Secrecy outage analysis for UAV assisted satellite-terrestrial SWIPT systems with NOMA

This paper studies the physical-layer security for a non-orthogonal multiple access (NOMA) based unmanned aerial vehicle (UAV) assisted hybrid satellite-terrestrial simultaneous wireless information and power transfer system. Specifically, a satellite sends confidential information on a NOMA basis to two terrestrial users through a UAV relay under the wiretapping of an eavesdropper. A power splitting protocol is deployed to coordinate information decoding and energy harvesting. Assuming the satellite link experiences Shadowed-Rician fading and the terrestrial links are subject to Nakagami-m fading, the analytical expressions for the secrecy outage probability and the probability of strictly positive secrecy capacity for two users are derived and the accuracy of the results is verified by Monte-Carlo simulations.