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Related papers: Phases Calibration of RIS Using Backpropagation Al…

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A reconfigurable intelligent surface (RIS) is a nearly-passive flat layer made of inexpensive elements that can add a tunable phase shift to the impinging electromagnetic wave and are controlled by a low-power electronic circuit. This paper…

Signal Processing · Electrical Eng. & Systems 2022-05-04 Stefano Buzzi , Emanuele Grossi , Marco Lops , Luca Venturino

This paper investigates the capabilities and effectiveness of backward sensing centered on reconfigurable intelligent surfaces (RISs). We demonstrate that the direction of arrival (DoA) estimation of incident waves in the far-field regime…

Signal Processing · Electrical Eng. & Systems 2024-07-31 Fuhai Wang , Tiebin Mi , Chun Wang , Rujing Xiong , Zhengyu Wang , Robert Caiming Qiu

An accurate and simple analytical model for the computation of the reflection amplitude and phase of Reconfigurable Intelligent Surfaces is presented. The model is based on a transmission-line circuit representation of the RIS which takes…

Signal Processing · Electrical Eng. & Systems 2021-11-16 Filippo Costa , Michele Borgese

Reconfigurable Intelligent Surfaces (RIS) are planar structures connected to electronic circuitry, which can be employed to steer the electromagnetic signals in a controlled manner. Through this, the signal quality and the effective data…

Information Theory · Computer Science 2021-12-21 Long Kong , Steven Kisseleff , Symeon Chatzinotas , Björn Ottersten , Melike Erol-Kantarci

Physically accurate and mathematically tractable models are presented to characterize scattering and reflection properties of reconfigurable intelligent surfaces (RISs). We take continuous and discrete strategies to model a single patch and…

Systems and Control · Electrical Eng. & Systems 2022-08-31 Tiebin Mi , Jianan Zhang , Rujing Xiong , Zhengyu Wang , Robert Caiming Qiu

Consider a communication system in which a single antenna user equipment exchanges information with a multi-antenna base station via a reconfigurable intelligent surface (RIS) in the presence of spatially correlated channels and…

Information Theory · Computer Science 2023-12-14 Wen-Xuan Long , Marco Moretti , Andrea Abrardo , Luca Sanguinetti , Rui Chen

Optimization of Reconfigurable Intelligent Surfaces (RIS) via a previously introduced method is effective, but time-consuming, because multiport impedance or scatter matrices are required for each transmitter and receiver position, which…

Optimization and Control · Mathematics 2025-01-31 Hans-Dieter Lang , Michel A. Nyffenegger , Heinz Mathis , Xingqi Zhang

Reconfigurable Intelligent Surface (RIS) plays an important role in enhancing source localization accuracy. Based on the information inequality of Fisher information analyses, the Cram\'{e}r-Rao Bound (CRB) of the localization error can be…

Systems and Control · Electrical Eng. & Systems 2023-04-18 Yuhua Jiang , Yuanwan Mai , Feifei Gao

A reconfigurable intelligent surface (RIS) consists of a large number of low-cost elements that can control the propagation environment seen from a transmitter by intelligently applying phase shifts to impinging signals before reflection.…

Signal Processing · Electrical Eng. & Systems 2023-11-14 Parisa Ramezani , Maksym A. Girnyk , Emil Björnson

A reconfigurable intelligent surface (RIS) is a prospective wireless technology that enhances wireless channel quality. An RIS is often equipped with passive array of elements and provides cost and power-efficient solutions for coverage…

Information Theory · Computer Science 2024-03-20 Hyuckjin Choi , Ly V. Nguyen , Junil Choi , A. Lee Swindlehurst

Thanks to the line-of-sight (LoS) transmission and flexibility, unmanned aerial vehicles (UAVs) effectively improve the throughput of wireless networks. Nevertheless, the LoS links are prone to severe deterioration by complex propagation…

Information Theory · Computer Science 2019-12-10 Sixian Li , Bin Duo , Xiaojun Yuan , Ying-Chang Liang , Marco Di Renzo

Time reversal (TR) is a promising technique that exploits multipaths for achieving energy focusing in high-frequency wideband communications. In this letter, we focus on a TR scheme facilitated by a reconfigurable intelligent surface (RIS)…

Signal Processing · Electrical Eng. & Systems 2024-08-27 Andreas Nicolaides , Constantinos Psomas , Ioannis Krikidis

Reconfigurable intelligent surfaces (RISs) represent a promising candidate for sixth-generation (6G) wireless networks, as the RIS technology provides a new solution to control the propagation channel in order to improve the efficiency of a…

Information Theory · Computer Science 2022-08-15 Mohamad H. Dinan , Nemanja Stefan Perovic , Mark F. Flanagan

This paper presents a unified modeling, estimation, and feedback framework for reconfigurable intelligent surface RIS-assisted optical wireless links. The key modeling element is a long-exposure pixel gain that extends the classical…

Signal Processing · Electrical Eng. & Systems 2025-10-30 Muhammad Khalil , Ke Wang , Jinho Choi

Reconfigurable intelligent surfaces (RIS) can improve signal propagation environments by adjusting the phase of the incident signal. However, optimizing the phase shifts jointly with the beamforming vector at the access point is challenging…

Signal Processing · Electrical Eng. & Systems 2024-10-28 Weijie Jin , Jing Zhang , Chao-Kai Wen , Shi Jin , Xiao Li , Shuangfeng Han

Reconfigurable intelligent surfaces (RIS) can be crucial in next-generation communication systems. However, designing the {RIS} phases according to the instantaneous channel state information (CSI) can be challenging in practice due to the…

Information Theory · Computer Science 2023-09-26 Athira Subhash , Abla Kammoun , Ahmed Elzanaty , Sheetal Kalyani , Yazan H. Al-Badarneh , Mohamed-Slim Alouini

Intelligent surfaces comprising of cost effective, nearly passive, and reconfigurable unit elements are lately gaining increasing interest due to their potential in enabling fully programmable wireless environments. They are envisioned to…

Information Theory · Computer Science 2022-05-26 George C. Alexandropoulos , Evangelos Vlachos

Smart radio environments (SREs) are seen as a key rising concept of next generation wireless networks, where propagation channels between transmitters and receivers are purposely controlled. One promising approach to achieve such channel…

Signal Processing · Electrical Eng. & Systems 2022-03-15 Moustafa Rahal , Benoît Denis , Kamran Keykhosravi , Furkan Keskin , Bernard Uguen , George C. Alexandropoulos , Henk Wymeersch

We consider a two--tile reconfigurable intelligent surface (RIS) assisted wireless network with a two-antenna transmitter and receiver over Rayleigh fading. We show that the average received signal-to-noise-ratio (SNR) optimal transmission…

Information Theory · Computer Science 2020-10-12 Prathapasinghe Dharmawansa , Saman Atapattu , Marco Di Renzo

The reconfigurable intelligent surface (RIS) technology for metasurfaces is ushering in a new paradigm for wireless communication systems. It provides an accessible way for controlling the interaction between electromagnetic waves with the…

Signal Processing · Electrical Eng. & Systems 2026-01-21 P. H. C. de Souza , M. Khazaee , L. L. Mendes