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Related papers: RIS-Aided Unsourced Multiple Access (RISUMA): Codi…

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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

Channel estimation in reconfigurable intelligent surface (RIS) assisted multiple input multiple output (MIMO) communication systems is challenging as pilots cannot be decoded at or transmitted from a RIS with only passive elements. We…

Signal Processing · Electrical Eng. & Systems 2021-03-22 Battu Deepak , R. S. Prasobh Sankar , Sundeep Prabhakar Chepuri

Reconfigurable intelligent surfaces (RISs) have attracted enormous interest thanks to their ability to overcome line-of-sight blockages in mmWave systems, enabling in turn accurate localization with minimal infrastructure. Less investigated…

Signal Processing · Electrical Eng. & Systems 2022-09-14 Alessio Fascista , Musa Furkan Keskin , Angelo Coluccia , Henk Wymeersch , Gonzalo Seco-Granados

We consider a reconfigurable intelligent surface (RIS) assisted cell-free massive multiple-input multiple-output non-orthogonal multiple access (NOMA) system, where each access point (AP) serves all the users with the aid of the RIS. We…

Information Theory · Computer Science 2024-09-18 Malay Chakraborty , Ekant Sharma , Himal A. Suraweera , Hien Quoc Ngo

This paper studies the interference broadcast channel comprising multiple multi-antenna Base Stations (BSs), each controlling a beyond diagonal Reconfigurable Intelligent Surface (RIS) and serving multiple single-antenna users. Wideband…

Information Theory · Computer Science 2024-09-09 Konstantinos D. Katsanos , Paolo Di Lorenzo , George C. Alexandropoulos

Unsourced random-access (U-RA) is a type of grant-free random access with a virtually unlimited number of users, of which only a certain number $K_a$ are active on the same time slot. Users employ exactly the same codebook, and the task of…

Information Theory · Computer Science 2021-12-10 Alexander Fengler , Peter Jung , Giuseppe Caire

In this paper, we study the transmission strategy of a ground-based beyond diagonal reconfigurable intelligent surface (BD-RIS), a.k.a RIS 2.0, in a network where multiple unmanned aerial vehicles (UAVs) simultaneously transmit signals to…

Signal Processing · Electrical Eng. & Systems 2023-12-18 Aamer Mohamed Huroon , Yu-Chih Huang , Li-Chun Wang

We consider reconfigurable intelligent surface (RIS) aided sixth-generation (6G) terahertz (THz) communications for indoor environment in which a base station (BS) wishes to send independent messages to its serving users with the help of…

Information Theory · Computer Science 2023-03-22 Najam Us Saqib , Shumei Hou , Sung Ho Chae , Sang-Woon Jeon

Reconfigurable intelligent surfaces (RISs) are set to be a revolutionary technology in the 6th generation of wireless systems. In this work, we study the application of RIS in a multi-user passive localization scenario, where we have one…

Signal Processing · Electrical Eng. & Systems 2021-04-27 Kamran Keykhosravi , Musa Furkan Keskin , Satyam Dwivedi , Gonzalo Seco-Granados , Henk Wymeersch

The reconfigurable intelligent surface (RIS) has drawn considerable attention for its ability to enhance the performance of not only the wireless communication but also the indoor localization with low-cost. This paper investigates the…

Information Theory · Computer Science 2023-03-28 Ziyi Gong , Liang Wu , Zaichen Zhang , Jian Dang , Yongpeng Wu , Jiangzhou Wang

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

In this paper, we propose a three-stage unified channel estimation strategy for reconfigurable intelligent surface (RIS)-aided multi-user (MU) multiple-input multiple-output (MIMO) millimeter wave (mmWave) systems with the existence of the…

Signal Processing · Electrical Eng. & Systems 2025-11-25 Taihao Zhang , Zhendong Peng , Cunhua Pan , Hong Ren , Jiangzhou Wang

A reconfigurable intelligent surface (RIS) is a holographic MIMO surface composed of a large number of passive elements that can induce adjustable phase shifts to the impinging waves. By creating virtual line-of-sight (LOS) paths between…

Signal Processing · Electrical Eng. & Systems 2023-04-06 Mehdi Haghshenas , Parisa Ramezani , Maurizio Magarini , Emil Björnson

With the rapid development of high-speed railway systems and railway wireless communication, the application of ultra-wideband millimeter wave band is an inevitable trend. However, the millimeter wave channel has large propagation loss and…

Information Theory · Computer Science 2022-11-29 Panpan Li , Yong Niu , Hao Wu , Zhu Han , Bo Ai , Ning Wang , Zhangdui Zhong

In this paper, Recofigurable Intelligent Surface (RIS) assisted dual-hop multicast wireless communication network is proposed with two source nodes and two destination nodes. RIS boosts received signal strength through an intelligent…

Signal Processing · Electrical Eng. & Systems 2020-06-30 Vetrivel Chelian Thirumavalavan , PGS Velmurugan , Thiruvengadam S J

In this work, in order to achieve higher spectrum efficiency, we propose a reconfigurable intelligent surface (RIS)-assisted multi-user communication uplink system. Different from previous work in which the RIS only optimizes the phase of…

Information Theory · Computer Science 2020-11-19 Liang Yang , Fanxu Meng , Mazen O. Hasna , Ertugrul Basar

This article focuses on the exploitation of reconfigurable intelligent surfaces (RISs) in multi-user networks employing orthogonal multiple access (OMA) or non-orthogonal multiple access (NOMA), with an emphasis on investigating the…

Information Theory · Computer Science 2022-09-14 Yuanwei Liu , Xidong Mu , Xiao Liu , Marco Di Renzo , Zhiguo Ding , Robert Schober

By activating blocked users and altering successive interference cancellation (SIC) sequences, reconfigurable intelligent surfaces (RISs) become promising for enhancing non-orthogonal multiple access (NOMA) systems. The downlink RIS-aided…

Information Theory · Computer Science 2020-08-20 Chao Zhang , Wenqiang Yi , Yuanwei Liu

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

This paper explores the fundamental limits of unsourced random access (URA) with a random and unknown number ${\rm{K}}_a$ of active users in MIMO quasi-static Rayleigh fading channels. First, we derive an upper bound on the probability of…

Information Theory · Computer Science 2024-04-16 Junyuan Gao , Yongpeng Wu , Giuseppe Caire , Wei Yang , Wenjun Zhang