Research On Physical Layer Security Mechanism Based On Primary And Secondary User Communication-energy Cooperation

The development of wireless communication technology has been integrated into the life of the public,deeply affecting our work and lifestyle.The security of information transmission in the field of wireless communication has attracted much attention.Especially in the case of national security,enterprise secrets and other scenarios with high security requirements,the security of communication systems is a crucial factor.Traditional information security mainly focuses on the upper structure,encrypts information based on cryptography,and uses relatively complicated mathematical calculations to ensure that information will not be cracked in a short time,but only if the underlying structure such as the physical layer has been provided safely and without transmission condition of the error.And with the isomerization and ubiquity of modern communication networks,network nodes are becoming more and more simplified,and some communication nodes have no upper structure,so it is difficult to implement encryption functions.As an effective supplement to the upper layer encryption,the physical layer security technology has attracted the attention of scholars in recent years,aiming to realize the secure transmission of information by utilizing the rich resources of the physical layer itself.There are three main aspects of security for physical layer security: based on physical layer keys,channel-based security coding,and signal-based processing.The physical layer security scheme based on signal processing in the three is more direct and effective than the other two.The core idea is to enhance the quality of the legal channel and deteriorate the eavesdropping channel through some physical layer technologies,thereby reducing the receiving signal-to-noise ratio of the eavesdropping.It fundamentally prevents eavesdroppers from demodulating legitimate user signals.The cooperative interference technology is the focus and hotspot of the research in the physical layer security field,but the technology requires additional interference nodes,which means that the cost of the communication system will be increased,and some energy problems existing in the coordination interference are also worthy of further research.Today,when communication resources are limited,the physical layer security technology that realizes the efficient use of energy and spectrum is an important issue while ensuring the security of the communication system.This dissertation proposes two complementary security transmission strategies that introduce cooperative secondary users for the physical layer security transmission scenario under energy-constrained conditions.Strategy 1 improves the traditional cooperative interference mode and improves spectrum efficiency;strategy 2 introduces energy collection,uses the signals with no need to decode for charging,which improves energy use efficiency.The two strategies dynamically switch in practice,ensuring efficient and continuous signal transmission in a scenario where the system node is limited in energy.Specifically,this dissertation studies the primary and secondary user cooperation problems in multiple sets of alternative cooperative users,and proposes mathematical models for system resource allocation under single-group secondary users and multiple sets of secondary users,then uses the algorithm of beetle antenna search to optimize the resource allocation scheme and give the strategy of system resource scheduling.At the same time,for the user selection problem in complex scenes,the complexity of the model is greatly reduced by sacrificing the accuracy of certain operations,and the user selection method and corresponding system resource allocation scheme are given.The simulation results show that the two strategies introduced in this dissertation can ensure that the system communication node can still achieve efficient and confidential transmission in the energy-constrained scenario,and the superiority of the proposed mechanism can be especially reflected in the continuous transmission.The accuracy of the proposed resource scheduling scheme and its solution efficiency are at a high level.