Sensing and Mitigation of Multi-Scatterer Self-Interference for Full-Duplex MIMO Communications

TL;DR

This paper introduces a combined digital and spatial approach to mitigate far-field self-interference in full-duplex MIMO systems, using scatterer modeling and adaptive action selection to improve communication reliability.

Contribution

It presents a novel joint digital and spatial suppression method with a scatterer map for effective self-interference mitigation in full-duplex MIMO systems.

Findings

The proposed policy effectively mitigates self-interference in challenging scenarios.

It outperforms individual digital or spatial methods in failure cases.

The approach enables sensing of environmental scatterers for communication enhancement.

Abstract

This paper proposes the joint use of digital self-interference cancellation (DSIC) and spatial suppression to mitigate far-field self-interference (SI) in full-duplex multiple-input multiple-output (MIMO) systems. Far-field SI, caused by echoes from environmental scatterers, is modeled based on the scatterers' angle and delay parameters, stored in a scatterer map. For each scatterer, the most suitable action regarding communication is selected from transmit beamforming, receive beamforming, DSIC, and no-action. This selection is based on simple metrics that show the expected uplink and downlink communication performance. In addition, emerging scatterers that deteriorate the communication are detected, and their delay and angles are acquired, providing an up-to-date scatterer map and presenting a \emph{sensing for communication} case. The proposed selection policy is compared with the individual implementations of DSIC and spatial suppression, highlighting the failure cases for each. It is shown that the proposed policy stays unaffected in these problematic cases and achieves SI-free performance.