DocumentCode :
1417450
Title :
Blind Spectrum Sensing for OFDM-Based Cognitive Radio Systems
Author :
Bokharaiee, Simin ; Nguyen, Ha H. ; Shwedyk, Ed
Author_Institution :
Dept. of Electr. & Comput. Engi neering, Univ. of Manitoba, Winnipeg, MB, Canada
Volume :
60
Issue :
3
fYear :
2011
fDate :
3/1/2011 12:00:00 AM
Firstpage :
858
Lastpage :
871
Abstract :
Given the ever-growing demand for radio spectrum, cognitive radio has recently emerged as an attractive wireless technology. Since orthogonal frequency-division multiplexing (OFDM) is one of the major wideband transmission techniques, detection of OFDM signals in low-signal-to-noise-ratio scenario is an important research problem. In this paper, it is shown that cyclic prefix (CP) correlation coefficient (CPCC)-based spectrum sensing, which was previously introduced as a simple and computationally efficient spectrum-sensing method for OFDM signals, is a special case of the constrained generalized likelihood ratio test (GLRT) in the absence of multipath. As such, the performance of this algorithm degrades in a multipath scenario, where OFDM is usually implemented. Furthermore, by considering multipath correlation in the GLRT algorithm and employing the inherent structure of OFDM signals, a simple and low-complexity algorithm called the multipath-based constrained-GLRT (MP-based C-GLRT) algorithm is obtained. The MP-based C-GLRT algorithm is shown to outperform the CPCC-based algorithm in a rich multipath environment. Further performance improvement can be achieved by simply combining both the CPCC- and MP-based C-GLRT algorithms. A simple GLRT-based detection algorithm is also developed for unsynchronized OFDM signals, whose performance is only slightly degraded when compared with the synchronized detection in a rich multipath environment.
Keywords :
OFDM modulation; cognitive radio; MP-based C-GLRT algorithm; OFDM signals; OFDM-based cognitive radio systems; blind spectrum sensing; constrained generalized likelihood ratio test; cyclic prefix correlation coefficient; low-signal-to-noise-ratio scenario; orthogonal frequency-division multiplexing; radio spectrum; spectrum-sensing method; wireless technology; Cognitive radio (CR); generalized likelihood ratio test (GLRT); likelihood ratio test (LRT); orthogonal frequency-division multiplexing (OFDM); spectrum sensing;
fLanguage :
English
Journal_Title :
Vehicular Technology, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9545
Type :
jour
DOI :
10.1109/TVT.2010.2103095
Filename :
5678847
Link To Document :
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