Impact of control channel design on cooperative spectrum sensing in opportunistic spectrum access networks

In Opportunistic Spectrum Access (OSA) networks, Secondary unlicensed Users (SUs) need a common Control Channel (CC) to identify the spectrum opportunities, i.e., common spectrum holes unused by licensed Primary Users (PUs). Typically, an interference-free CC is unrealistically assumed in the literature. In this paper we evaluate the impact of the availability and the characteristics of the CC on the performance of cooperative spectrum sensing. We deal with the dimensioning of an underlay Ultra-wideband (UWB) signalling network for the exchange of sensing data among secondary Cognitive Radio (CR) nodes avoiding harmful interference to PUs. To this aim, we analyse the trade-off between the connectivity degree of a multihop underlay UWB signalling network, directly related to the possibility to perform cooperative sensing, and its coexistence with PUs. It is observed that the correct dimensioning of the UWB signalling network allows to achieve high accuracy of PU detection without compromising primary systems.