Patent ID: 7032164
Filing Date: 2006-04-18
Classification: H03M,H04L

Abstract:
1. A soft-in soft-out functional block (SISO), within a turbo trellis coded modulation (TTCM) decoder, that calculates extrinsic information when iteratively decoding a plurality of symbols of a received data frame, the plurality of symbols being encoded according to a rate control sequence, the SISO comprising: an extrinsic calculation functional block that determines a plurality of minimum extrinsic outputs and a plurality of log extrinsic outputs according to the rate control sequence, the extrinsic functional block employs a plurality of trellis metrics, a plurality of forward metric values (alphas) and a plurality of backward metric values (betas) corresponding to a trellis, and a plurality of ‘a priori’ probability values (apps); an extrinsic decoding functional block that determines extrinsic information corresponding to input bits of symbols of the plurality of symbols using the plurality of minimum extrinsic outputs and the plurality of log extrinsic outputs, the decoding functional block also decodes the input bits using the extrinsic information corresponding to the input bits and the apps corresponding to the input bits; and an uncoded bit selection determination functional block that determines an uncoded bit select value that is used to selectively decode an uncoded bit when at least one symbol of the plurality of symbols comprises the uncoded bit; and wherein the uncoded bit selection determination functional block uses the decoded input bits to select a best estimate of the uncoded bit.