Muhammad farooq; Abdullah Aslam Raja MEE10:79, pp. 76. ING/School of Engineering, 2010.
Cognitive Radio is an innovative technology that allows the secondary unlicensed
users to share the spectrum with licensed primary users to utilize the spectrum. For
maximum utilization of spectrum, in cognitive radio network spectrum sensing is an
important issue. Cognitive user under extreme shadowing and channel fading can‟t
sense the primary licensed user signal correctly and thus to improve the performance
of spectrum sensing, collaboration between secondary unlicensed users is required.
In collaborative spectrum sensing the observation of each secondary user is received
by a base station acting as a central entity, where a final conclusion about the
presence or absence of the primary user signal is made using a particular decision
and fusion rule. Due to spatially correlated shadowing the collaborative spectrum
sensing performance decreases, and thus optimum secondary users must be selected
to, not only improve spectrum sensing performance but also lessen the processing
overhead of the central entity. A particular situation is depicted in the project where
according to some performance parameters, first those optimum secondary users that
have enough spatial separation and high average received SNR are selected using
Genetic Algorithm, and then collaboration among these optimum secondary users is
done to evaluate the performance. The collaboration of optimal secondary user
providing high probability of detection and low probability of false alarm, for
sensing the spectrum is compared with the collaboration of all the available
secondary users in that radio environment. At the end a conclusion has been made
that collaboration of selected optimum secondary users provides better performance,
then the collaboration of all the secondary users available.