Robust beamforming against direction-of-arrival mismatch via signal-to-interference-plus-noise ratio maximization
Huan Wan, Huiping Huang, Bin Yih Liao, Zhi Quan · 2017
In this paper, the problem of adaptive beamforming in the presence of direction-of-arrival (DOA) mismatch is investigated. To develop a robust beamformer against such an imperfection, a new approach is devised by formulating an output signal-to-interference-plus-noise ratio (SINR) maximization problem. In particular, the proposed robust beamforming approach consists of two steps. At first, the standard Capon beamformer (SCB) is applied to find out the sidelobe notches and hence, a set of angles including the interference DOAs and the corresponding response levels can be determined. Next, the output SINR is maximized subject to a number of constraints on the response levels at the region of interest (ROI) and angles determined in the first step. In order to tackle the resulting nonconvex optimization problem, semidefinite relaxation techniques are thus employed to achieve an approximated solution. Simulation results demonstrate that the proposed robust beamformer offers outstanding robustness against DOA mismatch, low sample size as well as the presence of the desired signal in the training samples.