RIS-Assisted Cell-Free MIMO: A Survey

doi:10.12142/ZTECOM.202401009

ZTE Communications ›› 2024, Vol. 22 ›› Issue (1): 77-86.DOI: 10.12142/ZTECOM.202401009

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RIS-Assisted Cell-Free MIMO: A Survey

ZHAO Yaqiong¹, KE Hongqin¹, XU Wei¹^,²(), YE Xinquan³, CHEN Yijian³

^1.National Mobile Communications Research Laboratory, Southeast University, Nanjing 211189, China
^2.Purple Mountain Laboratories, Nanjing 211111, China
^3.ZTE Corporation, Shenzhen 518507, China

Received:2023-07-15 Online:2024-03-29 Published:2024-03-28
About author:ZHAO Yaqiong received her BE degree in electrical engineering from Southeast University, China in 2018. She is currently working toward a PhD degree with the School of Information Science and Engineering, National Mobile Communications Research Laboratory, Southeast University. Her current research interests include massive MIMO, mmWave communications, and reconfigurable intelligent surfaces for wireless communications.
KE Hongqin received his BE degree in electrical engineering from Xiamen University, China in 2022. He is currently working toward an MS degree with the School of Information Science and Engineering, National Mobile Communications Research Laboratory, Southeast University, China. His current research interests include massive MIMO, integrated sensing and communication, and reconfigurable intelligent surfaces for wireless communications.
XU Wei (wxu@seu.edu.cn) received his BSc degree in electrical engineering and MS and PhD degrees in communication and information engineering from Southeast University, China in 2003, 2006 and 2009, respectively. Between 2009 and 2010, he was a post-doctoral research fellow with the Department of Electrical and Computer Engineering, University of Victoria, Canada. He is currently a professor at the National Mobile Communications Research Laboratory, Southeast University. He was an adjunct professor of the University of Victoria, Canada from 2017 to 2020, and a Distinguished Visiting Fellow of the Royal Academy of Engineering, UK in 2019. He is also with the Purple Mountain Laboratory and has served as a project leader since 2020. He has co-authored over 100 refereed journal papers in addition to 36 domestic patents and four US patents granted. His research interests include information theory, signal processing and machine learning for wireless communications. He was an editor of IEEE Communications Letters from 2012 to 2017. He is currently an editor of IEEE Transactions on Communications and a senior editor of IEEE Communications Letters. He received the Best Paper Awards from a number of prestigious IEEE conferences including IEEE Globecom/ICCC, etc. He received the Science and Technology Award for Young Scholars of the Chinese Institute of Electronics in 2018.
YE Xinquan received his MS degree from Xidian University, China in 2018. He is currently an engineer with ZTE Corporation. His research interests include cell-free massive MIMO and reconfigurable intelligent surface.
CHEN Yijian received his BS degree from Central South University, China in 2006. He is currently a senior engineer with ZTE Corporation. His current research interests include massive MIMO, coordinated multi-point transmission, high-frequency communications, and channel modeling.
Supported by:
ZTE Industry?University?Institute Cooperation Funds

Abstract

Abstract:

Cell-free (CF) multiple-input multiple-output (MIMO) is a promising technique to enable the vision of ubiquitous wireless connectivity for next-generation network communications. Compared to traditional co-located massive MIMO, CF MIMO allows geographically distributed access points (APs) to serve all users on the same time-frequency resource with spatial multiplexing techniques, resulting in better performance in terms of both spectral efficiency and coverage enhancement. However, the performance gain is achieved at the expense of deploying more APs with high cost and power consumption. To address this issue, the recently proposed reconfigurable intelligent surface (RIS) technique stands out with its unique advantages of low cost, low energy consumption and programmability. In this paper, we provide an overview of RIS-assisted CF MIMO and its interaction with advanced optimization designs and novel applications. Particularly, recent studies on typical performance metrics such as energy efficiency (EE) and spectral efficiency (SE) are surveyed. Besides, the application of RIS-assisted CF MIMO techniques in various future communication systems is also envisioned. Additionally, we briefly discuss the technical challenges and open problems for this area to inspire research direction and fully exploit its potential in meeting the demands of future wireless communication systems.

Key words: mmWave, beyond 5G (B5G), Internet of Everything (IoE), cell-free MIMO, RIS, unmanned aerial vehicle (UAV), physical layer security (PLS), wireless energy transfer (WET)

ZHAO Yaqiong, KE Hongqin, XU Wei, YE Xinquan, CHEN Yijian. RIS-Assisted Cell-Free MIMO: A Survey[J]. ZTE Communications, 2024, 22(1): 77-86.

Figures/Tables 6

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RIS-Assisted Cell-Free MIMO: A Survey

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