In this paper, we study the secrecy performance of mixed radio-frequency (RF) - free space optical (FSO) systems by considering both RF and FSO eavesdropper attacks. More precisely, we shed light into the design of secure mixed RF-FSO relay networks by questioning two critical design problems: 1) What are the main parameters in the design of secure RF-FSO relay networks? 2) How can we improve the confidentiality of the optical information? To do so, we derive the secrecy outage probability and the probability of positive secrecy capacity performance for mixed RF-FSO relaying schemes under RF and FSO eavesdropper attacks, respectively. To justify the problem, we consider two general fading models, Nakagami-m at the RF side and exponentiated Weibull distribution at the FSO side. The results, which are validated with the Monte-Carlo simulations, show that both the location and the size of the photo-aperture is very important in the design of RF-FSO relay networks to enhance the secrecy performance of the overall system.

中文翻译：

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RF-FSO混合中继网络中RF与FSO窃听攻击的保密性比较


在本文中，我们通过考虑 RF 和 FSO 窃听者攻击来研究混合射频 (RF) - 自由空间光学 (FSO) 系统的保密性能。更准确地说，我们通过质疑两个关键设计问题来阐明安全混合 RF-FSO 中继网络的设计：1）安全 RF-FSO 中继网络设计的主要参数是什么？ 2）如何提高光学信息的保密性？为此，我们分别推导了混合 RF-FSO 中继方案在 RF 和 FSO 窃听者攻击下的保密中断概率和正保密容量性能的概率。为了证明该问题的合理性，我们考虑两种通用衰落模型：RF 侧的 Nakagami-m 和 FSO 侧的指数 Weibull 分布。通过蒙特卡罗模拟验证的结果表明，在 RF-FSO 中继网络的设计中，光孔径的位置和尺寸对于增强整个系统的保密性能非常重要。