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Related papers: Channel Estimation for RIS-Empowered Multi-User MI…

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We consider a practical spatially correlated reconfigurable intelligent surface (RIS)-aided cell-free (CF) massive multiple-input-multiple-output (mMIMO) system with multi-antenna access points (APs) over spatially correlated Rician fading…

Information Theory · Computer Science 2022-09-29 Enyu Shi , Jiayi Zhang , Zhe Wang , Derrick Wing Kwan Ng , Bo Ai

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

With the rapid development of Internet of Things (IoT), massive machine-type communication has become a promising application scenario, where a large number of devices transmit sporadically to a base station (BS). Reconfigurable intelligent…

Information Theory · Computer Science 2021-01-26 Shuhao Xia , Yuanming Shi , Yong Zhou , Xiaojun Yuan

Reconfigurable intelligent surfaces (RISs) have been proposed as a key enabler to improve the coverage of the signals and mitigate the frequent blockages in millimeter wave (mmWave) multiple-input multiple-output (MIMO) communications.…

Signal Processing · Electrical Eng. & Systems 2021-07-16 Rafaela Schroeder , Jiguang He , Glauber Brante , Markku Juntti

To mitigate the effects of shadow fading and obstacle blocking, reconfigurable intelligent surface (RIS) has become a promising technology to improve the signal transmission quality of wireless communications by controlling the…

Information Theory · Computer Science 2021-11-10 Wangyang Xu , Jiancheng An , Yongjun Xu , Chongwen Huang , Lu Gan , Chau Yuen

The integration of reconfigurable intelligent surfaces (RIS) with extremely large multiple-input multiple-output (MIMO) arrays at the base station has emerged as a key enabler for enhancing wireless network performance. However, this setup…

Signal Processing · Electrical Eng. & Systems 2025-08-05 Ahmad Dkhan , Simon Tarboush , Hadi Sarieddeen , Tareq Y. Al-Naffouri

The accurate estimation of Channel State Information (CSI) is of crucial importance for the successful operation of Multiple-Input Multiple-Output (MIMO) communication systems, especially in a Multi-User (MU) time-varying environment and…

Information Theory · Computer Science 2022-02-22 Jide Yuan , George C. Alexandropoulos , Eleftherios Kofidis , Tobias Lindstrm Jensen , Elisabeth De Carvalho

Reconfigurable intelligent surface (RIS) is a promising candidate technology of the upcoming Sixth Generation (6G) communication system for its ability to provide unprecedented spectral and energy efficiency increment through passive…

Information Theory · Computer Science 2023-09-29 Haochen Li , Zhiwen Pan , Bin Wang , Nan Liu , Xiaohu You

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

For downlink massive multiple-input multiple-output (MIMO) operating in time-division duplex protocol, users can decode the signals effectively by only utilizing the channel statistics as long as channel hardening holds. However, in a…

Information Theory · Computer Science 2022-05-17 Tung T. Vu , Trinh Van Chien , Canh T. Dinh , Hien Quoc Ngo , Michail Matthaiou

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

Reconfigurable intelligent surfaces (RISs) have been introduced as a remedy for mitigating frequent blockages in millimeter wave (mmWave) multiple-input multiple-output (MIMO) communication networks. However, perfect or nearly perfect…

Signal Processing · Electrical Eng. & Systems 2021-06-22 Rafaela Schroeder , Jiguang He , Markku Juntti

Reconfigurable Intelligent Surfaces (RISs) are envisioned to play a key role in future wireless communications, enabling programmable radio propagation environments. They are usually considered as almost passive planar structures that…

Information Theory · Computer Science 2022-08-12 Haiyang Zhang , Nir Shlezinger , George C Alexandropoulos , Idban Alamzadeh , Mohammadreza F Imani , Yonina C Eldar

Reconfigurable intelligent surface (RIS) is a recent low-cost and energy-efficient technology with potential applicability for future wireless communications. Performance gains achieved by employing RIS directly depend on accurate channel…

Signal Processing · Electrical Eng. & Systems 2024-12-24 Paulo R. B. Gomes , Amarilton L. Magalhães , André L. F. de Almeida

In this paper, we propose a three-stage unified channel estimation strategy for reconfigurable intelligent surface (RIS)-aided multi-user (MU) multiple-input multiple-output (MIMO) millimeter wave (mmWave) systems with the existence of the…

Signal Processing · Electrical Eng. & Systems 2025-11-25 Taihao Zhang , Zhendong Peng , Cunhua Pan , Hong Ren , Jiangzhou Wang

A reconfigurable intelligent surface (RIS) consists of massive meta elements, which can improve the performance of future wireless communication systems. Existing RIS-aided channel estimation methods try to estimate the cascaded channel…

Information Theory · Computer Science 2021-08-20 Wei Zhang , Wee Peng Tay

Reconfigurable intelligent surfaces (RISs) have been recently considered as a promising candidate for energy-efficient solutions in future wireless networks. Their dynamic and lowpower configuration enables coverage extension, massive…

Information Theory · Computer Science 2021-07-22 Li Wei , Chongwen Huang , Qinghua Guo , Zhaoyang Zhang , Merouane Debbah , Chau Yuen

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

Cell-Free Massive multiple-input multiple-output (MIMO) and reconfigurable intelligent surface (RIS) are two promising technologies for application to beyond-5G networks. This paper considers Cell-Free Massive MIMO systems with the…

Information Theory · Computer Science 2021-12-20 Trinh Van Chien , Hien Quoc Ngo , Symeon Chatzinotas , Marco Di Renzo , Björn Ottersten

Reconfigurable Intelligent Surfaces (RISs) are envisioned to play a key role in future wireless communications, enabling programmable radio propagation environments. They are usually considered as nearly passive planar structures that…

Signal Processing · Electrical Eng. & Systems 2022-02-14 Haiyang Zhang , Nir Shlezinger , Idban Alamzadeh , George C. Alexandropoulos , Mohammadreza F. Imani , Yonina C. Eldar