SYSTEMS AND METHODS FOR DOPPLER SHIFT COMPENSATION IN OFDMA COMMUNICATIONS
First Claim
1. A method for determining the relative velocity of a subscriber station with respect to a basestation, the method comprising:
- sending a query message from a basestation to a subscriber station, the query message requesting a current modulation frequency used by the subscriber station to modulate transmissions;
receiving a response to the query message, the response including the current modulation frequency;
determining an offset between the current modulation frequency and a target carrier frequency value; and
calculating a velocity of the subscriber station based on the offset.
2 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods for determining the relative velocity of a subscriber station with respect to a basestation are provided. In one embodiment, the method comprises sending a query message from a basestation to a subscriber station, the query message requesting a current modulation frequency used by the subscriber station to modulate transmissions; receiving a response to the query message, the response including the current modulation frequency; determining an offset between the current modulation frequency and a target carrier frequency value; and calculating a velocity of the subscriber station based on the offset.
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Citations
7 Claims
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1. A method for determining the relative velocity of a subscriber station with respect to a basestation, the method comprising:
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sending a query message from a basestation to a subscriber station, the query message requesting a current modulation frequency used by the subscriber station to modulate transmissions; receiving a response to the query message, the response including the current modulation frequency; determining an offset between the current modulation frequency and a target carrier frequency value; and calculating a velocity of the subscriber station based on the offset. - View Dependent Claims (2, 3)
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4. A method for determining the relative velocity of a subscriber station with respect to a basestation, the method comprising:
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sending a query message from a basestation to a subscriber station, the query message requesting a value of a carrier frequency adjustment applied by the subscriber station to an uplink carrier with respect to a downlink carrier; receiving a response to the query message, the response including the value of the carrier frequency adjustment; calculating a velocity of the subscriber station based on the value of the carrier frequency adjustment. - View Dependent Claims (5, 6)
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7. A method for determining the relative velocity of a subscriber station with respect to a basestation, the method comprising:
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determining a frequency error of an upstream OFDM signal received from the subscriber station; transmitting a frequency adjustment instruction to the subscriber station based on the frequency error; maintaining a running sum of frequency adjustments transmitted to the subscriber station; determining an offset between a current carrier frequency and a target carrier frequency value based on the running sum; and calculating a velocity of the subscriber station based on the offset.
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Specification