A RIS-Based Single-Channel Direction-of-Arrival Estimation Method for Communication Signals

Abstract

The development of reconfigurable intelligent surface (RIS) makes direction-of-arrival (DOA) estimation possible for single-antenna receivers. However, non-ideal situations such as spectral aliasing occur when facing communication signals using orthogonal frequency division multiplexing modulation. This paper proposes a RIS-based single-channel DOA estimation method for communication signals. Specifically, by extending the time intervals to dynamically reduce the RIS state change rate, a real-time DOA estimation is achieved while mitigating the impact of non-ideal spectral shifts on communication. Then, based on the compressed sensing and mutual incoherence property, the method exploits the sparse property of the signal in space to reduce the estimation time while improving the estimation accuracy. Simulation results show an $86\%$ reduction in computation time for the proposed method compared to the traditional CVX tool. Additionally, the estimation accuracy is as low as $0.02deg$. To verify the practicality and robustness, we develop a prototype system and conduct extensive experiments. The results are consistent with our theoretical analysis, and the method proposed in this paper can realize single-path DOA estimation with an accuracy of less than $0.1deg$ within $0.4276s$. More excitingly, the presented experimental platform achieves DOA estimation for two coherent paths.