Reconfigurable Intelligent Surface Assisted Low-Cost DOA Estimation Using A Single Antenna

In this paper, a challenging direction-of-arrival DOA estimation problem is addressed in a non-line-of-sight (NLOS) scenario, with the aid of the reconfigurable intelligent surface (RIS). Different from traditional methods using sensor arrays, the proposed one can achieve low-cost DOA estimation with a single receiving antenna, which is motivated by the fact that the phase shifts on RIS elements can realize multiple measurements of the reflected signals. Under such configurations, a two-stage approach for high-efficiency RIS phase shift and robust covariance matrix reconstruction is first developed in the presence of phase shift errors. Then, satisfactory DOA estimation is achieved by applying the MUSIC algorithm. Simulation results are provided to demonstrate the superiority and effectiveness of the proposed method.