Abstract: Aiming at the problem that communication in energy harvesting cognitive radio network is easy to be eavesdropped, which seriously threatens information security, two antenna-user joint selection schemes were proposed and the Secrecy Outage Probability (SOP) of the system was analyzed. In a Cognitive Radio Network (CRN) with multiple primary user nodes, multiple secondary user nodes and an eavesdropping node, the energy of Secondary User Transmitting node (SUT) is limited and it transmits information by harvesting the radio frequency energy emitted by primary users. First, based on the joint selection of SUT antennas and secondary user receiving nodes, channel state Information of Eavesdropping channel is Known (IEK) and channel state Information of Eavesdropping channel is Unknown (IEU) selection schemes were proposed. Then, the closed-form expressions of the SOP and asymptotic SOP were derived, the secrecy diversity order and array gain were obtained accordingly. Finally, the performance of two schemes was compared and the influences of different parameters on SOP were analyzed through numerical simulations. The simulation results verify the correctness of the theoretical derivation and show that the security performance of IEK scheme is better than that of IEU scheme. The proposed scheme can reduce the risk of information being eavesdropped under the condition of limited energy for secondary transmitting users, thereby enhancing the security performance of radio frequency energy harvesting cognitive wireless network.

Key words: Cognitive Radio Network(CRN), energy harvesting, secrecy capacity, Secrecy Outage Probability(SOP), asymptotic secrecy outage probability

摘要： 针对射频能量采集认知无线网络中通信易被窃听、严重威胁信息安全的问题，提出了两种天线-用户联合选择方案并分析了系统的保密中断概率（SOP）。在含有多个主用户节点、次级用户节点和一个窃听节点的能量采集认知无线网络（CRN）中，次级发射节点（SUT）能量受限并通过采集主用户的射频信号能量发射信息。首先，通过对次级发射节点天线和次级接收节点的联合选择提出了窃听信道状态信息已知（IEK）和窃听信道状态信息未知（IEU）两种方案；其次，推导了系统的保密中断概率和渐近保密中断概率，相应地得到了保密分集阶和阵列增益；最后，通过数值仿真比较了两种方案的安全性能并分析了不同参数变化对保密中断概率的影响。仿真结果验证了理论推导的正确性，且表明窃听信道状态信息已知方案的安全性能更优。所提方案在次级发射用户能量受限的情况下能够降低信息被窃听的风险，提升射频能量采集认知无线网络的安全性能。

关键词: 认知无线网络, 能量采集, 保密容量, 保密中断概率, 渐近保密中断概率