Enhancing Sensing and Channel Access in Cognitive Radio Networks

Handle URI:
http://hdl.handle.net/10754/321828
Title:
Enhancing Sensing and Channel Access in Cognitive Radio Networks
Authors:
Hamza, Doha R.
Abstract:
Cognitive radio technology is a promising technology to solve the wireless spectrum scarcity problem by intelligently allowing secondary, or unlicensed, users access to the primary, licensed, users' frequency bands. Cognitive technology involves two main tasks: 1) sensing the wireless medium to assess the presence of the primary users and 2) designing secondary spectrum access techniques that maximize the secondary users' benefits while maintaining the primary users' privileged status. On the spectrum sensing side, we make two contributions. First, we maximize a utility function representing the secondary throughput while constraining the collision probability with the primary below a certain value. We optimize therein the channel sensing time, the sensing decision threshold, the channel probing time, together with the channel sensing order for wideband primary channels. Second, we design a cooperative spectrum sensing technique termed sensing with equal gain combining whereby cognitive radios simultaneously transmit their sensing results to the fusion center over multipath fading reporting channels. The proposed scheme is shown to outperform orthogonal reporting systems in terms of achievable secondary throughput and to be robust against phase and synchronization errors. On the spectrum access side, we make four contributions. First, we design a secondary scheduling scheme with the goal of minimizing the secondary queueing delay under constraints on the average secondary transmit power and the maximum tolerable primary outage probability. Second, we design another secondary scheduling scheme based on the spectrum sensing results and the primary automatic repeat request feedback. The optimal medium access probabilities are obtained via maximizing the secondary throughput subject to constraints that guarantee quality of service parameters for the primary. Third, we propose a three-message superposition coding scheme to maximize the secondary throughput without degrading the primary rate. Cognitive relaying is employed as an incentive for the primary network. The scheme is shown to outperform a number of reference schemes such as best relay selection. Finally, we consider a network of multiple primary and secondary users. We propose a three-stage distributed matching algorithm to pair the network users. The algorithm is shown to perform close to an optimal central controller, albeit at a reduced computational complexity.
Advisors:
Alouini, Mohamed-Slim ( 0000-0003-4827-1793 )
Committee Member:
Abed-Meraim, Karim ( 0000-0003-2652-1923 ) ; Aissa, Sonia; Salama, Khaled Nabil; Tempone, Raul F.
KAUST Department:
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Program:
Electrical Engineering
Issue Date:
18-Jun-2014
Type:
Dissertation
Appears in Collections:
Dissertations; Electrical Engineering Program; Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.advisorAlouini, Mohamed-Slimen
dc.contributor.authorHamza, Doha R.en
dc.date.accessioned2014-06-18T13:29:14Z-
dc.date.available2014-06-18T13:29:14Z-
dc.date.issued2014-06-18en
dc.identifier.urihttp://hdl.handle.net/10754/321828en
dc.description.abstractCognitive radio technology is a promising technology to solve the wireless spectrum scarcity problem by intelligently allowing secondary, or unlicensed, users access to the primary, licensed, users' frequency bands. Cognitive technology involves two main tasks: 1) sensing the wireless medium to assess the presence of the primary users and 2) designing secondary spectrum access techniques that maximize the secondary users' benefits while maintaining the primary users' privileged status. On the spectrum sensing side, we make two contributions. First, we maximize a utility function representing the secondary throughput while constraining the collision probability with the primary below a certain value. We optimize therein the channel sensing time, the sensing decision threshold, the channel probing time, together with the channel sensing order for wideband primary channels. Second, we design a cooperative spectrum sensing technique termed sensing with equal gain combining whereby cognitive radios simultaneously transmit their sensing results to the fusion center over multipath fading reporting channels. The proposed scheme is shown to outperform orthogonal reporting systems in terms of achievable secondary throughput and to be robust against phase and synchronization errors. On the spectrum access side, we make four contributions. First, we design a secondary scheduling scheme with the goal of minimizing the secondary queueing delay under constraints on the average secondary transmit power and the maximum tolerable primary outage probability. Second, we design another secondary scheduling scheme based on the spectrum sensing results and the primary automatic repeat request feedback. The optimal medium access probabilities are obtained via maximizing the secondary throughput subject to constraints that guarantee quality of service parameters for the primary. Third, we propose a three-message superposition coding scheme to maximize the secondary throughput without degrading the primary rate. Cognitive relaying is employed as an incentive for the primary network. The scheme is shown to outperform a number of reference schemes such as best relay selection. Finally, we consider a network of multiple primary and secondary users. We propose a three-stage distributed matching algorithm to pair the network users. The algorithm is shown to perform close to an optimal central controller, albeit at a reduced computational complexity.en
dc.language.isoenen
dc.subjectCognitive Radiosen
dc.subjectspectrum sensingen
dc.subjectSpectrum Accessen
dc.subjectWireless Schedulingen
dc.subjectCognitive Relayingen
dc.subjectMatching Theoryen
dc.titleEnhancing Sensing and Channel Access in Cognitive Radio Networksen
dc.typeDissertationen
dc.contributor.departmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberAbed-Meraim, Karimen
dc.contributor.committeememberAissa, Soniaen
dc.contributor.committeememberSalama, Khaled Nabilen
dc.contributor.committeememberTempone, Raul F.en
thesis.degree.disciplineElectrical Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id113321en
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