Research On Physical Layer Security Communication In Passive Eavesdropping Scenario

With the development of science and technology,the wireless communication has brought much convenience to the human’s production and life.Due to the broadcast nature of wireless communication,it is easier to be eavesdropped in the process of information transforming.Because passive eavesdroppers have no ability to send information,they only capture the electromagnetic wave in the environment,which has a higher concealment and thus has a serious impact on the security of the communication system.Therefore,the research of passive eavesdropping in wireless communication systems is very essential.Due to the fact that millimeter wave(mmWave)and intelligent reflecting surface(IRS)communication systems have the significant advantages in terms of spectrum efficiency,cost,power consumption,etc.,they will play an important role in future wireless communication networks.While the new communication systems have brought the performance improvements,its corresponding eavesdropping problems cannot be ignored.Thus,the researches on the passive eavesdropping in mm Wave communication systems and IRS communication systems have the important significance for ensuring the secure transmission in future communication networks.Specifically,the main work of this paper is mainly organized as follows:This paper investigates the secure transmission in the mm Wave hybrid communication system.We introduce the millimeter wave scatter sharing model.Then the matrix null space scheme is employed to eliminate the single from the common scatters and thus decreases the information leakage.Furthermore,through the design of the hybrid precoder/combiner,the secrecy rate is further improved.In the process of hybrid precoder/combiner design,a ShermanMorrison-based scheme is proposed to reduce the computational complexity.Finally,this paper compares with the classic scheme,and the simulation results show that our pro-posed scheme achieves good performance and guarantee secure communication in mm Wave hybrid system.This paper investigates the secure transmission in the IRS communication system.Based on the traditional beamforming technique,we introduce the IRS structure to reflect the signal from the base station.While enhancing the signal received by the legitimate user,it decreases the signal received by the eavesdropper and improves the secure performance of the system.By considering the statistical distribution of eavesdropper’s channel,the lower bound of secrecy rate is derived.Then,we propose the Rayleigh quotient transmit beamforming algorithm and the coordinate descend method to design the phase shifts at IRS,which can enhance the secrecy performance while decrease the computational complexity.Simulation results show that our proposed lower bound has a good performance in a lower signal-to-noise ratio,and the lower computational complexity algorithm we proposed has a similar performance of existing algorithm.