The future of autonomous transportation systems depends on energy sustainability and secure information exchange from low-power vehicular sensors, hence the increased interest in vehicular sensor charging using simultaneous wireless information and power transfer (SWIPT). This study investigates the physical layer security of a SWIPT-based radio frequency energy harvesting cooperative vehicular relaying network subjected to cascade Nakagami- and double Nakagami- (DN) fading channels. In the considered system model, a stationary source communicates with a mobile destination through a power-splitting-based decode-and-forward relay in the presence of a mobile passive eavesdropper. Based on the Gamma-distributed first term of the Laguerre series, new statistical probability density function (PDF) and cumulative distribution function (CDF) expressions for the DN are derived to accurately model the complex cascaded fading scenario. The secrecy performance metrics analyzed are the secrecy outage probability (SOP), the probability of non-zero secrecy capacity (PNZSC), and the intercept probability (IP). In addition, the asymptotic SOP (ASOP) is investigated in the high signal-to-noise ratio (SNR) to enhance the comprehension of the secrecy performance. Based on the derived ASOP, the secrecy diversity order (SDO) of the proposed system is determined and examined. Particularly, we present analytical closed-form expressions for the secrecy performance metrics and provide a detailed understanding of the impact of the system parameters under the cascade fading scenario. Then, a power splitting (PS) optimization problem is formulated to minimize the SOP. The results demonstrate a reduction in the SOP with the proposed PS scheme compared to the equal PS scheme. The obtained analytical findings are validated using Monte Carlo simulations.

中文翻译：

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基于 SWIPT 的协作车载中继网络中的物理层安全


自主交通系统的未来取决于能源可持续性和低功耗车辆传感器的安全信息交换，因此人们对使用同步无线信息和电力传输（SWIPT）的车辆传感器充电越来越感兴趣。本研究研究了基于 SWIPT 的射频能量收集协作车载中继网络在级联 Nakagami 和双 Nakagami (DN) 衰落信道下的物理层安全性。在所考虑的系统模型中，在存在移动被动窃听者的情况下，固定源通过基于功率分割的解码和转发中继与移动目的地进行通信。基于拉盖尔级数的伽玛分布第一项，推导了 DN 的新统计概率密度函数 (PDF) 和累积分布函数 (CDF) 表达式，以准确模拟复杂的级联衰落场景。分析的保密性能指标包括保密中断概率 (SOP)、非零保密容量概率 (PNZSC) 和拦截概率 (IP)。此外，在高信噪比（SNR）下研究了渐近SOP（ASOP），以增强对保密性能的理解。基于导出的 ASOP，确定并检查所提议系统的保密分集阶 (SDO)。特别是，我们提出了保密性能指标的分析封闭式表达式，并详细了解了级联衰落场景下系统参数的影响。然后，制定功率分配（PS）优化问题以最小化SOP。结果表明，与同等 PS 方案相比，所提出的 PS 方案的 SOP 有所降低。 使用蒙特卡罗模拟验证了获得的分析结果。