Nonlinear Transform CMA for Underwater Acoustic Channel under Impulsive Noise Environment

摘要

The traditional constant modulus algorithm (CMA) can't ensure robust convergence performance under impulsive noise environment, hereby a blind equalization by CMA with nonlinear transformation carrying on the received signal was proposed. The impulsive noise can be suppressed effectively by sine transform, in which the linear interval factor and the scale factor are set to keep the scatter plot of the output consistent with the send signal. By embedding nonlinear transformation in CMA blind equalization, the robust convergence performance can be obtained under the impulsive noise environment. The simulation results under the shallow sea channel show that compared with fractional low order CMA and CMA improved by error nonlinear transforming, the nonlinear transformation CMA has the fastest convergence rate and the lowest steady-state residual error. Meanwhile, the nonlinear transformation CMA has highest convergence ratio under different general signal to noise ratio.