Sequential sequence estimation for multiple-channel systems withintersymbol and interchannel interference

A vector sequential sequence estimator is proposed for multiple-channel systems with both intersymbol interference (ISI) and interchannel interference (ICI). Both finite ISI-ICI and infinite ISI-ICI are considered. The estimator consists of a multiple-dimensional whitened matched filter and a vector sequential decoder. The metric of the sequential algorithm is derived, and the algorithm's performance is analyzed. Computer simulation results for a two-dimensional finite ISI-ICI channel and a two-dimensional infinite ISI-ICI channel are presented. Analysis and simulation show that the symbol error probability of the vector sequential algorithm is essentially the same as for maximum-likelihood sequence estimation using the vector Viterbi algorithm, while its average computational complexity is much less, although computation per symbol is a random variable with the Pareto distribution. There exists a signal-to-noise ratio above which the ensemble average computation is bounded. An upper bound on this ratio is found