Application of multiple path sequential decoding for intersymbol interference reduction problem

The application of the stack algorithm of sequential decoding and some of its multiple-path variants to the ISI problem, especially over long memory channels are presented. The proper metric to use is analysed and computer simulation with channels having memory lengths up to nine symbols show that the achieved error performances fall within the theoretical upper and lower bounds of an optimal decoder at only a small fraction of the computational effort of an optimal decoder. As for the computational variability, it can be totally circumvented by simultaneously extending a sufficient number of paths. Finally with a simplified multiple path sequential decoder, all the drawbacks of sequential decoding may be avoided at a cost of a very slight error performance degradation.<>