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Related papers: Statistical CSI-based Beamforming for RIS-Aided Mu…

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As an emerging communication auxiliary technology, reconfigurable intelligent surface (RIS) is expected to play a significant role in the upcoming 6G networks. Due to its total reflection characteristics, it is challenging to implement…

Signal Processing · Electrical Eng. & Systems 2023-08-04 W. Li , Z. Lin , Q. Guo , B. Vucetic

In cell-free multiple input multiple output (MIMO) networks, multiple base stations (BSs) collaborate to achieve high spectral efficiency. Nevertheless, high penetration loss due to large blockages in harsh propagation environments is often…

Information Theory · Computer Science 2023-03-16 Chen Chen , Sai Xu , Jiliang Zhang , Jie Zhang

Active Reconfigurable Intelligent Surfaces (RIS) are a promising technology for 6G wireless networks. This paper investigates a novel hybrid deep reinforcement learning (DRL) framework for resource allocation in a multi-user uplink system…

Signal Processing · Electrical Eng. & Systems 2025-12-29 Mohamed Shalma , Engy Aly Maher , Ahmed El-Mahdy

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 investigates the integration of a reconfigurable intelligent surface (RIS) into a secure multiuser massive multiple-input multiple-output (MIMO) system in the presence of transceiver hardware impairments (HWI), imperfect channel…

Information Theory · Computer Science 2024-04-09 Dan Yang , Jindan Xu , Wei Xu , Bin Sheng , Xiaohu You , Chau Yuen , Marco Di Renzo

Antenna selection is capable of reducing the hardware complexity of massive multiple-input multiple-output (MIMO) networks at the cost of certain performance degradation. Reconfigurable intelligent surface (RIS) has emerged as a…

Information Theory · Computer Science 2020-09-17 Jinglian He , Kaiqiang Yu , Yuanming Shi , Yong Zhou , Wei Chen , Khaled B. Letaief

Reconfigurable intelligent surface (RIS) is considered as an extraordinarily promising technology to solve the blockage problem of millimeter wave (mmWave) communications owing to its capable of establishing a reconfigurable wireless…

Information Theory · Computer Science 2022-02-22 Yuqian Zhu , Ming Li , Yang Liu , Qian Liu , Zheng Chang , Yulin Hu

Reconfigurable intelligent surfaces (RIS) are key enablers for 6G wireless systems. This paper studies downlink transmission in an RIS-assisted MISO-OFDMA system, addressing resource allocation challenges. A two-stage unsupervised…

Signal Processing · Electrical Eng. & Systems 2025-07-01 Yu Ma , Xingyu Zhou , Xiao Li , Le Liang , Shi Jin

The reconfigurable intelligent surface (RIS) is a promising technology that enables wireless communication systems to achieve improved performance by intelligently manipulating wireless channels. In this paper, we consider the sum-rate…

Signal Processing · Electrical Eng. & Systems 2023-08-21 Bile Peng , Karl-Ludwig Besser , Ramprasad Raghunath , Vahid Jamali , Eduard A. Jorswieck

Stacked Intelligent Metasurfaces (SIM) have emerged as a revolutionary architecture for next-generation wireless communications, offering wave-domain signal processing capabilities with significantly reduced hardware complexity compared to…

Information Theory · Computer Science 2026-01-22 Yuhui Jiao , Qian Zhang , Xuejun Cheng , Yunxiao Li , Yufei Zhao , Ju Liu , Yong Liang Guan

We present efficient algorithms for the sum-spectral efficiency (SE) maximization of the multi-user reconfigurable intelligent surface (RIS)-aided multiple-input multiple-output (MIMO) broadcast channel based on a zero-forcing approach.…

Information Theory · Computer Science 2023-11-21 Dominik Semmler , Michael Joham , Wolfgang Utschick

Intelligent reflection surface (IRS) has recently been recognized as a promising technique to enhance the performance of wireless systems due to its ability of reconfiguring the signal propagation environment. However, the perfect channel…

Signal Processing · Electrical Eng. & Systems 2021-08-10 Gui Zhou , Cunhua Pan , Hong Ren , Kezhi Wang , Arumugam Nallanathan

Hybrid beamforming is a promising technique to reduce the complexity and cost of massive multiple-input multiple-output (MIMO) systems while providing high data rate. However, the hybrid precoder design is a challenging task requiring…

Signal Processing · Electrical Eng. & Systems 2021-05-28 Hamed Hojatian , Jeremy Nadal , Jean-Francois Frigon , Francois Leduc-Primeau

In this paper, intelligent reflecting surface (IRS) is introduced to enhance the network performance of cognitive radio (CR) systems. Specifically, we investigate robust beamforming design based on both bounded channel state information…

Signal Processing · Electrical Eng. & Systems 2024-01-08 Lei Zhang , Cunhua Pan , Yu Wang , Hong Ren , Kezhi Wang

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

A cell-free network merged with active reconfigurable reflecting surfaces (RIS) is investigated in this paper. Based on the imperfect channel state information (CSI), the aggregated channel from the user to the access point (AP) is…

Signal Processing · Electrical Eng. & Systems 2024-02-23 Mahdi Eskandari , Huiling Zhu , Jiangzhou Wang

Reciprocity-based beamforming-most commonly employed in time-division duplexing-uses noisy, estimated (i.e., measured) channel state information (CSI) acquired on the uplink. While computationally efficient, reciprocity-based beamforming…

Signal Processing · Electrical Eng. & Systems 2025-03-25 Benjamin J. B. Deutschmann , Erik Leitinger , Klaus Witrisal

The current literature on intelligent reflecting surface (IRS) focuses on optimizing the IRS phase shifts to yield coherent beamforming gains, under the assumption of perfect channel state information (CSI) of individual IRS-assisted links,…

Information Theory · Computer Science 2021-03-19 Qurrat-Ul-Ain Nadeem , Alessio Zappone , Anas Chaaban

This paper considers the design of the beamformers for a multiple-input single-output (MISO) downlink system that seeks to mitigate the impact of the imperfections in the channel state information (CSI) that is available at the base station…

Information Theory · Computer Science 2018-02-14 Mostafa Medra , Timothy N. Davidson

This paper investigates the problem of resource allocation for multiuser communication networks with a reconfigurable intelligent surface (RIS)-assisted wireless transmitter. In this network, the sum transmit power of the network is…

Signal Processing · Electrical Eng. & Systems 2020-09-25 Zhaohui Yang , Wei Xu , Chongwen Huang , Jianfeng Shi , Mohammad Shikh-Bahaei