From Single to Multi-Functional RIS: Architecture, Key Technologies, Challenges, and Applications

TL;DR

This paper explores the evolution from single to multi-functional RIS, detailing hardware, key technologies, challenges, and applications, and demonstrating its potential to significantly improve network spectral efficiency.

Contribution

It introduces the concept of multi-functional RIS, including hardware design and signal models, and discusses its deployment challenges and broad applications.

Findings

MF-RIS enhances spectral efficiency in simulations

Demonstrates superiority over traditional RIS architectures

Highlights potential in communication, sensing, and computation

Abstract

Although reconfigurable intelligent surfaces (RISs) have demonstrated the potential to boost network capacity and expand coverage by adjusting their electromagnetic properties, existing RIS architectures have certain limitations, such as double-fading attenuation and restricted half-space coverage. In this article, we delve into the progressive development from single to multi-functional RIS (MF-RIS) that enables simultaneous signal amplification, reflection, and refraction. We begin by detailing the hardware design and signal model that distinguish MF-RIS from traditional RISs. Subsequently, we introduce the key technologies underpinning MF-RIS-aided communications, along with the fundamental issues and challenges inherent to its deployment. We then outline the promising applications of MFRIS in the realm of communication, sensing, and computation systems, highlighting its transformative impact on these domains. Lastly, we present simulation results to demonstrate the superiority of MF-RIS in enhancing network performance in terms of spectral efficiency.