We analyze a secure dual-hop mixed radio frequency-free space optical (RF-FSO) downlink simultaneous wireless information and power transfer (SWIPT) systems. The FSO link and all RF links experience Gamma-Gamma, independent and identical Nakagami-m fading, respectively. We analyze the effects of atmospheric turbulence, pointing error, detection technology, path loss, and energy harvesting on secrecy performance. Signal-to-noise ratios at both legitimate and illegitimate receivers are not independent since they are both simultaneously influenced by the FSO link. We derive the closedform expression of the secrecy outage probability (SOP) as well as the asymptotic result for SOP when signal-to-noise ratios at relay and legitimate destinations tend to infinity. Monte-Carlo simulations are performed to verify the accuracy of our analysis. The results show that the secrecy diversity order (SDO) depends on the fading parameter of the relay-destination link and the number of the destination’s antennas. Additionally, the SDO also depends on the fading parameters, the pointing error parameter, and the detection type of the FSO link.
Bibliographical noteKAUST Repository Item: Exported on 2021-02-23
Acknowledgements: This work was supported in part by the National Natural Science Foundation of China (NSFC) under Grant 61471076, Chinese Scholarship Council under Grant 201607845004, the Program for Changjiang Scholars and Innovative Research Team in University under Grant IRT 16R72, the Project of Fundamental Science and Frontier Technology Research Plan of Chongqing under Grant cstc2017jcyjAX0204 and cstc2015jcyjBX0085, and the Scientific and Technological Research Program of Chongqing Municipal Education Commission under Grant KJ1704088.