A Spectrum Sensing Technique for Cognitive Radios in the Presence of Harmonic Images

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Abstract

Abstract—Harmonic downmixing is an important effect that must be taken into account when performing sensitive spectrum sensing using direct-conversion receivers. When the local oscillator waveform contains harmonics of the fundamental frequency, the quadrature mixer in the receiver will downconvert RF signals found at these harmonics, termed harmonic images, in addition to the RF signals around the fundamental frequency. The harmonic images will be detected by power spectral density based sensing algorithms and will cause certain parts of the desired spectrum to be mistakenly flagged as occupied. Although harmonic downmixing is important to consider, it is an often negelected effect. This paper presents a harmonic rejection spectral sensing technique, that exploits two quadrature mixers. The mixers work with different LO frequencies, which decorrelate the harmonic images so that cross-correlation of their outputs renders an improved spectral estimate. In addition to rejecting the harmonic images, spurious signals entering the receiver through the analog baseband inputs will also be rejected. The frequency resolutionof the spectral estimate is scalable and the rejection of the harmonic images increases 15 dB per 1000-fold increase of the correlation time. The complexity of the algorithm is analyzed and its performance is shown by means of simulations. The effect of I/Q imbalance is also taken into account.
Original languageEnglish
Title of host publicationProceedings of the 2008 IEEE Dynamic Spectrum Access Networks Conference (DySPAN)
Place of PublicationPiscataway
PublisherIEEE
Number of pages10
ISBN (Print)978-1-4244-2017-9
DOIs
Publication statusPublished - 14 Oct 2008
EventIEEE Dynamic Spectrum Access Networks Conference 2008 - Chicago, United States
Duration: 14 Oct 200817 Oct 2008
http://dyspan2008.ieee-dyspan.org/

Publication series

Name
PublisherIEEE Computer Society Press
Number412

Conference

ConferenceIEEE Dynamic Spectrum Access Networks Conference 2008
Abbreviated titleDySPAN 2008
CountryUnited States
CityChicago
Period14/10/0817/10/08
Internet address

Fingerprint

Cognitive radio
Power spectral density

Keywords

  • EWI-14995
  • IR-65357
  • METIS-255473

Cite this

Moseley, N. A., Klumperink, E. A. M., & Nauta, B. (2008). A Spectrum Sensing Technique for Cognitive Radios in the Presence of Harmonic Images. In Proceedings of the 2008 IEEE Dynamic Spectrum Access Networks Conference (DySPAN) Piscataway: IEEE. https://doi.org/10.1109/DYSPAN.2008.14
Moseley, N.A. ; Klumperink, Eric A.M. ; Nauta, Bram. / A Spectrum Sensing Technique for Cognitive Radios in the Presence of Harmonic Images. Proceedings of the 2008 IEEE Dynamic Spectrum Access Networks Conference (DySPAN). Piscataway : IEEE, 2008.
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abstract = "Abstract—Harmonic downmixing is an important effect that must be taken into account when performing sensitive spectrum sensing using direct-conversion receivers. When the local oscillator waveform contains harmonics of the fundamental frequency, the quadrature mixer in the receiver will downconvert RF signals found at these harmonics, termed harmonic images, in addition to the RF signals around the fundamental frequency. The harmonic images will be detected by power spectral density based sensing algorithms and will cause certain parts of the desired spectrum to be mistakenly flagged as occupied. Although harmonic downmixing is important to consider, it is an often negelected effect. This paper presents a harmonic rejection spectral sensing technique, that exploits two quadrature mixers. The mixers work with different LO frequencies, which decorrelate the harmonic images so that cross-correlation of their outputs renders an improved spectral estimate. In addition to rejecting the harmonic images, spurious signals entering the receiver through the analog baseband inputs will also be rejected. The frequency resolutionof the spectral estimate is scalable and the rejection of the harmonic images increases 15 dB per 1000-fold increase of the correlation time. The complexity of the algorithm is analyzed and its performance is shown by means of simulations. The effect of I/Q imbalance is also taken into account.",
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Moseley, NA, Klumperink, EAM & Nauta, B 2008, A Spectrum Sensing Technique for Cognitive Radios in the Presence of Harmonic Images. in Proceedings of the 2008 IEEE Dynamic Spectrum Access Networks Conference (DySPAN). IEEE, Piscataway, IEEE Dynamic Spectrum Access Networks Conference 2008, Chicago, United States, 14/10/08. https://doi.org/10.1109/DYSPAN.2008.14

A Spectrum Sensing Technique for Cognitive Radios in the Presence of Harmonic Images. / Moseley, N.A.; Klumperink, Eric A.M.; Nauta, Bram.

Proceedings of the 2008 IEEE Dynamic Spectrum Access Networks Conference (DySPAN). Piscataway : IEEE, 2008.

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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N2 - Abstract—Harmonic downmixing is an important effect that must be taken into account when performing sensitive spectrum sensing using direct-conversion receivers. When the local oscillator waveform contains harmonics of the fundamental frequency, the quadrature mixer in the receiver will downconvert RF signals found at these harmonics, termed harmonic images, in addition to the RF signals around the fundamental frequency. The harmonic images will be detected by power spectral density based sensing algorithms and will cause certain parts of the desired spectrum to be mistakenly flagged as occupied. Although harmonic downmixing is important to consider, it is an often negelected effect. This paper presents a harmonic rejection spectral sensing technique, that exploits two quadrature mixers. The mixers work with different LO frequencies, which decorrelate the harmonic images so that cross-correlation of their outputs renders an improved spectral estimate. In addition to rejecting the harmonic images, spurious signals entering the receiver through the analog baseband inputs will also be rejected. The frequency resolutionof the spectral estimate is scalable and the rejection of the harmonic images increases 15 dB per 1000-fold increase of the correlation time. The complexity of the algorithm is analyzed and its performance is shown by means of simulations. The effect of I/Q imbalance is also taken into account.

AB - Abstract—Harmonic downmixing is an important effect that must be taken into account when performing sensitive spectrum sensing using direct-conversion receivers. When the local oscillator waveform contains harmonics of the fundamental frequency, the quadrature mixer in the receiver will downconvert RF signals found at these harmonics, termed harmonic images, in addition to the RF signals around the fundamental frequency. The harmonic images will be detected by power spectral density based sensing algorithms and will cause certain parts of the desired spectrum to be mistakenly flagged as occupied. Although harmonic downmixing is important to consider, it is an often negelected effect. This paper presents a harmonic rejection spectral sensing technique, that exploits two quadrature mixers. The mixers work with different LO frequencies, which decorrelate the harmonic images so that cross-correlation of their outputs renders an improved spectral estimate. In addition to rejecting the harmonic images, spurious signals entering the receiver through the analog baseband inputs will also be rejected. The frequency resolutionof the spectral estimate is scalable and the rejection of the harmonic images increases 15 dB per 1000-fold increase of the correlation time. The complexity of the algorithm is analyzed and its performance is shown by means of simulations. The effect of I/Q imbalance is also taken into account.

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Moseley NA, Klumperink EAM, Nauta B. A Spectrum Sensing Technique for Cognitive Radios in the Presence of Harmonic Images. In Proceedings of the 2008 IEEE Dynamic Spectrum Access Networks Conference (DySPAN). Piscataway: IEEE. 2008 https://doi.org/10.1109/DYSPAN.2008.14