Distributed Wideband Spectrum Sensing for Cognitive Radio Networks

Wideband spectrum sensing improves the agility of spectrum sensing
and spectrum hand-off in cognitive radio systems. In this paper,
a distributed wideband spectrum sensing technique over adaptive
diffusion networks is proposed. Considering unknown and different
channels between the primary and the cognitive users, an averaged
received power spectrum across all the cognitive users is estimated
by each user using diffusion adaptation techniques. This averaged
power spectrum estimate is reliable enough for the users to perform
spectrum sensing and make a decision regarding the presence
or the absence of the primary user. The simulation results show
that the detection performance of the system improves with the
number of iterations. Further, a satisfactory detection performance
at low SNRs is achieved after a few iterations, which is a desired
characteristic for cognitive radio systems. Finally, it is shown that
the cooperative technique outperforms the non-cooperative one in
terms of estimation accuracy and detection performance.