University of Oulu

A. Shojaeifard et al., "MIMO Evolution Beyond 5G Through Reconfigurable Intelligent Surfaces and Fluid Antenna Systems," in Proceedings of the IEEE, vol. 110, no. 9, pp. 1244-1265, Sept. 2022, doi: 10.1109/JPROC.2022.3170247

MIMO evolution beyond 5G through reconfigurable intelligent surfaces and fluid antenna systems

Saved in:
Author: Shojaeifard, Arman1; Wong, Kai-Kit2; Tong, Kin-Fai2;
Organizations: 1InterDigital Communications Inc., Montreal, QC, Canada
2Department of Electronic and Electrical Engineering, University College London, London, U.K
3Faculty of Information Technology and Electrical Engineering, University of Oulu, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 4.8 MB)
Persistent link:
Language: English
Published: Institute of Electrical and Electronics Engineers, 2022
Publish Date: 2022-10-06


With massive deployment, multiple-input–multiple-output (MIMO) systems continue to take mobile communications to new heights, but the ever-increasing demands mean that there is a need to look beyond MIMO and pursue the next disruptive wireless technologies. Reconfigurable intelligent surface (RIS) is widely considered a key candidate technology block to provide the next generational leap. The first part of this article provides an updated overview of the conventional reflection-based RIS technology, which complements the existing literature to include active and semiactive RIS, and the synergies with cell-free massive MIMO (CF mMIMO). Then, we widen the scope to discuss the surface-wave-assisted RIS that represents a different design dimension in utilizing metasurface technologies. This goes beyond being a passive reflector and can use the surface as an intelligent propagation medium for superb radio propagation efficiency. The third part of this article turns the attention to the fluid antenna, a novel antenna technology that enables a diverse form of reconfigurability that can combine with RIS for ultrahigh capacity, power efficiency, and scalability. This article concludes with a discussion of the potential synergies that can be exploited between MIMO, RIS, and fluid antennas.

see all

Series: Proceedings of the IEEE
ISSN: 0018-9219
ISSN-E: 1558-2256
ISSN-L: 0018-9219
Volume: 110
Issue: 9
Pages: 1244 - 1265
DOI: 10.1109/jproc.2022.3170247
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: The work of Kai-Kit Wong was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) under Grant EP/V052942/1. The work of Nhan Thanh Nguyen, Visa Tapio, and Markku Juntti was supported in part by the Academy of Finland through 6G Flagship under Grant 318927 and the EERA Project under Grant 332362, in part by Infotech Oulu, and in part by InterDigital Europe Ltd.
Academy of Finland Grant Number: 318927
Detailed Information: 318927 (Academy of Finland Funding decision)
332362 (Academy of Finland Funding decision)
Copyright information: © 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.