On Physical Layer Security Analysis of Hybrid RF/FSO Wireless Networks over k – μ/GG Channels with Pointing Error Impairments

The integration of mixed Radio Frequency (RF) and Free-Space Optical (FSO) wireless models in 6G wireless systems is pivotal for harnessing the complementary strengths of both technologies, enabling unprecedented levels of reliability, capacity, and security in next-generation networks. To address this combined use, this paper delves into the secrecy performance of a hybrid RF-FSO mixed model. Moreover, the transmitter and receiver establish communication through two distinct paths: the first link utilizes RF technology, characterized by a
$\kappa-\mu$
shadowed fading distribution, while the second link employs FSO technology, encountering Gamma-Gamma (GG) turbulence with pointing error impairment. At the receiver, a selection combining technique is employed to choose between the incoming signals. In order to analytically assess the improvement, we deduce the analytical expressions of secrecy outage probability (SOP) in closed form. Our findings substantiate that the hybrid RF- FSO model surpasses a single FSO/RF link in terms of secrecy outage probability. Finally, Monte Carlo simulations are conducted to validate the accuracy of the derived expressions.