In this paper, we investigate physical-layer security performance of the cooperative vehicular relaying networks, wherein the communication from a source vehicle to the destination vehicle is assisted by an amplify-and-forward (AF) relay vehicle in the presence of a passive eavesdropper vehicle. We assume that the communication links between the vehicles experience double-Rayleigh fading. We also consider two AF relaying protocols: (1) fixed gain relaying which requires partial channel state information (CSI), and (2) variable gain relaying which requires full CSI. Specifically, we derive the novel intercept probability and ergodic secrecy capacity expressions for both fixed and variable gain relaying in the presence of double-Rayleigh fading channels. The numerical and simulation results verify our theoretical and analytical findings, and show the impacts of channel conditions and relay and eavesdropper locations on the system secrecy performance.

在本文中，我们研究了协作车辆中继网络的物理层安全性能，其中，在存在无源窃听器的情况下，由放大转发（AF）中继车辆辅助从源车辆到目标车辆的通信车辆。我们假设车辆之间的通信链路经历了两次瑞利衰落。我们还考虑了两种AF中继协议：（1）需要部分信道状态信息（CSI）的固定增益中继，以及（2）需要完整CSI的可变增益中继。具体来说，我们导出了在存在双瑞利衰落信道的情况下，固定增益和可变增益中继的新颖拦截概率和遍历保密能力表达式。数值和仿真结果验证了我们的理论和分析结果，