Multiple Access Outerbounds and the Inseparability of Parallel Interference Channels
Information Theory
2016-11-17 v1 math.IT
Abstract
It is known that the capacity of parallel (multi-carrier) Gaussian point-to-point, multiple access and broadcast channels can be achieved by separate encoding for each subchannel (carrier) subject to a power allocation across carriers. In this paper we show that such a separation does not apply to parallel Gaussian interference channels in general. A counter-example is provided in the form of a 3 user interference channel where separate encoding can only achieve a sum capacity of per carrier while the actual capacity, achieved only by joint-encoding across carriers, is per carrier. As a byproduct of our analysis, we propose a class of multiple-access-outerbounds on the capacity of the 3 user interference channel.
Cite
@article{arxiv.0802.2125,
title = {Multiple Access Outerbounds and the Inseparability of Parallel Interference Channels},
author = {Viveck R. Cadambe and Syed A. Jafar},
journal= {arXiv preprint arXiv:0802.2125},
year = {2016}
}