Patent ID: 7617441

Claim:
A method, comprising: for each non-zero sub-matrix in a row of a first LDPC (Low Density Parity Check) matrix that includes a plurality of sub-matrices, selecting a corresponding shift value that is less than at least one of a number of columns and a number of rows of each sub-matrix of the plurality of sub-matrices; for every non-zero sub-matrix of the first LDPC matrix except those sub-matrices in the row, selecting a corresponding shift value such that the corresponding shift values corresponding to all of the plurality of sub-matrices of the first LDPC matrix corporately either: induce cycles of a first predetermined size in a first LDPC bipartite graph of a first LDPC code that corresponds to the first LDPC matrix; or induce no cycles smaller that a second predetermined size in the first LDPC bipartite graph of the first LDPC code that corresponds to the first LDPC matrix; performing cyclic shifting according to the selected shift value corresponding to each non-zero sub-matrix of the first LDPC matrix thereby generating a plurality of CSI sub-matrices; arranging the plurality of CSI sub-matrices and any all-zero-valued sub-matrix of the first LDPC matrix thereby generating a second LDPC matrix that corresponds to a second LDPC code; and employing the second LDPC matrix when processing an LDPC coded signal.