Angle-Domain Intelligent Reflecting Surface Systems: Design and Analysis

This paper considers an angle-domain intelligent reflecting surface (IRS) system. We derive maximum likelihood (ML) estimators for the effective angles from base station (BS) to user and of propagation IRS user. It is demonstrated that accuracy estimated improves with number BS antennas. Also, deploying closer increases angle Then, based on angles, we propose a joint optimization beamforming beamforming, which achieves similar performance two benchmark algorithms full CSI multiple signal classification (MUSIC) method respectively. Simulation results show optimized beam becomes more focused towards direction as elements increases. Furthermore, closed-form approximation, upper bound lower achievable rate. The analytical findings indicate rate can be improved by increasing antennas or elements. Specifically, BS-user link BS-IRS-user obtain power gains order N NM 2 , respectively, where antenna M