A receiver, including a memory unit and a processor, wherein the memory unit stores a sorted parity check matrix that is sorted according to reliabilities of columns; wherein reliabilities of columns are responsive to values of information elements of a soft demodulated received information block, wherein the processor is adapted to: (a) iterate over columns of the sorted parity check matrix to find independent columns and dependent columns; (b) find non-redundant dependent columns out of the dependent columns; wherein the finding is responsive to a relationship between a reliability of a dependent column and a reliabilities of multiple independent columns on which the dependent column depends; (c) select, out of a group of combinations of columns, a selected combination; wherein each combination of the group equals a syndrome; wherein the group of combinations includes independent columns and the non-redundant dependent columns; and (d) correct errors in response to the selected combination.