Design And Detection Of Wireless Covert Communication System Based On Dual Relay And Precoding Technology

With the popularity of The Fifth Generation(5G)network and Internet of Things(Io T)technologies,more and more Io T devices have brought convenience to people's production and life.However,due to the broadcast nature of wireless communication signals,electromagnetic signals are directly exposed to the space medium,which posing a security threat to the communication system.Traditionally,a large number of covert communication researches have focused on the network layer,link layer and application layer,but researchers have not paid enough attention to covert communication which based on the related protocols of physical layer.However,the physical layer is also vulnerable to various attacks,including information tampering,eavesdropping,and malicious amplify and forwarding,which may cause information leakage in the wireless communication system.In order to prevent information leakage,this article focuses on the covert communication in the wireless network,and obtains the following research results:(1)Aiming at the problem of insufficient secure transmission capacity in wireless communication networks with relays,a joint beamforming and artificial interference mechanism based on dual relay separation is proposed.and joint optimization algorithm of relay power,beamforming matrix and artificial interference is designed.Simulation results show that the algorithm can effectively improve the security capacity of relay-based wireless communication networks.(2)Aiming at the problem of easy leakage of transmission information in wireless communication networks,a covert communication system based on antenna array coding and constellation offset is proposed.We have derived the amount of mutual information of the proposed covert communication system and the optimal distance between the constellation offset.The feasibility of the proposed system is verified by simulation.The simulation results show that the proposed covert communication system has high security capacity.(3)Aiming at the behavior of constellation modulation combined with time slot characteristics for covert information transmission under MIMO,a fully connected classification network framework based on Generative Adversarial Networks(GAN)is designed.A method to detect covert communication in communication data with unbalanced samples is proposed.The proposed detection algorithm has good expansibility,which verify the detection model can be dynamically adjusted by pre-setting multiple sets of control parameters,so as to detect the sample sets of different distributed covert communications.Finally,the detection accuracy and ROC index of the system are verified by simulation.Finally,the main work of this article is summarized,and the future work is also prospected.