Cooperative Hybrid Networks with Active Relays and RISs for B5G: Applications, Challenges, and Research Directions

TL;DR

This paper explores hybrid wireless networks combining active relays and reconfigurable intelligent surfaces (RISs) for beyond 5G, discussing architectures, use cases, a case study, and future research challenges.

Contribution

It introduces the concept of hybrid networks with active relays and RISs, analyzing their operation, applications, and performance benefits in B5G.

Findings

Hybrid networks can improve rate performance.

RISs and relays can coexist harmoniously.

Case study shows enhanced achievable rates.

Abstract

Among the recent advances and innovations in wireless technologies, reconfigurable intelligent surfaces (RISs) have received much attention and are envisioned to be one of the enabling technologies for beyond 5G (B5G) networks. On the other hand, active (or classical) cooperative relays have played a key role in providing reliable and power-efficient communications in previous wireless generations. In this article, we focus on hybrid network architectures that amalgamate both active relays and RISs. The operation concept and protocols of each technology are first discussed. Subsequently, we present multiple use cases of cooperative hybrid networks where both active relays and RISs can coexist harmoniously for enhanced rate performance. Furthermore, a case study is provided which demonstrates the achievable rate performance of a communication network assisted by either an active relay, an RIS, or both, and with different relaying protocols. Finally, we provide the reader with the challenges and key research directions in this area.