Simultaneously transmitting and reflecting(STAR)RISs for 6G:fundamentals,recent advances,and future directions  

作　　者：Yuanwei LIU Jiaqi XU Zhaolin WANG Xidong MU Jianhua ZHANG Ping ZHANG 

机构地区：[1]School of Electronic Engineering and Computer Science,Queen Mary University of London,London,E14NS,UK [2]State Key Laboratory of Networking and Switching Technology,Beijing University of Posts and Telecommunications,Beijing,100876,China

出　　处：《Frontiers of Information Technology & Electronic Engineering》2023年第12期1689-1707,共19页信息与电子工程前沿（英文版）

基　　金：Project supported by CHIST-ERA(SUNRISE CHIST-ERA-20-SICT-005);the Engineering and Physical Sciences Research Council(No.EP/W035588/1);the PHC Alliance Franco-British Joint Research Programme(No.822326028)。

摘　　要：Simultaneously transmitting and reflecting reconfigurable intelligent surfaces(STAR-RISs)have been attracting significant attention in both academia and industry for their advantages of achieving 360°coverage and enhanced degrees-of-freedom.This article first identifies the fundamentals of STAR-RIS,by discussing the hardware models,channel models,and signal models.Then,three representative categorizing approaches for STAR-RISs are introduced from the phase-shift,directional,and energy consumption perspectives.Furthermore,the beamforming design of STAR-RISs is investigated for both independent and coupled phase-shift cases.As a recent advance,a general optimization framework,which has high compatibility and provable optimality regardless of the application scenarios,is proposed.As a further advance,several promising applications are discussed to demonstrate the potential benefits of applying STAR-RISs in sixth-generation wireless communication.Lastly,a few future directions and research opportunities are highlighted.

关 键 词：Sixth-generation wireless communication(6G) Reconfigurable intelligent surface(RIS) Smart radio environment Simultaneous transmission and reflection 

分 类 号：TN929.5[电子电信—通信与信息系统]