Patent ID: 7120857
Filing Date: 2006-10-10
Classification: H03M

Abstract:
1. A low density parity code (LDPC) decoding apparatus performing LDPC decoding of a codeword formed by c code bits transmitted through a channel, the apparatus comprising: a first Q matrix generation unit receiving the codeword and a p×c parity check matrix formed of 0 and 1 values, comprising the codeword with each of p rows of the parity check matrix formed of c elements, replacing the element having a value of 1 in each of the p rows with a code bit value in a location of the codeword corresponding to the location of the c element, and generating a first Q matrix; an R matrix generation unit receiving the first Q matrix from the first Q matrix generation unit, and by using a first minimum value that is a minimum value among the elements that are not 0 in each row, a second minimum value that is a second minimum value in the same row, and the location of the first minimum value in each row of the first Q matrix, replacing the element that is not 0 in the row with the minimum value, among the remaining elements that are not 0 in the row excluding the value of the element, and generating an R matrix; a second Q matrix generation unit receiving the codeword and the R matrix from the R matrix generation unit, generating a second Q matrix by replacing each non-zero element in the R matrix with a value obtained by adding all non-zero elements in the column having the non-zero element being replaced, except the non-zero element which is being replaced, and the element in the same column of the codeword, and outputting the second Q matrix to the R matrix generation unit; and an output calculation unit receiving the R matrix from the R matrix generation unit and by determining one code bit by adding elements of each column of the R matrix, outputting a decoded codeword formed by the c code bits, wherein the R matrix generation unit receives the second Q matrix from the second Q matrix generation unit, generates a second R matrix and outputs the second R matrix to the second Q matrix generation unit and the output calculation unit.