Embodiments of the invention provide a decoder for decoding a signal represented by a vector of information symbols received through a transmission channel in a communication system, said the transmission system being represented by a channel state matrix, said information symbols being selected from a given set of values carrying a set of information bits, wherein said decoder comprises: a division unit (202) configured to divide the channel state matrix into a number of sub-blocks of column vectors, in accordance with a division of said vector of information symbols into a number of sub-vectors; a permutation unit (203) configured to determine a set of permuted channel state matrices by permuting said sub-blocks of column vectors, the permutation unit (203) being further configured to select at least one permuted channel state matrix among said set of permuted channel state matrices according to a selection criterion; a sub-block decoding unit (207) configured to determine a transformed signal from said signal and said at least one permuted channel state matrix and determine at least one estimate of each sub-vector of information symbols from said transformed signal by applying at least one iteration of a decoding algorithm; The decoder being configured to determine at least one estimate of a vector of transmitted information symbols from said at least one estimate of each sub-vector of information symbols.