Xilinx, Inc.
Sub-matrix reduction for quasi-cyclic LDPC codes

Abstract:

A decoder circuit includes an input to receive a first codeword encoded based on a quasi-cyclic low-density parity-check (QC LDPC) code. The first codeword includes a sequence of data arranged according to an order of columns in a first parity-check matrix associated with the QC LDPC code. A codeword reordering stage generates a reordered codeword by changing the sequence of the data in the first codeword based at least in part on a size of one or more circulant submatrices in the first parity-check matrix. An LDPC decoder generates a decoded codeword by decoding the reordered codeword based on a second parity-check matrix associated with the QC LDPC code. In some implementations, the second parity-check matrix may comprise a plurality of second circulant submatrices of a different size than the first circulant submatrices.