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Maximum-Minimum Eigen Value Based Spectrum Scanner. Mohamed Hamid and Niclas Björsell Center for RF measurement Technology, University of Gävle , Sweden Communications Systems Lab, Royal Institute of Technology, Stockholm, Sweden @RFMTC 2011, Gävle , October, 2011. Outlines. Introduction
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Maximum-Minimum Eigen Value Based Spectrum Scanner Mohamed Hamid and Niclas Björsell Center for RF measurement Technology, University of Gävle, Sweden Communications Systems Lab, Royal Institute of Technology, Stockholm, Sweden @RFMTC 2011, Gävle, October, 2011
Outlines Introduction Spectrum Detection Techniques Maximum-MinimumEigenValueDetection (MMEVD) RectangularFiltering for sub-bandsspectrum scanning with MMEVD MeasurementsResults Conclusions
Introduction Currentspectrumregulation policy relies on Staticspectrum access Wireless services and technologies are growingrapidly Lack of radio resources Radio Spectrum is under-utilized DynamicSpectrum access (DSA) policy
Introduction(Cont.) What is the spectrumopportuinty?! A free of usechannel (band) subject to the recieved power in a specific time at a specificlocation How to find a spectrumOpportuity SpectrumSensing and/or GeolocationDatabse Beacon based Spectrum Opportunities
Spectrum Detection Techniques Energy Detector Requires a prior knowledge of the system backgroundnoise Matched Filtering Auto-correlation Detection Require a prior knowledge of the primary system signal Maximum-MinimumEigenValueDetection
Maximum-MinimumEigenValueDetection (MMEVD) λmax Signal frequency components α Eigen values of the auto correlation Matrix of the signal 2 λmin = σn
Maximum-MinimumEigenValueDetection (MMEVD) Recieved Signal r(t) Uponpredefinedthresholdγ of the ratioλmax/ λmin the decission is madeif it is a signal or just noise MMEVD tests the extent of the flatnessof the spectrum Filtering is a problimaticwhen scanning for sub-bands is to takeplace
RectangularFiltering for sub-bandsspectrum scanning with MMEVD Solution: Rectangular Filtering , i.e. talking the spectrum lines lie inside the sub-band of interest and throw away the rest Time Domain Signals Do MMEVD
Measured BW : 10 MHz • # Sub-channels: 5 (2MHz each) MeasurementsResults
Conclusions • Sub-bands spectrum scanning is feasible with rectangular filtering and MMEVD • MMEVD introduces probability of false alarm much less than the one introduced by Energy Detection
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