7850

7315

كارشناسي ارشد

مخابرات

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1391

نه،85ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمد جواد اميدي

محمود مدرس هاشمي

22/4/92

مهندسي برق و كامپيوتر

ID7315

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Comparison of Spectrum Sensing in Two Physical Layer Candidates for Cognitive Radio Afrooz Jalali a jalali@ec iut ac ir Date of Submission 2013 16 03 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mohammad Javad Omidi omidi@cc iut ac irAbstract Recent researches on various parts of allocated spectrum have demonstrated the inefficiency of spectrumutilisiation On the other hand according to the noticeable growth of wireless communication systems thedemand for bandwidth has increased As a result the static frequency assignment approach needs to bereconsidered Cognitive radio offers a proper solution for efficient spectrum usage Detection of the idlefrequency bands is the first step for exploiting the spectrum Thus one of the main components of thecognitive radio is spectrum sensing In this thesis after presenting a brief introduction about cognitive radio different spectrum sensing techniques and their applications are introduced Afterwards considering theimportance of selecting the appropriate physical layer for cognitive radio we have considered two physicallayer candidates In order to reduce hardware complexity for spectrum sensing task we have compared theperformance of spectrum sensing in two physical layer candidates based on orthogonal frequency divisionmultiplexing OFDM and filter bank multicarrier FBMC Performance of the detectors is investigatedunder two different scenarios For this comparison the area under receiver operating characteristic ROC curve namely AUC is considered as a criterion In the first scenario it is assumed that the secondary userwhich does not perform the spectrum sensing is not permitted to transmit any signal quiet sensing In thiscase it is shown that the performance of both detectors is the same In the second scenario the secondry useris permitted to transmit in a frequency band adjacent to the primary user PU channel while spectrumsensing is performed non quiet sensing The results indicate that although DFT based detector iscomputationally less complex than filter bank based detector filter bank based detector s performance ismuch better than DFT based detector in heavy interference environment Consequently there is a trade offbetween the performance of the detector and its complexity when choosing one of the above mentionedphysical layer candidates Keywords Cognitive radio spectrum sensing OFDM FBMC quiet sensing non quiet sensing

محمد جواد اميدي

محمود مدرس هاشمي