Abstract:
Cognitive Radios is a promising technology for the opportunistic use of under-utilized
spectrum since they are able to sense the spectrum and use frequency bands. For this
purpose several spectrum sensing techniques are employed like Energy Detector, Matched
Filter and Cyclo-Stationary feature detector. The performance of these Spectrum Sensing
techniques for cognitive radios is limited by the received signal’s strength which may be
severely degraded due to pathloss. In such a scenario cooperative sensing may alleviate the
problem of detecting the primary user by reducing the probability of interference to a
primary user. The cooperative sensing relies on the variability of signal strength at various
locations. It is expected that a network of cognitive radios with sensing information
exchanged between neighbors will have a better chance of detecting the primary user
compared to the individual sensing. This thesis demonstrates that single node detection is
not sufficiently reliable in a lossy environment and how cooperative spectrum sensing can
be improved. Moreover cooperative and non cooperative spectrum sensing schemes have
been compared on the basis of reliability and performance. All simulations have been
carried out in MATLAB
