Spectrum sensing in low SNR: Diversity combining and cooperative communications

Abstract

In this paper, the detection performance of an energy detector used for cooperative spectrum sensing in cognitive radio networks is investigated under very low signal-to-noise ratio (SNR) levels. The analysis focuses on the derivation of closed-form expressions for the false-alarm and the average missed-detection probabilities for two cases over different fading channels: (i) with diversity combining; and (ii) with cooperative communications. The detection threshold is optimized by minimizing the total error rate. The analysis is validated by numerical and semi-analytical Monte-Carlo simulation results, which focus on the sensing requirements defined in IEEE 802.22. © 2011 IEEE.