A CMOS Spectrum Sensor Based on Quasi-Cyclostationary Feature Detection for Cognitive Radios

Sensitivity and sensing time are the key features for spectrum sensing in a cognitive radio (CR) which detects empty bands within VHF/UHF television broadcast bands and uses them as a secondary user. In this paper, an integrated CMOS CR spectrum sensor for a CR receiver in the 54-862 MHz band is presented. A quasi-cyclostationary feature (QCF) detector is proposed based on both energy and feature detection methods and can take advantage of both methods to reach a fast and accurate decision without the need for an analog-to-digital converter for decision making. The integrated chip has been fabricated in a standard 0.18-mu m CMOS IBM technology and has achieved minimum detection signal-to-noise ratio of as low as -24 dB and dynamic range (DR) of 39 dB.