Wireless Physical Layer Security: An Information Theoretic Approach
O. Ozan Koyluoglu · OhioLink ETD Center (Ohio Library and Information Network) · 2010
We are in the midst of wireless revolution, and increasing demand continues for wireless applications.This explosive growth, of wireless communications and services, inevitably renders security into a challenging quality of service constraint that must be accounted for in the network design.The state of the art methods in combating the security threats are usually founded on cryptographic approaches.These techniques typically assume limited computational resources at adversaries, are usually derived from unproven assumptions, and most of the time do not offer a measurable security notion.Information theoretic security, on the other hand, eliminates the aforementioned limitations of the cryptographic techniques at the physical layer of communication systems.In this thesis, we concentrate on both the theoretical and the practical aspects of physical layer security.We first start by analyzing elemental interference networks, in particular, two-user channels with an adversary.The problem here is to characterize the fundamental limits on secure transmission rates.Towards this end, we devise coding schemes, forming inner bounds to the capacity region, and compare the achievable rates with outer bounds.This analysis is useful to explore microscopic gains that can be leveraged by the different coding schemes, and our analysis shows that the inherent interference can in fact be exploited to cooperatively confuse the eavesdropping node.4.4 There are ⌈δ log n⌉ number of disjoint highways within each rectangle of size (κ log nǫ) × √ n.The legitimate users in the slab, denoted by dotted lines, of the rectangle is served by the highway denoted with red bold line. . . . . . . . . . . . . . . . . . .