A simple algorithm for asymptotically optimal reduced-state sequence estimation

A simple algorithm for reduced-state sequence estimation on channels with intersymbol interference is presented. The algorithm is based on the conventional Viterbi algorithm. The number of states is reduced by discarding trellis-paths based on their (modified) path metric and the minimum Euclidean distance in the trellis. An analysis of the error-event probability shows that the algorithm achieves the performance of the maximum likelihood sequence estimator at high signal-to-noise ratios. The computational complexity and memory requirements of the algorithm are derived, the implementation of the algorithm is described in detail and simulation results for a severe ISI channel are provided.