmitting a signal, supporting a variable coding rate, in a communication system, comprising: generating a child parity check matrix based on a parent parity check matrix according to a coding rate to be applied for generating a block Low Density Parity Check (LDPC) codeword; and generating the block LDPC codeword by encoding an information vector according to the child parity check matrix, wherein the parent parity check matrix includes a plurality of sub-blocks and child parity check matrixes corresponding independently to a plurality of coding rates each of the child parity check matrixes is generated such that it has an optimal degree distribution detected based on an optimal degree distribution of a child parity check matrix corresponding to a minimum coding rate among the child parity check matrixes, and the parent parity check matrix has a form of a parity check matrix of a semi-systematic block LDPC code in which a single parity check code is concatenated according to particular punctured information bits among a plurality of information bits included in the information vector.