In this paper, we analyze the secrecy outage performance for more realistic eavesdropping scenario of free-space optical (FSO) communications, where the main and wiretap links are correlated. The FSO fading channels are modeled by the well-known M\'alaga distribution. Exact expressions for the secrecy performance metrics such as secrecy outage probability (SOP) and probability of the non zero secrecy capacity (PNZSC) are derived, and asymptotic analysis on the SOP is also conducted. The obtained results reveal useful insights on the effect of channel correlation on FSO communications. Counterintuitively, it is found that the secrecy outage performance demonstrates a non-monotonic behavior with the increase of correlation. More specifically, there is an SNR penalty for achieving a target SOP as the correlation increases within some range. However, when the correlation is further increased beyond some threshold, the SOP performance improves significantly.

翻译：在本文中,我们分析自由空间光学通信(FSO)更现实的窃听情景的保密中断性能,其中主要和窃听连接是相互关联的。 FSO的退缩通道以众所周知的 M\'alaga 分布模式为模型。秘密中断概率(SOP)和非零保密能力(PNZSC)的概率(PNZSC)等保密性能度量的精细表达方式产生出来,对SOP的无干扰性能也进行了无线分析。获得的结果揭示了对频道对自由空间光学通信(FSO)相关效应的有用洞察力。反直观地说,发现保密中断性能显示出非移动性的行为与相关性的增加。更具体地说,随着关联性在某些范围内的增加,对达到目标SOP有国家情报局的处罚。然而,当相关关系进一步超过某些门槛时,SOP的性能将显著改善。