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Expired Canadian patentCanada

Doppler correction for airborne cellular system

CA 2412912 C · Owner: Cdc Propriete Intellectuelle · Inventors: Gross, Jonathan H.; Emmons, Thomas Peter Jr.; Hanson, Duke E.

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Abstract From the Canadian patent

The present invention corrects for Doppler shift in both forward and reverse links in a cellular communications system (10) including an airborne repeater. A reverse link pilot reference signal in a band similar to a communications signal band is received at a reverse link processor and the Doppler shift in , the reverse feeder link is corrected based on the reverse link pilot reference signal. The Doppler shift in the forward feeder link is also corrected based on the reverse link pilot reference signal prior to the forward feeder link being affected by the Doppler shift. The present invention also compensates for signal strength variations due to changing flight pattern positions …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Filed June 22, 2001 and granted September 27, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 22, 2021.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 22, 2023.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 22, 2001
GrantedSeptember 27, 2011
Term endedJune 22, 2021
Patent numberCA 2412912 C
Classification (IPC)H04B7/18

Timeline

Timeline From CIPO dates

2002200420062008201020122014201620182020Application filedJune 22, 2001Patent grantedSep 27, 2011Term endedJune 22, 2021

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.