MIMO窃听信道下的空时编码研究与设计

发布时间：2018-02-12 17:10

本文关键词： MIMO 窃听信道空时分组码保密通信保密容量　出处：《东华大学》2017年硕士论文　论文类型：学位论文

【摘要】：无线通信的广播特性使得无线网络缺乏物理边界,而这种没有物理连接的无线通信对于窃听者来说是开放的,无线通信物理层的安全已经成为通信系统安全性的一个关键问题。传统的安全机制是基于计算复杂度的安全体系,该体系的设计思路是加密算法破译所需的运算能力大于窃听者实际运算能力。随着现代计算机运算速度等性能的不断提升以及窃听者的运算能力存在极大的不确定性,基于计算复杂度的安全机制被窃听者破解的风险正在逐渐加大。物理层安全技术可作为传统安全机制的重要辅助,也可独立形成一套基于信息论的安全体系。本论文针对MIMO(Multiple-Input Multiple-Output)系统并结合信息理论,研究信号发射前的预编码技术,以强化物理层传输的安全。空时编码是一组实用的信号设计技术旨在接近理论极限MIMO信道的容量。空时编码的基本原理和相关MIMO信号处理很快就演变成一个无线通讯的最有活力的领域。该论文中以空时编码的性能研究以及扩展型的正交空时码在MIMO wiretap channel下的安全性能为研究对象。本论文接着研究了Wyner窃听信道逻辑模型。Wyner介绍了窃听通道,其中发射端在存在窃听者的情况下通过主信道向合法接收者发送保密信息,窃听者通过窃听信道实现窃听。Wyner曾经证明过如果窃听端的信道相比于主信道更差的情况下,合法接受端可以以不需要公共密钥的形式接收保密信息,从而秘密容量就可以实现。实际上窃听者的信道不一定比合法接收者的信道性能更差。如何设计建立合法通信双方的信道比窃听者的信道性能更好的信道模型将是实现无条件秘密通信的重要问题。这也是该论文将要解决的问题。为了确保在MIMO信道上的全速率全分集优势,本文研究了扩展型正交空时分组码。为了进一步提高接收端信噪比SNR,本文研究了2比特反馈方案的扩展型正交空时分组码。在该论文中,首先本文归纳了扩展型的正交空时块码并将其应用到双向MIMO wiretap channel中。然后基于归纳化扩展型正交空时块码,本文提出了一个简单的部分反馈方案。基于归纳化的扩展型正交空时块码和部分反馈方案,合法接收端相对于窃听端可以获得更高的信噪比SNR。因此,具有反馈的双向MIMO wiretap channel的保密容量能够被极大的扩大。
[Abstract]:The broadcast nature of wireless communication makes the wireless network lack physical boundaries, and this kind of wireless communication without physical connection is open to eavesdroppers. The security of the physical layer of wireless communication has become a key issue in the security of communication systems. The design idea of the system is that the encryption algorithm needs more computing power than the eavesdropper does. With the improvement of the performance of modern computer and so on, there is great uncertainty about the eavesdropper's computing ability. The security mechanism based on computational complexity is becoming more and more vulnerable to eavesdropping. Physical layer security technology can be used as an important aid of traditional security mechanism. In this paper, we study the pre-coding technology before signal transmission for MIMO(Multiple-Input Multiple-Output (MIMO(Multiple-Input) system and information theory. Space-time coding is a set of practical signal design techniques designed to approach the theoretical limit of the capacity of MIMO channels. The basic principle of space-time coding and related MIMO signal processing quickly evolved into a wireless. The most dynamic field of communication. In this paper, the performance of space-time coding and the security performance of extended orthogonal space-time codes under MIMO wiretap channel are studied. The thesis then studies the channel logic model of Wyner eavesdropping. The eavesdropping channel is introduced. In the case of eavesdropping, the transmitter sends confidential information to the legitimate receiver through the main channel. The eavesdropper has proved that if the eavesdropping channel is worse than the primary channel, the eavesdropping channel is worse than the main channel. The legitimate recipient may receive confidential information in a manner that does not require a public key, So the secret capacity can be realized. In fact, the channel of eavesdropper is not necessarily worse than that of the legitimate receiver. How to design the channel model of both sides of legal communication is better than the channel performance of eavesdropper. It is an important problem to realize unconditional secret communication. This is also the problem to be solved in this paper. In order to ensure the advantage of full rate full diversity in MIMO channel, In this paper, the extended orthogonal space-time block codes are studied. In order to further improve SNR of the receiver, the extended orthogonal space-time block codes with 2-bit feedback scheme are studied. In this paper, the extended orthogonal space-time block codes are first summarized and applied to bi-directional MIMO wiretap channel, and then based on inductive extended orthogonal space-time block codes, In this paper, a simple partial feedback scheme is proposed. Based on generalized orthogonal space-time block codes and partial feedback schemes, the SNR of lawful receiver is higher than that of eavesdropping. The security capacity of two-way MIMO wiretap channel with feedback can be greatly expanded.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.3;TN918

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