广义空间调制系统中的物理层抗窃听传输方案

摘要

为实现信息的保密传输,提出一种基于广义空间调制技术的物理层安全方案.发射端根据合法信道的状态信息对信号进行预处理,使合法接收者接收到来自各激活发射天线的信号相位对齐,并对不同激活天线组合的信号进行不同的相位旋转,提高合法接收者的接收性能.而窃听者接收到的信号相位仍然为随机分布,接收性能远低于合法接收者,有效地保护通过天线索引传输的信息.发送端同时发送指向窃听者的人工噪声,保护通过幅相调制携带的信息不被窃听.对保密容量、误码性能和信号与人工噪声的功率分配进行理论分析,仿真结果表明,通过合理分配功率,合法接收者的误码性能明显优于窃听者,能获得可观的系统保密容量.%For safety transmission,a security method in the physical layer is proposed based on generalized spatial modulation technique.The transmitter pretreats the signals according to the state information of the legal channel so that phases of all signals sent by different antennas are identical at the legal receiver.At the same time,different additional phase shift is imposed when different combination of the activated antennas is used,so the performance of the legitimate user is improved.However,phases of signals sent by different antennas are random at the eavesdropper,thus its performance is significantly lower than that of the legitimate user so that the information conveyed by the antenna index is protected.Artificial noise pointed to the eavesdropper is sent simultaneously at the transmitter to safeguard the information conveyed by amplitude and phase modulation symbols.Then the secrecy capacity,error performance and power assignment between signal and artificial noise are analyzed.The simulation results show that the legitimate receiver's error performance is superior to that of the eavesdropper,and a considerable secrecy capacity can be obtained.