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Recently, there has been a flurry of research on the use of Reconfigurable Intelligent Surfaces (RIS) in wireless networks to create dynamic radio environments. In this paper, we investigate the use of an RIS panel to improve bi-directional…

Signal Processing · Electrical Eng. & Systems 2021-06-30 Abdullah Almasoud , Mohamed Y. Selim , Ahamd Alsharoa , Ahmed E. Kamal

A wireless communication system is studied that operates in the presence of multiple reconfigurable intelligent surfaces (RISs). In particular, a multi-operator environment is considered where each operator utilizes an RIS to enhance its…

Information Theory · Computer Science 2024-03-04 Nikolaos I. Miridakis , Theodoros A. Tsiftsis , Panagiotis A. Karkazis , Helen C. Leligou , Petar Popovski

In this paper, we analyse the performance of a reconfigurable intelligent surface (RIS) aided system where the RIS is divided into subsurfaces. Each subsurface is designed specifically for one user, who is served on their own frequency…

Signal Processing · Electrical Eng. & Systems 2026-03-12 Amy S. Inwood , Peter J. Smith , Philippa A. Martin , Graeme K. Woodward

In this paper, we consider a hybrid reconfigurable intelligent surface (RIS) comprising of active and passive elements to aid an integrated sensing and communication (ISAC) system serving multiple users and targets. Active elements in a…

Signal Processing · Electrical Eng. & Systems 2022-03-14 R. S. Prasobh Sankar , Sundeep Prabhakar Chepuri

This paper proposes a quality-of-service (QoS)-aware multi-user communication framework facilitated by multiple simultaneously transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs). The user groups are established…

Systems and Control · Electrical Eng. & Systems 2025-08-26 Junfeng Wang , Xiao Tang , Jinxin Liu , Zhi Zhai , Qinghe Du , Naijin Liu

Smart radio environments aided by reconfigurable intelligent reflecting surfaces (RIS) have attracted much research attention recently. We propose a joint optimization strategy for beamforming, RIS phases, and power allocation to maximize…

Information Theory · Computer Science 2022-08-02 Athira Subhash , Abla Kammoun , Ahmed Elzanaty , Sheetal Kalyani , Yazan H. Al-Badarneh , Mohamed-Slim Alouini

We propose an alternating optimization framework for maximizing energy efficiency (EE) in reconfigurable intelligent surface (RIS) assisted distributed MIMO (D-MIMO) systems under both coherent and non-coherent reception modes. The…

Reconfigurable intelligent surfaces (RISs) are regarded as a promising emerging hardware technology to improve the spectrum and energy efficiency of wireless networks by artificially reconfiguring the propagation environment of…

Information Theory · Computer Science 2020-08-18 Xiaojun Yuan , Ying-Jun Angela Zhang , Yuanming Shi , Wenjing Yan , Hang Liu

This paper presents a multi-bit reconfigurable intelligent surface (RIS) with a high phase resolution, capable of beam-steering in the azimuthal plane at sub-6 Gigahertz (GHz). Field trials in realistic indoor deployments have been carried…

Signal Processing · Electrical Eng. & Systems 2022-10-21 James Rains , Jalil ur Rehman Kazim , Anvar Tukmanov , Tie Jun Cui , Lei Zhang , Qammer H. Abbasi , Muhammad Ali Imran

Reconfigurable intelligent surfaces (RIS) have drawn considerable attention recently due to their controllable scattering elements that are able to direct electromagnetic waves into desirable directions. Although RISs share some…

Information Theory · Computer Science 2021-04-08 Mohanad Obeed , Anas Chaaban

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

Cell-Free Massive multiple-input multiple-output (MIMO) and reconfigurable intelligent surface (RIS) are two promising technologies for application to beyond-5G networks. This paper considers Cell-Free Massive MIMO systems with the…

Information Theory · Computer Science 2021-12-20 Trinh Van Chien , Hien Quoc Ngo , Symeon Chatzinotas , Marco Di Renzo , Björn Ottersten

A reconfigurable intelligent surface (RIS) is a holographic MIMO surface composed of a large number of passive elements that can induce adjustable phase shifts to the impinging waves. By creating virtual line-of-sight (LOS) paths between…

Signal Processing · Electrical Eng. & Systems 2023-04-06 Mehdi Haghshenas , Parisa Ramezani , Maurizio Magarini , Emil Björnson

Intelligent reflecting surface (IRS) is a promising technology to extend the wireless signal coverage and support the high performance communication. By intelligently adjusting the reflection coefficients of a large number of passive…

Information Theory · Computer Science 2021-03-01 Yitao Han , Shuowen Zhang , Lingjie Duan , Rui Zhang

Reconfigurable intelligent surfaces (RIS) are key enablers for 6G wireless systems. This paper studies downlink transmission in an RIS-assisted MISO-OFDMA system, addressing resource allocation challenges. A two-stage unsupervised…

Signal Processing · Electrical Eng. & Systems 2025-07-01 Yu Ma , Xingyu Zhou , Xiao Li , Le Liang , Shi Jin

Reconfigurable intelligent surfaces (RISs) have attracted enormous interest thanks to their ability to overcome line-of-sight blockages in mmWave systems, enabling in turn accurate localization with minimal infrastructure. Less investigated…

Signal Processing · Electrical Eng. & Systems 2022-09-14 Alessio Fascista , Musa Furkan Keskin , Angelo Coluccia , Henk Wymeersch , Gonzalo Seco-Granados

The reconfigurable intelligent surface (RIS)-assisted sparse code multiple access (RIS-SCMA) is an attractive scheme for future wireless networks. In this letter, for the first time, the RIS phase shifts of the uplink RIS-SCMA system are…

Information Theory · Computer Science 2021-12-01 Ibrahim Al-Nahhal , Octavia A. Dobre , Ertugrul Basar , Telex M. N. Ngatched , Salama Ikki

The massive number of antennas in extremely large aperture array (ELAA) systems shifts the propagation regime of signals in internet of things (IoT) communication systems towards near-field spherical wave propagation. We propose a…

Signal Processing · Electrical Eng. & Systems 2025-04-18 Quan Zhou , Jingjing Zhao , Kaiquan Cai , Yanbo Zhu

We consider an uplink multi-user scenario and investigate the use of reconfigurable intelligent surfaces (RIS) to optimize spatial multiplexing performance when a linear receiver is used. We study two different formulations of the problem,…

Signal Processing · Electrical Eng. & Systems 2020-09-16 Mohamed A. ElMossallamy , Hongliang Zhang , Radwa Sultan , Karim G. Seddik , Lingyang Song , Geoffery Ye Li , Zhu Han

In traditional Reconfigurable Intelligent Surfaces (RIS) systems, the RIS is mounted on stationary structures like buildings, walls, or posts. They have shown promising results in enhancing the performance of wireless systems like capacity…

Signal Processing · Electrical Eng. & Systems 2024-12-24 I. Zakir Ahmed , Hamid Sadjadpour