On the Sum Capacity of Many-to-one and One-to-many Gaussian Interference Channels

TL;DR

This paper derives new sum capacity results for Gaussian many-to-one and one-to-many interference channels, showing that simple Han-Kobayashi schemes are optimal in certain regimes where previous bounds were loose.

Contribution

It provides the first sum capacity characterizations for these channels in specific regimes using simple Han-Kobayashi schemes and genie-aided bounds.

Findings

Sum capacity achieved by simple HK schemes in certain regimes

Genie-aided bounds match achievable sum rates

Extension of capacity results beyond constant gap regimes

Abstract

We obtain new sum capacity results for the Gaussian many-to-one and one-to-many interference channels in channel parameter regimes where the sum capacity was known only up to a constant gap. Simple Han-Kobayashi (HK) schemes, i.e., HK schemes with Gaussian signaling, no time-sharing, and no common-private power splitting, achieve sum capacity under the channel conditions for which the new results are obtained. To obtain sum capacity results, we show that genie-aided upper bounds match the achievable sum rate of simple HK schemes under certain channel conditions.