Privacy Security Analysis Of Wireless Multipoint Network Data Transmission

With the development of wireless communication technology,and the increase of communication equipment access,the amount of data produced grows rapidly,which can effectively meet the daily needs of users,but also poses more threats to the privacy and security of data transmitted over communication networks.At the same time,traditional computing based encryption technology has gradually lost its advantage in protecting data privacy security with the increase of computing power.Hence we need the underlying secure transmission technical support.Based on information theory,physical layer security technology can realize the secure transmission of private data in the communication networks through coding technology,which has become one of the important choices for the academic community to solve such problems.Studies on physical layer security initially include the situation that additional independent eavesdroppers steal private information in the channel model.However,in the complex wireless multi-point network model,a situation occurs where a legitimate receiver is both an eavesdropper.Therefore,this paper studies the wireless multi-point network transmission privacy security based on the channel with confidential messages,and different from previous studies,we focuses on the rank-deficient channel model,starting from the symmetric model,and further studies the asymmetric model according to the two factors that affect the safety performance.The main contributions of this paper are follows:Firstly,the privacy security performance of common rank-deficient channel with confidential messages is studied.In this paper,we focus on the situation that the channel gain matrices are rank-deficient,proposes a method of alignment in the case of rank-deficiency to design the signal space encoding method in the case of rank-deficiency,determine the secure degrees of freedom of the communication network,and analysis the influence of rank-deficiency on the security performance of the communication network by comparing the full rank model.The communication network models are rank-deficient broadcast channel with confidential messages and rank-deficient interference channel with confidential messages.We use various information theory derivation methods to give the outer bound of the secure degrees of freedom of the two channels with confidential messages,and use the null space transmission technique and various alignment techniques to give the achievable scheme.Then,in order to study the influence of the number of transmitting and receiving antenna on the privacy security performance of communication network,we focus on the rank-deficient channel with confidential messages under the arbitrary antenna configuration,propose the asymmetric alignment technique to encode the transmitting signal,and determine the secure degrees of freedom of the channel under different relation of the number of transmitting and receiving antenna.We add the information theory derivation to the proof of outer bound,and emphatically present the asymmetric real interference alignment technology to design the achievable schemes of the non-integral secure degrees of freedom.Finally,in order to explore the influence of the rank of channel gain matrices on the privacy security performance of communication network,we focus on the rank-deficient channel with confidential messages under the arbitrary rank configuration,convert the system into base systems by dividing the transmitting signal space several times and then encode,use the precoding matrices to divide and encode the transmitted signals,determine the final secure degrees of freedom expression,and analysis the influence of the rank of the gain matrices of the expected and unexpected receiving channel on the security performance of the communication network,respectively.We use the knowledge of information theory to prove the outer bound of the secure degrees of freedom,and give the necessity proof based on asymmetric alignment technology.For the situation that the secure degrees of freedom is non-integer,we converts the rank-deficient system to full rank system,three-quarters full rank system,half full rank system to discuss the coding schemes.