Methods for decoding, methods for retrieving, methods for encoding, method of transmitting, corresponding devices, information storage means and computer

摘要

A method for decoding comprises the following steps: receiving a first codeword comprising a plurality of elements of a first finite commutative group and associated to a plurality of symbols in accordance with a first code defining codeword elements by respective summations in said first commutative group; determining, by applying a projection onto elements of the first codeword, a second codeword comprising a plurality of elements of a second finite commutative group having a cardinal strictly smaller than the cardinal of the first finite commutative group, wherein the projection is a morphism from the first finite commutative group to the second finite commutative group; decoding the second codeword in accordance with a second code defining codeword elements by respective summations in said second commutative group.