Research On Physical Layer Security And Reliability Tradeoff Of Friendly Jammer Aided Relay Transmission

With the rapid development of wireless communication technology,a large amount of important and private information is transmitted through wireless links,so the secure and reliable transmission of information has attracted wide attention.In this context,the physical layer security strategy achieves secure communication by utilizing the inherent transmission characteristics of wireless channels.The friendly jamming technology can effectively improve the physical layer security by sending specially designed artificial noise to disturb eavesdropper.However,the friendly jamming technology needs to consume some power resources,which will lead to the decline of wireless transmission reliability.Therefore,the security-reliability tradeoff(SRT)performance is worth further study.In this regard,this thesis studies physical layer security and reliability tradeoff of friendly jammer aided relay transmission.The main work and innovation points are as follows:Firstly,a cooperative decode-and-forward relay network consisting of a source,a relay,and a destination node is studied,in which an eavesdropper node intercepts the confidential information transmitted by the source and relay.A jammer aided decode-and-forward relay(JDFR)scheme is proposed,in which the destination and source act as friendly jammer nodes in the two-time slots of the decode-and-forward protocol to emit artificial noise to interfere with the eavesdropper,respectively.The traditional non-jammer aided decode-and-forward relay(NJDFR)scheme is used as a comparison.The closed expressions of intercept and outage probabilities of the proposed and traditional schemes are derived.The optimal power allocation algorithm between friendly jammer and user information is designed for the problem of maximizing the security-reliability probability of the proposed scheme.Simulation results show that the SRT performance of the proposed scheme is better than that of the non-jammer scheme,while the SRT performance can be further improved by power optimization between friendly jammer and user information.Secondly,a multi-relay network consisting of a source,a destination,and multiple relays in eavesdropping environment is studied.A jammer aided optimal relay selection scheme(JORS)is proposed,in which the max-min relay selection strategy is used to select the optimal relay.The traditional non-jammer aided optimal relay selection(NJORS)scheme is used as a comparison.The outage probability and intercept probability of the proposed and traditional schemes are derived to analyze the SRT performance.Simulation results show that the SRT performance of the proposed scheme is superior to the traditional non-jammer scheme,and the SRT performance can be improved with the increase of the number of relays.In addition,the SRT performance of the proposed scheme can be further improved by optimizing the power allocation between user information and friendly jammer.Finally,an energy-carrying relay network consisting of a source,a destination,and multiple energy-carrying intermediate nodes in eavesdropping environment is studied.The energy-carrying intermediate nodes harvest energy from the RF signals emitted by the source,and can be used as a relay to forward the user signal,or can be used as a friendly jammer to emit artificial noise.Based on power splitting(PS)protocol,a best relay random jammer(PS-BRRJ)and best relay best jammer(PS-BRBJ)schemes are proposed,and the outage probability and intercept probability of the two schemes are derived.A security-reliability probability maximization model is constructed,and the optimal PS ratio algorithm of the energy-carrying relay node is designed.Simulation results show that the SRT performance of the PS-BRBJ scheme is better than that of the PS-BRRJ scheme,and the SRT performance can be improved by increasing the number of energy-carrying intermediate nodes,while the SRT performance of the proposed scheme can be further improved by optimizing the PS ratio.