Method for spectrum sensing of multi-carrier signals with equidistant sub-carriers
AssigneeQrc, Inc. Dba Qrc Technologies
InventorsSinisa Peric, Thomas F. Callahan, III
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Abstract
A multi carrier signal is typically comprised of many equidistant sub-carriers. This results in periodicity of spectrum within the bandwidth of such a multi-carrier signal. An unknown multi-carrier signal with equidistant sub-carriers can thus be sensed together with its sub-carrier spacing by finding a discernable local maximum in the cepstrum (Fourier transform of the log spectrum) of the multi-carrier signal.
Claims21
A processor-implemented method for sensing a presence of a multi-carrier signal with equidistant sub-carriers in a spectral sample, the method comprising:
- obtaining by a spectral sample collection system a spectrum sample;
- transforming by a cepstrum processor the spectrum sample to obtain a cepstrum;
- determining by a carrier identification processor a bin location within the cepstrum having a maximum bin magnitude;
- determining by a carrier identification processor whether the maximum bin magnitude at the cepstrum bin location exceeds a predetermined threshold;
- and
- issuing by the carrier identification processor an alert that the multi-carrier signal has been sensed in the spectrum sample when the maximum bin magnitude at the cepstrum bin location exceeds the predetermined threshold.
A processor-implemented method for sensing a presence of a multi-carrier signal with equidistant sub-carriers in a spectral sample, the method comprising:
- obtaining by a spectrum collection system spectrum sample, wherein the spectrum sample is larger than a maximum expected signal spectrum bandwidth;
- obtaining by a cepstrum processor from the spectrum sample a plurality of spectrum subsets,
- wherein each spectrum subset has a bandwidth that is approximately equal to the maximum expected signal spectrum bandwidth;
- transforming by the cepstrum processor each of the plurality of spectrum subsets to obtain a cepstrum of each spectrum subset;
- determining by a carrier identification processor a bin location within the cepstrum having a maximum bin magnitude across all of the spectrum subsets;
- determining by a carrier identification processor whether the maximum bin magnitude at the cepstrum bin location exceeds a predetermined threshold;
- and
- issuing by the carrier identification processor an alert that a multi-carrier signal has been sensed in the spectrum sample when the maximum bin magnitude at the cepstrum bin location exceeds a predetermined threshold.
A processor-implemented method for sensing a presence of a multi-carrier signal with equidistant sub-carriers having a known sub-carrier spacing and a known spectrum bandwidth in a spectral sample, the method comprising:
- obtaining by a spectrum collection system spectrum sample, wherein the spectrum sample is larger than a known signal spectrum bandwidth;
- obtaining by a cepstrum processor from the spectrum sample a plurality of spectrum subsets, wherein each spectrum subset has a bandwidth that is approximately equal to the known signal spectrum bandwidth;
- transforming by the cepstrum processor each of the plurality of spectrum subsets to obtain a magnitude of a particular cepstrum bin location within each spectrum subset, wherein the particular cepstrum bin location corresponds to the known sub-carrier spacing;
- determining by a carrier identification processor whether the bin magnitude at the particular cepstrum bin location of any of the spectrum subsets exceeds a predetermined threshold;
- and
- issuing by the carrier identification processor an alert that the multi-carrier signal having the known sub-carrier spacing and the known spectrum bandwidth has been sensed in the spectrum sample when the bin magnitude at the particular cepstrum bin location of any of the spectrum subsets exceeds a predetermined threshold.
Dependencies are inferred from the claim text.