Reconfigurable Intelligent Surface (RIS)-Assisted Co-Channel Interference Mitigation: Experimental Validation with Multi-User Testbed

The Reconfigurable Intelligent Surface (RIS) technology has been extensively studied to enhance the system performance in wireless networks. However, existing work lacks experimental validation of RIS-assisted co-channel interference suppression. Motivated by this, a software-defined radio multi-user testbed based on Universal Software Radio Peripheral is designed to evaluate the RIS performance for interference mitigation, where a time-division packet structure is proposed to facilitate algorithm training. The capability of RIS for multi-user co-channel interference mitigation is evaluated through an experimental case study by maximizing the minimum signal-to-interference-plus-noise ratio (SINR) of two users, where the RIS phase shifts are optimized by a lightweight reinforcement learning algorithm based on the multi-armed bandit framework. Experimental results demonstrate that the minimum SINR of two users is improved by around 13 dB compared to the conventional system without RIS.