Research On Physical Layer Information Security In 3D MIMO Heterogeneous Networks

Massive MIMO technology and heterogeneous networks are two key technologies in the fifth generation mobile communication system.Due to space limitations,large-scale antennas are deployed with full-dimension MIMO style;the traditional plane random geometric method has been unable to accurately describe the distribution of heterogeneous networks.We need to adopt a suitable deployment of dense heterogeneous network analysis,it can improve the physical layer security performance of ultra-dense heterogeneous networks.To solve this problem,we model the ultra-dense heterogeneous networks based on the theory of spatial stochastic distribution.And we use 3D MIMO transmission scheme to analysis of the network physical layer security.The topic research on heterogeneous networks physical layer information security with 3D MIMO deployment as follow:First,this paper analyzes the research status of multi-antenna deployment heterogeneous networks,physical layer information security,the performance advantages of 3D MIMO deployment heterogeneous networks and current research situation of ultra-dense distributed heterogeneous networks.We summarize and analyze the physical layer of information security research methods as well as the existing technology.We expound the stochastic geometric method for analyzing the performance of heterogeneous networks,which can provide a theoretical basis for the subsequent performance analysis and optimization.Second,with the scenario of 3D MIMO small cell base stations downlink transmission link,we consider that the small cell base stations have complete channel state information,and use the best beamforming scheme that can make the legitimate users maximize the average signal-to-noise ratio.We propose the analysis method with stochastic geometric theory to obtain the closed-form expression of the secure connection probability on the legitimate users.And by optimizing the distribution density of the base station,the security connection rate of the legitimate users is improved.Finally,an adjustment in three-dimensional heterogeneous network is proposed that the vertical dimension of the base station with full dimension antenna is controlled.The signal-to-noise ratio of the legitimate users and the eavesdroppers with the tilt angle of the BS antenna available are formulated,and the cumulative distribution functions of SNR are deduced according to spatial random Poisson Point Process distribution of the BSs and the users,and then the average security rates closure expressions of the heterogeneous network are obtained.The simulation results show the correctness of the closed expression among the density of the small cells,the tilt angles and the average security rates.The feasibility of the scenario that the physical layer security can be improved by adjusting the vertical tilt angle,meanwhile the reasonable the distribution of small cells are proposed.