Outage Performance Analysis of Unmanned Aerial Vehicle Assisted Satellite Communication System with Cooperative Non-Orthogonal Multiple Access

Multi-user transmission system combined multi-antenna beamforming with cooperative NonOrthogonal Multiple Access (NOMA) technique is investigated for Unmanned Aerial Vehicle (UAV) assisted satellite communication system. Firstly, in case that UAV employs multi-antenna and NOMA technique to serve multiple users, a beamforming scheme is proposed to maximize the average signal-to-interference-plusnoise ratio by using angle information of users. Secondly, under the condition that the satellite - UAV link follows the correlated Shadowed-Rician fading while the UAV - terrestrial link follows Nakagami-m fading, the closed-form expressions of outage probability for system are derived. Furthermore, the asymptotic outage probability formulas in the high signal- to-noise ratio regime are also developed to analyze the system performance. Finally, computer simulations are provided to validate the correctness of the theoretical analysis and the superiority of the proposed scheme.