jsr-a Journal of Scientific Reports-A 2687-6167 Kütahya Dumlupinar University 10.59313/jsr-a.1802717 Wireless Communication Systems and Technologies (Incl. Microwave and Millimetrewave) Kablosuz Haberleşme Sistemleri ve Teknolojileri (Mikro Dalga ve Milimetrik Dalga dahil) Ubiquity, applications, and potential of emerging MIMO technologies https://orcid.org/0000-0002-1121-7331 Yılmaz Mümtaz Aydın Adnan Menderes University, Faculty of Engineering, Department of Electrical and Electronics Engineering https://orcid.org/0000-0003-1869-6010 Baştürk İlhan Manisa Celal Bayar University, Faculty of Engineering and Natural Sciences, Department of Electrical and Electronics Engineering https://orcid.org/0000-0003-1261-5857 Kalkan Yılmaz Aydın Adnan Menderes University, Faculty of Engineering, Department of Electrical and Electronics Engineering 03 30 2026 064 90 105 10 13 2025 01 26 2026 Copyright © 2020, Journal of Scientific Reports-A 2020 Journal of Scientific Reports-A

Multiple-Input Multiple-Output (MIMO) technologies utilize multiple antennas at the transceivers and enable enhanced diversity or multiplexing gain. The first implementations of MIMO technology appeared in cellular communication and Wi-Fi systems. One of the main problems with early MIMO systems is their limited performance in meeting the requirements of next generation communication systems. Specifically, the parameters like peak data rates, spectrum efficiency and energy efficiency constraints cannot be met with existing MIMO architectures. Hence, early MIMO techniques evolved to massive MIMO (mMIMO) type of communication as the number of antennas at both transmitters and receivers increased. Included in 5G New Radio standard, mMIMO enabled an increase the spectral efficiency and coverage compared with earlier MIMO techniques. Nowadays, there exists an ever-increasing interest in the application of advanced MIMO technologies in 6G networks. These applications include ultra massive MIMO (mMIMO), holographic MIMO and intelligent reflecting surface (IRS) assisted MIMO. These new advanced MIMO techniques either employ larger number of antennas or extremely large aperture arrays compared with mMIMO and are named as extremely large-scale MIMO. This paper presents a detailed overview of all these techniques. Joint design of wireless communication and radar sensing, named as integrated sensing and communication (ISAC) as well, has shown to improve spectrum efficiency and reduce power consumption. Recent novel research on ISAC exploits the application of MIMO technology specifically in joint communication and radar sensing (JCS) systems. In this aspect, the other objective of this work is to exploit MIMO communication and MIMO radar coexistence. After summarizing the current state of the art on MIMO radar systems, this paper exploits joint application of advanced MIMO communication and radar sensing. Finally, it aims to offer a perspective on future research directions and the potential of overall MIMO systems discussed in the paper.

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