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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

Reconfigurable intelligent surface (RIS) assisted millimeter-wave (mmWave) communication systems relying on hybrid beamforming structures are capable of achieving high spectral efficiency at a low hardware complexity and low power…

Signal Processing · Electrical Eng. & Systems 2022-01-13 Chenghao Feng , Wenqian Shen , Jianping An , Lajos Hanzo

In this letter, we present in detail the system-level modeling of reconfigurable intelligent surface (RIS)-assisted cellular systems by considering a 3-dimensional channel model between base station, RIS, and user. We prove that the optimal…

Information Theory · Computer Science 2023-05-03 Pavan Reddy M. , SaiDhiraj Amuru , Kiran Kuchi

Integrating the reconfigurable intelligent surface (RIS) into a cell-free massive multiple-input multiple-output (CF-mMIMO) system is an effective solution to achieve high system capacity with low cost and power consumption. However,…

Information Theory · Computer Science 2024-03-27 Jianxin Dai , Jin Ge , Kangda Zhi , Cunhua Pan , Youguo Wang

Integrating reconfigurable intelligent surfaces (RIS) into wireless communication systems is a promising approach for enhancing coverage and data rates by intelligently redirecting signals, through a process known as beamforming. However,…

Systems and Control · Electrical Eng. & Systems 2025-08-26 Luis C. Mathias , Atefeh Termehchi , Taufik Abrão , Ekram Hossain

By reconfiguring the propagation environment of electromagnetic waves artificially, reconfigurable intelligent surfaces (RISs) have been regarded as a promising and revolutionary hardware technology to improve the energy and spectrum…

Signal Processing · Electrical Eng. & Systems 2020-12-08 Huiyuan Yang , Xiaojun Yuan , Jun Fang , Ying-Chang Liang

This paper investigates the performance of downlink simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS)-assisted cell-free (CF) massive multiple-input multiple-output (mMIMO) systems, where user equipments…

Information Theory · Computer Science 2023-12-01 Anastasios Papazafeiropoulos , Hien Quoc Ngo , Pandelis Kourtessis , Symeon Chatzinotas

Reconfigurable intelligent surface (RIS) is an attractive technology to improve the transmission rate of millimetre-wave (mmWave) communication systems. The previous {research} on RIS technology mainly focused on improving the transmission…

Signal Processing · Electrical Eng. & Systems 2022-11-01 Yunis Xanthos , Wanting Lyu , Songjie Yang , Chadi Assi , Xianbing Zou , Ning Wei

Reconfigurable intelligent surface (RIS) is known as a promising technology to improve the performance of wireless communication networks, which has been extensively studied. Movable antenna (MA) is a novel technology that fully exploits…

Signal Processing · Electrical Eng. & Systems 2023-11-14 Yunan Sun , Hao Xu , Chongjun Ouyang , Hongwen Yang

The objective of this paper is to evaluate the effectiveness of a two-timescale transmission design in cell-free massive multi-input multiple-output (MIMO) systems incorporating reconfigurable intelligent surfaces (RISs) under the…

Signal Processing · Electrical Eng. & Systems 2023-04-06 Mahdi Eskandari , Kangda Zhi , Huiling Zhu , Cunhua Pan , Jiangzhou Wang

Reconfigurable intelligent surface (RIS) constitutes a disruptive technology for enhancing vehicular communication performance through reconfigurable propagation environments. In this paper, we propose an adaptive channel estimation…

Systems and Control · Electrical Eng. & Systems 2026-03-03 Tianyou Li , Haifeng Hu , Dapeng Li

This paper investigates the passive beamforming and information transfer (PBIT) technique for the multiuser multiple-input multiple-output (MIMO) systems with the aid of a reconfigurable intelligent surface (RIS), where the RIS enhances the…

Information Theory · Computer Science 2020-01-01 Wenjing Yan , Xiaojun Yuan , Zhen-Qing He , Xiaoyan Kuai

The prospects of using a reconfigurable intelligent surface (RIS) to aid wireless communication systems have recently received much attention. Among the different use cases, the most popular one is where each element of the RIS scatters the…

Signal Processing · Electrical Eng. & Systems 2021-12-09 Andrea De Jesus Torres , Luca Sanguinetti , Emil Björnson

This paper investigates a modular beamforming framework for reconfigurable intelligent surface (RIS)-aided multi-user (MU) communications in the near-field regime, built upon a novel antenna architecture integrating an active multi-antenna…

Signal Processing · Electrical Eng. & Systems 2025-08-13 Giulia Torcolacci , Malte Schellmann , Davide Dardari

The reconfigurable intelligent surface (RIS) is useful to effectively improve the coverage and data rate of end-to-end communications. In contrast to the well-studied coverage-extension use case, in this paper, multiple RIS panels are…

Information Theory · Computer Science 2023-01-31 Zhong Zheng , Siqiang Wang , Zesong Fei , Zhi Sun , Jinhong Yuan

Mutual Coupling (MC) is an unavoidable feature in Reconfigurable Intelligent Surfaces (RISs) with sub-wavelength inter-element spacing. Its inherent presence naturally leads to non-local RIS structures, which can be efficiently described…

Information Theory · Computer Science 2024-04-09 Dilki Wijekoon , Amine Mezghani , George C. Alexandropoulos , Ekram Hossain

A multiple antenna base station (BS) with an intelligent reflecting surface (IRS) platform, and several single antenna users are considered in the downlink mode. Simultaneous wireless information and power transfer (SWIPT) is utilized by…

Signal Processing · Electrical Eng. & Systems 2021-11-30 Shayan Zargari , Shahrokh Farahmand , Bahman Abolhassani

The reconfigurable intelligent surface (RIS), which consists of a large number of passive and low-cost reflecting elements, has been recognized as a revolutionary technology to enhance the performance of future wireless networks. This paper…

Signal Processing · Electrical Eng. & Systems 2021-05-25 Linsong Du , Shihai Shao Gang Yang , Jianhui Ma , Qinpeng Liang , Youxi Tang

In this paper, we propose a robust secure transmission scheme for an active reconfigurable intelligent surface (RIS) enabled symbiotic radio (SR) system in the presence of multiple eavesdroppers (Eves). In the considered system, the active…

Information Theory · Computer Science 2023-04-14 Bin Lyu , Chao Zhou , Shimin Gong , Dinh Thai Hoang , Ying-chang Liang

Thanks to the line-of-sight (LoS) transmission and flexibility, unmanned aerial vehicles (UAVs) effectively improve the throughput of wireless networks. Nevertheless, the LoS links are prone to severe deterioration by complex propagation…

Information Theory · Computer Science 2019-12-10 Sixian Li , Bin Duo , Xiaojun Yuan , Ying-Chang Liang , Marco Di Renzo