Optimal detector randomization in cognitive radio receivers in the presence of imperfect sensing decisions

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buir.advisorGezici, Sinan
dc.contributor.authorSezer, Ahmet Dündar
dc.date.accessioned2016-01-08T20:06:34Z
dc.date.available2016-01-08T20:06:34Z
dc.date.issued2013
dc.descriptionAnkara : The Department of Electrical and Electronics Engineering and the Graduate School of Engineering and Science of Bilkent Univ., 2013.en_US
dc.descriptionThesis (Master's) -- Bilkent University, 2013.en_US
dc.descriptionIncludes bibliographical references leaves 36-39.en_US
dc.description.abstractIn cognitive radio systems, spectrum sensing is one of the crucial tasks to be performed by secondary users in order to limit the interference to primary users. Therefore various spectrum sensing methods have been proposed in the literature. Once secondary users make a sensing decision, they adapt their communication parameters accordingly, which means that they perform communications when the channel is sensed as idle whereas they either do not transmit at all or transmit at a reduced power when the channel is sensed as busy. However, in practical systems, sensing decisions of secondary users are never perfect; hence, there can be cases in which the sensing decision is idle (busy) but primary user activity actually exists (does not exist). Therefore, the optimal design of secondary systems requires the consideration of imperfect sensing decisions. In this thesis, optimal detector randomization is developed for secondary users in a cognitive radio system in the presence of imperfect spectrum sensing decisions. Also, suboptimal detector randomization is proposed under the assumption of perfect sensing decisions. It is shown that the minimum average probability of error can be achieved by employing no more than four maximum a-posteriori probability (MAP) detectors at the secondary receiver. Optimal and suboptimal MAP detectors and generic expressions for their average probability of error are derived in the presence of possible sensing errors. Numerical results are presented and the importance of taking possible sensing errors into account is illustrated in terms of average probability of error optimization.en_US
dc.description.provenanceMade available in DSpace on 2016-01-08T20:06:34Z (GMT). No. of bitstreams: 1 0007077.pdf: 439198 bytes, checksum: a11a8e7549cd42ed63a9e7e2e2899698 (MD5)en
dc.description.statementofresponsibilitySezer, Ahmet Dündaren_US
dc.format.extentx, 39 leaves, graphs, tablesen_US
dc.identifier.urihttp://hdl.handle.net/11693/17101
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectCognitive radioen_US
dc.subjectspectrum sensingen_US
dc.subjectdetector randomizationen_US
dc.subjectprobability of erroren_US
dc.subject.lccTK5103.4815 .S49 2013en_US
dc.subject.lcshCognitive radio networks.en_US
dc.subject.lcshSoftware radio.en_US
dc.subject.lcshSignal detection.en_US
dc.titleOptimal detector randomization in cognitive radio receivers in the presence of imperfect sensing decisionsen_US
dc.typeThesisen_US
thesis.degree.disciplineElectrical and Electronic Engineering
thesis.degree.grantorBilkent University
thesis.degree.levelMaster's
thesis.degree.nameMS (Master of Science)

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