5386

5046

كارشناسي ارشد

مخابرات﴿سيستم﴾

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1389

نه،87ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمد جواد اميدي

محمود مدرس هاشمي

23/5/89

علي محمد دوست حسيني، مهدي مهدوي

مهندسي برق و كامپيوتر

ID5046

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

A new method for the detection of LTE based on Constant False Alarm Rate CFAR methods and Constant Amplitude Zero Autocorrelation Sequence CAZAC Marjan Mazrooei Sebdani m mazrooei@ec iut ac ir Date of Submission 2010 04 25 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mohammad javad omidi omidi@cc iut ac ir Abstract The demand for the radio frequency RF is increasing to support the user s needs in wireless communication RF spectrum is a scarce resource and requires efficient utilization The most important methods for solving this problem are to let wireless users to share wide access spectrum Due to the limitation of access spectrum and helpless uses of spectrum a new idea is needed that is known as a cognitive radio Cognitive radio has been proposed to promote the efficient use of spectrum In this method secondary users use the spectrum if a part of spectrum is not used by the primary users To detect the presence of the primary users the spectrum sensing is one of the fundamental enabling technologies for cognitive radio communication This ensures the efficient utilization of the spectrum According to cognitive radio the secondary users might not have sufficient data to detect the primary users There are some methods for signal detection such as cyclostationary feature detector energy detector autocorrelation detector and matched filter detector The aim of this research is to propose a new method for detection of LTE long term evolution One of the properties of LTE is preamble that it uses CAZAC Constant Amplitude Zero Autocorrelation Sequence CAZAC is one of the polyphase code has a lot of applications in channel estimation and equalization and it shows periodic correlation properties The final aim of this research is to use of this sequence to detect LTE as a primary user and to improve detecting of primary users in cognitive radio In this research CFAR constant false alarm rate methods are used in noise power estimation such as CA CFAR and determine threshold based on noise power so that the effect of noise power is decreased in the proposed method Finally the proposed method is compared to other methods such as energy detector and autocorrelation detector and it is shown that the proposed method has better performance than energy detector In order to decrease the computional complexing it is shown that sign bit could be used in detection Moreover to decrease the effect of interference in desirable signal detection the use of other CFAR methods such as CML and FCME are possible Keywords cognitive radio spectrum sensing cross correlation CAZAC

محمد جواد اميدي

محمود مدرس هاشمي

علي محمد دوست حسيني، مهدي مهدوي