Underwater acoustics communications in a time-varying enviroment

This paper addresses the problem of underwater acoustic channel estimation for communications in time-varying environments. In the case of a rapidly time-varying environment, the channel needs to be estimated and tracked continuously, Prior information on the channel can be used to improve channel estimation performance. In this paper, a-priori statistics on the channel time-variations are used in order to obtain a maximum a-posteriori estimator for channel tap-coefficients. The results demonstrate performance gain of 5-10 dB in terms of signal-to-noise ratio in decision-feedback equalizer mean-squared error, compared to the least-squares method, which ignores the a-priori statistics on the channel time-variations.