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Reconfigurable intelligent surface (RIS)-empowered communication is one of the promising 6G technologies that allows the conversion of the wireless channel into an intelligent transmit entity by manipulating the impinging waves using…

Information Theory · Computer Science 2020-09-01 I. Yildirim , A. Uyrus , E. Basar

Optimally extracting the advantages available from reconfigurable intelligent surfaces (RISs) in wireless communications systems requires estimation of the channels to and from the RIS. The process of determining these channels is…

Information Theory · Computer Science 2021-10-04 A. Lee Swindlehurst , Gui Zhou , Rang Liu , Cunhua Pan , Ming Li

This work studies the net sum-rate performance of a distributed reconfigurable intelligent surfaces (RISs)-assisted multi-user multiple-input-single-output (MISO) downlink communication system under imperfect instantaneous-channel state…

Information Theory · Computer Science 2023-07-04 Bayan Al-Nahhas , Qurrat-Ul-Ain Nadeem , Anas Chaaban

In this letter, we study efficient uplink channel estimation design for a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisted two-user communication systems. We first consider the time switching…

Information Theory · Computer Science 2021-12-03 Chenyu Wu , Changsheng You , Yuanwei Liu , Xuemai Gu , Yunlong Cai

Reconfigurable intelligent surface (RIS) is a promising technology that can reshape the electromagnetic environment in wireless networks, offering various possibilities for enhancing wireless channels. Motivated by this, we investigate the…

Information Theory · Computer Science 2024-09-02 Shengguo Meng , Wankai Tang , Weicong Chen , Jifeng Lan , Qun Yan Zhou , Yu Han , Xiao Li , Shi Jin

Intelligent reflection surface (IRS) has recently been recognized as a promising technique to enhance the performance of wireless systems due to its ability of reconfiguring the signal propagation environment. However, the perfect channel…

Signal Processing · Electrical Eng. & Systems 2021-08-10 Gui Zhou , Cunhua Pan , Hong Ren , Kezhi Wang , Arumugam Nallanathan

Reconfigurable intelligent surface (RIS) is a promising technology to enhance the spectral efficiency of wireless communication systems. By optimizing the RIS elements, the performance of the overall system can be improved. Yet, in contrast…

Information Theory · Computer Science 2023-10-13 Mohammad Soleymani , Ignacio Santamaria , Aydin Sezgin , Eduard Jorswieck

Continuous efforts have been devoted to integrate millimeter wave (mmWave) and terahertz (THz) bands into future communication standards in order to overcome the bandwidth shortage problem and achieve high data rates, primarily through…

Signal Processing · Electrical Eng. & Systems 2026-03-05 Sung Hyuck Hong , Junil Choi

In this paper, we propose a novel two-stage based uplink channel estimation strategy with reduced pilot overhead and error propagation for a reconfigurable intelligent surface (RIS)-aided multi-user (MU) millimeter wave (mmWave) system.…

Signal Processing · Electrical Eng. & Systems 2022-08-24 Zhendong Peng , Cunhua Pan , Gui Zhou , Hong Ren

Reconfigurable intelligent surface (RIS) is a newly-emerged technology that, with its unique features, is considered to be a game changer for future wireless networks. Channel estimation is one of the most critical challenges for the…

Signal Processing · Electrical Eng. & Systems 2023-03-30 Mehdi Haghshenas , Parisa Ramezani , Emil Björnson

This paper examines how to minimize the energy consumption of a user equipment (UE) when transmitting short data payloads. The receiving base station (BS) controls a reconfigurable intelligent surface (RIS), which requires additional pilot…

Information Theory · Computer Science 2023-10-19 Anders Enqvist , Özlem Tuğfe Demir , Cicek Cavdar , Emil Björnson

The optimization of the \gls{pdpr} is a recourse that helps wireless systems to acquire channel state information while minimizing the pilot overhead. While the optimization of the \gls{pdpr} in cellular networks has been studied…

Information Theory · Computer Science 2025-07-30 Masoud Sadeghian , Angel Lozano , Gabor Fodor

Different from conventional passive reconfigurable intelligent surfaces (RISs), incident signals and thermal noise can be amplified at active RISs. By exploiting the amplifying capability of active RISs, noticeable performance improvement…

Information Theory · Computer Science 2025-04-02 Jinho Yang , Hyeongtaek Lee , Junil Choi

By reconfiguring wireless channels via passive signal reflection, intelligent reflecting surface (IRS) can bring significant performance enhancement for wireless communication systems. However, such performance improvement generally relies…

Signal Processing · Electrical Eng. & Systems 2024-07-31 Ge Yan , Lipeng Zhu , Rui Zhang

Reconfigurable intelligent surface (RIS) has been explored as a supportive technology for wireless communication since around 2019. While the literature highlights the potential of RIS in different modern applications, two key issues have…

Signal Processing · Electrical Eng. & Systems 2025-06-10 Daniel C. Alcantara , Daniel V. C. de Oliveira , Gilderlan T. de Araújo , Paulo R. B. Gomes , André L. F. de Almeida

The paper studies a reconfigurable intelligent surface (RIS)-assisted multi-user uplink massive multiple-input multiple-output (MIMO) system with imperfect hardware. At the RIS, the paper considers phase noise, while at the base station,…

Information Theory · Computer Science 2022-08-18 Zhangjie Peng , Xianzhe Chen , Cunhua Pan , Maged Elkashlan , Jiangzhou Wang

Reconfigurable intelligent surfaces (RISs) are considered as potential technologies for the upcoming sixth-generation (6G) wireless communication system. Various benefits brought by deploying one or multiple RISs include increased spectrum…

Signal Processing · Electrical Eng. & Systems 2021-04-16 Jiguang He , Nhan Thanh Nguyen , Rafaela Schroeder , Visa Tapio , Joonas Kokkoniemi , Markku Juntti

Channel estimation is challenging for the reconfigurable intelligent surface (RIS)-aided wireless communications. Since the number of coefficients of the cascaded channel among the base station (BS), the RIS and the user equipments (UEs) is…

Signal Processing · Electrical Eng. & Systems 2020-05-19 Chen Hu , Linglong Dai

In this paper, the problem of maximizing the sum-rate is addressed for a multi-user uplink scenario that is assisted by an active reconfigurable intelligent surface (RIS). The maximization is achieved by optimizing the beamforming at the…

Signal Processing · Electrical Eng. & Systems 2026-04-06 Mohamed Shalma , Engy Maher , Ahmed El-Mahdy

Reconfigurable intelligent surfaces (RISs) have recently gained significant interest as an emerging technology for future wireless networks. This paper studies an RIS-assisted propagation environment, where a single-antenna source transmits…

Information Theory · Computer Science 2021-10-27 Trinh Van Chien , Lam Thanh Tu , Dinh-Hieu Tran , Hieu Van Nguyen , Symeon Chatzinotas , Marco Di Renzo , Björn Ottersten