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Related papers: RIS-Aided Near-Field Channel Estimation under Mutu…

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This paper proposes a correlation-based three-stage channel estimation strategy with low pilot overhead for reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) multi-user (MU) MIMO systems, in which both users and base…

Signal Processing · Electrical Eng. & Systems 2025-02-11 Liuchang Zhuo , Cunhua Pan , Hong Ren , Ruisong Weng , Shi Jin , A. Lee Swindlehurst , Jiangzhou Wang

We study the channel estimation problem for a reconfigurable intelligent surface (RIS)-assisted millimeter-wave (mmWave) multi-user multiple-input multiple-output (MU-MIMO) system. In particular, it is assumed that the channel between a RIS…

Signal Processing · Electrical Eng. & Systems 2024-10-18 Jeongjae Lee , Songnam Hong

Amid the demand for densely integrated elements in techniques such as holographic reconfigurable intelligent surfaces (RISs), the mutual coupling effect has gained prominence. By performing a misspecified Cramer-Rao bound analysis within an…

Signal Processing · Electrical Eng. & Systems 2024-02-21 Pinjun Zheng , Xiuxiu Ma , Tareq Y. Al-Naffouri

Accurate channel estimation is essential to achieve the performance gains promised by the use of reconfigurable intelligent surfaces (RISs) in wireless communications. In the uplink of multi-user orthogonal frequency division multiple…

Signal Processing · Electrical Eng. & Systems 2022-01-25 Sumin Jeong , Arman Farhang , Nemanja Stefan Perović , Mark F. Flanagan

Accurate estimation of the cascaded channel from a user equipment (UE) to a base station (BS) via each reconfigurable intelligent surface (RIS) element is critical to realizing the full potential of the RIS's ability to control the overall…

Signal Processing · Electrical Eng. & Systems 2024-11-08 Özlem Tuğfe Demir , Emil Björnson , Luca Sanguinetti

Mutual Coupling (MC) emerges as an inherent feature in Reconfigurable Intelligent Surfaces (RISs), particularly, when they are fabricated with sub-wavelength inter-element spacing. Hence, any physically-consistent model of the RIS operation…

Information Theory · Computer Science 2024-06-11 Dilki Wijekoon , Amine Mezghani , George C. Alexandropoulos , Ekram Hossain

We investigate a multi-user multiple-input multiple-output interference network in the presence of multiple reconfigurable intelligent surfaces (RISs). The entire system is described by using a circuit-based model for the transmitters,…

Information Theory · Computer Science 2021-02-16 Andrea Abrardo , Davide Dardari , Marco Di Renzo , Xuewen Qian

Extremely large-scale reconfigurable intelligent surfaces (XL-RISs) have emerged as a promising technology for millimeter-wave (mmWave) communications. However, the exceedingly large aperture of XL-RISs renders the RIS-user links likely to…

Information Theory · Computer Science 2026-05-11 Erkang Dong , Taihao Zhang , Cunhua Pan , Hong Ren , Jiangzhou Wang

Reconfigurable intelligent surface (RIS) is a newly-emerged technology that, with its unique features, is considered to be a game changer for future wireless networks. Channel estimation is one of the most critical challenges for the…

Signal Processing · Electrical Eng. & Systems 2023-03-30 Mehdi Haghshenas , Parisa Ramezani , Emil Björnson

Reconfigurable Intelligent Surfaces (RIS) represent a transformative technology for sixth-generation (6G) wireless communications, but it suffers from a significant limitation, namely the double-fading attenuation. Active RIS has emerged as…

Information Theory · Computer Science 2025-04-23 Yang Cao , Wenchi Cheng , Jingqing Wang , Wei Zhang

The reconfigurable intelligent surface (RIS) technology is a promising enabler for millimeter wave (mmWave) wireless communications, as it can potentially provide spectral efficiency comparable to the conventional massive multiple-input…

Information Theory · Computer Science 2022-02-22 Xuemeng Zhou , Zhiyu Yang , Tianyi Zhang , Yi Jiang

Smart wireless environments enabled by multiple distributed Reconfigurable Intelligent Surfaces (RISs) have recently attracted significant research interest as a wireless connectivity paradigm for sixth Generation (6G) networks. In this…

Information Theory · Computer Science 2024-10-11 Aris L. Moustakas , George C. Alexandropoulos

Reconfigurable intelligent surfaces (RISs) are an emerging technology for enhancing the performance of wireless networks at a low and affordable cost, complexity, and power consumption. We introduce an algorithm for optimizing a…

Information Theory · Computer Science 2020-12-01 Xuewen Qian , 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

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

A reconfigurable intelligent surface (RIS) can be used to improve the channel gain between a base station (BS) and user equipment (UE), but only if its $N$ reflecting elements are configured properly. This requires accurate estimation of…

Signal Processing · Electrical Eng. & Systems 2022-05-24 Özlem Tuğfe Demir , Emil Björnson , Luca Sanguinetti

Massive multiple-input multiple-output (MIMO) and reconfigurable intelligent surface (RIS) are two promising technologies for 5G-and-beyond wireless networks, capable of providing large array gain and multiuser spatial multiplexing. Without…

Information Theory · Computer Science 2021-09-07 Trinh Van Chien , Hien Quoc Ngo , Symeon Chatzinotas , Björn Ottersten

A reconfigurable intelligent surface (RIS) is a holographic MIMO surface composed of a large number of passive elements that can induce adjustable phase shifts to the impinging waves. By creating virtual line-of-sight (LOS) paths between…

Signal Processing · Electrical Eng. & Systems 2023-04-06 Mehdi Haghshenas , Parisa Ramezani , Maurizio Magarini , Emil Björnson

Reconfigurable intelligent surface (RIS) has been anticipated to be a novel cost-effective technology to improve the performance of future wireless systems. In this paper, we investigate a practical RIS-aided multiple-input-multiple-output…

Information Theory · Computer Science 2023-03-23 Jintao Wang , Shiqi Gong , Qingqing Wu , Shaodan Ma

Can the smart radio environment paradigm measurably enhance the performance of contemporary urban macrocells? In this study, we explore the impact of reconfigurable intelligent surfaces (RISs) on a real-world sub-6 GHz MIMO channel. A…

Signal Processing · Electrical Eng. & Systems 2023-11-30 James Rains , Anvar Tukmanov , Qammer Abbasi , Muhammad Imran