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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

Reconfigurable intelligent surfaces (RISs) have tremendous potential to boost communication performance, especially when the line-of-sight (LOS) path between the user equipment (UE) and base station (BS) is blocked. To control the RIS,…

Signal Processing · Electrical Eng. & Systems 2023-11-21 Fan Jiang , Andrea Abrardo , Kamran Keykhoshravi , Henk Wymeersch , Davide Dardari , Marco Di Renzo

This paper proposes a three-stage uplink channel estimation protocol for reconfigurable intelligent surface (RIS)-aided multi-user (MU) millimeter-wave (mmWave) multiple-input single-output (MISO) systems, where both the base station (BS)…

Signal Processing · Electrical Eng. & Systems 2026-02-24 Tian Qiu , Ruidong Li , Cunhua Pan , Taihaon Zhang , Dongnan Xia , Changhong Wang , Hong Ren

In this paper, we investigate channel estimation for reconfigurable intelligent surface (RIS) empowered millimeter-wave (mmWave) multi-user single-input multiple-output communication systems using low-resolution quantization. Due to the…

Information Theory · Computer Science 2025-10-21 Gyoseung Lee , In-soo Kim , Yonina C. Eldar , A. Lee Swindlehurst , Hyeongtaek Lee , Minje Kim , Junil Choi

We consider a reconfigurable intelligent surface (RIS)-aided massive multi-user multiple-input multiple-output (MIMO) communication system with transceiver hardware impairments (HWIs) and RIS phase noise. Different from the existing…

Information Theory · Computer Science 2021-10-14 Jianxin Dai , Feng Zhu , Cunhua Pan , Hong Ren , Kezhi Wang

In this paper, reconfigurable intelligent surface (RIS) is employed in a millimeter wave (mmWave) integrated sensing and communications (ISAC) system. To alleviate the multi-hop attenuation, the semi-self sensing RIS approach is adopted,…

Signal Processing · Electrical Eng. & Systems 2024-01-03 Wanting Lyu , Songjie Yang , Yue Xiu , Ya Li , Hongjun He , Chau Yuen , Zhongpei Zhang

Reconfigurable intelligent surfaces (RISs) have emerged as a promising solution that can provide dynamic control over the propagation of electromagnetic waves. The RIS technology is envisioned as a key enabler of sixth-generation networks…

Signal Processing · Electrical Eng. & Systems 2025-02-26 Ishan Koralege , Arthur S. de Sena , Nurul H. Mahmood , Farjam Karim , Dimuthu Lesthuruge , Samitha Gunarathne

Intelligent surfaces that reshape electromagnetic waves are regarded as disruptive technologies for wireless networks. However, existing designs sit at two costly extremes: dynamic reconfigurable intelligent surfaces (RISs) offer fine beam…

Signal Processing · Electrical Eng. & Systems 2025-11-24 Ziyuan Zheng , Qingqing Wu , Wen Chen , Weiren Zhu , Ying Gao

Reconfigurable intelligent surface (RIS) is a candidate technology for future wireless networks. It enables to shape the wireless environment to reach massive connectivity and enhanced data rate. The promising gains of RIS-assisted networks…

Signal Processing · Electrical Eng. & Systems 2022-06-09 Paulo R. B. Gomes , Gilderlan T. de Araújo , Bruno Sokal , André L. F. de Almeida , Behrooz Makki , Gábor Fodor

This paper presents a physics-based channel modeling and optimization framework for reconfigurable intelligent surface (RIS)-assisted downlink multi-user multiple-input single-output (MU-MISO) communication systems in site-specific…

Signal Processing · Electrical Eng. & Systems 2026-03-24 Ziqi Liu , Wei Yu , Sean Victor Hum

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 surfaces (RISs) can establish favorable wireless environments to combat the severe attenuation and blockages in millimeter-wave (mmWave) bands. However, to achieve the optimal enhancement of performance, the…

Information Theory · Computer Science 2022-03-02 Muxin He , Jindan Xu , Wei Xu , Hong Shen , Ning Wang , Chunming Zhao

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

A reconfigurable intelligent surface (RIS) alters the reflection of incoming signals based on the phase-shift configuration assigned to its elements. This feature can be used to improve the signal strength for user equipments (UEs), expand…

Signal Processing · Electrical Eng. & Systems 2024-12-19 Alva Kosasih , Ozlem Tugfe Demir , Emil Bjornson

In wireless systems aided by reconfigurable intelligent surfaces (RISs), channel state information plays a pivotal role in achieving the performance gain of RISs. Mobility renders accurate channel estimation (CE) more challenging due to the…

Information Theory · Computer Science 2021-02-01 Shu Sun , Hangsong Yan

In the research of RIS-assisted communication systems, channel estimation is a problem of vital importance for further performance optimization. In order to reduce the pilot overhead to the greatest extent, blind channel estimation methods…

Signal Processing · Electrical Eng. & Systems 2025-08-26 Dianhao Jia , Wenqian Shen , Jianping An , Byonghyo Shim

To achieve the more promising passive beamforming gains in the double-intelligent reflecting surface (IRS) assisted system over the conventional single-IRS system, channel estimation is practically indispensable but also a more challenging…

Information Theory · Computer Science 2020-10-14 Beixiong Zheng , Changsheng You , Rui Zhang

The linear minimal mean square error (LMMSE) estimator for active reconfigurable intelligent surface (RIS)-aided wireless systems is formulated. Furthermore, based on the moment-matching method, we employ the Gamma distribution to…

Information Theory · Computer Science 2023-01-25 Qingchao Li , Mohammed El-Hajjar , Ibrahim Hemadeh , Deepa Jagyasi , Arman Shojaeifard , Lajos Hanzo

Pixel-based reconfigurable intelligent surfaces (RISs) employ a novel design to achieve high reflection gain at a lower hardware cost by eliminating the phase shifters used in traditional RIS. However, this design presents challenges for…

Signal Processing · Electrical Eng. & Systems 2025-10-24 Huayan Guo , Junhui Rao , Alex M. H. Wong , Ross Murch , Vincent K. N. Lau

Intelligent surfaces comprising of cost effective, nearly passive, and reconfigurable unit elements are lately gaining increasing interest due to their potential in enabling fully programmable wireless environments. They are envisioned to…

Information Theory · Computer Science 2022-05-26 George C. Alexandropoulos , Evangelos Vlachos