A Novel Relaying Mechanism for Multi-Cast Transmission with Ground-Aerial NOMA

Unmanned aerial vehicles (UAVs) are gaining recognition as aerial base station and as relays to provide coverage in fifth-generation and beyond networks. With a multitude of devices present in future wireless networks, a ground or an aerial device, both can act as a relay for coverage extension. We propose to utilise either ground or aerial device as a relay based on the channel characteristics of the device with transmit source. Non-orthogonal multiple access (NOMA) is enforced to pair the ground and aerial device. In our scheme, a device which establishes strong communication link with transmit source is selected as a relay. The relay communication is further fuelled by harvesting energy from the radio signals of transmit source using power-splitting energy harvesting protocol. It is shown that the channel fading characteristics and path-loss environment of a ground and aerial user which are different in nature, contribute towards the relay selection. The results indicate that the proposed scheme achieves improved signal reception at the end user with the use of this dynamic relaying scheme.