A simple Constant Modulus Algorithm for blind equalization suitable for 16-QAM signal

Abstract

Blind equalization is a technique for adaptive equalization of a communication channel without the aid of training sequences. This paper proposes a simple blind equalization algorithm suitable for 16-QAM signal. In this proposed algorithm, we study a new style of error function of constant modulus algorithm (CMA) aiming at the character of 16-QAM signals constellation. By adjusting the coordinates of received signals this error function will become exactly zero when the channel is perfectly equalized. The superior performance of the proposed algorithm is illustrated for the 16-QAM signal constellation. Compared with CMA, the proposed algorithm has faster convergence rate and lower residual error. In the computer simulation, an underwater acoustic channel model is assumed as a transmission medium and the simulation results demonstrate that the significant improvements in performance is achieved with the proposed equalization algorithm.