High-SNR Capacity of Wireless Communication Channels in the Noncoherent Setting: A Primer

TL;DR

This tutorial paper explores the high-SNR capacity of noncoherent wireless channels, emphasizing fundamental analytical tools like duality and escape-to-infinity, to refine and simplify existing theoretical results.

Contribution

It introduces and explains key tools for high-SNR capacity analysis in noncoherent channels, providing clearer insights and simplified proofs of prior results.

Findings

Refined high-SNR capacity bounds for noncoherent channels

Simplified proofs of existing capacity results

Enhanced understanding of capacity-achieving distributions

Abstract

This paper, mostly tutorial in nature, deals with the problem of characterizing the capacity of fading channels in the high signal-to-noise ratio (SNR) regime. We focus on the practically relevant noncoherent setting, where neither transmitter nor receiver know the channel realizations, but both are aware of the channel law. We present, in an intuitive and accessible form, two tools, first proposed by Lapidoth & Moser (2003), of fundamental importance to high-SNR capacity analysis: the duality approach and the escape-to-infinity property of capacity-achieving distributions. Furthermore, we apply these tools to refine some of the results that appeared previously in the literature and to simplify the corresponding proofs.