Cluster-Based Differential Energy Detection for Spectrum Sensing in Multi-Carrier Systems

• Published in: IEEE transactions on signal processing Vol. 60; no. 12; pp. 6450 - 6464
• Main Authors: Cheraghi, P., Yi Ma, Tafazolli, R., Zhengwei Lu
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Detection, estimation, filtering, equalization, prediction; Differential; Electrostatic discharges; energy detection; Exact sciences and technology; Frequency diversity; Information, signal and communications theory; low signal-to-noise ratio (SNR); multi-carrier; Noise; Reliability; Sensors; Signal and communications theory; Signal representation. Spectral analysis; Signal to noise ratio; Signal, noise; spectrum sensing; Studies; Telecommunications and information theory; Uncertainty; Performance evaluation; Automatic classification; Differential detection; Electrostatic discharge; multi-carrier; Subcarrier; Spectrum analysis; Robustness; High rate transmission; Fading channels; Availability; Energy spectrum; low signal-to-noise ratio (SNR); Differential; Rayleigh channels; Multicarrier; Order statistic; Energy density; Signal classification; False alarm rate; spectrum sensing; Signal processing; energy detection; Frequency diversity; Frequency offset; Spectral density; Differential method; Signal analysis; Signal to noise ratio
• ISSN: 1053-587X; 1941-0476
• DOI: 10.1109/TSP.2012.2212434

This paper presents a novel differential energy detection scheme for multi-carrier systems, which can form fast and reliable decision of spectrum availability even in very low signal-to-noise ratio (SNR) environment. For example, the proposed scheme can reach 90% in probability of detection (PD) and 10% in probability of false alarm (PFA) for the SNRs as low as -21 dB, while the observation length is equivalent to 2 multi-carrier symbol duration. The underlying initiative of the proposed scheme is applying order statistics on the clustered differential energy-spectral-density (ESD) in order to exploit the channel frequency diversity inherent in high data-rate communications. Specifically, to enjoy a good frequency diversity, the clustering operation is utilized to group uncorrelated subcarriers, while, the differential operation applied onto each cluster can effectively remove the noise floor and consequently overcome the impact of noise uncertainty while exploiting the frequency diversity. More importantly, the proposed scheme is designed to allow robustness in terms of both, time and frequency offsets. In order to analytically evaluate the proposed scheme, PFA and PD for Rayleigh fading channel are derived. The closed-form expressions show a clear relationship between the sensing performance and the cluster size, which is an indicator of the diversity gain. Moreover, we are able to observe up to 10 dB gain in the performance compared to the state-of-the-art spectrum sensing schemes.