频率选择性信道下基于时间反转的物理层安全技术研究

发布时间：2018-05-09 14:31

本文选题：物理层安全 + 时间反转　；参考：《国防科学技术大学》2014年硕士论文

【摘要】：作为增强无线通信安全的一种新思路,物理层安全技术旨在利用丰富的物理层资源来增强通信系统的安全性,具有广阔的研究和应用前景。随着宽带、超宽带通信技术的迅猛发展,频率选择性信道下的物理层安全技术研究逐渐引起人们的关注。时间反转(Time Reversal,TR)技术不仅可以缓解多径传播的不良影响,还能够自动收集各路径的信号能量并在预定的合作接收机处相干叠加,从而实现信号在时域和空域上的二维聚焦,因而是频率选择性信道下实现物理层安全的一种有效技术手段。本文针对频率选择性信道下基于时间反转的物理层安全技术展开研究,主要工作如下:1、首先详细介绍了基于时间反转的无线通信系统的时域与频域模型,其次研究了时间反转的时间压缩、空间聚焦、信道固化以及多径分集这四大性能特点,为后续章节的研究工作奠定基础。2、研究了单载波通信系统中基于时间反转的物理层安全设计问题。在未知窃听者信道状态信息的情况下,在频率选择性信道下将人工噪声引入到传统的时间反转预滤波器方案中,提出一种人工噪声和时间反转相结合的安全设计方案,仿真结果表明所提方案的安全性能优于传统的时间反转预滤波器方案。而在已知窃听者信道状态信息的情况下,设计了一种可达到保密容量的时间反转预滤波器方案,仿真结果表明所提方案的安全性能优于屏蔽Eve的时间反转预滤波器方案。利用上述不同安全等级的时间反转预滤波器,建立了具有不等保护能力的无线广播通信系统,能够为不同用户提供不同等级的安全保护策略。3、研究了多载波通信系统中基于时间反转的物理层安全设计问题。首先介绍了TR OFDM系统的时域与频域模型,然后通过与最大比传输预编码方案相比,分析了时间反转预编码方案在多输入单输出(Multiple-input Single-output,MISO)OFDM系统中的安全性能,最后在MISO OFDM系统中提出了一种时间反转与人工噪声相结合的安全设计方案。仿真结果表明,时间反转技术能够有效增强多载波通信系统的安全性能。
[Abstract]:As a new way to enhance the security of wireless communication, the physical layer security technology aims to enhance the security of the communication system by using abundant physical layer resources, which has a broad research and application prospects. With the rapid development of broadband and ultra-wideband (UWB) communication technology, the research of physical layer security technology in frequency-selective channels has attracted more and more attention. Time reversal (TRT) not only can mitigate the adverse effects of multipath propagation, but also can automatically collect the signal energy of each path and stack it coherently at the predetermined cooperative receiver, thus realizing the two-dimensional focusing of the signal in the time domain and the spatial domain. Therefore, it is an effective technique to realize physical layer security in frequency selective channel. In this paper, the physical layer security technology based on time reversal in frequency-selective channel is studied. The main work is as follows: 1. Firstly, the time-domain and frequency-domain models of wireless communication system based on time-reversal are introduced in detail. Secondly, the characteristics of time compression, space focusing, channel solidification and multipath diversity are studied. This paper studies the physical layer security design based on time reversal in single carrier communication system. In the case of unknown eavesdropping channel state information, artificial noise is introduced into the traditional time reversal prefilter scheme in frequency-selective channel, and a security design scheme combining artificial noise and time reversal is proposed. The simulation results show that the security performance of the proposed scheme is better than that of the traditional time reversal prefilter scheme. When the channel state information of eavesdroppers is known, a time reversal prefilter scheme with secure capacity is designed. The simulation results show that the proposed scheme has better security performance than the time reversal prefilter scheme with shielded Eve. Using the time reversal prefilter of different security levels, a wireless broadcast communication system with unequal protection capability is established. This paper studies the physical layer security design problem based on time reversal in multicarrier communication system, which can provide different levels of security protection policy for different users. Firstly, the time domain and frequency domain models of tr OFDM system are introduced. Then, compared with the maximum ratio transmission precoding scheme, the security performance of the time reversal precoding scheme in multiple-input single-output MIMO MISOO OFDM systems is analyzed. Finally, a security design scheme combining time reversal and artificial noise is proposed in MISO OFDM system. Simulation results show that the time reversal technique can effectively enhance the security performance of multicarrier communication systems.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN92

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