The performance of multiple reconfigurable intelligent surfaces (RISs) receives limited attention in previous studies. This article fills this research gap by investigating the capabilities of multiple RISs in real-world networks. We propose a simplified yet highly scalable sandwich architecture for implementing one-bit unit cells, with the flexibility to accommodate multi-bit unit cells. To effectively control multiple RISs, we present a cost-effective remote-controlling scheme and develop a cloud-based RIS management system. Through a series of four field trials, we demonstrate the effectiveness of multi-hop routing schemes in establishing reliable links. Our experiments reveal significant improvements in signal strength and data transmission in multi-RIS-aided Wi-Fi and commercial 5G networks. Furthermore, we investigate the power scaling law of RIS-aided beamforming and provide insights into the roles of the later nodes in multi-hop relay chains.
@article{arxiv.2303.03287,
title = {Multi-RIS-aided Wireless Communications in Real-world: Prototyping and Field Trials},
author = {Rujing Xiong and Jianan Zhang and Xuehui Dong and Zhengyu Wang and Junshuo Liu and Wei Yang and Tiebin Mi and Wenbo Huang and Robert Caiming Qiu},
journal= {arXiv preprint arXiv:2303.03287},
year = {2023}
}