| Summary: | 碩士 === 元智大學 === 通訊工程學系 === 104 ===
Cognitive Radio (CR) users can observe surroundings changes about wireless communication at any time without interferences to authorized primary user (PU). CR can improve resources of spectrum more effectively to be used by spectrum sensing (SS).
This thesis tackles the problem of wideband spectrum sensing (WBSS) by improving the methods that predecessors had proposed. First, adding super-heterodyne in front of receiver cutting up a wideband to multiple mid-bands, and then choose a mid-band that wanted to be detected. According to a parallel construction of multi-rate filter banks formed by a prototype filter and multiple sub-prototype filters, “ FFT-based Channelizer in Frequency Domain WBSS ” can cut up a mid-band to multiple narrowbands by single CR node sensing. Completed a hybrid sweep-tune WBSS with lower computational complexity. Second, in order to increase probabilities of detection, we proposed “ Muli-CR nodes Cooperative WBSS ”. Because signals transported in wireless channels would be caused fading by shadow effect, adopting multi-CR nodes to increase probabilities of detection. To investigate and improve the WBSS detection performance, simulation results and discussions are also included.
Finally, we resort to an USRP-in-MATLAB SDR platform to generate multiple PU signals modulate realistic transmitter and receiver in the lab. The experimental results show both has the feasibility for practical WBSS applications.
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