A General Coding Scheme for Two-User Fading Interference Channels

TL;DR

This paper introduces a coding scheme for two-user fading interference channels that optimizes performance across all channel states, demonstrating when interference can be ignored to maximize sum-rate.

Contribution

It proposes a Han-Kobayashi based scheme for ergodic fading IFCs that outperforms separable coding in certain subclasses and provides conditions for when interference can be ignored.

Findings

Joint coding across all states matches or exceeds separable coding performance.

Sufficient conditions identified for maximizing sum-rate by ignoring interference.

Performance analysis for uniformly weak and hybrid IFC subclasses.

Abstract

A Han-Kobayashi based achievable scheme is presented for ergodic fading two-user Gaussian interference channels (IFCs) with perfect channel state information at all nodes and Gaussian codebooks with no time-sharing. Using max-min optimization techniques, it is shown that jointly coding across all states performs at least as well as separable coding for the sub-classes of uniformly weak (every sub-channel is weak) and hybrid (mix of strong and weak sub-channels that do not achieve the interference-free sum-capacity) IFCs. For the uniformly weak IFCs, sufficient conditions are obtained for which the sum-rate is maximized when interference is ignored at both receivers.