Abstract—More releases of 5G operating in the millimeter wave (mmwave) range are now underway. In conjunction with the actual 5G updating process, researchers have already begun designing a new core for the 6G system. As expected, by 2030, the 6G mobile system will be employed internationally. 6G will operate at the THz gap, where Free Space Path Loss (FSPL) and atmospheric absorption loss become significant challenges. This means that new technologies need to be invented and tested to overcome these challenges and make the 6G system a reality. Among these technologies, 6G will be entirely Artificial Intelligence (AI) based. Several 6G applications are discussed in this paper, along with the general characteristics of the sub-Terahertz band and channel losses. An evaluation of the most significant 6G enabling technologies is also conducted in this paper, including AI technology, Cell-Free Massive Multiple-Input-Multi-Output (CF massive MIMO), THz band antenna technologies, Non-Orthogonal Multiple Access (NOMA), energy harvesting scenarios, Free Space Optic (FSO) backhaul technology, and 6G security technologies. The non-technological challenges issue was also considered in this paper.
 

Index Terms—6G, Artificial Intelligence (AI), Cell-Free Massive Multiple-Input-Multi-Output (CF massive MIMO), Free Space Path Loss (FSPL), Free Space Optic (FSO), Non-Orthogonal Multiple Access (NOMA), quantum computing, terahertz-band, security

Cite: Abdulsattar M. Ahmed, Sayf A. Majeed, and Younis S. Dawood, "A Survey of 6G Mobile Systems, Enabling Technologies, and Challenges," International Journal of Electrical and Electronic Engineering & Telecommunications, Vol. 12, No. 1, pp. 1-21, January 2023. Doi: 10.18178/ijeetc.12.1.1-21