Research On Physical Layer Security Based On Game Theory

The broadcast feature of wireless communication facilitates the spread of information and also brings great challenges to the communication security.Malicious nodes within the broadcast range can easily eavesdrop on secret information.Traditional cryptography-based high-level encryption and decryption security methods is not suitable for wireless communication,so people have turned their attention to the physical layer security.The physical layer security uses the physical characteristics of wireless communication channels to ensure the communication security of legitimate communication nodes through signal processing,code modulation,and other technologies.Collaboration nodes are often used in physical layer security research to help legitimate communication nodes or interfere with eavesdroppers.In previous studies,it was considered that the collaboration nodes would help the legitimate communication nodes without remuneration.In actual situations,the collaboration nodes may not be part of the legal communication system.They will ask for benefit from the help action because of their selfishness.In recent years,researchers have often used game theory to deal with this problem of multiple stakeholders.Game theory has provided new ideas for the study of physical layer security.This thesis uses game theory to study the physical layer security in collaborative communication networks:First,this thesis discusses a model of interference wiretap channel composed of a sending end,a legitimate receiving end,an eavesdropper and a friendly interfering node.In this model,the friendly interference node acts as a seller,and the legitimate communication pair acts as a buyer.They form a Stakelberg game.Then we build the benefit function of both parties and calculated the equilibrium point of the game.By additionally adding a friendly interference node in the above model,the number of sellers has changed from one to two,and the double interference nodes with the legitimate channels constitute the Bertrand game model.Through the analysis of the game model,the optimal purchase power of the legitimate channel and the power unit price of the two friendly interference nodes in equilibrium are got.Next,a brand new single-interference node and multi-antenna transmitter game model was constructed.When there is only one interference node in the system,the node occupies the advantage in the game with the legitimate channel;when there are multiple interference nodes in the system,the legal channel dominates.This thesis proposes that when there is only one interference node in the system but the transmitting end is equipped with multiple antennas,the transmitting end simultaneously sends useful signals and noise to form an analog interfering node.The simulated interference node changed the game structure and enhanced the status of the legal channel.Experiments show that the new game model can effectively improve the revenue of legitimate channels.Finally,the study was extended to eavesdrop channels for untrusted collaboration nodes.Because untrusted nodes may choose to help eavesdroppers,system security cannot be guaranteed.In response to this situation,this thesis proposes a solution:Add an additional friendly node.Friendly interference nodes increase the choice of legitimate channels so that they are no longer subject to the behavior of untrusted nodes.Simulation shows that regardless of how untrusted nodes select helpers,friendly interference nodes can increase the security performance of legitimate channels.