Patent ID: 7216283
Filing Date: 2007-05-08
Classification: H03M,H04L

Abstract:
1. A decoding method that performs updating of a bit metric when decoding an LDPC (Low Density Parity Check) coded signal, the method comprising: receiving a symbol block of the LDPC coded signal wherein the symbol block includes a plurality of symbols; mapping a symbol of the plurality of symbols according to a code rate and modulation that corresponds to the symbol wherein the modulation includes a constellation and a mapping; making initial estimates of I,Q (In-phase, Quadrature) values of the symbol at a plurality of symbol nodes that are connected to a plurality of bit nodes within an LDPC bipartite graph that includes a plurality of edges that connect a plurality of bit nodes to a plurality of check nodes; computing a plurality of m-bit symbol metrics that correspond to the symbol wherein the symbol has m-bits; with respect to the plurality of symbol nodes, calculating a plurality of bit metrics that corresponds to the m-bits of the symbol using the plurality of m-bit symbol metrics; passing the plurality of bit metrics from the plurality of symbol nodes to the plurality of bit nodes connected thereto; performing iterative decoding processing that includes: making hard decisions of the m-bits of the symbol using the latest updated soft bit information corresponding to the m-bits of the symbol.