Adaptive receiver for data transmission over time-dispersive channels

Optimum nonlinear receivers for digital signaling over channels with a relatively long impulse response become too complex to be practical. In this paper a suboptimum but simple and practical receiver is proposed for such channels. The receiver consists of a linear adaptive equalizer in cascade with a maximum-likelihood sequence estimator. A general method of finding the error probability of a maximum-likelihood sequence estimator (MLSE) in the presence of correlated noise is developed. An upper bound on the performance of an MLSE is also presented for the case when thc actual channel is different from the channel estimate known to the MLSE. The performance of the proposed receiver is analyzed and results of the analysis and computer simulation are shown for a typical telephone channel.