Unified Analysis of Low-SNR Energy Detection and Threshold Selection

• Published in: IEEE transactions on vehicular technology Vol. 64; no. 11; pp. 5006 - 5019
• Main Authors: Atapattu, Saman, Tellambura, Chintha, Jiang, Hai, Rajatheva, Nandana
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cognitive radio; Detectors; Diversity reception; energy detection; low-SNR; Rayleigh channels; Signal to noise ratio; spectrum sensing; threshold selection; energy detection; low signal-to-noise ratio (SNR); Cognitive radio; threshold selection; spectrum sensing
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2014.2381648

For spectrum sensing in cognitive radio networks, the IEEE 802.22 standard requires the detection of primary signals with a signal-to-noise ratio (SNR) as low as -20 dB and receiver sensitivity as low as -116 dBm. Under such low-SNR levels, the performance of a conventional energy detector is analyzed in this paper. The analysis includes novel expressions for missed-detection probability and area under the receiver operating characteristic (ROC) curve. Thus, a unified framework covering fading channels, square-law diversity combining, and cooperative spectrum-sensing scenarios is developed. The detection threshold is optimized to minimize the total error rate subject to bounded false-alarm and missed-detection probabilities, which outperforms traditional detection threshold selection. Numerical results and Monte Carlo simulation results with the IEEE 802.22 sensing requirements are provided and discussed.