Blind Equalization Algorithm of Underwater Acoustic Sparse Time-Varying SIMO Channel

Based on the complex exponential basis expansion model (CE-BEM), in view of the channel’s sparse characteristic and signals’ Constant Modulus (CM), a blind equalization algorithm of underwater acoustic sparse time-varying (TV) single input multiple output (SIMO) channel is proposed in this paper. Firstly, using the l0-norm constraint improved proportionate normalized least mean square constant modulus algorithm (l0-IPNLMS-CMA) to equalize the sparse time-invariant (TIV) part of channel matrix, then using the frequency estimation method to compensate the Doppler shifts, finally, estimate and compensate the phase offset in the recovered signals. Simulation results demonstrate that the proposed algorithms improve the performance effectively.