Iterative Broad Null Steering

Abstract

Forming a broad null around the direction of interferences and keeping the main beam toward the desired direction is desirable to suppress interferences in the multipath environment. In this paper, a null broadening beamforming is proposed to enhance the iterative optimal beamformer. Placing broaden null is achieved through the projection and diagonal loading approach. MUltiple SIgnal Classification (MUSIC) is used to estimate the directions of arrival and angular spread. The null width is the estimated angular spread. A criteria based on the convergence of the output SINR is proposed to terminate the iteration. Simulation results are presented for illustration that the proposed iterative broad null beamformer is capable of steering broad nulls to interference signals, consequently, increasing the output signal to interference plus noise ration (SINR) and decreasing the number of iterations.