An improved digital communication system for doubly-spread underwater acoustic channels using evolutionary algorithms

This paper presents an improved system for high data rate digital acoustic communication over a shallow underwater channel that is doubly spread. The method uses cancellation of interfering multipath signals rather than delay equalisation. In this improved system, an Evolutionary Algorithm is used to obtain an accurate estimate of the Doppler spread. This novel implementation of a Doppler estimator significantly improves the accuracy of the channel estimator thus enabling more effective interference cancellation. BER performance results of the improved system in a typical underwater scenario are presented.