Performance analysis of a two-stage spectrum sensing scheme for dynamic spectrum access in TV bands

Spectrum Sensing schemes in Cognitive Radio systems are fundamental elements for a complete opportunistic communication technology. They usually reveal the presence of occupied bands without performing a measurement of the spectrum portion actually occupied. Considering that the final aim of Cognitive Radios is the exploitation, in the most efficient way, of the spectrum holes left free by primary users, the measurement of the actual occupied spectrum becomes a fundamental task. In this framework, this paper proposes a two-stage spectrum sensing method, tailored to work in TV bands, offering a good detection of the occupied bands with selectable false alarm rates (Stage 1) and an accurate measurement of the real occupied spectrum (Stage 2). Performance results, achieved in simulation and emulation environments, prove the method's goodness and robustness to non-idealities of real acquisition systems. A comparison, with another two-stage method available in literature, has confirmed its efficacy in real contexts