Physical Layer Security Of Relay System Based On Cooperative Jamming

In recent years,with the rapid development of wireless communication field,the number of wireless terminals has increased dramatically,and the total amount of communication data has grown exponentially,and the security problem of wireless communication has attracted widespread attention.The physical layer technology based on the information theory makes full use of the various propagation characteristics of wireless channel,there is no key management and distribution problems,and complements with the encryption technology,and can further ensure the security of the wireless communication transmission,which has received wide attention in recent years.The relevant technologies associated with it are developing rapidly.As an important branch of physical layer security technology,cooperative jamming technology mainly uses the transmission of artificial jamming signals or noise to deteriorate the quality of the eavesdropper's reception,so as to ensure the secure transmission of the communication system.Base on this,this thesis makes a research on the security performance and outage probability of the relay system based on the physical layer security under cooperative jamming mechanism.The specific contents include:1.Based on the traditional four-node relay system eavesdropping channel model,which includes source node,relay node,destination node and eavesdropping node,the influence of introducing extra jamming nodes on the system security performance is studied when the relay node adopts decoding and forwarding protocol.At the same time,the introduced jamming node is divided into two cases,namely general jamming node(which will cause interference to the reception of the destination node)and friendly jamming node(which will not cause interference to the reception of the destination node).The expression of the secure outage probability of the corresponding system under different conditions is derived theoretically and the related performance verified by simulation.The results show that the effect of introducing general jamming node on the system security performance varies with their relative positions,but introducing friendly jamming node can always improve the system security performance.2.In view of the security of the trusted relay system with eavesdropping node,the security performance of relay system under cooperative jamming mechanism is studied based on the theory of physical layer security and the relay node in this system uses the decoding and forwarding protocol.Without introducing the additional interference node,the method of transmitting jamming signals by the source node and destination node in turn is proposed to realize the security of information transmission.The theoretical derivation of the system's secure outage probability is made and the effectiveness of the proposed method is verified by simulation.The simulation results show that compared with the traditional relay network,the proposed system's secure outage probability is significantly reduced after using cooperative jamming technology.In addition,with the using of the proposed cooperative jamming mechanism,the security performance of proposed half-duplex network is better than that of full-duplex network.