On the Physical Layer Security of a Decode and Forward Based Mixed FSO/RF Cooperative System

Abstract

In this letter, the secrecy performance of a mixed free space optics (FSO) and radio frequency (RF) system is analyzed from physical layer security (PHY) perspective. In this scenario, one or more eavesdroppers are trying to intercept the confidential signal in a mixed FSO/RF system. The faded FSO links are modeled by Malaga ($\mathcal{M} $) distribution and RF link is characterized by Nakagami-$m$ distribution. Exact closed form expressions for secrecy performance metrics such as secrecy outage probability and strictly positive secrecy capacity are derived and analyzed for the proposed system in terms of Fox's H-function. Furthermore, the asymptotic expressions for these performance metrics are analyzed. Finally, all the results are verified by Monte-Carlo simulations.