Research On Physical Layer Security Technology Combined With Wireless Energy Harvesting

With the advent of the fifth-generation(5G)wireless communication technology era,the wireless information transmission rate and the number of mobile terminals have been rapidly increased,it is especially important to ensure the security and reliability of information transmission.However,with the rapid development of modern processor,traditional cryptography-based information encryption technology may be easily cracked,which greatly threatens the security of wireless communication.The security technology which ensures the secrecy and reliable transmission of wireless information directly from the physical layer by utilizing the time-varying and spatial characteristics of wireless channels has received wide attention.At the same time,cooperative relay network technology is widely used due to its advantages of increasing signal coverage and enhancing network capacity.In the past,communication networks mainly relied on battery power which leads to high maintenance costs and environmental pollution.Based on wireless signals which contain information and energy,wireless energy harvesting technology was applied,which is promising to solve the power-constraint problems of various nodes in the wireless communication system,and also is in line with the environmental protection needs of green communications.In the third chapter,a full-duplex relay secure transmission system based on wireless energy harvesting technology is studied,and the strategy of full-duplex relay jamming for illegal eavesdroppers is proposed.The approximate expression of ergodic achievable secrecy rate is first derived.Simulation analysis is carried out under different source transmission power,average channel gain of different legal channels and different relay self-interference conditions.And then the closed-form expressions of system outage probability and eavesdropping probability are derived and simulated,which proves the superiority and reliability of our proposed system.The fourth chapter studies an active eavesdropping system based on wireless energy harvesting technology and proposes a strategy of active jamming based on full-duplex legal eavesdropping nodes.Furthermore,the connection outage probability of suspicious communication networks,the eavesdropping outage probability of active eavesdropping nodes and the average eavesdropping rate are derived.The comprehensive conclusion prove that the legitimate eavesdropping node in our proposed wireless communication system is efficient to wiretap confidential information and send the jamming signals.The above two systems use the finite state Markov chain to simulate energy changes while the battery energy states are not easily analyzed.All results are verified by Monte Carlo simulation.The research results show that in the full-duplex relay secure transmission system based on wireless energy harvesting technology,raising the energy threshold of the relay battery,keeping the source transmission power within a reasonable interval,increasing the average channel gain of the legal channel,and reducing the relay selfinterference are efficient to improve the safety and reliability of the system.In the active eavesdropping system based on wireless energy harvesting technology,increasing the battery energy threshold and jamming power of the active eavesdropping node can increase the outage probability of the suspicious communication network,but the eavesdropping demand,charging time and jamming effect should be weighed according to actual needs.The impact of the eavesdropping non-outage probability and the average eavesdropping rate of active eavesdropping node are maintained at a high level for the suspicious communication network,highlighting the good active eavesdropping capabilities of system.