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Sensing-assisted communication schemes have recently garnered significant research attention. In this work, we design a dual-function reconfigurable intelligent surface (RIS), integrating both active and passive elements, referred to as the…

Signal Processing · Electrical Eng. & Systems 2025-08-14 Cheng Luo , Luping Xiang , Jie Hu , Kun Yang

We consider unmanned aerial vehicle (UAV)-enabled wireless systems where downlink communications between a multi-antenna UAV and multiple users are assisted by a hybrid active-passive reconfigurable intelligent surface (RIS). We aim at a…

Information Theory · Computer Science 2023-09-22 Nhan Thanh Nguyen , Van-Dinh Nguyen , Hieu Van Nguyen , Qingqing Wu , Antti Tolli , Symeon Chatzinotas , Markku Juntti

The recent trend towards the high-speed transportation system has spurred the development of high-speed trains (HSTs). However, enabling HST users with seamless wireless connectivity using the roadside units (RSUs) is extremely challenging,…

Networking and Internet Architecture · Computer Science 2023-10-27 Yu Min Park , Yan Kyaw Tun , Zhu Han , Choong Seon Hong

Reconfigurable intelligent surfaces (RISs) comprised of tunable unit cells have recently drawn significant attention due to their superior capability in manipulating electromagnetic waves. In particular, RIS-assisted wireless communications…

Signal Processing · Electrical Eng. & Systems 2020-10-16 Wankai Tang , Ming Zheng Chen , Xiangyu Chen , Jun Yan Dai , Yu Han , Marco Di Renzo , Yong Zeng , Shi Jin , Qiang Cheng , Tie Jun Cui

Transmission through reconfigurable intelligent surfaces (RISs), which control the reflection/scattering characteristics of incident waves in a deliberate manner to enhance the signal quality at the receiver, appears as a promising…

Information Theory · Computer Science 2020-01-30 Ertugrul Basar

The concept of reconfiguring wireless propagation environments using intelligent reflecting surfaces (IRS)s has recently emerged, where an IRS comprises of a large number of passive reflecting elements that can smartly reflect the impinging…

Information Theory · Computer Science 2020-05-05 Qurrat-Ul-Ain Nadeem , Hibatallah Alwazani , Abla Kammoun , Anas Chaaban , Merouane Debbah , Mohamed-Slim Alouini

Reconfigurable intelligent surface (RIS) has drawn considerable attention from the research society recently, which creates favorable propagation conditions by controlling the phase shifts of the reflected waves at the surface, thereby…

Information Theory · Computer Science 2019-11-01 Boya Di , Hongliang Zhang , Lingyang Song , Yonghui Li , Zhu Han , H. Vincent Poor

One technology that has the potential to improve wireless communications in years to come is integrated sensing and communication (ISAC). In this study, we take advantage of reconfigurable intelligent surface's (RIS) potential advantages to…

Signal Processing · Electrical Eng. & Systems 2023-08-22 Panpan Li , Yong Niu , Hao Wu , Zhu Han , Guiqi Sun , Ning Wang , Zhangdui Zhong , Bo Ai

To reap the benefits of reconfigurable intelligent surfaces (RIS), channel state information (CSI) is generally required. However, CSI acquisition in RIS systems is challenging and often results in very large pilot overhead, especially in…

Signal Processing · Electrical Eng. & Systems 2023-09-21 Ly V. Nguyen , A. Lee Swindlehurst

Reconfigurable intelligent surface (RIS) emerges as an efficient and promising technology for the next wireless generation networks and has attracted a lot of attention owing to the capability of extending wireless coverage by reflecting…

Information Theory · Computer Science 2023-10-20 Changzhu Liu , Ruisi He , Yong Niu , Zhu Han , Bo Ai , Meilin Gao , Zhangfeng Ma , Gongpu Wang , Zhangdui Zhong

This paper considers a hybrid reconfigurable intelligent surface (RIS) assisted integrated sensing and communication (ISAC) system, where each RIS element can flexibly switch between the active and passive modes. Subject to the…

Information Theory · Computer Science 2024-12-06 Yingbin Lin , Feng Wang , Xiao Zhang , Guojun Han , Vincent K. N. Lau

Reconfigurable intelligent surfaces (RISs) not only assist communication but also help the localization of user equipment (UE). This study focuses on the indoor localization of UE with a single access point (AP) aided by multiple RISs.…

Information Theory · Computer Science 2025-05-06 Xiyu Wang , Yixuan Huang , Jie Yang , Yu Han , Shi Jin

Reconfigurable intelligent surface (RIS) has been deemed as one of potential components of future wireless communication systems because it can adaptively manipulate the wireless propagation environment with low-cost passive devices.…

Signal Processing · Electrical Eng. & Systems 2024-10-28 Yanan Ma , Ming Li , Yang Liu , Qingqing Wu , Qian Liu

In Reconfigurable intelligent surface (RIS)-assisted systems the acquisition of CSI and the optimization of the reflecting coefficients constitute a pair of salient design issues. In this paper, a novel channel training protocol is…

Information Theory · Computer Science 2021-06-01 Jiancheng An , Chao Xu , Li Wang , Yusha Liu , Lu Gan , Lajos Hanzo

In this paper, we propose a network architecture where two types of aerial infrastructures together with a ground station provide connectivity to a remote area. A high altitude platform station (HAPS) is equipped with reconfigurable…

Signal Processing · Electrical Eng. & Systems 2025-09-30 Arman Azizi , Mustafa A. Kishk , Arman Farhang

This paper investigates an intelligent reflecting surface (IRS) enabled multiuser integrated sensing and communications (ISAC) system, which consists of one multi-antenna base station (BS), one IRS, multiple single-antenna communication…

Signal Processing · Electrical Eng. & Systems 2023-07-03 Xianxin Song , Xiaoqi Qin , Jie Xu , Rui Zhang

The upper mid-band (UMB) spectrum is a key enabler for 6G systems, yet reconfigurable intelligent surface (RIS)-assisted UMB communications face severe channel estimation challenges due to near-field propagation and transitional scattering,…

Signal Processing · Electrical Eng. & Systems 2026-03-09 Jeongjae Lee , Chanwon Kim , Songnam Hong

We consider transmit beamforming and reflection pattern design in reconfigurable intelligent surface (RIS)-assisted integrated sensing and communication (ISAC) systems to jointly precode communication symbols and radar waveforms. We treat…

Signal Processing · Electrical Eng. & Systems 2022-06-16 R. S. Prasobh Sankar , Sundeep Prabhakar Chepuri , Yonina C. Eldar

Hybrid reconfigurable intelligent surfaces (HRIS) enhance wireless systems by combining passive reflection with active signal amplification. However, jointly optimizing the transmit beamforming with the HRIS reflection and amplification…

Signal Processing · Electrical Eng. & Systems 2026-04-13 Phuong Nam Tran , Nhan Thanh Nguyen , Markku Juntti

Cognitive radio (CR) is an effective solution to improve the spectral efficiency (SE) of wireless communications by allowing the secondary users (SUs) to share spectrum with primary users. Meanwhile, intelligent reflecting surface (IRS),…

Signal Processing · Electrical Eng. & Systems 2019-12-24 Jie Yuan , Ying-Chang Liang , Jingon Joung , Gang Feng , Erik G. Larsson