Patent ID: 8457254

Claim:
A method of equalizing inter-symbol interference (ISI) present in a received signal corresponding to a transmitted signal carried over a channel, comprising: grouping points of a constellation used to modulate the transmitted signal into a plurality of subsets, at least two adjacent ones of the subsets having one or more common constellation points so that the at least two adjacent subsets overlap; determining a centroid-based value for each of the subsets of constellation points; localizing a search for a final symbol decision at a non-final equalization stage of a multi-stage equalizer using a set of the centroid-based values as constellation points; suppressing residual self-interference which arises from using the set of centroid-based values as constellation points to localize the search for the final symbol decision instead of the constellation points used to modulate the transmitted signal; determining the final symbol decision at a final equalization stage of the multi-stage equalizer using a subset of the constellation points used to modulate the transmitted signal; modeling a total noise signal, including the residual self-interference, as a colored noise; suppressing the colored noise with a whitening filter as part of a maximum likelihood sequence estimator of the non-final equalization stage; whitening the total noise signal, including the residual self-interference, at the maximum likelihood sequence estimator along a trellis path leading to state j; computing an innovation value at the maximum likelihood sequence estimator for each of N states along the trellis path, where N is an integer, the whitening filter having N+1 taps and each of the innovation values accounting for the residual self-interference at the respective states; and determining a branch metric for a portion of the trellis path from state j−1 to state j based on the innovation values computed for the N states.