UAV assisted communication such as UAV-BS can prove to be instrumental in supporting ground cellular networks in areas of erratic demand which otherwise require an over-engineered network. The inherited ease of deployment and robustness to changing communication scenario due to its ability to manoeuvre and adjust its parameters such as horizontal and vertical position make UAV-BS ideal for cases such as mobile or static hot spots with continuously varying cell size , or to support disaster-hit areas with many malfunctioning ground base stations.

OMA has been proved to exhibit improved spectral efficient, balanced and fair access as compared to Orthogonal Multiple Access (OMA) technologies. NOMA has the ability to cater for multiple devices in the same frequency or time or code resource thus providing an efficient access to massive connected device. NOMA allows users simultaneous access to bandwidth. resources that provides the means to meet the challenging 5G envisioned requirements of the Internet of Things (IoT) of ultra-low latency and ultra-high connectivity.

Multi-input and Multi-output (MIMO) is one of the key technologies for modern communication system such as 4G LTE and upcoming 5G. MIMO spatial multiplexing technique is able to scale the date rate as a function of the number of antennas at the transceiver, while MIMO diversity technique is able to improve the reliability of wireless transmission, all achieved without the use of additional bandwidth. MIMO has been extended to massive MIMO scenario where base station is equipped with a large number of antennas to provide multi-user multiplexing gain, while using lower transmission power and simpler beamforming techniques. For 5G mmWave, massive MIMO and hybrid beamforming are considered to guarantee data rate and coverage.

Wireless power transfer emerges as new means to power up and/or charge up the mobile and IoT devices. Since the far-field power transfer uses the same RF waves as the conventional wireless information transfer, the concept of sending energy and information using the same RF signal has been proposed. Such concept is generally known as wireless powered communication. There are generally two major categories of WPC. The first is known as the simultaneous wireless information and power transfer (SWIPT) which enables the concurrent decoding of information and harvesting of energy at the SWIPT receiver. The second is known as harvest-then-transmit (HTT), where the receiver harvests energy in the downlink and uses the energy harvested to transmit in the uplink in the subsequent time slots