A new joint best relay and jammer selection (JBRJS) scheme is conceived for enhancing the physical layer security (PLS) of cooperative networks relying on multiple energy harvesting (EH) aided intermediate nodes, which accumulate energy based on the power splitting (PS) protocol. Specifically, we select the best intermediate node as the relay, whilst exploiting all the remaining nodes as friendly jammers. Furthermore, we investigate the joint optimization of the PS ratio and the relay-aided beamforming for maximizing the system’s secrecy rate and present a full channel state information (CSI) based joint PS and beamforming ( $\it {f}$ JPSB) scheme as the optimal solution by converting the optimization problem formulated into a single-variable optimization problem. We also propose a partial-CSI based JPSB ( $\it {p}$ JPSB) method for the scenario where only the main link’s CSI is available. Our numerical results show that the proposed JBRJS scheme beneficially enhances the PLS compared to the joint random relay and jammer selection (JRRJS) and to the pure best relay selection (PBRS) schemes. Moreover, the secrecy rate of the proposed $\it {f}$ JPSB and $\it {p}$ JPSB schemes is obviously higher than that of the fixed PS and beamforming (FPSB) method, and it further increases with the number of the relay’s transmit antennas.

中文翻译：

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能量收集协作网络中功率分束和波束成形的联合优化

构想了一种新的联合最佳中继和干扰器选择 (JBRJS) 方案，以增强依赖于多个能量收集 (EH) 辅助中间节点的协作网络的物理层安全性 (PLS)，这些中间节点基于功率分配 (PS) 协议积累能量. 具体来说，我们选择最好的中间节点作为中继，同时利用所有剩余节点作为友好干扰器。此外，我们研究了 PS 比率和中继辅助波束成形的联合优化，以最大化系统的保密率，并提出基于全信道状态信息 (CSI) 的联合 PS 和波束成形（ $\it {f}$ JPSB) 方案作为最优解，将优化问题转化为单变量优化问题。我们还提出了一种基于部分 CSI 的 JPSB（ $\it {p}$ JPSB) 方法用于只有主链路的 CSI 可用的场景。我们的数值结果表明，与联合随机中继和干扰选择 (JRRJS) 以及纯最佳中继选择 (PBRS) 方案相比，所提出的 JBRJS 方案有益地增强了 PLS。此外，拟议的保密率 $\it {f}$ JPSB 和 $\it {p}$ JPSB方案明显高于固定PS和波束成形（FPSB）方法，并且随着中继发射天线的数量进一步增加。