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The paper studies a reconfigurable intelligent surface (RIS)-assisted multi-user uplink massive multiple-input multiple-output (MIMO) system with imperfect hardware. At the RIS, the paper considers phase noise, while at the base station,…

Information Theory · Computer Science 2022-08-18 Zhangjie Peng , Xianzhe Chen , Cunhua Pan , Maged Elkashlan , Jiangzhou Wang

Reconfigurable intelligent surface (RIS) is a newly-emerged technology that might fundamentally change how wireless networks are operated. Though extensively studied in recent years, the practical limitations of RIS are often neglected when…

Signal Processing · Electrical Eng. & Systems 2023-12-12 Parisa Ramezani , Yasaman Khorsandmanesh , Emil Björnson

This paper investigates a joint beamforming and resource allocation problem in downlink reconfigurable intelligent surface (RIS)-assisted orthogonal frequency division multiplexing (OFDM) systems to minimize the average delay, where data…

Artificial Intelligence · Computer Science 2025-07-25 Yu Ma , Xiao Li , Chongtao Guo , Le Liang , Michail Matthaiou , Shi Jin

This paper studies a reconfigurable intelligent surface (RIS)-assisted cell-free massive multiple-input multiple-output (CF-mMIMO) system with multiple RISs. Joint design of transmit precoding, RIS coefficients, and receive combining is…

Signal Processing · Electrical Eng. & Systems 2025-10-21 Navid Reyhanian , Reza Ghaderi Zefreh , Parisa Ramezani , Emil Bjornson

Reconfigurable intelligent surfaces (RISs) have attracted great attention as a potential beyond 5G technology. These surfaces consist of many passive elements of metamaterials whose impedance can be controllable to change the phase,…

Information Theory · Computer Science 2021-09-09 Özlem Tuğfe Demir , Emil Björnson

In next-generation wireless networks, reconfigurable intelligent surface (RIS)-assisted multiple-input multiple-output (MIMO) systems are foreseeable to support a large number of antennas at the transceiver as well as a large number of…

Information Theory · Computer Science 2023-01-24 Chang Cai , Xiaojun Yuan , Ying-Jun Angela Zhang

Reconfigurable Intelligent Surfaces (RISs) constitute a promising emerging technology that enables wireless systems to control the propagation environment to enhance diverse communication objectives. To mitigate double-fading attenuation in…

Signal Processing · Electrical Eng. & Systems 2025-04-01 Panagiotis Gavriilidis , Deepak Mishra , Besma Smida , Ertugrul Basar , Chau Yuen , George C. Alexandropoulos

Reconfigurable intelligent surface (RIS) provides a promising way to build the programmable wireless transmission environments in the future. Owing to the large number of reflecting elements used at the RIS, joint optimization for the…

Information Theory · Computer Science 2021-01-11 Xiaoyan Ma , Shuaishuai Guo , Haixia Zhang , Yuguang Fang , Dongfeng Yuan

Intelligent reflecting surface (IRS) is considered as an enabling technology for future wireless communication systems since it can intelligently change the wireless environment to improve the communication performance. In this paper, an…

Signal Processing · Electrical Eng. & Systems 2019-09-26 Hongyu Li , Rang Liu , Ming Li , Qian Liu

In millimeter-wave (mmWave) cellular systems, reconfigurable intelligent surfaces (RISs) are foreseeably deployed with a large number of reflecting elements to achieve high beamforming gains. The large-sized RIS will make radio links fall…

Information Theory · Computer Science 2023-12-20 Baojia Luo , Yili Deng , Miaomiao Dong , Zhongyi Huang , Xiang Chen , Wei Han , Bo Bai

In orthogonal frequency division multiplexing with index modulation (OFDM-IM), the active subcarriers can convey information bits by modulated symbols as well as their indices. OFDM-IM has attracted a great deal of attention from…

Information Theory · Computer Science 2020-01-07 Kee-Hoon Kim

Reconfigurable Intelligent Surfaces (RIS) are an emerging technology that can be used to reconfigure the propagation environment to improve cellular communication link rates. RIS, which are thin metasurfaces composed of discrete elements,…

Signal Processing · Electrical Eng. & Systems 2020-11-11 Pooja Nuti , Brian L. Evans

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) 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 a revolutionary technology for sixth-generation (6G) networks owing to its ability to manipulate wireless environments. As a frequency-selective device, RIS can only effectively shape the…

Information Theory · Computer Science 2022-11-01 Sifan Liu , Rang Liu , Ming Li , Yang Liu , Qian Liu

An intelligent reflecting surface (IRS) consists of passive reflective elements capable of altering impinging waveforms. The IRS-aided radar systems have recently been shown to improve detection and estimation performance by exploiting the…

Signal Processing · Electrical Eng. & Systems 2023-03-27 Zahra Esmaeilbeig , Arian Eamaz , Kumar Vijay Mishra , Mojtaba Soltanalian

We consider channel estimation in systems equipped with a reconfigurable intelligent surface (RIS). In order to illuminate the additional cascaded channel as compared to systems without a RIS, commonly an unaffordable amount of pilot…

Signal Processing · Electrical Eng. & Systems 2023-01-27 Benedikt Fesl , Andreas Faika , Nurettin Turan , Michael Joham , Wolfgang Utschick

Intelligent reflecting surfaces (IRSs) are a promising technology for enhancing coverage and spectral efficiency, both in the sub-6 GHz and the millimeter wave (mmWave) bands. Existing approaches to leverage the benefits of IRS involve the…

Information Theory · Computer Science 2023-07-03 L. Yashvanth , Chandra R. Murthy

This paper investigates the system spectral efficiency (SE) in reconfigurable intelligent surface (RIS)-aided multiuser multiple-input single-output (MISO) systems, where RIS can reconfigure the propagation environment via a large number of…

Information Theory · Computer Science 2020-01-31 Yulan Gao , Chao Yong , Zehui Xiong , Dusit Niyato , Yue Xiao , Jun Zhao

We consider secure transmission of a deterministic complex-valued parameter vector from a transmitter to an intended receiver in the presence of an eavesdropper in a reconfigurable intelligent surface (RIS)-integrated environment. We aim to…

Signal Processing · Electrical Eng. & Systems 2023-09-26 Erfan Mehdipour Abadi , Ayda Nodel Hokmabadi , Sinan Gezici