RIS codebook-based beamsteering validation and field trials

Abstract

Reconfigurable intelligent surface (RIS), equipped with a large number of small, low-cost, and re-configurable elements, is envisioned as a potential enabler for the upcoming 5G-Advanced and 6G networks. Here, based on a flexibly tunable and readily programmable RIS, the capability of beamforming toward arbitrary desired directions and coverage enhancement are investigated and experimentally demonstrated. The theory of RIS-based beamforming is introduced, the simulated beamforming radiation patterns are provided, and an over-the-air radiated testing platform is designed for characterizing RIS beamforming performance. The RIS beam steering radiation performance tests are conducted, and the radiation patterns for different directions are extracted and analyzed. In addition, the indoor field trials on the RIS performance evaluation of enhancing coverage are reported. The field trials for multiple RIS-deployed scenarios, including RIS mirror placement, RIS non-mirror placement, and non-RIS assisted scenarios, are conducted, and the channel characteristics for those scenarios are extracted and modelled. Significant improvements in overcoming path loss and shadow fading in typical coverage holes can be observed. The proposed testing method and measurement results may provide some insights into the design and optimization of RIS-aided wireless communications.