  Due to limited availability of spectrum for licensed users only, the need for
secondary access by unlicensed users is increasing. Cognitive radio turns out
to be helping this situation because all that is needed is a technique that
could efficiently detect the empty spaces and provide them to the secondary
devices without causing any interference to the primary (licensed) users.
Spectrum sensing is the foremost function of the cognitive radio which senses
the environment for white spaces. Energy detection is one of the various
spectrum sensing techniques that are under research. Earlier it was shown that
energy detection works better under AWGN channel as compared to Rayleigh
channel, however the conventional spectrum sensing techniques have a high
probability of false alarm and also show a better probability of detection for
higher values of SNR. There is a need for a new technique that shows a reduced
probability of false alarm as well as an increase in the probability of
detection for lower values of SNR. In the present work the conventional energy
detection technique has been enhanced to get better results.
