Physical layer (PHY) security is an important issue in wireless communication systems. In this study, the authors investigate the interactions between the PHY security performance and the spectrum access technique in a cooperative cognitive radio (CR) network. In the classical spectrum access, if the measured energy on a given subchannel is less than a threshold, the subband is dedicated for CR transmission. Here, they consider a probabilistic spectrum access (PSA), which assigns to each primary subchannel a probability which is determined according to the measured energy on that subchannel. In addition, both spectrum access and CR power allocation are performed simultaneously. They formulate the general outage probability and some important PHY security performance metrics, such as average secrecy rate, secrecy outage probability, and probability of positive secrecy rate in terms of the spectrum access and optimal power allocation functions. The authors' numerical analysis indicates that the PSA method achieves a superior PHY security and outage performance compared to the classical threshold-based spectrum sensing and power allocation method.

中文翻译：

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通过联合频谱访问和功率分配，增强了认知无线电系统的物理层安全性

物理层（PHY）安全性是无线通信系统中的重要问题。在这项研究中，作者研究了协作认知无线电（CR）网络中PHY安全性能与频谱访问技术之间的相互作用。在经典频谱访问中，如果在给定子信道上测得的能量小于阈值，则该子带专用于CR传输。在这里，他们考虑了一个概率频谱访问（PSA），它为每个主要子信道分配了一个概率，该概率是根据该子信道上测得的能量确定的。另外，频谱接入和CR功率分配都同时进行。他们制定了一般中断概率和一些重要的PHY安全性能指标，例如平均保密率，保密中断概率，频谱访问和最佳功率分配函数方面的正保密率概率。作者的数值分析表明，与传统的基于阈值的频谱感测和功率分配方法相比，PSA方法具有更高的PHY安全性和中断性能。