At least a method and an apparatus are presented for decoding a signal. For example, a decoder is presented for determining an estimate of an encoded signal. The decoder comprises one or more variable node processing units and one or more check node processing units configured to exchange messages, each message comprising one or more components, a component comprising a symbol and a reliability metric associated with the symbol. The at least one check processing unit is further configured to calculate at two or more elementary check node processors a set of syndromes from at least three permuted messages, a syndrome comprising a binary vector; generate at least one check node message from the set of syndromes depending on the binary vector, and send the at least one check node message to a signal estimation unit.