PROJECT TITLE :

Covert Communication Over Noisy Channels: A Resolvability Perspective

ABSTRACT:

We tend to contemplate things in which a transmitter makes an attempt to communicate reliably over a discrete memoryless channel, while simultaneously ensuring covertness (low likelihood of detection) with respect to a warden, who observes the signals through another discrete memoryless channel. We develop a coding scheme primarily based on the principle of channel resolvability, that generalizes and extends previous work in many directions. Initial, it shows that no matter the quality of the channels, it's doable to communicate on the order of reliable and covert bits over channel uses if the transmitter and also the receiver share on the order of key bits. This improves upon earlier results requiring on the order of key bits. Second, it proves that if the receiver’s channel is healthier than the warden’s channel during a sense that we tend to build precise, it is potential to speak on the order of reliable and covert bits over channel uses without a secret key. This generalizes earlier results established for binary symmetric channels. We conjointly establish the fundamental limits of covert and secret communications in terms of the optimal asymptotic scaling of the message size and key size, and we have a tendency to extend the analysis to Gaussian channels. The most technical downside that we address is how to develop concentration inequalities for low-weight sequences. The crux of our approach is to outline suitably changed typical sets that are amenable to concentration inequalities.