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A Matter of Perspective: Reliable Communication and Coping with Interference with Only Local Views

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dc.contributor.advisor Sabharwal, Ashutosh
dc.creator Kao, David
dc.date.accessioned 2012-09-06T04:36:16Z
dc.date.accessioned 2012-09-06T04:36:20Z
dc.date.available 2012-09-06T04:36:16Z
dc.date.available 2012-09-06T04:36:20Z
dc.date.created 2012-05
dc.date.issued 2012-09-05
dc.date.submitted May 2012
dc.identifier.uri http://hdl.handle.net/1911/64691
dc.description.abstract This dissertation studies interference in wireless networks. Interference results from multiple simultaneous attempts to communicate, often between unassociated sources and receivers, preventing extensive coordination. Moreover, in practical wireless networks, learning network state is inherently expensive, and nodes often have incomplete and mismatched views of the network. The fundamental communication limits of a network with such views is unknown. To address this, we present a local view model which captures asymmetries in node knowledge. Our local view model does not rely on accurate knowledge of an underlying probability distribution governing network state. Therefore, we can make robust statements about the fundamental limits of communication when the channel is quasi-static or the actual distribution of state is unknown: commonly faced scenarios in modern commercial networks. For each local view, channel state parameters are either perfectly known or completely unknown. While we propose no mechanism for network learning, a local view represents the result of some such mechanism. We apply the local view model to study the two-user Gaussian interference channel: the smallest building block of any interference network. All seven possible local views are studied, and we find that for five of the seven, there exists no policy or protocol that universally outperforms time-division multiplexing (TDM), justifying the orthogonalized approach of many deployed systems. For two of the seven views, TDM-beating performance is possible with use of opportunistic schemes where opportunities are revealed by the local view. We then study how message cooperation --- either at transmitters or receivers --- increases capacity in the local view two-user Gaussian interference channel. The cooperative setup is particularly appropriate for modeling next-generation cellular networks, where costs to share message data among base stations is low relative to costs to learn channel coefficients. For the cooperative setting, we find: (1) opportunistic approaches are still needed to outperform TDM, but (2) opportunities are more abundant and revealed by more local views. For all cases studied, we characterize the capacity region to within some known gap, enabling computation of the generalized degrees of freedom region, a visualization of spatial channel resource usage efficiency.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subject Wireless Networks
Interference
Distributed Systems
Information Theory
Local Views
Robust Systems
dc.title A Matter of Perspective: Reliable Communication and Coping with Interference with Only Local Views
dc.contributor.committeeMember Aazhang, Behnaam
dc.contributor.committeeMember Knightly, Edward W.
dc.contributor.committeeMember Tapia, Richard A.
dc.contributor.committeeMember Chiang, Mung
dc.date.updated 2012-09-06T04:36:20Z
dc.identifier.slug 123456789/ETD-2012-05-165
dc.type.material Text
thesis.degree.department Electrical and Computer Engineering
thesis.degree.discipline Electrical Engineering
thesis.degree.grantor Rice University
thesis.degree.level Doctoral
thesis.degree.name Doctor of Philosophy
dc.identifier.citation Kao, David. (2012) "A Matter of Perspective: Reliable Communication and Coping with Interference with Only Local Views." Doctoral Thesis, Rice University. http://hdl.handle.net/1911/64691.

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