Research On Full-duplex Based Secure Transmission Technologies In Cooperative Relay Networks

With the rapid development of communication technology,cooperative communication technology has received more and more attention.Half-duplex relay technology,to a certain extent,expands the effective range of communication coverage and improves communication quality of communication systems.However,the increasing information security and the depletion of spectrum resources seriously affect the further development of wireless communication technology.The emergence of full-duplex cooperative relay technology has greatly promoted the progress of communication technology.Compared with the half-duplex cooperative relay technology,the full-duplex cooperative technology has the potential to double the spectrum efficiency,and can further improve the security of the system.Therefore,considering full duplex relay and physical layer secure transport technology,the thesis has done two aspects:1)In full-duplex cooperative relay networks,we treat safety and energy efficiency as the optimization index while meeting the peak power constraint of the source and the relay node,and the minimum rate requirements of the target system security constraints.Our goal is to maximize the energy efficiency of security system.Due to the fractional form of safe energy efficiency function and the non-convexity of optimization problem,the optimization methods,such as fractional programming,DC programming and convex optimization,are introduced to solve the problem.Simulation results show that the proposed scheme can achieve better balance between security and energy efficiency.2)Based on social trust model,a reliable relay node selection scheme is introduced to select the proper relay node with high reliability,so as to further guarantee the safety of the cooperative communication.In addition,a full duplex wiretap node that can simultaneously eavesdrop secret information and transmit interference is considered.Considering the security rate as the optimization objective,the security rate of the system is maximized under the constraints of the peak power constraint of the source node,the relay node and the eavesdropping node,and the minimum target secrecy rate of the system.Due to the non-convexity of the problem,the optimization theory and method such as DC programming and convex optimization are introduced to solve the optimization problem.Simulation results show that the reasonable power allocation can effectively resist the eavesdropping and interference of full duplex eavesdroppers.