SYSTEMS AND METHODS FOR DOPPLER SHIFT COMPENSATION IN OFDMA COMMUNICATIONS

• US 20090267591A1
• Filed: 01/21/2009
• Published: 10/29/2009
• Est. Priority Date: 04/25/2008
• Status: Abandoned Application

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Roberts, Harold A.
• Application Number:
  US12/356,750
• Publication Number:
  US 20090267591A1
• Time in Patent Office: Days
• US Class Current: 324/160
• CPC Class Codes: G01S 11/10 using Doppler effect
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/2657 Carrier synchronisation

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.

Claims

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. The method of claim 1, wherein the current modulation frequency is stored by the subscriber station in a queryable memory.

3. The method of claim 1, wherein the current modulation frequency is stored by the subscriber station in a management information base.

4. 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 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.

5. The method of claim 4, wherein the value of the carrier frequency adjustment is stored by the subscriber station in a queryable memory.

6. The method of claim 4, wherein the value of the carrier frequency adjustment is stored by the subscriber station in a management information base.

7. A method for determining the relative velocity of a subscriber station with respect to a basestation, the method comprising:

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.