Taking into account the wireless physical layer security in energy-constrained relaying systems, a secure resource allocation scheme was proposed under simultaneous wireless information and power transfer (SWIPT) protocol. The utility optimization problem was considered aiming to maximize the secrecy rate by jointly optimizing the power splitting (PS) ratio and the transmit powers under the constraint of the transmit powers of the nodes and the harvested energy of the relay. The objective problem, which is non-convex, was decoupled into two subproblems. One was to optimize the PS ratio, another was to optimize the transmit powers. The optimal solution of the subproblems can be obtained in the closed-form. Then, the suboptimal solution is obtained with the proposed convergent iterative algorithm. Simulation results show the effects of artificial noise signal, residual self-interference signal, transmit power of nodes, amplification factor of relay and other factors on the security performance. Compared with the traditional gradient descent algorithm, the proposed algorithm can reduce more than 80％ of the computational load, while the algorithm has the slightly better performance.%针对能量受限中继系统的无线物理层安全问题,提出了一种基于无线信能同传的安全传输方案.该方案在节点传输功率和中继收集能量等条件共同约束下,通过对功率分配因子和传输功率等参数的联合优化来实现系统保密速率最大化.对于提出的非凸优化问题,首先采用分步优化方法分别优化功率分配因子和传输功率,得到其闭式解,然后使用收敛迭代算法求出原问题的次优解.数值仿真分析了人工噪声强度、剩余自干扰大小、节点传输功率及中继放大倍数等不同因素对系统安全性能的影响.与传统的梯度下降法相比,所提联合优化算法在性能略好的前提下可降低时间复杂度80％以上.
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