Method for synchronizing a radio network using end user radio terminals

• US 7,877,104 B2
• Filed: 05/21/2002
• Issued: 01/25/2011
• Est. Priority Date: 05/21/2001
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Turetzky, Gregory B., Garin, Lionel J.
• Primary Examiner(s): Maung; Nay A
• Assistant Examiner(s): PEREZ, ANGELICA
• Application Number:
  US10/154,138
• Publication Number:
  US 20020173322A1
• Time in Patent Office: 3,171 Days
• Field of Search: 455/502, 455/456.1, 455/456.3, 455/456.5, 455/456.6, 342/357.64
• US Class Current: 455/502
• CPC Class Codes: H04B 7/2693 Centralised synchronisation, i.e. using external universal time reference, e.g. by using a global positioning system [GPS] or by distributing time reference over the wireline network

Abstract

The present invention discloses a method and system for monitoring a wireless network clock compared to an absolute time scale using the user mobile stations themselves. The major advantage is the capability to transfer GPS time to a Mobile Station in a wireless network, and thus to decrease the time necessary for the mobile receiver to perform position calculations, with minimal additional hardware required by the network.

Claims

1. A method for synchronizing an unsynchronized radio network, comprising:

determining GPS time at a mobile GPS receiver which is not synchronized to the radio network;

comparing the determined GPS time to a second time source;

storing an offset between the GPS time and the second time source to synchronize the mobile GPS receiver to the radio network; and

using the stored offset to acquire GPS satellites.

2. The method of claim 1, wherein the storing is performed at the mobile GPS receiver.

3. The method of claim 2, wherein the stored offset is used at a second mobile GPS receiver.

4. The method of claim 2, wherein the comparing is performed at the mobile GPS receiver.

5. The method of claim 4, wherein the second time source is outside of a cellular infrastructure.

6. The method of claim 5, wherein the second time source is a time source selected from a group comprising digital television (DTV), GSM time, TDMA cellular time, WCDMA cellular time, or CDMA2000 cellular time.

7. The method of claim 5, wherein the stored offset is used at the mobile GPS receiver at a later time.

8. The method of claim 5, wherein the stored offset is used at a second mobile GPS receiver.

9. The method of claim 8, wherein the stored offset is transmitted from the first mobile GPS receiver to the second mobile GPS receiver through a communication system.

10. The method of claim 9, wherein the transmitted stored offset is transmitted through a cellular telephone system.

11. The method of claim 9, wherein the storing is performed other than at the mobile GPS receiver.

12. A method for synchronizing an unsynchronized radio network, comprising:

computing an offset between GPS time and a local time source where the offset is computed by a mobile GPS receiver;

storing the offset; and

using the stored offset at a later time to aid in the acquisition of at least one GPS satellite signal.

13. The method of claim 12, wherein the local time source is selected from a group comprising:

digital television (DTV), GSM time, TDMA cellular time, WCDMA cellular time, or CDMA2000 cellular time.

14. The method of claim 13, wherein the offset is computed by more than one mobile GPS receiver.

15. The method of claim 14, wherein the offset is aggregated.

16. The method of claim 14, wherein the offset computed by each mobile GPS receiver is averaged to determine an average offset.

17. The method of claim 16, wherein the offset computed by each mobile GPS receiver is used to model the drift of the local time source.

18. The method of claim 16, wherein the modeled drift is used to determine at least one of a group comprising:

rate of change of the local time source, rate of offset of the local time source, and expected error of the local time source.

19. The method of claim 16, wherein the offset is used in an internet-enable cellular telephone to aid other internet-enabled cellular telephones from the interne server.

20. The method of claim 19, wherein the offset is transmitted from one cellular telephone to another using one of a group comprising SMS, a cellular telephone infrastructure, and a local area network.