基于信道估计的物理层安全多天线选择功率分配方案

Improving physical layer security exploiting multi-antennas selection with training sequence channel estimation

针对多天线选择方案提高物理层安全的研究中信道已知条件的设定过于理想这一问题,提出利用导频信号估计主信道并进行多天线选择的方案。接收端发送导频信号供发射端进行主信道估计,发射端利用估计的信道状态信息选出多根天线并进行功率分配,推导所提方案的保密容量并设计仿真实例。结果表明,所提方案在估计误差条件下达成了低信噪比时的非零保密容量,且接收方误码率随信噪比增大急剧减小至10-4,而窃听方的误码率保持较高,验证了所提方案的有效性和可行性。

In current research about improving physical layer security exploiting multi-antennas selection at the transmitter,the assumption of knowing the channel state information（ CSI） of main channel has been excessively idealized. This paper considered a practical scheme based on channel estimation at the transmitter,which selected multiple antennas using the estimated CSI of main channel. First of all,transmitter estimated the CSI of main channel by receiving the training sequence sending by the receiver. Then it selected antennas and allocated transmit power of each antenna using the estimated CSI. It deduced the secrecy capacity of the proposed scheme and designed a simulation for test and verify. The results show the proposed scheme achieves the non-zero secrecy capacity in low signal-to-noise ratio with channel estimation error. Bit error rate（ BER） of receiver is sharply decreasing to 10- 4along with the rising signal to noise ratio,besides the bit error rate of eavesdropper stays high relatively. It shows the validity and feasibility of the proposed scheme.