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On Spectrum Sensing of OFDM Signals at Low SNR: New Detectors and Asymptotic Performance

Journal Article


Abstract


  • This paper deals with near-optimal spectrum sensing of orthogonal frequency division multiplexing (OFDM) signals to achieve reliable detection at low signal-to-noise ratio (SNR). The likelihood ratio test (LRT), a simple hypothesis test, delivers the optimal performance, but it requires that the parameters involved in the test are known. Hence, the generalized likelihood ratio test (GLRT), a composite hypothesis test, has often been employed. However, GLRT-based detectors involve biased parameter estimation, which may lead to inferior performance. In this paper, with proper approximation, the LRT is reduced to a simpler form, which only requires the knowledge of noise power. Then a novel unbiased and consistent estimator of the noise power is developed. This estimator is combined with the approximate LRT, leading to an asymptotic simple hypothesis test (ASHT). Two ASHT-based detectors are presented for cases with and without time synchronization, and their theoretical performances are analyzed. Simulation results show that the ASHT-based detectors deliver performances very close to that of the optimal LRT, and significantly outperform the existing GLRT-based detectors. It is also shown that the ASHT-based detectors exhibit robustness against the influence of multipath channels.

UOW Authors


  •   Jin, Ming (external author)
  •   Guo, Qinghua
  •   Xi, Jiangtao
  •   Li, Youming (external author)
  •   Li, Yonghui (external author)

Publication Date


  • 2017

Citation


  • M. Jin, Q. Guo, J. Xi, Y. Li & Y. Li, "On Spectrum Sensing of OFDM Signals at Low SNR: New Detectors and Asymptotic Performance," IEEE Transactions on Signal Processing, vol. 65, (12) pp. 3218-3233, 2017.

Scopus Eid


  • 2-s2.0-85019065251

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/127

Number Of Pages


  • 15

Start Page


  • 3218

End Page


  • 3233

Volume


  • 65

Issue


  • 12

Place Of Publication


  • United States

Abstract


  • This paper deals with near-optimal spectrum sensing of orthogonal frequency division multiplexing (OFDM) signals to achieve reliable detection at low signal-to-noise ratio (SNR). The likelihood ratio test (LRT), a simple hypothesis test, delivers the optimal performance, but it requires that the parameters involved in the test are known. Hence, the generalized likelihood ratio test (GLRT), a composite hypothesis test, has often been employed. However, GLRT-based detectors involve biased parameter estimation, which may lead to inferior performance. In this paper, with proper approximation, the LRT is reduced to a simpler form, which only requires the knowledge of noise power. Then a novel unbiased and consistent estimator of the noise power is developed. This estimator is combined with the approximate LRT, leading to an asymptotic simple hypothesis test (ASHT). Two ASHT-based detectors are presented for cases with and without time synchronization, and their theoretical performances are analyzed. Simulation results show that the ASHT-based detectors deliver performances very close to that of the optimal LRT, and significantly outperform the existing GLRT-based detectors. It is also shown that the ASHT-based detectors exhibit robustness against the influence of multipath channels.

UOW Authors


  •   Jin, Ming (external author)
  •   Guo, Qinghua
  •   Xi, Jiangtao
  •   Li, Youming (external author)
  •   Li, Yonghui (external author)

Publication Date


  • 2017

Citation


  • M. Jin, Q. Guo, J. Xi, Y. Li & Y. Li, "On Spectrum Sensing of OFDM Signals at Low SNR: New Detectors and Asymptotic Performance," IEEE Transactions on Signal Processing, vol. 65, (12) pp. 3218-3233, 2017.

Scopus Eid


  • 2-s2.0-85019065251

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/127

Number Of Pages


  • 15

Start Page


  • 3218

End Page


  • 3233

Volume


  • 65

Issue


  • 12

Place Of Publication


  • United States