Security Analysis of NOMA-FSO/RF Network Over Double Shadowed $k-\mu$ and Málaga-$\mathcal{M}$ Channels

In this paper, we aim at tackling the security performances of dual-hop mixed free-space optical (FSO)/radio frequency (RF) cooperative with the non-orthogonal multiple access (NOMA) technique. Particularly, we consider a downlink communication scenario, where a base station (BS) is commu-nicating with remote users in the existence of an eavesdropping attack. The hop from the BS to the relaying system is considered an FSO link, where the atmospheric turbulences are described by Málaga-
$\mathcal{M}$
. Besides, the RF links between the relay and users/attacker are assumed to follow the Double
$\kappa-\mu$
Shadowed fading since it unifies a wide set of special-case fading models. Moreover, we derive the closed-form expressions of the outage probability at the 1
^st
legitimate user and at the attacker, as well as the secrecy outage probability (SOP) in terms of the multivariate Fox-H function. Finally, we investigate the impact of the RF fading parameters, path-loss, power ratio, and pointing error on the secrecy performance.