Blind Adaptive Equalization of Complex Signals based on the Constant Modulus Algorithm

The paper discuss, applicability of the second-order Newton gradient descent method for blind equalization of complex signals based on the Constant Modulus Algorithm (CMA). The Constant Modulus (CM) loss function is real with complex valued arguments, and, hence, non-analytic. The Hessian for noiseless FIR channels and rederive the known fact that the full Hessian of the CM loss function is always singular in a simpler manner. The channel model shows that the perfectly equalizing solutions are stationary points of the CM loss function and also evaluate the bit error rate. The paper also discuss of the full Newton method. Finally, to validate the proposed algorithm, simulation studies have been carried out and results are presented and compared. The simulation results show the effectiveness of the proposed algorithm. General Terms Mobile communications, FIR channels.