模拟主用户攻击下协作频谱感知检测阈值的优化研究

Optimal detection threshold of cooperative spectrum sensing in presence of primary user emulation attack

认知无线电网络中提出的协作频谱感知技术利用多个认知用户的本地感知,克服了多径效应、阴影效应等问题,提高了系统的检测性能。然而动态频谱接入方法也给系统带来了主用户模拟攻击(PUEA)的威胁,即一些恶意用户试图模仿主用户信号来欺骗次级用户,从而阻止次级用户访问空闲频段。文中提出了一个智能攻击者能够感知并判决主用户是否存在,并在主用户不存在时发送伪造信号的系统。在这个系统中推导了基于能量检测的协作频谱感知检测概率,并进一步对检测阈值进行了优化,从而得到了总误差概率最小时的最佳检测阈值。最后通过在PUEA存在情况下,基于能量检测的协作频谱感知的最佳检测阈值的仿真进一步验证了推导结果。

In cognitive radio network, a cooperative spectrum sensing technology can overcome the problems of multi-path effects, shadow effects and such constraints by using local sensing results of cognitive users, thus improving the detection performance. However, the dynamic spectrum access imposes some threats to the network. One of these common threats is primary user emulation attack （ PUEA）, where some malicious users try to mimic the primary signal and deceive secondary users to prevent them from accessing the vacant frequency bands. A system is considered in which a smart attacker performs its own spectrum sensing according to its acquired knowledge about the presence or absence of the primary signal. And fake signals are sent when the primary user signal is not presented in the radio environment. In the system, the detection probability of cooperative spectrum sensing based on energy detection in the presence of a PUEA is deduced, and the detection threshold is optimized, thus the optimal detection threshold on the minimum total error probability is obtained. Finally, the optimal detection threshold for the cooperative spectrum sensing based on the energy detection in the presence of PUEA is simulated. The results verify the conclusions of theory deducing.