Time Interference Alignment via Delay Offset for Long Delay Networks

TL;DR

This paper analyzes Time Interference Alignment in networks with random user placement, deriving sum degrees of freedom analytically and showing that coordinated delays can improve capacity, especially for satellite networks.

Contribution

It generalizes existing analysis of Time Interference Alignment, providing analytical expressions for sum dof and demonstrating capacity gains with delay coordination.

Findings

Analytical expressions for sum dof in uncoordinated case.

20% of cases show increased dof with delay coordination.

Potential capacity improvements for satellite networks.

Abstract

Time Interference Alignment is a flavor of Interference Alignment that increases the network capacity by suitably staggering the transmission delays of the senders. In this work the analysis of the existing literature is generalized and the focus is on the computation of the dof for networks with randomly placed users in a n-dimensional Euclidean space. In the basic case without coordination among the transmitters analytical expressions of the sum dof can be derived. If the transmit delays are coordinated, in 20% of the cases time Interference Alignment yields additional dof with respect to orthogonal access schemes. The potential capacity improvements for satellite networks are also investigated.