基于人工噪声和SWIET的安全双向中继通信

Artificial noise and SWIET-based secure bi-directional relay communication

针对基于解码转发的对称双向中继网络的安全传输问题,提出一种基于人工噪声干扰和信息、能量同时传输技术(SWIET)的物理层安全传输策略.系统采用两时隙传输方案,能量收集节点利用第一时隙收集的能量发射人工噪声干扰,而用户节点和中继分别通过功率分配技术将目的节点先验已知的人工噪声干扰添加到有用信息中,以降低窃听信道的传输质量.建立双向中继网络窃听信道下联合能量收集和无能量收集节点的两种数学模型,推导基于人工噪声干扰的系统保密容量的数学表达式,分别求解两种模型的最大化系统保密容量下最优功率分配因子,并分析了SWIET技术对系统保密容量的增益.仿真结果表明:对应于不同的窃听节点位置,所提出的联合SWIET技术的方案能使双向中继网络保密性能改善3%~90%,且能量收集节点越靠近窃听节点,系统性能越好.

A physical-layer security transmission strategy was proposed for decode-and-forward symmetrical bi-directional relay network.Artificial noise and simultaneous wireless information and energy transfer（SWIET）technique were employed to improve its secrecy.A two-slot transmission strategy was used.Specifically,energy harvested by energy receivers in the first slot was used to transmit artificial jamming signal,while the pre-defined jamming signals were added to the confidential information by using power allocation technique at user nodes and the relay.Two mathematical models were established for bi-directional relay network with eavesdroppers in the presence of energy-harvesting nodes and nodes incapability of energy harvesting.The secrecy rate obtained by using artificial jamming were derived under the above two models.Moreover,the optimal power allocation factors were obtained to maximize the system secrecy rate.Additionally,the secrecy rate gain achieved by exploiting SWIET was analyzed.Simulation results further show that the proposed strategy can yield the performance improvement of 3% ~90% depending on the location of the eavesdropper,and the performance increases with the decrease of the distance between the energy harvesting nodes and the eavesdroppers.