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Reconfigurable intelligent surfaces (RISs) allow controlling the propagation environment in wireless networks by tuning multiple reflecting elements. RISs have been traditionally realized through single connected architectures,…

Information Theory · Computer Science 2023-06-16 Matteo Nerini , Shanpu Shen , Bruno Clerckx

Reconfigurable intelligent surface (RIS) has been deemed as one of potential components of future wireless communication systems because it can adaptively manipulate the wireless propagation environment with low-cost passive devices.…

Signal Processing · Electrical Eng. & Systems 2024-10-28 Yanan Ma , Ming Li , Yang Liu , Qingqing Wu , Qian Liu

This paper investigates the two-timescale transmission design for reconfigurable intelligent surface (RIS)-aided massive multiple-input multiple-output (MIMO) systems, where the beamforming at the base station (BS) is adapted to the…

Hybrid beamforming is an emerging technology for massive multiple-input multiple-output (MIMO) systems due to the advantages of lower complexity, cost, and power consumption. Recently, intelligent reflection surface (IRS) has been proposed…

Signal Processing · Electrical Eng. & Systems 2024-04-26 Jeongjae Lee , Songnam Hong

In this paper, we investigate an intelligent reflecting surface (IRS) assisted cell-free multiple input multiple output (MIMO) communication system, where distributed multiple IRSs are dedicated deployed to assist distributed multiple base…

Information Theory · Computer Science 2021-08-18 Xie Xie , Chen He , Xiaoya Li , Kun Yang , Z. Jane Wang

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

This paper introduces a reconfigurable intelligent surface (RIS) to support parameter estimation in machine-type communications (MTC). We focus on a network where single-antenna sensors transmit spatially correlated measurements to a…

Signal Processing · Electrical Eng. & Systems 2026-01-28 Sergi Liesegang , Antonio Pascual-Iserte , Olga Muñoz

In millimeter wave (mmWave) systems, it is challenging to ensure the reliable connectivity of communications due to its sensitivity to the presence of blockages. In order to improve the robustness of the mmWave system under the presence of…

Information Theory · Computer Science 2021-09-01 Gui Zhou , Cunhua Pan , Hong Ren , Kezhi Wang , Marco Di Renzo

One of the key enablers of future wireless communications is constituted by massive multiple-input multiple-output (MIMO) systems, which can improve the spectral efficiency by orders of magnitude. However, in existing massive MIMO systems,…

Information Theory · Computer Science 2019-12-10 Linglong Dai , Bichai Wang , Min Wang , Xue Yang , Jingbo Tan , Shuangkaisheng Bi , Shenheng Xu , Fan Yang , Zhi Chen , Marco Di Renzo , Lajos Hanzo

Reconfigurable intelligent surface (RIS) is a promising technology to enhance the spectral and energy efficiency in a wireless communication system. The design of the phase shifts of an RIS in every channel coherence interval demands a huge…

Signal Processing · Electrical Eng. & Systems 2024-05-15 Sadaf Syed , Dominik Semmler , Donia Ben Amor , Michael Joham , Wolfgang Utschick

Reconfigurable intelligent surface (RIS) or intelligent reflecting surface (IRS) has recently been envisioned as one of the most promising technologies in the future sixth-generation (6G) communications. In this paper, we consider the joint…

Information Theory · Computer Science 2021-12-14 Zhangjie Peng , Zhiwei Chen , Cunhua Pan , Gui Zhou , Hong Ren

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

Future wireless networks are envisioned to deliver not only gigabit communications but also ubiquitous sensing. Reconfigurable intelligent surfaces (RISs) have emerged to reshape radio propagation, recently showing considerable promise for…

Signal Processing · Electrical Eng. & Systems 2025-09-22 Ziyuan Zheng , Qingqing Wu , Yanze Zhu , Wen Chen , Ying Gao , Honghao Wang

In this letter, we investigate joint application of reconfigurable intelligent surface (RIS) and vertical beamforming in cognitive radio networks (CRN). After properly modeling the network, an optimization problem is formed to jointly…

Information Theory · Computer Science 2021-03-17 S. Fatemeh Zamanian , S. Mohammad Razavizadeh , Qingqing Wu

Reconfigurable intelligent surface (RIS) technique stands as a promising signal enhancement or signal cancellation technique for next generation networks. We design a novel passive beamforming weight at RISs in a multiple-input…

Information Theory · Computer Science 2020-03-05 Tianwei Hou , Yuanwei Liu , Zhengyu Song , Xin Sun , Yue Chen

Orthogonal multi-user multiple-input multiple-output (MU-MIMO) channels allow for optimum performance with simplified precoding/equalization, and they achieve maximum multiplexing gain which is shared fairly among users. Reconfigurable…

Information Theory · Computer Science 2023-05-01 Juan Vidal Alegria , Fredrik Rusek

Active reconfigurable intelligent surface (RIS) emerges as an effective technique to resist the double-fading attenuation of passive RIS. By embedding with power harvesting function, it further evolves to zero-power active RIS, which can…

Information Theory · Computer Science 2025-10-17 Xiao Zheng , Wenchi Cheng , Jingqing Wang , Zhuohui Yao , Jiangzhou Wang

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

Reconfigurable Intelligent Surfaces (RISs) are an emerging technology for future wireless communication systems, enabling improved coverage in an energy efficient manner. RISs are usually metasurfaces, constituting of two-dimensional…

Information Theory · Computer Science 2022-03-28 Konstantinos D. Katsanos , Nir Shlezinger , Mohammadreza F. Imani , George C. Alexandropoulos

A communication link aided by a Reconfigurable Intelligent Surface (RIS) is studied, in which the transmitter can control the state of the RIS via a finite-rate control link. Prior work mostly assumed a fixed RIS configuration irrespective…

Information Theory · Computer Science 2019-11-22 Roy Karasik , Osvaldo Simeone , Marco Di Renzo , Shlomo Shamai