Simultaneous Transmitting and Reflecting-Reconfigurable Intelligent Surface in 6G: Design Guidelines and Future Perspectives

TL;DR

This paper provides a comprehensive framework for designing and implementing simultaneous transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs) in 6G networks, addressing modeling, control, and future research directions.

Contribution

It introduces a general framework and operating protocols for STAR-RISs, enhancing their design, analysis, and application in 6G wireless networks.

Findings

Systematic introduction to STAR-RIS operating protocols

Discussion of research challenges and potential solutions

Future directions for hardware and channel modeling

Abstract

Reconfigurable intelligent surfaces (RISs) have been considered as a promising technology for the sixth-generation (6G) wireless networks that can control wireless channels in a desirable way and significantly enhance the network performance. Simultaneous transmitting and reflecting-RISs (STAR-RISs) can overcome limitation of reflecting-only RISs by leveraging the higher design flexibility and full-space coverage. Despite the benefits, the modeling and analysis of STAR-RISs are complicated because of various control parameters for both transmission and reflection links. In this article, a general framework to facilitate the design and implementation of STAR-RISs in 6G scenarios and network topologies is presented. We provide a systematic introduction to the STAR-RIS operating protocols for different communication modes and discuss recent efforts to identify the research progress and combination solutions. Finally, we provide the design concepts, research challenges, potential solutions, and future directions related to the channel modeling, channel estimation, hardware implementations, modeling and limitations, and optimization.