UAV-BS-based Hybrid OMA-NOMA System with Multiple Antennas for Multi-user Communication

Abstract

In this paper, an unmanned aerial vehicle (UAV) using hybrid orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) solutions aided by multiple input multiple output (MIMO) technology is proposed to provide wireless communication for ground users (GUs). The proposed OMA-NOMA-MIMO system aims to improve throughput and spectrum efficiency. Additionally, it also strives to maximize the sum rate while achieving good user fairness. UAVs are considered as base stations (BSs) that provide services to users in multiple real-life scenarios, e.g. during natural disasters. They also enable aerial surveillance and help establish BSs during mass events. A pairing algorithm is proposed for far-near NOMA users with an optimized power allocation (PA) mechanism to improve the performance of NOMA-UAV-BS. Channels between UAV-BS and GU are established as being of the line-of-sight (LoS) and non-line-of-sight (NLoS) varieties, taking into consideration the angle of departure (AoD) and the angle of arrival (AoA). The results obtained demonstrate that NOMA performs best in specific scenarios, while OMA overcomes NOMA in others. The outcomes of the project may be utilized to control the transmission performed by the UAV-BS by serving the GUs depending on the required quality of service.