On feasibility of perfect interference alignment in interference networks

TL;DR

This paper investigates the conditions under which perfect interference alignment is feasible in a 3-user interference channel, highlighting the importance of channel structure and specific coefficient design for practical implementation.

Contribution

It identifies necessary and sufficient channel conditions for perfect interference alignment with limited channel extensions in 3-user interference networks.

Findings

Interference can be perfectly aligned if only one interfering channel coefficient is designed to a specific value.

Feasibility of perfect IA depends on channel structure and limited extensions.

Provides conditions for practical implementation of interference alignment.

Abstract

Interference alignment(IA) is mostly achieved by coding interference over multiple dimensions. Intuitively, the more interfering signals that need to be aligned, the larger the number of dimensions needed to align them. This dimensionality requirement poses a major challenge for IA in practical systems. This work evaluates the necessary and sufficient conditions on channel structure of a 3 user interference channel(IC) to make perfect IA feasible within limited number of channel extensions. It is shown that if only one of interfering channel coefficients can be designed to a specific value, interference would be aligned perfectly at all receivers.