Multi-stage and sparse equalizer design for communication systems in reverberant underwater channels

Coherent underwater communication systems in shallow water must compensate for several impairments, including Doppler shift and reverberant channels. In this paper, we quantify tradeoffs in communication performance vs. computational complexity in designing receivers to compensate for these impairments. Our communication system is unidirectional, single-carrier, wideband, and packet-based. We use 1.5 hours of recorded data from an experimental system on a public lake with a moving transmitter and stationary receiver. Our contributions include acoustic channel modeling and a tradeoff analysis for Doppler shift estimation, multi-stage equalizers and sparse equalizers. We compare multi-stage and sparse equalizers against traditional equalizers.