Patent ID: 8468438

Claim:
A method of elementary updating of a check node of a graph of a non-binary Low Density Parity Check (LDPC) code during a decoding of a block encoded with said LDPC code, comprising: receiving a first input message and a second input message each comprising n m doublets, each doublet possessing a symbol and a metric associated with said symbol, the input messages being ordered according to a monotonic function applied to the metrics, delivering an output message possessing n m output doublets by (i) computing a matrix comprising a first subset of p combined doublets on the basis of a combination of the doublets of the two input messages, p being greater than n m , the p combined doublets possessing either the largest metrics or the lowest metrics and forming a chosen pattern within the matrix, and (ii) reducing the first subset so as to obtain the n m output doublets of the output message possessing either the n m largest metrics or the n m lowest metrics, and (iii) tagging redundant symbols within each input message; and fixing at a reference value dependent on the choice of the values of metrics retained for the n m output doublets, the value of the metric of each combined doublet resulting from a combination of at least one doublet comprising a tagged redundant symbol.