Patent ID: 8306102

Claim:
A method of demodulating a received signal corresponding to a transmitted signal carried over a channel, comprising: grouping points of a constellation associated with the transmitted signal into a plurality of subsets, adjacent ones of the subsets having one or more common constellation points so that at least two adjacent subsets overlap; determining a centroid-based value for each of the subsets of constellation points; grouping the centroid-based values into one or more sets for input to a demodulator having a plurality of stages wherein a first one of the stages localizes the search for a final symbol decision by: demodulating the received signal using the set of centroids input to the first stage to generate a localized symbol decision output by the first stage; generating a re-modulated signal associated with the first stage as a function of the localized symbol decision generated by the first stage and the channel over which the transmitted signal is carried; and removing the re-modulated signal associated with the first stage from the received signal to generate a modified signal for input to the stage immediately following the first stage; demodulating the received signal using the demodulator, each of the stages except for a last one of the stages localizing a search for the final symbol decision using the set of centroid-based values input to or selected by the stage as constellation points and the last stage generates a localized symbol decision for determining the final symbol decision by using one of the subsets of constellation points input to or selected by the last stage; and summing each of the localized symbol decisions generated by each of the plurality of stages to generate the final symbol decision.