Discrete Signaling and Treating Interference as Noise for the Gaussian Interference Channel

TL;DR

This paper introduces a novel discrete signaling scheme for the Gaussian interference channel that achieves near-capacity performance with treating interference as noise, applicable to both real and complex channels, and outperforms Gaussian signaling.

Contribution

It proposes the first constant-gap discrete signaling scheme for the entire capacity region of the G-IC under TIN, extending to complex channels with phase considerations.

Findings

Achieves the entire capacity region within a constant gap for real G-IC.

Extends the scheme to complex G-IC, accounting for phase rotations.

Significantly outperforms Gaussian signaling with TIN in simulations.

Abstract

The two-user Gaussian interference channel (G-IC) is revisited, with a particular focus on practically amenable discrete input signalling and treating interference as noise (TIN) receivers. The corresponding deterministic interference channel (D-IC) is first investigated and coding schemes that can achieve the entire capacity region of D-IC under TIN are proposed. These schemes are then systematically translate into multi-layer superposition coding schemes based on purely discrete inputs for the real-valued G-IC. Our analysis shows that the proposed scheme is able to achieve the entire capacity region to within a constant gap for all channel parameters. To the best of our knowledge, this is the first constant-gap result under purely discrete signalling and TIN for the entire capacity region and all the interference regimes. Furthermore, the approach is extended to obtain coding scheme based on discrete inputs for the complex-valued G-IC. For such a scenario, the minimum distance and the achievable rate of the proposed scheme under TIN are analyzed, which takes into account the effects of random phase rotations introduced by the channels. Simulation results show that our scheme is capable of approaching the capacity region of the complex-valued G-IC and significantly outperforms Gaussian signalling with TIN in various interference regimes.