Beamforming Robust in Interferer Direction of Arrival Uncertainties with Side lobes Level Control

One of the ways to deal with the effect of jammers, especially intra-band jammers, is to use beamforming (BF) in multi-antenna systems. In this method, based on the DOA of desired signal and DOA of interference, it is tried to design peak of beam pattern in the direction of the desired source and null of pattern in the direction of interferer. Since the depth of null and its location depend on the direction of interferer and in practice, it is not possible to obtain accurate information from electronic support measure (ESM) system, in this paper, a beamforming method which is robust to DOA estimation error has been proposed. Furthermore, nulling the interferer’s direction results in side lobes level increment. This can decreas communication systems performance. So, in adition to robust jammer nulling, the side lobe level of considered directions is controlled, too. In this paper, three BF weights optimization from three points of view are defined and solved analytically based on convex optimization framework. Simulation results show that proposed method is more efficient than previous and traditional methods. The proposed method keeps SINR in the order of SNR which can be obtained by DOA estimation error free methods.