Secrecy Performance Analysis for Hybrid Satellite-UWOC Systems

With the expansion of human activities into the ocean, there is an urgent need for information transmission technology with higher data rates and more security. On the other hand, satellite communication plays an important role in the maritime area, but is also vulnerable to eavesdropping because of its broadcast nature. Therefore, in this study, the physical-layer security for a hybrid satellite and underwater wireless optical communication (UWOC) system is considered. Specifically, a satellite source first broadcasts information to an overwater relay via an RF link, and then the relay converts the electrical signal to an optical one and transmits it to an underwater destination via a UWOC link, while an eavesdropper is overhearing this transmission. We derived the closed-form expressions for several system performance metrics, i.e., secrecy outage probability (SOP), and average secrecy capacity (ASC). Finally, Monte-Carlo simulations verify the accuracy of those results.