5G多天线系统中毫米波物理层安全设计

Design of Millimeter Wave Physical Layer Security in 5G Multi Antenna System

三维MIMO(3D Multiple Input Multiple Output,3D MIMO)技术是一种提高第5代(The Fifth Generation,5G)无线网络覆盖和频谱效率的潜在技术。三维信道空间模型(Three-Dimensional SCM,3D SCM)作为3D MIMO技术的一部分,它在2D SCM的基础上增加了垂直维自由度。在考虑毫米波段传输方案基础上,文中重点探讨了3D SCM对物理层安全设计的影响。首先简述了2D SCM和3D SCM模型,接着基于毫米波段路径损耗模型,主要研究3D SCM如何影响毫米波段的安全容量。文中采用1.9 GHz频段和28 GHz及73 GHz两个毫米波频段,引入相应的路径损耗模型,最后在不同载波频率以及基站下倾角下采用计算机仿真评估了毫米波通信的信道安全容量。结果表明,相对于传统2D SCM模型,3D SCM在28 GHz和73 GHz频段上的安全容量有一定程度的提升。与此同时,适当地调整基站天线阵列的下倾角也利于优化期望用户的安全容量。

Three- dimensional Multiple Input Multiple Output（ 3D MIMO） is one of potential techniques to improve coverage and spectrum efficiency of 5G networks. Three- dimensional channel model（ 3D SCM）,as an important part of 3D MIMO technology,has the additional vertical dimension of freedom compared with Tw o- dimensional channel model（ 2D SCM）. The effect of 3D SCMto the physical layer security design is discussed in this paper where mm Wave communications are considered. Firstly it outlines the 2D SCMand the 3D SCMmodel,and then by using the mm Wave path loss models,analyzes the effect on security capacity of 5G mm Wave communications systems based on 3D SCM. In this paper,the 1. 9 GHz band and two millimeter wave frequency bands,28 GHz and 73 GHz,are used,and the two path loss models are introduced. Finally the secure capacity performance of the millimeter- wave communication scheme is evaluated by using computer simulations under the different carrier frequencies and different base station downtilts. The results show that compared with traditional 2D SCM,the security capacity of 3D SCMhas a certain increase under the 28 GHz band and the 73 GHz band. Meanwhile,right adjustment of the base station antenna array tilt angle can also be benefit to optimize the security capacity of the desired user.