Performance evaluation of random step-size NLMS in adaptive channel equalization

Abstract

Adaptive filtering algorithms have been widely applied to solve the problem of channel equalization in digital communication systems. So far, the LMS and the NLMS adaptive algorithms have been the most commonly adopted approaches owing to the clarity of the mean-square-error cost function in terms of statistical concept and the simplicity for computation. However, a critical issue associated with both algorithms is the choice of the step-size parameter that is the trade-off between the steady-state misadjustment and the speed of adaptation. The aim of this paper is to investigate the performance, in terms of MSE, of random step-size NLMS algorithm in adaptive channel equalization. The proposed idea of this paper is that the adaptive filter will change its coefficients according to the NLMS algorithm in which its step size is multiplied by PN (pseudo random number generator) to pseudo randomize the step size.