On Secure Uplink Transmissions in Satellite-Aerial Systems

Satellite communication plays an increasingly important role in global wireless systems, which leads to rising concerns about the secure transmission of confidential information. In this article, we investigate the secrecy outage performance of an uplink satellite-aerial communication system, in which an aerial platform (S) transmits its information over the uplink to a legitimate satellite(D), while an eavesdropping satellite (E) trying to overhear the information delivery between S and D. Specifically, considering the randomness of the positions of D and E and employing the geometric probability theory, a closed-form expression for the lower bound on the secrecy outage probability of the considered system is derived. Finally, Monte-Carlo simulations are conducted to verify our proposed analytical models.