Spread & Focus: Enhancing Wireless Environments with Multi-RIS Networks

Description

Wireless communications design typically assumes that the transmission environment is fixed, albeit uncertain, and cannot be proactively augmented between a transmitter and a receiver except at either end. The emergence of reconfigurable intelligent surfaces (RISs) has changed this situation. Through the manipulation of RIS elements and their deployment in transmission environments, electromagnetic waves can be adaptively reshaped and redirected, both passively and actively, in a tailored manner for significant network performance gain. Nonetheless, current RIS designs primarily concentrate on single-hop communications, typically involving a single RIS or single-hop RISs, and lack a comprehensivenetwork-level design.Consequently, these methods fail to fully harness the potential of multi-hop multiple RISs to collaboratively enhance and proactively augment wireless environments. In this project, we embark on a cohesive research endeavor to harness the potential of RISs in fostering richer link and path diversities to amplify network performance. Our overarching objective is to establish a comprehensive and intelligent multi-RIS framework, Spread and Focus (S&F), facilitating the intelligent customization of wireless transmission environments for 6G communications. We initiate this journey with an innovative architectural design for S&F that encompasses the following critical aspects: 1) Guiding multi-RIS placement while accounting for practical considerations such as cost and environmental constraints; 2) Coordinating system components, including base stations and RISs, through communication-efficient collaboration and control strategies; 3) Exploring performance enhancements in conventional wireless technologies like MIMO under multi-RIS-augmented transmission environments to improve link diversity; and 4) Leveraging over-the-air RIS networks, e.g., UAV-aided RIS networks, to enhance end-to-end path diversity. Under this framework, we subsequently devise strategies to effectively harness the rich link diversity and path diversity provided by RISs, leading to significant network performance gain. To validate our proposed schemes rigorously, we establish experimental testbed. This project is anticipated to pioneer a novel research direction, namely, leveraging an analog network of RISs and network-level design in multi-RIS systems to substantially enhance communication capacity. This project will fortify multidisciplinary research efforts spanning wireless communications and networks, system management and control, machine learning, optimization, and diverse IoT applications, thereby driving digital innovations in the wireless future and foster economic growth. On the engineering front, the proposed research establishes a disruptive paradigm for wireless telecommunications, significantly enriching the scientific knowledge of information and communications technologies (ICT) and contributing to the innovative usage of RISs in 6G. In the realm of education, the experimental testbed can be tailored to support specific applications, such as smart home solutions for elderly care and industrial IoT, which can serve as an attractive platform to engage undergraduate students for their research experiences.