University of Twente Student Theses


Cognitive radio: comparing cross-correlators

Rolink, S. (2013) Cognitive radio: comparing cross-correlators.

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Abstract:Because the free bands in the electromagnetic spectrum are becoming scarce, numerous techniques have been developed throughout the years to increase capacity. But studies have shown that when the activity on the band is measured a lot of the segments are unused. The concept of Cognitive Radio is that it can intelligently detect and utilize the unused segments when available, without interfering primary users. Sensing the spectrum for spectrum holes is one of the key function of a cognitive radio. The limiting element in this process is the Signal-to-Noise Ratio wall. Cross-correlation was proposed as a solution for noise reduction in spectrum sensing. If two receivers both receive the same wirelessly transmitted data, they each will also contain some random noise. Correlation emphasizes shared signal properties (the transmitted data) and filters the - for each signal unique - noise. During the graduation period a cross-correlation architecture was created and simulated in ClaSH. This is an at the University of Twente developed Hardware Description language, that can create a formal description of digital logic and electronic circuits, which can be mapped on a FPGA. It was necessary that the resolution and the numbers of lags of the correlator architecture could be adjusted without much effort, so that the circuit could be easily analyzed. The goal of this research was to find a relation between the resolution and number of lags of the correlator and the necessary chip area, the maximum clock frequency the correlation operation could be executed and the sensitivity of the correlator.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering MSc (60353)
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