Research On Physical Layer Security In MmWave Massive MIMO System

With the rapid growth of mobile wireless traffic and the access of mass devices brought by social development,the performance and function of mobile communication services have also been improved.The requirement of system capacity,transmission rate and security will become higher and higher in the future 5G mobile communication.Therefore,the key technologies of next generation mobile communication are considered to be millimeter-wave(mmWave)with rich frequency resources and massive multiple-input multiple-output(MIMO)with high gain effect,as will as physical layer security is also the research hotspot because it can improve the security by using channel characteristics at the bottom level of the system.For the next generation mobile communication system,the physical layer security in mm Wave massive MIMO system is studied in this paper.The main work of this paper is as follows:First,the development history of wireless communication system,mm Wave wireless transmission,massive MIMO system and physical layer security are introduced in this paper.The transmission rate of users and total system rate are given through three mm Wave massive MIMO system scenarios.Because the existing research only considers the direct path and does not consider the shared path,the performance of zero-space eavesdropping prevention scheme based on the direct path will be degraded when considering the shared path.Then,the mm Wave massive MIMO wireless propagation scenario based on shared path is considered in this paper.The channel vectors of shared path and their correlation are analyzed,as well as an anti-eavesdropping scheme based on shared path is proposed.It combines the shared path correlation matrix and the eavesdropping channel matrix to generate the joint eavesdropping channel matrix,generates the zero-space projection matrix through singular value decomposition,and maps the system channel matrix to the projection matrix,which can eliminate the received signal of eavesdropping terminal and achieve secure.Finally,using Matlab to simulate the two different scenarios in urban and suburban areas.The impact of the number and the distribution distance of eavesdroppers on the channel security capacity of users is analyzed and compared.The results show that the presented anti-eavesdropping scheme based on shared path,when considering the mm Wave massive MIMO system with shared path,can eliminate the eavesdropping capacity generated by both direct path and shared path,and ensure the safe transmission of system signal.