Reconfigurable Intelligent Surfaces for 6G:Nine Fundamental Issues and One Critical Problem

作     者：Zijian Zhang Linglong Dai Zijian Zhang;Linglong Dai

作者机构：Department of Electronic EngineeringTsinghua Universityand also with Beijing National Research Center for Information Science and Technology(BNRist)Beijing 100084China 

出 版 物：《Tsinghua Science and Technology》 (清华大学学报（自然科学版（英文版）)

年 卷 期：2023年第28卷第5期

页      面：929-939页

核心收录：

学科分类：12[管理学] 1201[管理学-管理科学与工程(可授管理学、工学学位)] 081104[工学-模式识别与智能系统] 08[工学] 0835[工学-软件工程] 0802[工学-机械工程] 0811[工学-控制科学与工程] 080201[工学-机械制造及其自动化] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：supported by the National Key Research and Development Program of China(No.2020YFB1805005) the National Natural Science Foundation of China(No.62031019) the European Commission through the H2020-MSCA-ITN META WIRELESS Research Project(No.956256) 

主　　题：Reconfigurable Intelligent Surface(RIS) sixth generation mobile system(6G) wireless communications 

摘      要：Thanks to the recent advances in metamaterials,Reconfigurable Intelligent Surface(RIS)has emergedas a promising technology for future 6G wireless *** from its high array gain,low cost,and low power consumption,RISs are expected to greatly enlarge signal coverage,improve system capacity,andincrease energy *** this article,we systematically overview the emerging RIS technology with the focuson its key basics,nine fundamental issues,and one critical ***,we first explain the RIS basics,including its working principles,hardware structures,and potential benefits for *** on thesebasics,nine fundamental issues of RISs,such as“What’s the differences between RISs and massive MIMO?and“Is RIS really intelligent?,are explicitly addressed to elaborate its technical features,distinguish it from existingtechnologies,and clarify some misunderstandings in the ***,one critical problem of RISs is revealedthat,due to the“multiplicative fadingeffect,existing passive RISs can hardly achieve visible performance gains inmany communication scenarios with strong direct *** address this critical problem,a potential solution calledactive RISs is introduced,and its effectiveness is demonstrated by numerical simulations.