Robust interference suppression using a new LMS-based adaptive beamforming algorithm

This paper introduces a robust variable step size NLMS algorithm to improve interference suppression in smart antenna system. This algorithm is able to resolve signals arriving from narrowband sources propagating plane waves close to the array endfire. The results of the fixed step size NLMS will result in a trade-off issue between convergence rate and steady-state MSE of NLMS algorithm. This issue is solved by changing the step size from constant to variable. The proposed VSSNLMS algorithm reduces the mean square error (MSE) and shows faster convergence rate when compared to the conventional NLMS. Moreover, the enhanced performance of the new VSSNLMS algorithm is validated from the output beam pattern which introduces deeper nulls to mitigate the effect of interfering signals.