Probability of reclustering with different number of cognitive sensor nodes versus the primary arrival rate .

<p>Probability of reclustering with different number of cognitive sensor nodes versus the primary arrival rate .</p

Switch.

<p>Switch.</p

Interference probability of cluster heads with different number of cognitive sensor nodes in comparison.

<p>Interference probability of cluster heads with different number of cognitive sensor nodes in comparison.</p

Clustering Estimation.

<p>Clustering Estimation.</p

A snapshot of clustering using the proposed scheme for a large scale deployment of cognitive sensor nodes, with different colored dots representing individual cognitive sensor nodes in different clusters, and the small black squares representing the logical centers of the clusters.

<p>A snapshot of clustering using the proposed scheme for a large scale deployment of cognitive sensor nodes, with different colored dots representing individual cognitive sensor nodes in different clusters, and the small black squares representing the logical centers of the clusters.</p

Cluster Formation.

<p>Cluster Formation.</p

Stages of proposed clustering scheme.

<p>Stages of proposed clustering scheme.</p

Cluster head selection overhead vs. number of cognitive sensor nodes in comparison.

<p>Cluster head selection overhead vs. number of cognitive sensor nodes in comparison.</p

Cluster joining estimation error with different number of channel and different number of cognitive sensor nodes.

<p>Cluster joining estimation error with different number of channel and different number of cognitive sensor nodes.</p

Cluster head selection overhead vs. maximum number of clusters in comparison.

<p>(a) 100 cognitive sensor nodes, (b) 500 cognitive sensor nodes, and (c) 1000 cognitive sensor nodes.</p