Physical-Layer Security for Spectrum Sharing Systems
Physical-Layer Security for Spectrum Sharing Systems
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DOI：
10.1109/twc.2016.2645200
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发表时间：
2016-12
影响因子：
10.4
通讯作者：
Yulong Zou
中科院分区：
文献类型：
--
作者：
Yulong Zou
在本文中，我们研究了由多个源-目的对组成的频谱共享系统的物理层安全性，这些系统在窃听者存在的情况下动态访问它们的共享频谱进行数据传输。为了保护频谱共享系统的传输保密性，提出了一种SC辅助的机会干扰框架。具体而言，当允许一个源节点访问共享频谱进行数据传输时，在频谱共享系统中机会地选择另一个源来传输人工噪声，以在不影响合法传输的情况下干扰窃听者。我们提出了两种特定的SC辅助机会干扰方案，即SC辅助随机干扰器选择（RJS）和最优干扰器选择（OJS），分别称为SC-RJS和SC-OJS。我们也把传统的不合作作为基准。我们推导了非合作、SC-RJS和SC-OJS方案的封闭式截获概率表达式，并在此基础上通过高信噪比（SNR）区域的渐近截获概率分析确定了它们的保密分集增益。结果表明，传统非合作协议的保密分集为0，而SC-RJS和SC-OJS的保密分集为1。这也令人惊讶地意味着，与随机选择策略相比，最佳干扰器选择没有获得额外的保密分集增益。此外，数值结果表明，即使合法信道比窃听信道差，SC-OJS的截获概率性能也始终优于SC-RJS和非合作信道。
In this paper, we examine the physical-layer security for a spectrum sharing system consisting of multiple source-destination pairs, which dynamically access their shared spectrum for data transmissions in the presence of an eavesdropper. We propose a source cooperation (SC) aided opportunistic jamming framework for protecting the transmission confidentiality of the spectrum sharing system against eavesdropping. Specifically, when a source node is allowed to access the shared spectrum for data transmissions, another source is opportunistically selected in the spectrum sharing system to transmit an artificial noise for disrupting the eavesdropper without affecting the legitimate transmissions. We present two specific SC aided opportunistic jamming schemes, namely the SC aided random jammer selection (RJS) and optimal jammer selection (OJS), which are referred to as the SC-RJS and SC-OJS, respectively. We also consider the conventional non-cooperation as a baseline. We derive closed-form intercept probability expressions for the non-cooperation, SC-RJS and SC-OJS schemes, based on which their secrecy diversity gains are determined through an asymptotic intercept probability analysis in the high signal-to-noise ratio (SNR) region. It is proved that the conventional non-cooperation exhibits a secrecy diversity of zero, whereas the proposed SC-RJS and SC-OJS achieve a higher secrecy diversity of one. This also surprisingly means that no additional secrecy diversity gain is achieved by the optimal jammer selection compared to the random selection strategy. In addition, numerical results show that the intercept probability performance of the SC-OJS is always better than that of the SC-RJS and non-cooperation, even when the legitimate channel is worse than the eavesdropping channel.