Degrees of Freedom of Spatial Self-Interference Suppression for In-Band Full-Duplex with Inter-node Interference

TL;DR

This paper analyzes the spatial degrees of freedom in a three-node full-duplex network with interference, demonstrating that spatial isolation generally outperforms time division unless scattering angles overlap.

Contribution

It provides a channel model-based analysis of spatial degrees of freedom in full-duplex networks with interference, highlighting conditions where spatial isolation is advantageous.

Findings

Spatial isolation generally outperforms time division.

Performance depends on scattering angle overlaps.

Spatial degrees of freedom are characterized for interference management.

Abstract

We study a three-node network with a full-duplex base-station communicating with one uplink and one downlink half-duplex node. In this network, both self-interference and inter-node interference are present. We use an antenna-theory-based channel model to study the spatial degrees of freedom of such network, and study if and how much does spatial isolation outperforms time-division (i.e. half-duplex) counterpart. Using degrees of freedom analysis, we show that spatial isolation outperforms time division, unless the angular spread of the objects that scatters to the intended users is overlapped by the spread of objects that back scatters to the receivers.