部分信道特征下的物理层安全编码方法

摘要

针对部分信道特征(授权信道特征存在估计误差且窃听信道特征未知)下的物理层安全传输问题,结合人工噪声和安全编码,提出了一种实用的物理层安全编码方法.多天线发射机采用波束成型传输信号时添加与授权信道特征正交的人工噪声,利用交织LDPC码缩小安全距离,在授权信道SNR约束下求最小私密中断概率,实现功率优化分配,尽可能使窃听信道保持低SNR高BER,授权信道保持高SNR低BER,从而实现物理层安全传输.仿真结果表明,在授权信道SNR约束下,本方法可以实现较低的私密中断概率.%This paper proposed a scheme of physical layer secrecy coding under partial channel characteristics aiming at physical layer secure transmission problem. The multi-antenna transmitter exploited beam-former to send signal with artificial noise which was orthogonal with authorized channel characteristics. It used interleaving LDPC to reduce the security gap between authorized channel and eavesdropping channel. Then found the minimum secrecy outage probability with authorized channel SNR constraint, and archived the optimal power allocation for physical layer secure transmission. So the authorized channel could keep low BER with high SNR, while the eavesdropping channel could only have high BER with low SNR. Simulation results show that, the proposed method can realize lower secrecy outage probability with authorized channel SNR constraint.