Unlocking MIMO Potential: Transmit Antenna Selection and Maximal Ratio Combining Meet Keyhole RIS for Enhanced Performance

Abstract

In this study, the performance of a reconfigurable intelligent surfaces (RIS)-assisted multiple-input multiple output system with transmit and antenna selection/maximal-ratio combining scheme is examined. A concept inspired by the diffraction phenomenon observed when electromagnetic waves pass through a keyhole is proposed for the first time, the exploration of modeling RIS as keyholes. The system consists of a multi-antenna source S, a destination D, and an RIS R equipped with multiple meta-surfaces. The signals received through the main and reflecting links are combined at D. Outage probabilities are studied in Rayleigh fading channels and analytical results are verified by Monte-Carlo simulations.