储能-发送模式的单天线两跳中继系统保密速率的优化

该文研究节点具有能量收集能力的两跳中继系统的物理层安全传输方案。考虑窃听节点与源和中继节点间都有直接链路的情况。每个数据传输时隙分为能量收集和数据传输两个阶段，各节点用收集的能量发送信号。中继采用放大转发方式，目的节点发送人工噪声进行协作干扰，保护在两跳传输中传输的保密信息。以最大化保密速率为目标，采用迭代算法优化能量吸收和数据传输两阶段的时间分配比例系数和协作干扰功率分配因子。仿真结果表明优化算法准确，优化后的协作干扰方案能显著提高系统的保密传输速率。由于考虑了窃听节点在两跳传输中都能接收到信号的可能性，文中方案更贴近实际，并解决了一个复杂的优化问题。

Secrecy Rate Optimization for Single Antenna Two-hop Relay System in Energy-saving-then-transmitting Mode

A physical layer security transmission protocol in a two-hop relay system is studied. All nodes are equipped with an antenna and have the ability of energy harvesting. There are direct links between the source node and the eavesdropper as well as the relay node and the eavesdropper. Each transmission time slot is divided into two stages, which are respectively used for energy harvesting and data transmitting. The energy harvested is used to send data. The amplify-and-forward protocol is adopted, and the destination node sends artificial noise to protect the information transmitted in the first and second hop. To maximize the secrecy rate, iterative algorithm is used to optimize two variables of the time for energy harvesting and the power of artificial noise. Simulation results show that the optimization algorithm is accurate and the cooperative jamming can effectively improve the secrecy rate. Considering that eavesdropper can intercept the information transmitted in the two hops, the proposed scheme is more practical and can solve a complicate optimization problem.