Research On Physical Layer Security Technology Of Wireless Communication Network

With the development of the Internet of Things,the number of mobile terminals receiving explosive growth has led to a thousand-fold increase in data traffic,and the security problem of wireless communication has become increasingly serious.With the improvement of computing power,traditional information encryption methods based on computation complexity are not suitable.Based on the information theory,the physical layer security applies the random characteristics of the main and the eavesdropping channels to make the mutual information between the legitimate node and the eavesdropper zero,and achieves absolute security,so it has become an important supplement to the traditional security system.This thesis studies the application of physical layer security technology in wireless communication networks with eavesdroppers,and combines cooperative interference technology,full-duplex technology,and so on,to improve the safety performance of the communication system.Specific research contents and innovation results include:1)A low-latency transmission scheduling method based on Markov chain for wireless body area network is proposed.In this thesis,we model the process of routing selection as a Markov decision process.And the routing with minimum delay,under the constraint of secure outage probability,is modeled as a control strategy problem,which is to find the minimum delay cost of a dynamic system.Next,this thesis uses Lagrange multiplier method and real-time dynamic programming algorithm to solve this problem.The simulation results show that the method can select the optimal relay node in real time according to the change of the state under the security constraints,so that the message transmission has the smallest average delay.2)A joint energy saving scheduling and secure routing algorithm for critical event reporting in wireless sensor networks is proposed.In the uplink,with the end-to-end bit error rate(BER)and the routing strategy of maximizing the routing secure connection probability(RSCP)as constraints,the power minimization problem is modeled,and the problem is converted into the classical dijkstra algorithm to calculate a secure route.According to the power allocation strategy,the transmission power of each node on the secure route is allocated.In the downlink,an energy-first multi-point relays set selection algorithm(EFMSS)is designed.In the uplink and downlink,the wake-up mechanism of level-by-level sleeping scheduling is combined to further save overhead.Simulation results show that this method can effectively reduce energy consumption and improve the safety of the system.3)This thesis proposes a trust-based power minimization algorithm for wireless relay networks.Considering a wireless communication network with one source node,one destination node,one eavesdropper,and multiple relay nodes with a known trust degree.Consider the case of non-cooperative interference,cooperative interference and simultaneous wireless information and power transfer(SWIPT),taking the average security rate as the constraint,and minimizing the relay power as the optimization objective to model,derive the accurate expression between the trust degree and the relay power.And the accurate relation expressions of the trust degree and the slot division coefficient are derived in SWIPT.Through simulation analysis,the correctness of these precise expressions is verified.