METHODS AND SYSTEMS FOR MOBILE DEVICE CLOCK MANAGEMENT

• US 20150124675A1
• Filed: 09/30/2014
• Published: 05/07/2015
• Est. Priority Date: 11/04/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Farmer, Dominic Gerard, Wu, Jie, Morrison, William James, Lin, Tong, Rao, Krishnaranjan S.
• Granted Patent: US 10,149,261 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04J 3/0661 using timestamps
• CPC Class Codes: H04J 3/0685 Clock or time synchronisation in a node; Intranode synchronisation
• CPC Class Codes: H04L 7/0012 by comparing receiver clock with transmitter clock
• CPC Class Codes: H04L 7/0025 interpolation of clock signal
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Disclosed are methods, systems and/or devices to calibrate a network time by acquisition of satellite positioning system (SPS) signals and different instances of time, and time-tagging SPS times according to the network time. In particular, the network time may be calibrated based, at least in part, on a first difference between first and second SPS times obtained at two SPS position fixes and a second difference between corresponding first and second time stamps.

Claims

1. A method, at a mobile device, comprising:

obtaining a first value of a sleep counter and a first time stamp in response to the mobile device entering a lower power state, wherein the first time stamp is referenced to a local network time;

entering a higher power state to acquire a paging signal;

obtaining a second value of the sleep counter and a second time stamp while in the higher power state, wherein the second time stamp is referenced to the local network time;

returning to the lower power state; and

estimating an increment cycle of the sleep counter based, at least in part, on a first difference between the first time stamp and the second time stamp, and second difference between the first value of the sleep counter and the second value of the sleep counter.

2. The method of claim 1, and further comprising determining the local network time based, at least in part, on acquisition of the paging signal.

3. The method of claim 1, and further comprising:

propagating a system clock time based, at least in part, on the estimated increment cycle of the sleep counter.

4. The method of claim 3, wherein the system clock time is propagated by an amount based, at least in part, on the second difference multiplied by the estimated increment cycle of the sleep counter.

5. The method of claim 3, and further comprising initiating acquisition of one or more satellite positioning system (SPS) signals based, at least in part, on the propagated system clock time.

6. The method of claim 5, and further comprising determining a time uncertainty for acquisition of the one or more SPS signals based, at least in part, on a temperature of the mobile device.

7. The method of claim 6, wherein the time uncertainty is further determined based, at least in part, on an uncertainty is the local network time.

8. The method of claim 1, and further comprising:

receiving a request to perform an SPS position fix while the mobile device is in the lower power state; and

attempting to perform the SPS position fix based, at least in part, on the estimated increment cycle.

9. The method of claim 1, wherein the lower power state comprises a sleep state.

10. The method of claim 1, wherein the first time stamp and the second time stamp are obtained during paging slots.

11. A mobile device comprising:

a receiver;

a sleep counter circuit; and

one or more processors configured to;

obtain a first value of a sleep counter and a first time stamp in response to the mobile device entering a lower power state, wherein the first time stamp is referenced to a local network time;

transition the mobile device to a higher power state to acquire a paging signal received at the receiver;

obtain a second value of the sleep counter and a second time stamp while in the higher power state, wherein the second time stamp is referenced to the local network time;

transition the mobile device to the lower power state; and

estimate an increment cycle of the sleep counter based, at least in part, on a first difference between the first time stamp and the second time stamp, and second difference between the first value of the sleep counter and the second value of the sleep counter.

12. The mobile device of claim 11, wherein the one or more processors are further configured to determine the local network time based, at least in part, on acquisition the paging signal.

13. The mobile device of claim 11, wherein the one or more processors are further configured to propagate a system clock time based, at least in part, on the estimated increment cycle of the sleep counter circuit.

14. The mobile device of claim 13, wherein the one or processors are further configured to propagate the system clock time by an amount based, at least in part, on the second difference multiplied by the estimated increment cycle.

15. The mobile device of claim 13, and wherein the one or more processors are further configured to initiate acquisition of one or more satellite positioning system (SPS) signals based, at least in part, on the propagated system clock time.

16. The mobile device of claim 15, wherein the one or more processors are further configured to determine a time uncertainty for acquisition of the one or more SPS signals based, at least in part, on a temperature of the mobile device.

17. A non-transitory storage medium comprising machine-readable instructions stored thereon which are executable by one or more processors of a mobile device to:

obtain a first value of a sleep counter and a first time stamp in response to the mobile device entering a lower power state, wherein the first time stamp is referenced to a local network time;

transition the mobile device to a higher power state to acquire a paging signal;

obtain a second value of the sleep counter and a second time stamp while in the higher power state, wherein the second time stamp is referenced to the local network time;

transition the mobile device to the lower power state; and

estimate an increment cycle of the sleep counter based, at least in part, on a first difference between the first time stamp and the second time stamp, and second difference between the first value of the sleep counter and the second value of the sleep counter.

18. The non-transitory storage medium of claim 17, wherein the machine-readable instructions are further executable to determine the local network time based, at least in part, on acquisition of the paging signal.

19. The non-transitory storage medium of claim 18, wherein the machine-readable instructions are further executable to:

propagate a system clock time based, at least in part, on the estimated increment cycle of the sleep counter.

20. The non-transitory storage medium of claim 19, wherein the system clock time is propagated by an amount based, at least in part, on the second difference multiplied by the estimated increment cycle.

21. The non-transitory storage medium of claim 19, wherein the machine-readable instructions are further executable to initiate acquisition of one or more satellite positioning system (SPS) signals based, at least in part, on the propagated system clock time.

22. At a mobile device, an apparatus comprising:

means for obtaining a first value of a sleep counter and a first time stamp in response to the mobile device entering a lower power state, wherein the first time stamp is referenced to a local network time;

means for entering a higher power state to acquire a paging signal;

means for obtaining a second value of the sleep counter and a second time stamp while in the higher power state, wherein the second time stamp is referenced to the local network time;

means for returning to the lower power state; and

means for estimating an increment cycle of the sleep counter based, at least in part, on a first difference between the first time stamp and the second time stamp, and second difference between the first value of the sleep counter and the second value of the sleep counter.

23. The apparatus of claim 22, and further comprising means for determining the local network time based, at least in part, on acquisition of the paging signal.

24. The apparatus of claim 22, and further comprising:

means for propagating a system clock time based, at least in part, on the estimated increment cycle of the sleep counter.

25. The apparatus of claim 24, wherein the system clock time is propagated by an amount based, at least in part, on the second difference multiplied by the estimated increment cycle of the sleep counter.

26. The apparatus of claim 24, and further comprising means for initiating acquisition of one or more satellite positioning system (SPS) signals based, at least in part, on the propagated system clock time.

27. The apparatus of claim 26, and further comprising means for determining a time uncertainty for acquisition of the one or more SPS signals based, at least in part, on a temperature of the mobile device.

28. The apparatus of claim 27, wherein the time uncertainty is further determined based, at least in part, on an uncertainty is the local network time.