Research On Physical Layer Security Strategy Of Backscatter Communication System

At present,my country has fully entered the commercial era of the fifth generation(5G)mobile communication technology.The wide-connected characteristics of 5G technology will further promote the vigorous development of the Internet of Things(Io T)industry.It is estimated that by 2025,more than 50 billion Io T devices will be interconnected worldwide.Traditional Io T devices mostly use active radio frequency units.When there are more devices connected to the network,the total energy consumption cannot be underestimated,and the active devices are usually larger in size.The backscatter communication method is considered to be a new opportunity to promote the further development of the Internet of Things industry.The backscatter communication system provides the possibility to realize low power consumption and high efficiency data communication with the advantages of passive terminals and small size.In this paper,Radio Frequency Identification(RFID)and Ambient Backscatter Communication(ABC)system are studied.However,due to the inherent characteristics of backscatter communication,it is vulnerable to attacks such as eavesdropping.How to ensure the communication security of Io T devices has become a subject of important research value.The backscatter terminal is usually a relatively simple passive device with limited computing power and energy supply,and is not suitable for traditional encryption algorithms to ensure communication security.As an important supplement to traditional encryption schemes,the research on physical layer(PHY)-based security mechanisms is considered a promising direction for exploration.From the point of view of PHY security theory and technology,this paper studies the secure transmission performance of two backscatter communication system models based on relay selection strategy and cooperative relay strategy respectively.The specific content includes:In the RFID scenario,the system models of three relay cooperation schemes are established,and the achievable security rate of different cooperation schemes is analyzed as a metric of the system security performance.Then,under the condition that there are single or multiple eavesdropping nodes in the system,the three relay cooperation schemes are discussed to maximize the confidentiality rate under the constraint of the total transmission power.First,the distribution of the optimal relay weight is determined,and the power distribution between the tag terminal and the relay is determined on the basis of the optimal relay weight.Next,we discuss how to minimize the total transmission power required by the system under the constraint that the confidentiality rate is not lower than a certain limit value.Finally,through the numerical simulation results,the influence of the distance and number of nodes on the system secrecy rate and total transmission power are analyzed.In the context of ABC,a physical layer security strategy IANT is proposed,which injects artificial noise from the tag side to realize the secure communication function.As far as I know,in the previous research on the ABC physical layer security strategy,no scheme for injecting artificial noise from the tag side has been proposed.Different from previous studies,this paper adopts a dynamic channel parameter estimation method based on the expectation maximization algorithm.This method is compatible with ABC and does not need to send pilot symbols,thus effectively eliminating the influence of artificial noise on the reader.Numerical simulation results show that compared with the control scheme,the IANT scheme can achieve a security rate that is about twice that of the control scheme at the premise of slightly sacrificing the bit error rate performance,which can effectively improve the security performance of the system.