Comparison of equalization algorithms for underwater acoustic channels

Adaptive equalization and blind equalization used in underwater acoustic communication and some representative algorithms are briefly introduced in this paper. The computer simulations of adaptive and blind algorithms about mean square error (MSE) ability are carried out respectively under sparse multi-paths and mixed phase underwater acoustic channels, the simulation results demonstrate that the algorithms using decision feedback equalizer (DFE) structure have better equalization result in above complex underwater acoustic environment; and then the simulation comparison of some representative adaptive and blind equalization algorithms are carried out under sparse multi-paths phase rotation complex channels, the results show that the affected degree of adaptive equalization algorithm to phase is smaller than that of blind equalization algorithms and the convergence speed of adaptive equalization algorithm is faster than that of blind equalization algorithms. At the same time, the anechoic tank experiment is carried out to verify the performance of algorithms about carrier recovery, the experiments verify that equalization algorithms with second order digital phase-locked loop (DPLL) and DFE structure have better performance and realize the tracking ability of phase deviation and improve the compensation ability of Doppler shift.