As in IEEE 802.22 proposal, the spectrum sensing technique should be capable enough to sense the primary signal with very low receiver sensitivity such as at -116 dBm. In this paper, the detection performance of an energy detector used for the spectrum sensing in cognitive radio networks is investigated under very low signal-to-noise ratio (SNR) level. The analysis focuses on the derivation of a closed-form expression for the average missed-detection probability over Rayleigh fading and Nakagami-$m$ fading channels. Subsequently, the detection threshold is optimized as minimizing the total error rate. The analysis is validated by numerical and simulation results. The sensing requirements defined in IEEE 802.22 are also discussed with numerical examples.
['Saman Atapattu', 'Chintha Tellambura', 'Jiang H']
Spectrum Sensing via Energy Detector in Low SNR