Reconfigurable Intelligent Surfaces for Smart Wireless Environments: Channel Estimation, System Design, and Applications in 6G Networks

Ying-Chang Liang (1) , Jie Chen (1) , Ruizhe Long (1) , Zhen-Qing He (1) , Xianqi Lin (1) , Chenlu Huang (1) , Shilin Liu (1) , Sherman Shen (2) , Marco Di Renzo (3, 4, 5)

1 UESTC - University of Electronic Science and Technology of China [Chengdu]
2 University of Waterloo [Waterloo]
3 L2S - Laboratoire des signaux et systèmes
4 Université Paris-Saclay
5 CNRS - Centre National de la Recherche Scientifique

Reconfigurable intelligent surface (RIS), one of the key enablers for the sixth-generation (6G) mobile communication networks, is considered by designers to smartly reconfigure the wireless propagation environment in a controllable and programmable manner. Specifically, RIS consists of a large number of low-cost and passive reflective elements (REs) without radio frequency chains. The system gain of RIS wireless systems can be achieved by adjusting the phase shifts and amplitudes of REs so that the desired signals can be added constructively at the receiver. However, RIS typically has limited signal processing capability and cannot perform active transmitting/receiving in general, which leads to new challenges in the physical layer design of RIS wireless systems. In this paper, we provide an overview over the RIS based wireless systems, including the reflection principle, channel estimation, and system design. In particular, two types of emerging RIS systems are considered: RIS aided wireless communications (RAWC) and RIS based information transmission (RBIT), where the RIS plays the role of the reflector and the transmitter, respectively. We also envision the potential applications of RIS in 6G networks.

Mots clés: Reconfigurable intelligent surface; channel estimation; RIS aided wireless communications; RIS based information transmission; 6G; Reconfigurable intelligent surface

Domaines: Traitement du signal et de l'image [eess.SP]

Ying-Chang Liang, Jie Chen, Ruizhe Long, Zhen-Qing He, Xianqi Lin, et al.. Reconfigurable Intelligent Surfaces for Smart Wireless Environments: Channel Estimation, System Design, and Applications in 6G Networks. Science China Information Sciences, 2021, ⟨10.1007/s11432-020-3261-5⟩. ⟨hal-03843835⟩