A Performance Evaluation of VSS-MMA Adaptive Equalization Algorithm using the Non-Linear Fuction of Error Signal for QAM System

This paper relates with the VSS-MMA (Variable Step Size-Multiple Modulus Algorithm) adaptive equalization algorithm which is possible to improving the equalization performance by use the nonlinear function of error signal in the MMA adaptive equalization algorithm that are used for the minimization of the inter-symbol interference due to the distortion which occurs in the time disperse channel for the transmission of QAM signal in the system.. In the conventional MMA, we obtains the tap coefficient of adaptive equalizer using the fixed step size, but in the VSS-MMA, we obtains the tap coefficient of adaptive equalizer using the variable step size based on a nonlinear function of error signal. By adapting the variable step size, it was confirmed that the improved equalization performance were obtained by computer simulation. For this, the equalizer output signal constellation, residual isi, maximum distortion, MSE and SER were used in the performance index.