An alternative or supplementary approach named as physical layer security has been proposed to afford an extra security layer on top of the conventional cryptography technique. In this paper, an overview of secrecy performance investigations over the classic Alice-Bob-Eve wiretap fading channels is conducted. On the basis of the classic wiretap channel model, we have comprehensively listed and thereafter compared the existing works on physical layer secrecy analysis considering the small-scale, large-scale, composite, and cascaded fading channel models. Exact secrecy metrics expressions, including secrecy outage probability (SOP), the probability of non-zero secrecy capacity (PNZ), average secrecy capacity (ASC), and secrecy bounds, including the lower bound of SOP and ergodic secrecy capacity, are presented. In order to encompass the aforementioned four kinds of fading channel models with a more generic and flexible distribution, the mixture gamma (MG), mixture of Gaussian (MoG), and Fox's $H$-function distributions are three useful candidates to largely include the above-mentioned four kinds of fading channel models. It is shown that they are flexible and general when assisting the secrecy analysis to obtain closed-form expressions. Their advantages and limitations are also highlighted. Conclusively, these three approaches are proven to provide a unified secrecy analysis framework and can cover all types of independent wiretap fading channel models. Apart from those, revisiting the existing secrecy enhancement techniques based on our system configuration, the on-off transmission scheme, jamming approach (including artificial noise (AN) & artificial fast fading (AFF)), antenna selection, and security region are presented.
翻译:在本文中,介绍了对传统的Alice-Bob-Eve窃听系统失密通道进行秘密性能调查的概况。根据传统的窃听频道模型,我们全面列出并随后比较了现有的物理性能保密分析工作,其中考虑到小规模、大规模、复合和逐步淡化的频道模型,包括保密性故障概率(SOP)、非零保密能力概率(PNZ)、平均保密能力(ASC)和保密界限(包括SOP的较低约束和egodic 保密能力)。为了包括上述四种具有更通用和灵活分布的变形频道模型,我们全面列出并随后对物理性层保密分析的现有工作进行了比较。混合伽马(MG)、高音混合(MG)和福克斯的美元功能分布是三个有用的候选人,其中主要包括上述四种变形频道模型(PNPZ)、平均保密能力(ASC)和保密性约束(A)的概率较低限制和保密性选择(SOP),这些以透明性选择方法为基础分析(A),这些基于保密性变现的保密性分析的系统提供了保密性分析,这些保密性格式(A)可以提供。