Patent ID: 7203893

Claim:
In a receiver comprising a decoder, a method of decoding a transmitted word of a linear block code (n, k) of length n and dimension k in a signal received via a communication channel, the method comprising the steps of: providing input information related to the transmitted word to the decoder, said input information comprising a sequence of samples of the signal or at least in part obtained from said sequence; using one or more computation devices for estimating original transmitted data by performing the following steps: forming a reliability vector from the input information; identifying (n−k) linearly independent least reliable symbols and k most reliable symbols, and converting a parity check matrix P of the linear block code to a pseudo-systematic parity check matrix Ps with respect to the least reliable symbols so that each of (n−k) parity equations associated with the (n−k) rows of the pseudo-systematic parity check matrix Ps includes only one least reliable symbol; determining extrinsic information for each most reliable symbol from the input information and the pseudo-systematic parity check matrix Ps, and storing said extrinsic information; e) generating output information providing an estimate of the original transmitted data by calculating extrinsic information for the least reliable symbols using parity equations associated with the rows of the pseudo-systematic parity check matrix Ps, the input information, and the stored extrinsic information for the most reliable symbols, and/or assigning hard information values for the least reliable symbols using parity equations associated with the rows of the pseudo-systematic parity check matrix Ps, and hard information values for the most reliable symbols.