US5742908A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency error correction in a satellite-mobile communications system
Assignee: Ericsson Inc
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Filing: 1994-09-14
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Granted: 1998-04-21
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Expires: 2014-09-14
Abstract
Abstract Mobile stations correct their frequencies using a signal received from the moving relay station including correction of any Doppler shift caused by the satellite's movement. The mobile station includes a receiver for receiving a paging channel signal broadcast by the moving relay station and demodulators and decoders for decoding the information in the paging channel signal. Using the decoded information, the mobile station can determine an estimate of its position within the communication system. The mobile station can also determine a frequency error and a Doppler shift using the decoded information and the position estimate. A frequency controlling signal is determined using the determined frequency error and the Doppler shift. A controlled reference oscillator then uses the frequency correcting signal as a control input signal. Finally, the mobile station contains a transmitter for transmitting a signal using the voltage controlled oscillator as a reference.
Inventors
- 👤 Paul W. Dent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:38
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/1851; H04B7/18513; H03; H03J; H03J7/00; H03J7/02; H04B7/01; H04B7/204; H04B7/208
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
188 words
A mobile station for use in a satellite communication system with at least one moving relay station, comprising: receiver means for receiving a paging channel signal broadcast by said relay station; means for demodulating said paging channel signal to produce a demodulated signal; means for decoding said demodulated signal to produce a decoded signal; means for determining a position estimate of said mobile station; means for determining a frequency error and a Doppler shift using said decoded signal and said position estimate; temperature sensor means for making temperature measurements; memory means for storing average frequency control signal values for each of a plurality of temperatures; frequency correcting means for determining a frequency correcting signal based on said determined frequency error and Doppler shift or based on said stored values and said temperature measurement; averaging means for averaging said stored average values with frequency-correcting signal values and storing said average values in said memory means in positions determined by said temperature measurements; controlled oscillator means having a control input for a frequency-correcting signal; and transmitter means for generating a transmit signal using said controlled oscillator means as a reference.
Claim 2
Dependent Claim
188 words
A mobile station for use in a satellite communication system with at least one moving relay station, comprising: receiver means for receiving a paging channel signal broadcast by said relay station; means for demodulating said paging channel signal to produce a demodulated signal; means for decoding said demodulated signal to produce a decoded signal; means for determining a position estimate of said mobile station; means for determining a frequency error and a Doppler shift using said decoded signal and said position estimate; temperature sensor means for making temperature measurements; memory means for storing average frequency control signal values for each of a plurality of temperatures; frequency correcting means for determining a frequency correcting signal based on said determined frequency error and Doppler shift or based on said stored values and said temperature measurement; averaging means for averaging said stored average values with frequency-correcting signal values and storing said average values in said memory means in positions determined by said temperature measurements; controlled oscillator means having a control input for a frequency-correcting signal; and transmitter means for generating a transmit signal using said controlled oscillator means as a reference.
Claim 3
Dependent Claim
16 words
The mobile station according to claim 1, wherein said moving relay station is an orbiting satellite.
Claim 4
Dependent Claim
23 words
The mobile station according to claim 1, wherein said position estimate is within several kilometers of an actual position of said mobile station.
Claim 5
Dependent Claim
18 words
The mobile station according to claim 1, wherein said paging signal contains information about the relay station's motion.
References Cited (Backward Citations)
JPH03131131A
Cited
US5287541A
Cited
JPH04207530A
Cited
US5343512A
Cited
US5313215A
Cited
US5471648A
Cited
US5432521A
Cited
US5552795A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-20 | 2001-10-20 | 2002-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-20 | 2005-10-20 | 2006-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-20 | 2009-10-20 | 2010-04-21 | $7700.00 | Window Closed / Lapsed |