Opportunistic Spectrum Access based on underlay UWB signalling

Opportunistic Spectrum Access (OSA) is a promising solution to increase spectral efficiency in the Cognitive Radio (CR) framework. In OSA networks, unlicensed Secondary Users (SUs) need a Common Control Channel (CCC) to identify the spectrum opportunities, i.e., common spectrum holes unused by licensed Primary Users (PUs). To fulfill this requirement, the sharing of the spectrum sensing data via Ultra-wideband (UWB) has been proposed in the literature. In this paper we evaluate the design of a highly available underlay UWB signalling network for the exchange of sensing information among SUs avoiding harmful interference to PUs. We analyse the trade-off between the connectivity degree of a multi-hop underlay signalling network, related to the CCC parameters, and its coexistence with PUs. Moreover, we assess the performance of cooperative sensing in terms of detection probability accounting for the availability and the characteristics of the CCC. Results show that a correct dimensioning of the UWB signalling network allows to achieve high accuracy of PU detection avoiding harmful interference.