{"title":"Efficient Codebook Design and User Scheduling for Large STAR-RIS-Aided Downlink URLLC Transmission","authors":"Mostafa Darabi;Ata Khalili;Lutz Lampe;Robert Schober","doi":"10.1109/LCOMM.2024.3510464","DOIUrl":null,"url":null,"abstract":"To ensure ultra-reliable, low-latency communications (URLLC) despite blockages, we propose using simultaneously transmitting and reflecting (STAR) reconfigurable intelligent surfaces (RISs). These surfaces can transmit and reflect signals, expanding coverage on both sides of the RIS. However, phase shifter adjustments in STAR-RIS are limited by coupling constraints. We introduce a codebook design for phase-shift adjustment that accounts for these constraints. Leveraging this design, we jointly optimize base station beamforming and STAR-RIS phase-shifting to maximize the number of admitted URLLC users in a downlink multi-user communication system. Numerical results show that the proposed STAR-RIS codebook surpasses existing designs and effectively admits more URLLC users.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"205-209"},"PeriodicalIF":3.7000,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Communications Letters","FirstCategoryId":"94","ListUrlMain":"https://ieeexplore.ieee.org/document/10772565/","RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"TELECOMMUNICATIONS","Score":null,"Total":0}
引用次数: 0
Abstract
To ensure ultra-reliable, low-latency communications (URLLC) despite blockages, we propose using simultaneously transmitting and reflecting (STAR) reconfigurable intelligent surfaces (RISs). These surfaces can transmit and reflect signals, expanding coverage on both sides of the RIS. However, phase shifter adjustments in STAR-RIS are limited by coupling constraints. We introduce a codebook design for phase-shift adjustment that accounts for these constraints. Leveraging this design, we jointly optimize base station beamforming and STAR-RIS phase-shifting to maximize the number of admitted URLLC users in a downlink multi-user communication system. Numerical results show that the proposed STAR-RIS codebook surpasses existing designs and effectively admits more URLLC users.
期刊介绍:
The IEEE Communications Letters publishes short papers in a rapid publication cycle on advances in the state-of-the-art of communication over different media and channels including wire, underground, waveguide, optical fiber, and storage channels. Both theoretical contributions (including new techniques, concepts, and analyses) and practical contributions (including system experiments and prototypes, and new applications) are encouraged. This journal focuses on the physical layer and the link layer of communication systems.