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Related papers: Channel Estimation for Reconfigurable Intelligent …

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A reconfigurable intelligent surface (RIS) can shape the radio propagation by passively changing the directions of impinging electromagnetic waves. The optimal control of the RIS requires perfect channel state information (CSI) of all the…

Signal Processing · Electrical Eng. & Systems 2020-02-18 Jiguang He , Markus Leinonen , Henk Wymeersch , Markku Juntti

In this paper, we investigate cascaded channel estimation for reconfigurable intelligent surface (RIS)-aided millimeter-wave multi-user communication systems. Since the complex channel gains of the cascaded RIS channel are generally…

Signal Processing · Electrical Eng. & Systems 2025-10-21 Gyoseung Lee , Junil Choi

Recent research has focused on reconfigurable intelligent surface (RIS)-assisted cell-free systems with the goal of enhancing coverage and lowering the cost of cell-free networks. However, current research makes the assumption that the…

Signal Processing · Electrical Eng. & Systems 2022-07-29 Songjie Yang , Chenfei Xie , Mingwei Wang , Zhongpei Zhang

In this paper, we consider channel estimation for intelligent reflecting surface (IRS)-assisted millimeter wave (mmWave) systems, where an IRS is deployed to assist the data transmission from the base station (BS) to a user. It is shown…

Signal Processing · Electrical Eng. & Systems 2020-07-15 Peilan Wang , Jun Fang , Huiping Duan , Hongbin Li

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

Reconfigurable intelligent surface (RIS) has emerged as a promising technology for improving capacity and extending coverage of wireless networks. In this work, we consider RIS-aided millimeter wave (mmWave) multiple-input and…

Information Theory · Computer Science 2023-04-17 Yabo Guo , Peng Sun , Zhengdao Yuan , Qinghua Guo , Zhongyong Wang

In this letter, we optimize the channel estimator of the cascaded channel in an intelligent reflecting surface (IRS)-assisted millimeter wave (mmWave) multi-antenna system. In this system, the receiver is equipped with a hybrid architecture…

Information Theory · Computer Science 2020-10-05 Wenhui Zhang , Jindan Xu , Wei Xu , Derrick Wing Kwan Ng , Huan Sun

Deploying multiple beyond diagonal reconfigurable intelligent surfaces (BD-RISs) can potentially improve the communication performance thanks to inter-element connections of each BD-RIS and inter-surface cooperative beamforming gain among…

Signal Processing · Electrical Eng. & Systems 2026-02-23 Junyuan Gao , Shuowen Zhang , Liang Liu

Beyond diagonal reconfigurable intelligent surface (BD-RIS) architectures offer superior beamforming gain over conventional diagonal RISs. However, the channel estimation overhead is the main hurdle for reaping the above gain in practice.…

Signal Processing · Electrical Eng. & Systems 2026-02-25 Rui Wang , Junyuan Gao , Shuowen Zhang , Bruno Clerckx , Liang Liu

Channel estimation in reconfigurable intelligent surface (RIS) assisted multiple input multiple output (MIMO) communication systems is challenging as pilots cannot be decoded at or transmitted from a RIS with only passive elements. We…

Signal Processing · Electrical Eng. & Systems 2021-03-22 Battu Deepak , R. S. Prasobh Sankar , Sundeep Prabhakar Chepuri

Reconfigurable intelligent surfaces (RISs) are eminently suitable for improving the reliability of wireless communications by jointly designing the active beamforming at the base station (BS) and the passive beamforming at the RIS.…

Information Theory · Computer Science 2025-01-23 Qingchao Li , Mohammed El-Hajjar , Ibrahim Hemadeh , Arman Shojaeifard , Lajos Hanzo

A reconfigurable intelligent surface (RIS) can shape the radio propagation environment by virtue of changing the impinging electromagnetic waves towards any desired directions, thus, breaking the general Snell's reflection law. However, the…

Signal Processing · Electrical Eng. & Systems 2021-01-15 Jiguang He , Henk Wymeersch , Markku Juntti

Beyond diagonal reconfigurable intelligent surface (BD-RIS) represents a promising architecture for advancing millimeter-wave (mmWave) communications. However, its intricate inter-element connections invalidate the conventional decoupled…

Signal Processing · Electrical Eng. & Systems 2026-05-20 Linyu Peng , Tian Qiu , Cunhua Pan , Jiangzhou Wang , Taihao Zhang , Hong Ren

Due to their ability to create favorable line-of-sight (LoS) propagation environments, intelligent reflecting surfaces (IRSs) are regarded as promising enablers for future millimeter-wave (mm-wave) wireless communication. In this paper, we…

Information Theory · Computer Science 2021-07-27 Tian Lin , Xianghao Yu , Yu Zhu , Robert Schober

This chapter focuses on a hardware architecture for semi-passive Reconfigurable Intelligent Surfaces (RISs) and investigates its consideration for boosting the performance of Multiple-Input Multiple-Output (MIMO) communication systems. The…

Signal Processing · Electrical Eng. & Systems 2025-06-19 George C. Alexandropoulos , Konstantinos D. Katsanos , Evangelos Vlachos

Reconfigurable Intelligent Surfaces (RISs) have been recently considered as an energy-efficient solution for future wireless networks due to their fast and low-power configuration, which has increased potential in enabling massive…

Information Theory · Computer Science 2022-06-27 Li Wei , Chongwen Huang , George C. Alexandropoulos , Chau Yuen , Zhaoyang Zhang , Mérouane Debbah

In this paper, we adopt a three-stage based uplink channel estimation protocol with reduced pilot overhead for an reconfigurable intelligent surface (RIS)-aided multi-user (MU) millimeter wave (mmWave) communication system, in which both…

Signal Processing · Electrical Eng. & Systems 2023-04-18 Zhendong Peng , Gui Zhou , Cunhua Pan , Hong Ren , A. Lee Swindlehurst , Petar Popovski , Gang Wu

Reconfigurable Intelligent Surfaces (RISs) have been recently considered as an energy-efficient solution for future wireless networks. Their dynamic and low-power configuration enables coverage extension, massive connectivity, and…

Information Theory · Computer Science 2020-11-30 Li Wei , Chongwen Huang , George C. Alexandropoulos , Zhaohui Yang , Chau Yuen , Zhaoyang Zhang

Reconfigurable intelligent surface (RIS) has recently drawn significant attention in wireless communication technologies. However, identifying, modeling, and estimating the RIS channel in multiple-input multiple-output (MIMO) systems are…

Signal Processing · Electrical Eng. & Systems 2021-11-04 Salah Eddine Zegrar , Liza Afeef , Huseyin Arslan

We consider the problem of channel estimation and joint active and passive beamforming for reconfigurable intelligent surface (RIS) assisted millimeter wave (mmWave) multiple-input multiple-output (MIMO) orthogonal frequency division…

Signal Processing · Electrical Eng. & Systems 2022-10-05 Xi Zheng , Jun Fang , Hongwei Wang , Peilan Wang , Hongbin Li