Physical-Layer Security in Wireless and Wireline Transmission

本文重点研究了物理层安全的密钥生成和对账过程，其中物理层安全主要采用二进制和非二进制LDPC码。这个应用程序的LDPC代码的优化是相当苛刻的，因为通常的一致高斯假设不成立，实际的密度演化必须应用，这通常不是情况，即使大多数作者使用的名称。几乎总是，在线性程序中只处理一个参数（均值或方差），这只有在一致性假设下才有可能，这显然在我们的物理层安全应用程序中不成立。除了信道编码方法外，还讨论了底层量化和保护带。我们已经研究了基于无线互易时分双工（TDD）信道的一些方面，但现在还将物理层密钥生成和协调扩展到无线频分双工（FDD）和有线信道，这开辟了两个新的额外方向。对于FDD，我们将使用波分量的到达方向作为将用于密钥生成的双工通道探测的通用测量。对于电力线应用，电源插座之间传递函数的最大值和切迹在两个方向上都显示出相似性，而窃听者则期望看到不同的方向。该项目包含了物理层密钥生成实际应用的重要步骤，并为其开辟了新的渠道。因此，这是对未来物联网发展的重大贡献。

This proposal focuses on key generation and reconciliation procedures for physical layer security, for the latter mainly employing binary and non-binary LDPC codes. The optimization of LDPC codes for this application is quite demanding, since the usual consistent Gaussian assumption does not hold and actual density evolution has to be applied, which is usually not the case, even if the name is used by most authors. Almost always, only one parameter (the mean or variance) are treated in a linear program, which is only possible under a consistency assumption, which clearly does not hold in our physical-layer security application.Apart from channel coding methods, the underlying quantization together with guard bands is discussed, as well.We have already studied some aspects based on wireless reciprocal time-division duplex (TDD) channels, but would also now extend physical-layer key generation and reconciliation to wireless frequency-division duplexing (FDD) and wireline channels,which opens two new additional directions. For FDD, we will use the directions of arrival of wave components as the common measure from duplex channel probing that will be used for key generation. For power line applications, maxima and notches in the transfer functions between power outlets show similarities in both directions, whereas an eavesdropper is expected to see different ones.The project contains important steps for the practical application of physical-layer key generation and opens it for new channels. It is hence a major contribution for the upcoming development of the Internet of Things.