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dc.contributor.authorFazeli Dehkordy, Siavash
dc.contributor.otherQueen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.))en
dc.date2008-09-17 13:07:21.505en
dc.date.accessioned2008-09-18T12:36:17Z
dc.date.available2008-09-18T12:36:17Z
dc.date.issued2008-09-18T12:36:17Z
dc.identifier.urihttp://hdl.handle.net/1974/1442
dc.descriptionThesis (Master, Electrical & Computer Engineering) -- Queen's University, 2008-09-17 13:07:21.505en
dc.description.abstractIn this thesis, we consider a wireless network consisting of d source-destination pairs and R relaying nodes. Each source wishes to communicate to its corresponding destination. By exploiting the spatial multiplexing capability of the wireless medium, we develop two cooperative beamforming schemes in order to establish wireless connections between multiple source-destination pairs through a collaborative relay network. Our first communication scheme consists of two steps. In the first step, all sources transmit their signals simultaneously to the relay network. As a result, each relay receives a noisy faded mixture of all source signals. In the second step, each relay transmits an amplitude- and phase-adjusted version of its received signal, i.e., the relay received signals are multiplied by a set of complex coefficients and are retransmitted. Our goal is to obtain these complex coefficients (beamforming weights) through minimization of the total relay transmit power while the signal-to-interference-plus-noise ratio at the destinations are guaranteed to be above certain pre-defined thresholds. Our second scheme is a distributed downlink beamforming technique which is performed in d + 1 successive time slots. In the first d time slots, the d sources transmit their data to the relay network successively. The relay nodes receive and store the noisy faded versions of the source signals. In the (d + 1)th time slot, the relays aim to collectively provide downlink connections to all d destinations. To do so, each relay transmits a linear combination of the stored signals received during the first d time slots. Again, our goal is to determine the complex weights (used at the relaying nodes to linearly combine the source signals) by minimizing the total relay transmit power while satisfying certain quality of services at the destinations. We use semi-definite relaxation to turn both problems into semi-definite programming (SDP) problems. Therefore, they can be efficiently solved using interior point methods. We showed that our proposed schemes significantly outperform orthogonal multiplexing schemes, such as time-division multiple access schemes, in a large range of network data rates.en
dc.format.extent584283 bytes
dc.format.mimetypeapplication/pdf
dc.languageenen
dc.language.isoenen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectdistributed beamformingen
dc.subjectspace division multiplexingen
dc.subjectcooperative communicationen
dc.subjectrelay networken
dc.subjectsdpen
dc.titleDistributed Beamforming in Wireless Relay Networksen
dc.typethesisen
dc.description.degreeMasteren
dc.contributor.supervisorGazor, Saeeden
dc.contributor.supervisorShahbazpanahi, Shahramen
dc.contributor.departmentElectrical and Computer Engineeringen


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