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Related papers: Low-Complexity Channel Estimation for RIS-Assisted…

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Accurate channel estimation is essential to achieve the performance gains promised by the use of reconfigurable intelligent surfaces (RISs) in wireless communications. In the uplink of multi-user orthogonal frequency division multiple…

Signal Processing · Electrical Eng. & Systems 2022-01-25 Sumin Jeong , Arman Farhang , Nemanja Stefan Perović , Mark F. Flanagan

Reconfigurable intelligent surface (RIS) is a promising technique to improve the performance of future wireless communication systems at low energy consumption. To reap the potential benefits of RIS-aided beamforming, it is vital to enhance…

Information Theory · Computer Science 2024-04-01 Zhenyao He , Jindan Xu , Hong Shen , Wei Xu , Chau Yuen , Marco Di Renzo

Reconfigurable intelligent surfaces (RISs) have been introduced as a remedy for mitigating frequent blockages in millimeter wave (mmWave) multiple-input multiple-output (MIMO) communication networks. However, perfect or nearly perfect…

Signal Processing · Electrical Eng. & Systems 2021-06-22 Rafaela Schroeder , Jiguang He , Markku Juntti

Reconfigurable intelligent surface (RIS) has been recognized as a potential technology for 5G beyond and attracted tremendous research attention. However, channel estimation in RIS-aided system is still a critical challenge due to the…

Information Theory · Computer Science 2021-09-01 Xu Shi , Jintao Wang , Guozhi Chen , Jian Song

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

We consider the problem of channel estimation and joint active and passive beamforming for reconfigurable intelligent surface (RIS) assisted millimeter wave (mmWave) multiple-input multiple-output (MIMO) orthogonal frequency division…

Signal Processing · Electrical Eng. & Systems 2022-10-05 Xi Zheng , Jun Fang , Hongwei Wang , Peilan Wang , Hongbin Li

A reconfigurable intelligent surface (RIS) can be used to improve the channel gain between a base station (BS) and user equipment (UE), but only if its $N$ reflecting elements are configured properly. This requires accurate estimation of…

Signal Processing · Electrical Eng. & Systems 2022-05-24 Özlem Tuğfe Demir , Emil Björnson , Luca Sanguinetti

Deploying multiple beyond diagonal reconfigurable intelligent surfaces (BD-RISs) can potentially improve the communication performance thanks to inter-element connections of each BD-RIS and inter-surface cooperative beamforming gain among…

Signal Processing · Electrical Eng. & Systems 2026-02-23 Junyuan Gao , Shuowen Zhang , Liang Liu

Reconfigurable Intelligent Surfaces (RISs) are envisioned to play a key role in future wireless communications, enabling programmable radio propagation environments. They are usually considered as almost passive planar structures that…

Information Theory · Computer Science 2022-08-12 Haiyang Zhang , Nir Shlezinger , George C Alexandropoulos , Idban Alamzadeh , Mohammadreza F Imani , Yonina C Eldar

Beyond Diagonal Reconfigurable Intelligent Surfaces (BD-RIS) has emerged as a promising evolution of RIS technology. By enabling interconnections between RIS elements, BD-RIS architectures offer greater flexibility in wave manipulation…

Signal Processing · Electrical Eng. & Systems 2025-12-08 Kangchun Zhao , Yijie Mao

Beyond diagonal reconfigurable intelligent surface (BD-RIS) is a new advance and generalization of the RIS technique. BD-RIS breaks through the isolation between RIS elements by creatively introducing inter-element connections, thereby…

Signal Processing · Electrical Eng. & Systems 2024-06-11 Hongyu Li , Shanpu Shen , Yumeng Zhang , Bruno Clerckx

Reconfigurable intelligent surfaces (RISs) consist of many passive elements of metamaterials whose impedance can be controllable to change the characteristics of wireless signals impinging on them. Channel estimation is a critical task when…

Information Theory · Computer Science 2023-09-14 Özlem Tuğfe Demir , Emil Björnson

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

The recent combination of the rising architectures, known as stacked intelligent metasurface (SIM) and holographic multiple-input multiple-output (HMIMO), drives toward breakthroughs for next-generation wireless communication systems. Given…

Information Theory · Computer Science 2025-02-19 Anastasios Papazafeiropoulos , Pandelis Kourtessis , Dimitra I. Kaklamani , Iakovos S. Venieris

In intelligent reflecting surface (IRS) assisted communication systems, the acquisition of channel state information (CSI) is a crucial impediment for achieving the beamforming gain of IRS because of the considerable overhead required for…

Information Theory · Computer Science 2020-06-25 Zhaorui Wang , Liang Liu , Shuguang Cui

Beyond diagonal reconfigurable intelligent surface (BD-RIS) refers to a family of RIS architectures characterized by scattering matrices not limited to being diagonal and enables higher wave manipulation flexibility and large performance…

Signal Processing · Electrical Eng. & Systems 2025-04-16 Rui Wang , Shuowen Zhang , Bruno Clerckx , Liang Liu

Reconfigurable intelligent surface (RIS) is a promising technology for future wireless communications due to its capability of optimizing the propagation environments. Nevertheless, in literature, there are few prototypes serving multiple…

Signal Processing · Electrical Eng. & Systems 2024-05-14 Zhibo Zhou , Haifan Yin , Li Tan , Ruikun Zhang , Kai Wang , Yingzhuang Liu

Reconfigurable intelligent surface (RIS) is very promising for wireless networks to achieve high energy efficiency, extended coverage, improved capacity, massive connectivity, etc. To unleash the full potentials of RIS-aided communications,…

Information Theory · Computer Science 2022-01-03 Yabo Guo , Peng Sun , Zhengdao Yuan , Chongwen Huang , Qinghua Guo , Zhongyong Wang , Chau Yuen

A reconfigurable intelligent surface (RIS) alters the reflection of incoming signals based on the phase-shift configuration assigned to its elements. This feature can be used to improve the signal strength for user equipments (UEs), expand…

Signal Processing · Electrical Eng. & Systems 2024-12-19 Alva Kosasih , Ozlem Tugfe Demir , Emil Bjornson

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