A Low Complexity Robust Adaptive Beamforming Method with Orthogonality Constraint

Abstract

Performance of many adaptive beamforming methods degrades when antenna array steering vector mismatch exists and popular optimization-based methods suffer from heavy computation complexity. In this paper, we investigate robust adaptive beamforming technique with low complexity. An optimization problem is constructed based on orthogonality constraint instead of conventional norm constraint; therefore, semidefinite programming (SDP) relaxation is avoided. We present the approach to obtain closed-form solution by imposing Lagrange multiplier methodology. Numerical experiments demonstrate that proposed low complexity method outperforms other previously developed beamforming methods and reduces computation time significantly.