Joint channel estimation, equalization, and symbol detection for underwater communication

Reliable, high data rate, acoustic communication in a time-varying multipath shallow water environment is a recent research area. This paper is concerned with the challenging and timely problem of joint channel estimation, equalization, and symbol detection for underwater communication in the presence of frequency selective and very rapidly time varying channels. The resulting algorithm is based on space alternating generalized expectation maximization(SAGE) technique. In order to reduce the computational complexity of the algorithm, discrete Fourier basis expansion channel model are employed to represent the rapidly time-varying fading channel by the discrete basis coefficients. Numerical results show that the basis expansion represents the time-varying channel very effectively and the proposed algorithm has excellent symbol error rate and channel estimation performance.