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US 12,119,922 B2Granted
System with modulated signal to compensate frequency errors in LTE signals
AssigneeAST & Science, LLC
InventorsHuiwen Yao, Praveen Kumar Tangutoori
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Abstract
A satellite communication system leverages the carrier offset detection capability of the demodulator contained in an on-board modem of M&C channel. The modem detects the frequency error Δf introduced in the signal path from the output of the base station at ground to the output of baseband conversion on the satellite, by analyzing the baseband signal at the baseband conversion to estimate the received carrier f′c and subtracting it the from the expected frequency (fc).
Claims20
A communication ground station comprising:
- an antenna configured to receive a signal for a satellite,
- a compensator configured to compensate the signal for delay and Doppler variations;
- and
- a modem configured to determine, based on the signal compensated for delay and Doppler variations, a residual frequency error in the signal compensated for delay and Doppler variations, wherein the residual frequency error is estimated based on a received carrier frequency determined from the signal and an expected frequency determined from the signal,
- wherein the compensator is further configured to compensate the signal compensated for delay and Doppler variations for the residual frequency error.
2 more elements
A method comprising:
- receiving, by a communication ground station, a signal for a satellite,
- compensating, by the communication ground station, the signal for delay and Doppler variations;
- determining, by the communication ground station and based on the signal compensated for delay and Doppler variations, a residual frequency error in the signal compensated for delay and Doppler variations, wherein the residual frequency error is determined based on a received carrier frequency determined from the signal and an expected frequency determined from the signal;
- and
- compensating, by the communication ground station, the signal compensated for delay and Doppler variations for the residual frequency error.
2 more elements
A satellite system comprising:
- an antenna configured to receive, from a communication ground station, a signal for a user equipment, the signal compensated for delay and Doppler variations;
- a modem configured to determine, based on the signal compensated for delay and Doppler variations, a residual frequency error in the signal based on a received carrier frequency determined from the signal and an expected frequency determined from the signal;
- and
- a compensator configured to compensate the signal for the residual frequency error.
1 more element
Dependencies are inferred from the claim text.