Methods and apparatus for providing base station position information and using position information to support timing and/or frequency corrections

• US 20070021122A1
• Filed: 08/31/2005
• Published: 01/25/2007
• Est. Priority Date: 07/20/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Li, Junyi, Lane, Frank
• Granted Patent: US 8,798,638 B2
• Time in Patent Office: Days
• US Class Current: 455/441
• CPC Class Codes: H04B 7/01 Reducing phase shift
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 56/0025 synchronizing potentially movable access points
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: H04W 56/006 using known positions of transmitter and receiver
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 88/005 Data network PoA devices
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A wireless terminal receives base station position over an airlink, determines its relative position with respect to the base station and determines a timing adjustment correction. The wireless terminal applies the determined timing correction to control uplink signaling timing and achieve synchronization at the base station'"'"'s receiver. The wireless terminal determines its relative velocity with respect to the base station and determines a Doppler shift adjustment which it adds to the uplink carrier frequency or to its baseband signal. A wireless terminal determines the position of a moving base station and determines timing and/or frequency corrections. Base station position is determined from the current time and stored information correlating the base station position with time, e.g., for a geo-synchronous satellite. Base station position information is determined from broadcast information, e.g., GPS base station position, for an aircraft base station. Wireless terminals may be mobile and include a GPS receiver for WIRELESS TERMINAL position determination.

Claims

1. A method of operating a wireless communications terminal comprising:

receiving base station position information over an airlink; and

determining one of a timing and frequency correction based on the received base station position information and wireless terminal position information.

2. The method of claim 1, wherein the frequency correction is a Doppler shift correction.

3. The method of claim 1, wherein the timing correction is an uplink roundtrip timing delay correction.

4. The method of claim 1, wherein base station position information is location coordinate information.

5. The method of claim 4, wherein said base station position information is received at periodic intervals.

6. The method of claim 4, wherein base station position is communicated at a rate sufficient to determine the distance between the base station and wireless terminal such that the determined distance does not change by more than 11 km between updates.

7. The method of claim 4, wherein base station position is communicated at a rate equal to or exceeding one base station position determination per 11 msec.

8. The method of claim 1, wherein wireless terminal position is pre-programmed.

9. The method of claim 1, wherein wireless terminal position is determined from GPS.

10. The method of claim 1, wherein wireless terminal position is determined from triangulation of received signals.

11. The method of claim 4, wherein the wireless terminal is in an air vehicle and base station position information is sent at least once every 36 seconds.

12. The method of claim 11, wherein base station position information is sent at least once every 1 second.

13. The method of claim 1, wherein base station position information communicated over the airlink is communicated using OFDM signaling.

14. A wireless communications terminal comprising:

a receiver for receiving base station position information over an airlink;

a base station position determination module for determining a position of a base station from the received signal;

a relative distance determination module for determining the relative distance between the base station and the wireless terminal; and

a timing synchronization module for performing a timing adjustment operation as a function of the determined relative distance.

15. The wireless communication terminal of claim 14, further comprising:

a relative velocity determination module coupled to said base station position determination module for determining the relative velocity of said wireless terminal relative to said base station.

16. The wireless communication terminal of claim 15, further comprising a wireless terminal position determination module for providing wireless terminal position information to said relative distance determination module.

17. The wireless communication terminal of claim 15, wherein updated base station position is received at different points in time;

and wherein said relative distance determination module operates, using said updated base station position information, at a rate sufficient to determine the distance between the base station and wireless terminal such that the determined distance does not change by more than 11 km between sequential distance determinations.

18. The wireless terminal of claim 15, wherein base station position information is received by said receiver at time intervals less than or equal to 11 msec.

19. The wireless terminal of claim 14, wherein said wireless terminal position is fixed, said wireless terminal including memory storing pre-programmed wireless terminal position information.

20. The wireless terminal of claim 15,

wherein said wireless terminal includes a global positioning signal receiver;

and

a global positioning signal based wireless position determination module which determines the wireless terminal position from received global positioning signals.

21. The method of claim 16, wherein said wireless terminal position determination module is a triangulation module which determines wireless terminal position from signals received from a plurality of base stations.

22. The wireless terminal of claim 15, wherein said wireless terminal is in an air vehicle.

23. The wireless terminal of claim 22, wherein base station position information is received at least once every 36 seconds.

24. The wireless terminal of claim 14, wherein said receiver is an OFDM receiver and wherein base station position information is communicated over the airlink using OFDM signaling.

25. The wireless terminal of claim 24, further comprising:

a decoder for decoding the received OFDM signals to obtain the communicated base station position information.

26. A communications method comprising:

operating a first base station to;

periodically transmit first base station identification information identifying the first base station; and

periodically transmit first base station location information.

27. The method of claim 26, wherein the first base station is a moving base station, wherein the step of periodically transmitting base station location information includes:

updating said location information to reflect changes in base station position over time.

28. The method of claim 27, wherein base station position information is location coordinate information.

29. The method of claim 28, wherein said base station position information is updated at periodic intervals using stored location information included in said first base station indicating the location where the first base station will be at different points in time.

30. The method of claim 29, wherein the first base station is a non-geostationary satellite base station and wherein said stored location information includes information on the orbital path of said satellite base station.

31. The method of claim 29, wherein the first base station transmits base station position at a rate sufficient to determine the distance between the base station and a wireless terminal such that the determined distance does not change by more than 11 km between location transmission updates.

32. The method of claim 28, wherein said base station position is transmitted on a periodic basis at a rate which results in at least one location information transmission every 11 msec.

33. The method of claim 26, further comprising:

operating the first base station to receive global positioning signals; and

operating the first base station to determine the first base stations location from the received global positioning signals, the determined location being transmitted in said location information.

34. The method of claim 26, further comprising:

operating the first base station to determine its position by triangulating received signals.

35. The method of claim 34, wherein the received signals are OFDM beacon signals from a plurality of base stations.

36. The method of claim 28, wherein the first base station is included in an air vehicle.

37. The method of claim 36, wherein base station position information is sent at least once every 1 second.

38. The method of claim 26, wherein said first base station transmits said position information over a wireless communications channel using OFDM signaling.

39. The method of claim 26, further comprising:

operating the first base station to transmit user data to a wireless terminal using OFDM signaling; and

operating the first base station to receive user data communicated using OFDM signaling from said wireless terminal.

40. The method of claim 26, further comprising:

operating a second base station having, for at least a period of time, a transmission coverage area located adjacent a coverage area of said first base station to;

periodically transmit second base station identification information identifying the second base station, said second base station identification information being different from said first base station identification information; and

periodically transmit second base station location information.

41. The method of claim 27,

wherein the first and second base stations are moving base stations;

and

wherein the step of periodically transmitting second base station location information includes;

updating said second base station location information to reflect changes in the position of said second base station over time.

42. The method of claim 41, wherein said first and second base stations are air vehicle based base stations.

43. The method of claim 41, wherein said first and second base stations are satellite based base stations.

44. The method of claim 26, wherein the first base station is a portable ground based base station using OFDM signaling.