Research On The Physical Layer Security Technique In Wireless Mesh Networks Based On Full-duplex And Cooperative Jamming

Wireless mesh networks realize connection and communication between nodes through multi-hop wireless channels and establish communication coverage for specific areas without a fixed network infrastructure.Wireless mesh networks are applied in many fields.With the advent of the information age,the security of communication has received more and more attention.In the case of the wireless communication signal openly transmitting,the security of the wireless mesh networks has become more prominent.Traditionally,network security relies on cryptographic methods,encrypting the information through encryption algorithms.And the defence of eavesdroppers mainly depends on the computational complexity of the encryption algorithm.With the continuous improvement of computing capabilities for computers,communication security based on cryptography is increasingly threatened,which constantly prompts people to seek various measures strengthening information security.In recent years,people pay close attention to physical layer security based on the information theory.Physical layer security technique seeks an absolute security method for information transmission,which prevent eavesdroppers obtaining the transmitted information from their intercepted signals.According to the research and analysis,this dissertation studies the physical layer security problems and proposes a new physical layer security scheme for different cooperative relays in wireless mesh networks.The main contributions of this dissertation are as follows:Firstly,the basic concepts and theoretical basis of physical layer security are introduced.In addition,the system model and the current research status of the physical layer security in wireless communication were investigated and analysed.Secondly,the physical layer security in wireless mesh networks with randomize-and-forward cooperative relays is studied.Aiming at the lack of the location and channel state information of the eavesdroppers in wireless mesh networks,a layer security strategy combining simultaneous co-frequency co-time full-duplex and cooperative jamming is proposed,which degrades the eavesdropper receiving performance and improves the security of the transmission path through receiving nodes and cooperative jammers sending interference signals at the same time.The secure connection probability of the predefined multi-hop connection is derives and the cooperative jammers are selected under specific conditional restrictions.The simulation results verify the rationality of the proposed scheme.Thirdly,the physical layer security in wireless mesh network with decode-and-forward cooperative relays is studied.Different from randomize-and-forward cooperative relays,the information transmitting in any two hops is no longer independent.In that case,it is assumed that colluding eavesdroppers may wiretap signals from multi hops,which is the worst scenario.The physical layer security performance with the security strategy combining co-frequency co-time full-duplex and cooperative jamming in the wireless mesh networks,which is applied in the scenario with randomize-and-forward cooperative relays is analysedFinally,an outlook of the future work is provided.