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Related papers: Joint Active and Passive Beamforming for RIS-aided…

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Intelligent reflecting surface (IRS) is envisioned to have abundant applications in future wireless networks by smartly reconfiguring the signal propagation for performance enhancement. Specifically, an IRS consists of a large number of…

Information Theory · Computer Science 2018-09-13 Qingqing Wu , Rui Zhang

This study focuses on the optimization of a single-cell multi-user multiple-input multiple-output (MIMO) system with multiple large-size reconfigurable intelligent surfaces (RISs). The overall transmit power is minimized by optimizing the…

Information Theory · Computer Science 2024-10-08 Silvia Palmucci , Giulio Bartoli , Andrea Abrardo , Marco Moretti , Marco Di Renzo

A reconfigurable intelligent surface (RIS) is a planar surface that can enhance the quality of communication by providing control over the communication environment. Reflection optimization is one of the pivotal challenges in RIS setups.…

Information Theory · Computer Science 2024-11-26 Seyedkhashayar Hashemi , Masoud Ardakani , Hai Jiang

Reconfigurable intelligent surfaces (RISs) are able to provide passive beamforming gain via low-cost reflecting elements and hence improve wireless link quality. This work considers two-way passive beamforming design in RIS-aided frequency…

Information Theory · Computer Science 2021-01-26 Bei Guo , Chenhao Sun , Meixia Tao

Millimeter wave (mmWave) band, or high frequencies such as THz, has large undeveloped band of spectrum. However, wireless channels over the mmWave band usually have one or two paths only due to the severe attenuation. The channel property…

Information Theory · Computer Science 2020-04-14 Xi Yang , Chao-Kai Wen , Shi Jin

Given its ability to control and manipulate wireless environments, reconfigurable intelligent surface (RIS), also known as intelligent reflecting surface (IRS), has emerged as a key enabler technology for the six-generation (6G) cellular…

Signal Processing · Electrical Eng. & Systems 2021-02-01 Ahmed Al-Hilo , Moataz Samir , Mohamed Elhattab , Chadi Assi , Sanaa Sharafeddine

Reconfigurable intelligent surfaces (RISs) and cell-free massive multiple-input multiple-output (CF-mMIMO) are effective solutions for mitigating large path loss and inter-cell interference in terahertz (THz) systems. However, passive RISs…

Signal Processing · Electrical Eng. & Systems 2025-05-14 Mario R. Camana , Zaid Abdullah , Carla E. Garcia , Chandan Kumar Sheemar , Eva Lagunas , Symeon Chatzinotas

Low peak-to-average power ratio (PAPR) transmission is an important and favorable requirement prevalent in radar and communication systems, especially in transmission links integrated with high power amplifiers. Meanwhile, motivated by the…

Signal Processing · Electrical Eng. & Systems 2025-04-11 Jinlong Wu , Lixin Li , Wensheng Lin , Wei Liang , Decan Zhao , Zhu Han

In this paper, we investigate an reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) system. Our objective is to maximize the achievable sum rate of the multi-antenna communication users through the…

Signal Processing · Electrical Eng. & Systems 2024-02-09 Yasheng Jin , Hong Ren , Cunhua Pan , Zhiyuan Yu , Ruisong Weng , Boshi Wang , Gui Zhou , Yongchao He , Maged Elkashlan

Sensing-assisted communication schemes have recently garnered significant research attention. In this work, we design a dual-function reconfigurable intelligent surface (RIS), integrating both active and passive elements, referred to as the…

Signal Processing · Electrical Eng. & Systems 2025-08-14 Cheng Luo , Luping Xiang , Jie Hu , Kun Yang

This letter investigates the secure communication in a reconfigurable intelligent surface (RIS)-aided multiuser massive multiple-input multiple-output (MIMO) system exploiting artificial noise (AN). We first derive a closed-form expression…

Information Theory · Computer Science 2023-01-11 Dan Yang , Jindan Xu , Wei Xu , Yongming Huang , Zhaohua Lu

This work considers a reconfigurable intelligent surface (RIS)-aided cell-free massive multiple-input multiple-output (MIMO) system with RIS spatial correlation and electromagnetic interference (EMI). We propose a two-phase channel…

Information Theory · Computer Science 2024-11-18 Jun Qian , Chi Zhang , Khaled B. Letaief , Ross Murch

This paper provides a theoretical framework for understanding the performance of reconfigurable intelligent surface (RIS)-aided massive multiple-input multiple-output (MIMO) with zero-forcing (ZF) detectors under imperfect channel state…

Information Theory · Computer Science 2021-11-03 Kangda Zhi , Cunhua Pan , Gui Zhou , Hong Ren , Maged Elkashlan , Robert Schober

This paper proposes a two-timescale transmission scheme for extremely large-scale (XL)-reconfigurable intelligent surfaces (RIS)-aided massive multi-input multi-output (MIMO) systems considering visibility regions (VRs). The beamforming of…

Information Theory · Computer Science 2024-07-11 Luchu Li , Kangda Zhi , Cunhua Pan

This paper proposes a reconfigurable intelligent surface (RIS)-aided and angular-based hybrid beamforming (AB-HBF) technique for the millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems. The proposed RIS-AB-HBF…

Information Theory · Computer Science 2022-08-16 Ibrahim Yildirim , Asil Koc , Ertugrul Basar , Tho Le-Ngoc

Flexible intelligent metasurface (FIM) technology holds immense potential for increasing the spectral efficiency and energy efficiency of wireless networks. In contrast to traditional rigid reconfigurable intelligent surfaces (RIS), an FIM…

Signal Processing · Electrical Eng. & Systems 2025-10-10 Hanwen Hu , Jiancheng An , Lu Gan , Naofal Al-Dhahir

In this letter, we study an active reconfigurable intelligent surfaces (RIS) assisted Low Earth orbit (LEO) satellite communications under non-line-of-sight (NLoS) scenarios, where the active RIS is deployed to create visual line-of-sight…

Signal Processing · Electrical Eng. & Systems 2025-06-26 Ziwei Liu , Junyan He , Shanshan Zhao , Meng Hua , Bin Lyu , Xinjie Zhao , Gengxin Zhang

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

In this paper, we consider a reconfigurable intelligent surface (RIS)-assisted two-way relay network, in which two users exchange information through the base station (BS) with the help of an RIS. By jointly designing the phase shifts at…

Information Theory · Computer Science 2021-05-11 Jun Wang , Ying-Chang Liang , Jingon Joung , Xiaojun Yuan , Xinguo Wang

Physically accurate and mathematically tractable models are presented to characterize scattering and reflection properties of reconfigurable intelligent surfaces (RISs). We take continuous and discrete strategies to model a single patch and…

Systems and Control · Electrical Eng. & Systems 2022-08-31 Tiebin Mi , Jianan Zhang , Rujing Xiong , Zhengyu Wang , Robert Caiming Qiu