A matched field processing approach to underwater acoustic communication

Experiments on phase conjugation have shown that the temporal stability of the underwater acoustic propagation channel may be larger than what had been previously anticipated. Using a source/receiver array to implement a time-reversal mirror, acoustic energy was successfully refocused back at the source position with small temporal dispersion. The focusing effect proved to be quite robust, and was still observed after significant environment variations. These properties suggest that the technique may be used as a self-adaptive way of combating intersymbol interference in underwater acoustic communications. In this paper, the concept of a simulated time-reversal mirror is used to derive a model-based receiver that assumes prior knowledge of the environment characteristics and emitter/receiver positions to counter the effects of multipath propagation. Simulation results show that this receiver may experience less performance degradation than conventional multichannel equalizers with respect to variations in the incoming signal