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Recently, the reconfigurable intelligent surface (RIS) technology has ushered in the prospect of control over the wireless propagation environment. By establishing alternative propagation paths for the transmitted signals, and by reflecting…

Signal Processing · Electrical Eng. & Systems 2025-11-18 Pedro H. C. de Souza , Luciano Mendes

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

We consider the problem of channel estimation in a multiple-input-multiple-output (MIMO) full-duplex (FD) wireless communication system assisted by a reconfigurable intelligent surface (RIS) with hardware impairments (HI) occurring at the…

Signal Processing · Electrical Eng. & Systems 2023-07-25 Alexander James Fernandes , Ioannis Psaromiligkos

The reconfigurable intelligent surface (RIS) is an emerging technology that changes how wireless networks are perceived, therefore its potential benefits and applications are currently under intense research and investigation. In this…

Information Theory · Computer Science 2023-05-18 Placido Mursia , Sendy Phang , Vincenzo Sciancalepore , Gabriele Gradoni , Marco Di Renzo

Channel estimation in reconfigurable intelligent surfaces (RIS)-aided systems is crucial for optimal configuration of the RIS and various downstream tasks such as user localization. In RIS-aided systems, channel estimation involves…

Signal Processing · Electrical Eng. & Systems 2023-12-19 Firas Fredj , Amal Feriani , Amine Mezghani , Ekram Hossain

Recent advances in reconfigurable antennas have led to the new concept of the fluid antenna system (FAS) for shape and position flexibility, as another degree of freedom for wireless communication enhancement. This paper explores the…

Signal Processing · Electrical Eng. & Systems 2025-04-15 Jiangong Chen , Yue Xiao , Zhendong Peng , Jing Zhu , Xia Lei , Christos Masouros , Kai-Kit Wong

Despite the promising gains, free-space optical (FSO) communication is severely influenced by atmospheric turbulence and pointing error issues, which make its practical design a bit challenging. In this paper, with the aim to increase the…

Information Theory · Computer Science 2020-12-02 Liang Yang , Wang Guo , Daniel Benevides da Costa , Mohamed-Slim Alouini

Reconfigurable intelligent surface (RIS) is envisioned to be an essential component of the paradigm for beyond 5G networks as it can potentially provide similar or higher array gains with much lower hardware cost and energy consumption…

Information Theory · Computer Science 2020-07-09 Hang Liu , Xiaojun Yuan , Ying-Jun Angela Zhang

Reconfigurable intelligent surfaces (RISs) have emerged as a promising technology to enhance the performance of sixth-generation (6G) and beyond communication systems. The passive nature of RISs and their large number of reflecting elements…

Information Theory · Computer Science 2024-06-12 Nipuni Ginige , Arthur Sousa de Sena , Nurul Huda Mahmood , Nandana Rajatheva , Matti Latva-aho

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

Novel reconfigurable intelligent surface (RIS) architectures, known as beyond diagonal RISs (BD-RISs), have been proposed to enhance reflection efficiency and expand RIS capabilities. However, their passive nature, non-diagonal reflection…

Signal Processing · Electrical Eng. & Systems 2024-11-28 Nipuni Ginige , Arthur Sousa de Sena , Nurul Huda Mahmood , Nandana Rajatheva , Matti Latva-aho

Reconfigurable intelligent surfaces (RIS) is a promising solution to build a programmable wireless environment via steering the incident signal in fully customizable ways with reconfigurable passive elements. In this paper, we consider a…

Signal Processing · Electrical Eng. & Systems 2019-12-30 Huayan Guo , Ying-Chang Liang , Jie Chen , Erik G. Larsson

This paper investigates the impact of the recently proposed concept of fluid reconfigurable intelligent surfaces (FRIS) on covert communications. Specifically, we consider a communication scenario where a legitimate transmitter aims to…

Information Theory · Computer Science 2025-12-05 Farshad Rostami Ghadi , Masoud Kaveh , Hanjiang Hong , Kai-Kit Wong , Riku Jantti , F. Javier Lopez-Martinez

Wireless communications are nowadays shifting to higher operation frequencies with the aim to meet the ever-increasing demand for bandwidth. While reconfigurable intelligent surfaces (RISs) are usually envisioned to restore the…

Signal Processing · Electrical Eng. & Systems 2024-05-02 Giorgos Stratidakis , Sotiris Droulias , Angeliki Alexiou

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

Reconfigurable Intelligent Surfaces (RISs) are recently attracting a wide interest due to their capability of tuning wireless propagation environments in order to increase the system performance of wireless networks. In this paper, a…

Information Theory · Computer Science 2020-04-21 Stefano Buzzi , Carmen D'Andrea , Alessio Zappone , Maria Fresia , Yong-Ping Zhang , Shulan Feng

Reconfigurable intelligent surface (RIS) is an emerging technology for future wireless communication systems. In this work, we consider downlink spatial multiplexing enabled by the RIS for weighted sum-rate (WSR) maximization. In the…

Signal Processing · Electrical Eng. & Systems 2022-09-22 Bile Peng , Jan-Aike Termöhlen , Cong Sun , Danping He , Ke Guan , Tim Fingscheidt , Eduard A. Jorswieck

This paper investigates wireless systems aided by dual-polarized intelligent surfaces. We compare reconfigurable intelligent surface (RIS), which adjust their reflection matrices, with movable signals operating with fixed intelligent…

Information Theory · Computer Science 2026-02-03 Matteo Nerini , Bruno Clerckx

In this paper, we investigate reconfigurable intelligent surface (RIS)-assisted communication systems which involve a fixed-antenna base station (BS) and a mobile user (MU) that is equipped with fluid antenna system (FAS). Specifically, the…

Signal Processing · Electrical Eng. & Systems 2024-07-12 Junteng Yao , Xiazhi Lai , Kangda Zhi , Tuo Wu , Ming Jin , Cunhua Pan , Maged Elkashlan , Chau Yuen , Kai-Kit Wong

Reconfigurable intelligent surfaces (RISs), with the potential to realize a smart radio environment, have emerged as an energy-efficient and a cost-effective technology to support the services and demands foreseen for coming decades. By…

Information Theory · Computer Science 2021-07-13 Sarah Basharat , Syed Ali Hassan , Haris Pervaiz , Aamir Mahmood , Zhiguo Ding , Mikael Gidlund