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Related papers: RIS-Aided Cell-Free Massive MIMO: Performance Anal…

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The integration of electromagnetic metasurfaces into wireless communications enables intelligent control of the propagation environment. Recently, flexible intelligent metasurfaces (FIMs) have evolved beyond conventional reconfigurable…

Signal Processing · Electrical Eng. & Systems 2026-01-23 Ling He , Vaibhav Kumar , Anastasios Papazafeiropoulos , Miaowen Wen , Le-Nam Tran , Marwa Chafii

We propose an alternating optimization framework for maximizing energy efficiency (EE) in reconfigurable intelligent surface (RIS) assisted distributed MIMO (D-MIMO) systems under both coherent and non-coherent reception modes. The…

Reconfigurable intelligent surfaces (RIS)-assisted massive multiple-input multiple-output (mMIMO) is a promising technology for applications in next-generation networks. However, reflecting-only RIS provides limited coverage compared to a…

Information Theory · Computer Science 2023-09-18 Anastasios Papazafeiropoulos , Le-Nam Tran , Zaid Abdullah , Pandelis Kourtessis , Symeon Chatzinotas

Cell-free (CF) massive multiple-input-multiple-output (MIMO) has emerged as an alternative deployment for conventional cellular massive MIMO networks. Prior works relied on the strong assumption (quite idealized) that the APs are uniformly…

Information Theory · Computer Science 2020-10-27 Anastasios Papazafeiropoulos , Pandelis Kourtessis , Marco Di Renzo , Symeon Chatzinotas , John M. Senior

Cell-free (CF) massive multiple-input multiple-output (mMIMO) and reconfigurable intelligent surface (RIS) are two advanced transceiver technologies for realizing future sixth-generation (6G) networks. In this paper, we investigate the…

Information Theory · Computer Science 2024-11-19 Enyu Shi , Jiayi Zhang , Ziheng Liu , Yiyang Zhu , Chau Yuen , Derrick Wing Kwan Ng , Marco Di Renzo , Bo Ai

In a cell-free (CF) massive MIMO architecture a very large number of distributed access points (APs) simultaneously and jointly serves a much smaller number of mobile stations (MSs); a variant of the cell-free technique is the user-centric…

Information Theory · Computer Science 2017-11-07 Mario Alonzo , Stefano Buzzi

Mutual Coupling (MC) is an unavoidable feature in Reconfigurable Intelligent Surfaces (RISs) with sub-wavelength inter-element spacing. Its inherent presence naturally leads to non-local RIS structures, which can be efficiently described…

Information Theory · Computer Science 2024-04-09 Dilki Wijekoon , Amine Mezghani , George C. Alexandropoulos , Ekram Hossain

Reconfigurable Intelligent Surface (RIS) has becoming a useful tool in future wireless communication systems for close-distance communication network. This paper we use Reconfigurable Intelligent Surface (RIS) for downlink multi-user…

Information Theory · Computer Science 2021-02-02 RuiTianYi Lu

Reconfigurable intelligent surface (RIS) is an emerging technology to enhance wireless communication in terms of energy cost and system performance by equipping a considerable quantity of nearly passive reflecting elements. This study…

Information Theory · Computer Science 2021-03-17 Jun Zhang , Jie Liu , Shaodan Ma , Chao-Kai Wen , Shi Jin

Although reconfigurable intelligent surfaces (RISs) can improve the performance of wireless networks by smartly reconfiguring the radio environment, existing passive RISs face two key challenges, i.e., double-fading attenuation and…

Signal Processing · Electrical Eng. & Systems 2023-10-05 Wen Wang , Wanli Ni , Hui Tian , Naofal Al-Dhahir

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

This paper investigates the downlink power allocation of the simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS)-assisted cell-free massive multiple-input multiple-output (MIMO) system with multi-antenna…

Information Theory · Computer Science 2025-12-23 Jun Qian , Ross Murch , Khaled B. Letaief

This paper proposes a two-timescale transmission scheme for extremely large-scale (XL)-reconfigurable intelligent surfaces (RIS)-aided massive multi-input multi-output (MIMO) systems considering visibility regions (VRs). The beamforming of…

Information Theory · Computer Science 2024-07-11 Luchu Li , Kangda Zhi , Cunhua Pan

We investigate the integration of beyond diagonal reconfigurable intelligent surfaces (BDRISs) into cell free massive multiple input multiple output (CFmMIMO) systems to enhance simultaneous wireless information and power transfer (SWIPT).…

Information Theory · Computer Science 2025-08-20 Duc Thien Hua , Mohammadali Mohammadi , Hien Quoc Ngo , Michail Matthaiou

In this paper, we investigate an reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) system. Our objective is to maximize the achievable sum rate of the multi-antenna communication users through the…

Signal Processing · Electrical Eng. & Systems 2024-02-09 Yasheng Jin , Hong Ren , Cunhua Pan , Zhiyuan Yu , Ruisong Weng , Boshi Wang , Gui Zhou , Yongchao He , Maged Elkashlan

Active reconfigurable intelligent surfaces (RISs) employ amplification to overcome attenuation caused by the RIS cascaded link. In this paper, we analyze the effects of phase errors and channel aging in active simultaneously transmitting…

Information Theory · Computer Science 2025-10-16 Jun Qian , Ross Murch , Khaled B. Letaief

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

Programmable metasurfaces have garnered significant attention due to their exceptional ability to manipulate electromagnetic (EM) waves in real time, leading to the emergence of a prominent area in wireless communication, namely…

In this paper, we investigate a simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisting a massive multiple-input multiple-output (mMIMO) system. In particular, we derive a closed-form expression for…

Information Theory · Computer Science 2022-06-01 Anastasios Papazafeiropoulos , Zaid Abdullah , Pandelis Kourtessis , Steven Kisseleff , Ioannis Krikidis

Intelligent reflecting surfaces (IRSs) have received considerable attention from the wireless communications research community recently. In particular, as low-cost passive devices, IRSs enable the control of the wireless propagation…

Information Theory · Computer Science 2019-04-30 Xianghao Yu , Dongfang Xu , Robert Schober