Passive Self-Interference Suppression for Full-Duplex Infrastructure Nodes

Accepted and to appear in IEEE Transactions on Wireless Communication - October 2013

Authors: Evan Everett, Achaleshwar Sahai, Ashutosh Sabharwal

Abstract

Recent research results have demonstrated the feasibility of full-duplex wireless communication for short-range links. Although the focus of the previous works has been active cancellation of the self-interference signal, a majority of the overall self-interference suppression is often due to passive suppression, i.e., isolation of the transmit and receive antennas. We present a measurement-based study of the capabilities and limitations of three key mechanisms for passive self-interference suppression: directional isolation, absorptive shielding, and cross-polarization. The study demonstrates that more than 70 dB of passive suppression can be achieved in certain environments, but also establishes two results on the limitations of passive suppression: (1) environmental reflections limit the amount of passive suppression that can be achieved, and (2) passive suppression, in general, increases the frequency selectivity of the residual self-interference signal. These results suggest two design implications: (1) deployments of full-duplex infrastructure nodes should minimize near-antenna reflectors, and (2) active cancellation in concatenation with passive suppression should employ higher-order filters or per-subcarrier cancellation.

Citation

@unpublished{Everett2013PassiveSuppressionFD,
Author = {Evan Everett and Achaleshwar Sahai and Ashutosh Sabharwal},
Date-Modified = {2013-02-17 17:35:49 -0600},
Keywords = {full-duplex},
Month = {January},
Note = {Submitted to \emph{IEEE Transactions on Wireless Communication}},
Title = {Passive Self-Interference Suppression for Full-Duplex Infrastructure Nodes},
Url = {http://arxiv.org/abs/1302.2185},
Year = {2013}}