Research On Cooperative Physical Layer Security Mechanism Of Wireless Communication Network

With the rapid development of wireless technology,the way of people's life and work is undergoing constant changes,and wireless communication networks become an indispensable part of people's daily life.When people use wireless network for com-munication or data transmission,they always want to obtain more secure communication service.However,the openness,instability,and broadcast nature of wireless channel make the wireless network more vulnerable to be attacked through eavesdropping,which in turn results in the leakage of confidential information.Therefore,how to ensure the security of confidential information in wireless transmission process is an urgent problem in the field of wireless communication.To overcome these problems and make people's expectation become true,physical layer security technology will be a very useful tool.Through exploiting the fading and changing characteristics of the wireless channel,physical layer security technique can achieve secrecy at physical and avoid the usage of complex encryption algorithms.Therefore,physical layer security technique is the preferred technique to guarantee communication security.However,when using physical layer security technology to protect the security of wireless communication,to ensure the secrecy capacity is greater than zero,eavesdropper channel must be a degraded version of the main channel.In the real network environment,this special channel constraint condition is difficult to be satisfied at any moment.At this point,the cooperation between nodes can be used to improve the main channel or to degrade the eavesdropper channel,and then the channel constrain can be satisfied.There have been many studies on cooperative physical layer security mechanisms,but for some special network scenarios,the existing mechanisms will not be applicable or achieve poor performance.This dissertation is dedicated to developing some new physical layer security schemes for wireless communication networks in some certain scenarios.The main contributions are summarized as follows.1.A Stackelberg game based cooperative security scheme is proposed for cognitive radio network with multiple primary users.Existing methods only consider a simple scenario which contains only one primary user in cognitive radio network.Compared with the real scenario,this scenario is too simple to be satisfied.To overcome this limitation,we investigate a more complicated scenario which contains more than one primary user.For this scenario,we propose a novel cooperative security scheme in which many primary users will transfer their frequency resource at the same time in exchange for cooperative jamming service provided by secondary user.Considering the rational and selfish of each user,a multi-leader and single-follower Stackelberg game will be used to formulate the interactive between primary users and secondary user.Moreover,our proposed Stackelberg game is transformed into a generalized Nash equilibrium problem,and then the existence of equilibrium is proved.An iterative algorithm is proposed to find an equilibrium result.The simulation results show that using our proposed scheme,primary user and secondary user make the decision according to equilibrium result,and a stable cooperation relationship between primary user and secondary user will be established.Through cooperation,the secrecy capacity of many primary users can be improved and more transmission opportunity can be obtained by secondary user.2.A cooperative physical layer scheme based on two-side stable matching is proposed for cognitive radio network with multiple primary users and multiple secondary users.When secondary user share the frequency resource of primary user with underlay method,the mutual interference will be generated between primary user and secondary user.When secondary user needs to ensure communication security,using the interference caused by primary user will improve secrecy capacity of secondary users.Based on this fact,we propose a new cooperative physical layer scheme for the underlay cognitive radio network.In our proposed scheme,each secondary user will be assigned a primary user and their transmission power will be controlled.For maximize the total secrecy rate obtained by all secondary users,we firstly model this problem as a global programming problem,and a corresponding algorithm is proposed to find an optimal result.Then,the rational and selfish of each user is considered,and the reciprocal selection problem between primary user and secondary user is formulated as a stable marriage problem.The interference price is introduced into the problem,and the interaction between primary user and secondary user is described as a Stackelberg game.To find an equilibrium result,an iterative algorithm is proposed,and the convergence of the algorithm is proved.According to the equilibrium result,preference list of each user can be established.Finally,a stable matching result between primary user and secondary user can be found through using Gale-Shaply algorithm.The simulation results show that using our proposed scheme in the underlay cognitive radio networks,the secrecy capacity of secondary user can be improved on the premise of ensuring the communication quality of primary user.3.In a non-cognitive radio network,when the channel constraint cannot be satisfied,network operator needs some cooperative jamming service which provided by third party collaboration nodes to meet the user's information security requirements.Due to providing cooperative jamming service will consume its own resources,as a selfish individual,collaboration node do not selflessly provide cooperative jamming service to users.Therefore,network operator needs to pay a certain fee to incent the collaboration node providing cooperative jamming service.In order to meet the security needs of as many users as possible with minimal payment,network operator needs to reasonably select some available collaboration nodes and allocate users between these nodes.For this reason,we will use reverse combinational auction mechanism to complete the selection and allocation of collaboration nodes.First,an optimization based reverse combinational auction mechanism is proposed,and incentive compatibility and individual rational are also proved for our proposed auction mechanism.Considering the excessive computational complexity of the optimization based reverse combinational auction mechanism,a greedy based reverse combinational auction mechanism is proposed.The greedy based auction mechanism can obviously reduce the computational complexity under the premise of ensuring incentive compatibility and individual rational.The simulation results show that using our proposed schemes,network operator can meet the security needs of as many users as possible with less payment,and the network benefit can be improved.4.When the third party collaboration node do not exist within the coverage of the wireless network,in order to satisfy the communication security requirement of users,the cooperative relationship between users need to be established to satisfy the channel constraints.Two types of user cooperation scheme are proposed to establish the cooperative relationship between users,one of them is one-to-one cooperation scheme,and the other is multi-user cooperation scheme.To ensure the stability of cooperative relationship between users,in the one-to-one cooperation scheme,the mutual selection problem among users is formulated as a stable roommate problem.And a stable roommate algorithm is also provided to find a stable matching result.For the same reasons,in the multi-users cooperation scheme,the establishment process of cooperation relationship between multiple users is formulated as a hedonic coalition formation game.And a hedonic shift algorithm is proposed to find a stable coalition structure.Simulation results show that using our proposed schemes,the secrecy capacity obtained by users can be improved through establishing the cooperative relationship between them.In summary,this dissertation proposes some cooperative physical layer security schemes to improve secrecy performance of wireless network in some certain scenarios.Theoretical analysis and simulation results show the superior performance over the existing methods.