Energy Detector Using a Hybrid Threshold in Cognitive Radio Systems

Jong-Ho KIM  Seung-Hoon HWANG  Deok-Kyu HWANG  

IEICE TRANSACTIONS on Communications   Vol.E92-B   No.10   pp.3079-3083
Publication Date: 2009/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.3079
Print ISSN: 0916-8516
Type of Manuscript: Special Section LETTER (Special Section on Advanced Information and Communication Technologies and Services in Conjunction with Main Topics of APCC/COIN 2008)
cognitive radio,  primary user,  secondary user,  energy detector,  fixed threshold,  adaptive threshold,  hybrid threshold,  

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Cognitive radio systems offer the opportunity to improve the spectrum utilization by detecting unused frequency bands while avoiding interference to primary users. This paper proposes a new algorithm for spectrum sensing, which is an energy detector using a hybrid (adaptive and fixed) threshold, in order to compensate the weak points of the existing energy detector in the distorted communication channel environment. Simulation results are presented which show that the performance of the new proposed scheme is better than the existing scheme using a fixed threshold or an adaptive threshold. Additionally, the performance is investigated in terms of several parameters such as the mobile speed and the probability of false alarms. The simulation results also show that the proposed algorithm makes the detector highly robust against fading, shadowing, and interference.