Patent ID: 7757151
Filing Date: 2010-07-13
Classification: H03M

Abstract:
1. A method of decoding channel samples to generate decoded data, the method comprising the steps of: for a given time instant, (a) updating forward and backward state metrics of a trellis having corresponding states for decoded channel samples using one or more paths that are only surviving paths; and (b) calculating reliability information for decoded channel samples from the updated forward and backward state metrics using only the one or more surviving paths through the trellis, wherein: the method is embodied in a simplified maximum a posteriori (SMAP) decoding algorithm employed as steps of a constituent decoding method of a turbo decoder, the SMAP decoding algorithm adapted to calculate reliability information as a log-likelihood ratio for a log-MAP algorithm using a reduced set of path metrics recursively updated based on maximum likelihood recursion; and the constituent decoding method further includes the steps of decoding the channel samples with at least one other decoding algorithm, wherein reliability information in the other decoding algorithm is calculated using at least one non-surviving path.