  We propose an energy-efficient network architecture that consists of ad hoc
(mobile) cognitive radios (CRs) and infrastructure wireless sensor nodes. The
sensor nodes within communications range of each CR are grouped into a cluster
and the clusters of CRs are regularly updated according to the random mobility
of the CRs. We reduce the energy consumption and the end-to-end delay of the
sensor network by dividing each cluster into disjoint subsets with overlapped
sensing coverage of primary user (PU) activity. Respective subset of a CR
provides target detection and false alarm probabilities. Substantial energy
efficiency is achieved by activating only one subset of the cluster, while
putting the rest of the subsets in the cluster into sleep mode.
