窃听者位置估计下的系统保密容量优化

Secrecy capacity optimization based on estimation of eavesdropper location

保密容量最大化是物理层安全(PLS)的主要目标。本文首先利用到达角(AOA)估计窃听者位置,然后通过向窃听者发送人工噪声增大保密容量,并联合优化人工噪声和有用信号的波束成形向量,实现人工噪声发射机传输功率最小和系统保密容量最大的多目标优化。针对此多目标优化问题的非凸性,利用半定规划(SDP)松弛将其转化为凸优化问题后求解。数值仿真结果表明,本文所提多目标优化方法明显改善了系统的保密性能,同时通过调整保密容量和人工噪声发射机传输功率所对应的权重,实现了资源的有效分配和合理利用。

Maximizing the secrecy capacity is a key goal of physical layer security(PLS).In this paper,the location of an eavesdropper is estimated based on angle of arrival(AOA)at first.Then,through sending artificial noise to the eavesdropper for increasing the secrecy capacity,and jointly optimizing the beamforming vectors of artificial noise and information signals,the multi-objective optimization that minimizes transmission power of the artificial noise and maximizes the secrecy capacity is obtained.The multi-objective optimization problem is nonconvex and converted to a convex optimization problem via semi-definite programming(SDP)relaxation.The results show that the proposed multi-objective optimization method can improve the secrecy performance obviously.Moreover,the effective allocation and reasonable utilization of resources are obtained by adjusting the weights of the secrecy capacity and the transmission power of the artificial noise.