  Cognitive radio networks (CRNs) propose a smart solution for spectrum usage
inefficiency. Routing protocols for CRNs follow different criteria to choose
the best route to the destination and to avoid the interference with primary
users. Some protocols use cooperative communication techniques to achieve the
full coexistence between secondary users (SUs) and primary users (PUs).
Although using such cross-layer techniques have a great impact on the quality
of the chosen routes, the existing work do not choose the best channel to send
the data over. Thus, the available spectrum is not utilized efficiently. In
this work, we propose CSCR, a channel selection scheme for cooperation-based
routing protocols in CRNs. The proposed scheme increases the spectrum
utilization through integrating the channels selection in the route discovery
phase of the cooperation-based routing protocols. The best channels, that are
less congested with primary users and that lead to minimum switching overhead,
are chosen while constructing the cooperative group. Evaluating CSCR via NS2
simulations shows that it outperforms its counterparts in terms of goodput,
end-to-end delay, and packet delivery ratio. The proposed scheme can enhance
the network goodput, in some cases, by more than 150%, as compared to other
related protocols.
