Abstract: This paper investigates the secure communication in the Radio Frequency（RF） powered Wireless Sensor Networks（WSNs）. Employing the Physical Layer Security（PLS） technique, the secure two-phase communication protocol is proposed. By jointly designing the transmit power, RF signal covariance, information signal beamforming and assisting jamming covariance, the Secure Energy Efficiency（SEE） is maximized in the paper. The SEE maximization is fractional and non-convex, hence an iterative algorithm is proposed by combining the Dinkelbach method and the Sequential Parametric Convex Approximation（SPCA） method. The simulation results show that the proposed transmit scheme can significantly increase the SEE under the security constraint, compared with the baseline schemes.

Key words: wireless powered communication networks, wireless sensor networks, physical layer security, Secure Energy Efficiency（SEE）

摘要： 研究了射频无线充能传感器网络通信系统的安全传输及能量效率问题，针对传感器网络能量受限而无线通信容易被窃听的问题，利用物理层安全技术，提出了一种两阶段的安全传输协议。通过联合优化发送功率、射频能量协方差矩阵、敏感信息波束成型以及协作干扰协方差矩阵，使得传感器网络的安全能量效率达到最大。针对所提出的非凸问题，利用Dinkelbach方法将包含分式形式的目标函数简化，利用连续参数凸近似方法将非凸问题转化为可解形式，进而使用收敛迭代算法得到原问题的近似最优解。仿真结果表明，与对比方案相比，提出的传输方案可以在保证安全通信的基础上有效提高安全能量效率。

关键词: 无线充能网络, 传感器网络, 物理层安全, 安全能量效率