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dc.contributor.advisor Sabharwal, Ashutosh
dc.creatorEverett, Evan
dc.date.accessioned 2012-09-06T04:43:22Z
dc.date.accessioned 2012-09-06T04:43:26Z
dc.date.available 2012-09-06T04:43:22Z
dc.date.available 2012-09-06T04:43:26Z
dc.date.created 2012-05
dc.date.issued 2012-09-05
dc.date.submitted May 2012
dc.identifier.urihttps://hdl.handle.net/1911/64704
dc.description.abstract One of the primary sources of inefficiency in today's wireless networks is the half-duplex constraint - the assumption that nodes cannot transmit and receive simultaneously in the same band. The reason for this constraint and the hurdle to full-duplex operation is self-interference: a node's transmit signal appears at its own receiver with very high power, desensitizing the receiver electronics and precluding the reception of a packet from a distant node. Recent research has demonstrated that full-duplex can indeed be feasible by employing a combination of analog and digital self-interference cancellation mechanisms. However, two glaring limitations remain. The first is that the full-duplex state-of-the-art requires at least two antennas and extra RF resources that space-constrained mobile devices may not be able to accommodate. The second limitation is range: current full-duplex demonstrations have been for ranges less than 10~m. At longer distances nodes must transmit with higher power to overcome path loss, and the power differential between the self-interference and the signal-of-interest becomes more that the current cancellation mechanisms can handle. We therefore present engineering solutions for answering the following driving questions: (a) can we leverage full-duplex in a network consisting mostly of half-duplex mobiles? and (b) can we extend the range of full-duplex by achieving self-interference suppression sufficient for full-duplex to outperform half-duplex at ranges exceeding 100 m? In answer to the first question, we propose moving the burden of full-duplexing solely to access points (APs), enabling the AP to boost network throughput by receiving an uplink signal from one half-duplex mobile, while simultaneously transmitting a downlink signal to another half-duplex mobile in the same band. In answer to the second question we propose an AP antenna architecture that uses a careful combination of three mechanisms for passive suppression of self-interference: directional isolation, absorptive shielding, and cross-polarization. Results from a 20 MHz OFDM prototype demonstrate that the proposed AP architecture can achieve 90+ dB total self-interference suppression, enabling >50% uplink rate gains over half-duplex for ranges up to 150 m.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subjectFull-duplex
Wireless communication
Antennas
Polarization
WiFi
802.11
dc.title Full-Duplex Infrastructure Nodes: Achieving Long Range with Half-duplex Mobiles
dc.contributor.committeeMember Knightly, Edward W.
dc.contributor.committeeMember Aazhang, Behnaam
dc.date.updated 2012-09-06T04:43:26Z
dc.identifier.slug 123456789/ETD-2012-05-180
dc.type.genre Thesis
dc.type.material Text
thesis.degree.department Electrical and Computer Engineering
thesis.degree.discipline Engineering
thesis.degree.grantor Rice University
thesis.degree.level Masters
thesis.degree.name Master of Science
dc.identifier.citation Everett, Evan. "Full-Duplex Infrastructure Nodes: Achieving Long Range with Half-duplex Mobiles." (2012) Master’s Thesis, Rice University. https://hdl.handle.net/1911/64704.


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