Method and system to correct for Doppler shift in moving nodes of a wireless network
First Claim
1. A method to reduce Doppler induced errors in mobile nodes of a wireless network, the method comprising:
- receiving a Doppler shifted signal having a Doppler shifted transmission frequency at a mobile node moving at a velocity;
measuring an acceleration of the mobile node in three directions;
generating an array of Doppler shifted frequency estimates based on the measured acceleration and a previously generated pseudo-transmission frequency;
generating a current pseudo-transmission frequency based on the array of Doppler shifted frequency estimates; and
tracking the Doppler shifted transmission frequency of the received signal to the current pseudo-transmission frequency.
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Abstract
A method to reduce Doppler induced errors in mobile nodes of a wireless network. The method includes receiving a Doppler shifted signal having a Doppler shifted transmission frequency at a mobile node moving at a velocity, measuring an acceleration of the mobile node in three directions, generating an array of Doppler shifted frequency estimates based on the measured acceleration and a previously generated pseudo-transmission frequency, generating a current pseudo-transmission frequency based on the array of Doppler shifted frequency estimates and tracking the Doppler shifted transmission frequency of the received signal to the current pseudo-transmission frequency. In this manner, the mobile node nominally tracks and decodes a Doppler shifted signal.
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Citations
20 Claims
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1. A method to reduce Doppler induced errors in mobile nodes of a wireless network, the method comprising:
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receiving a Doppler shifted signal having a Doppler shifted transmission frequency at a mobile node moving at a velocity;
measuring an acceleration of the mobile node in three directions;
generating an array of Doppler shifted frequency estimates based on the measured acceleration and a previously generated pseudo-transmission frequency;
generating a current pseudo-transmission frequency based on the array of Doppler shifted frequency estimates; and
tracking the Doppler shifted transmission frequency of the received signal to the current pseudo-transmission frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A Doppler-shift error-reducing mobile node in a wireless network, the mobile node comprising:
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an antenna adapted to receive a Doppler shifted signal having a Doppler shifted transmission frequency, wherein the Doppler shifted signal is emitted from a transmitter as a transmission signal having a transmission frequency;
a velocity calculating unit including an accelerometer adapted to determine a velocity of the mobile node;
a Doppler shifting unit adapted to generate an array of Doppler shifted frequency estimates based on the change in velocity of the mobile node;
a frequency checking unit adapted to match a frequency in the array of Doppler shifted frequency estimates to the Doppler shifted transmission frequency of the received Doppler shifted signal and to generate a pseudo-transmission frequency; and
a tracking loop unit adapted to synchronize the pseudo-transmission frequency with the received Doppler shifted signal, wherein the pseudo-transmission frequency is about the transmission frequency. - View Dependent Claims (17, 18)
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19. A program product comprising program instructions, embodied on a storage medium, that are adapted to cause a programmable processor to:
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receive a signal having a Doppler shifted transmission frequency at a mobile node moving at a velocity;
measure a mobile node acceleration in three directions;
generate an array of Doppler shifted frequency estimates based on the measured acceleration and a previously generated pseudo-transmission frequency;
generate a current pseudo-transmission frequency based on the array of Doppler shifted frequency estimates;
track the Doppler shifted transmission frequency of the received signal to the current pseudo-transmission frequency;
decode the data on the received signal based on the tracking of Doppler shifted transmission frequency of the received signal to the current pseudo-transmission frequency; and
update the current pseudo-transmission frequency. - View Dependent Claims (20)
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Specification