基于OFDM系统物理层安全的滤波器及人工噪声设计

Filter and Artificial Noise Design based on the Physical Layer Security of OFDM Systems

物理层安全作为新兴的安全技术可以有效防止窃听、保障系统安全。提出了一种适用于OFDM(orthogonal frequency division multiplexing)无线通信系统的物理层安全(physical layer security)的滤波器加人工噪声设计技术,首先通过在发送端加入滤波器来破坏窃听者接收信号的正交性,再加入降噪算法设计,利用剩余能量产生在合法信道的零空间,进一步干扰窃听者的接收,确保信息安全传输。结果表明所用的滤波器和人工噪声技术,较大程度增加了窃听者的误码率,增强了OFDM系统的物理层安全。

Physical layer security is an emerging technique which can effectively prevent eavesdropping and ensure the security of the systems.This paper investigates two physical layer security techniques for OFDM(orthogonal frequency division multiplexing)wireless communication systems.Firstly,a transmit filter-aided technique is developed which can destroy the orthogonality of the eavesdropper’s received signal.This technique can maintain the legitimate transmission while interfering with the receiption of the eavesdropper.Then,in an effort to further disturb the reception of eavesdropper,an artificial noise(AN)scheme is proposed to improve the security performance.AN is generated in the null space of the legitimate channel by using the residual power and interferes with the reception of the eavesdropper while not affect the legitimate users.With the transmit filter and artificial noise techniques,the bit error rate performance of eavesdroppers can be increased,the physical layer security for OFDM systems can be enhanced,and the secure transmission of systems can be maintained.