TIMING SYNCHRONIZATION METHODS AND APPARATUS

• US 20120307698A1
• Filed: 06/06/2012
• Published: 12/06/2012
• Est. Priority Date: 01/12/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sampath, Ashwin, Li, Junyi, Tavildar, Saurabh
• Granted Patent: US 8,923,226 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Various methods and apparatus are directed to achieving timing synchronization and propagating timing information pertaining to an external, e.g., non Wi-Fi, timing signal source. In some embodiments, a mobile communications device receives and processes a timing signal, e.g., a first Wi-Fi beacon, which is propagating timing information about an external timing signal from a device which directly received the external timing signal. Thus, a mobile wireless communications device achieves timing synchronization with respect to an external timing signal which it is unable to receive directly. In various embodiments, the mobile communications device may, and sometimes does, further propagate the timing information about the external timing signal, e.g., via a second Wi-Fi beacon signal which it generates and transmits. Synchronization with respect to an external signal source facilitates longer sleep states and decreased power consumption.

Claims

1. (canceled)

2. An apparatus for wireless communications, comprising:

a first circuit configured to alternate the apparatus between a sleep mode and a wake mode at similar time periods as one or more other apparatuses,

wherein the apparatus alternates between the sleep mode and the wake mode with a frequency similar to one or more frequencies of alternating between sleep and wake modes of the one or more other apparatuses.

3. The apparatus of claim 2, wherein the first circuit is also configured to alternate the apparatus between the sleep mode and the wake mode at same time instants as the one or more other apparatuses.

4. The apparatus of claim 3, further comprising:

a receiver configured to receive information about the time instants from an external source device.

5. The apparatus of claim 4, wherein the information comprises information about at least one of a calibrated clock or a reference time, and the apparatus further comprising:

a second circuit configured to obtain the time instants based on the at least one of calibrated clock or reference time.

6. The apparatus of claim 5, wherein:

the receiver is also configured to receive information about the calibrated clock from a Global Positioning System (GPS) based device comprising the external source device.

7. The apparatus of claim 5, wherein:

the receiver is also configured to receive information about the calibrated clock from the external source device associated with a Code Division Multiple Access (CDMA) wireless communications system.

8. The apparatus of claim 5, wherein:

the receiver is also configured to receive information about the calibrated clock from the external source device associated with a Universal Mobile Telecommunications System (UMTS) wireless communications system.

9. The apparatus of claim 2, further comprising:

a second circuit configured to discover the one or more other apparatuses for communication during the wake mode of the apparatus.

10. A method for wireless communications, comprising:

alternating an apparatus between a sleep mode and a wake mode at similar time periods as one or more other apparatuses,

wherein the apparatus alternates between the sleep mode and the wake mode with a frequency similar to one or more frequencies of alternating between sleep and wake modes of the one or more other apparatuses.

11. The method of claim 10, wherein alternating comprises:

alternating the apparatus between the sleep mode and the wake mode at same time instants as the one or more other apparatuses.

12. The method of claim 11, further comprising:

receiving information about the time instants from an external source device.

13. The method of claim 12, wherein the information comprises information about at least one of a calibrated clock or a reference time, and the method further comprising:

obtaining the time instants based on the at least one of calibrated clock or reference time.

14. The method of claim 13, further comprising:

receiving information about the calibrated clock from a Global Positioning System (GPS) based device comprising the external source device.

15. The method of claim 13, further comprising:

receiving information about the calibrated clock from the external source device associated with a Code Division Multiple Access (CDMA) wireless communications system.

16. The method of claim 13, further comprising:

receiving information about the calibrated clock from the external source device associated with a Universal Mobile Telecommunications System (UMTS) wireless communications system.

17. The method of claim 10, further comprising:

discovering the one or more other apparatuses for communication during the wake mode of the apparatus.

18. An apparatus for wireless communications, comprising:

means for alternating the apparatus between a sleep mode and a wake mode at similar time periods as one or more other apparatuses,

wherein the apparatus alternates between the sleep mode and the wake mode with a frequency similar to one or more frequencies of alternating between sleep and wake modes of the one or more other apparatuses.

19. The apparatus of claim 18, wherein the means for alternating comprises:

means for alternating the apparatus between the sleep mode and the wake mode at same time instants as the one or more other apparatuses.

20. The apparatus of claim 19, further comprising:

means for receiving information about the time instants from an external source device.

21. The apparatus of claim 20, wherein the information comprises information about at least one of a calibrated clock or a reference time, and the apparatus further comprising:

means for obtaining the time instants based on the at least one of calibrated clock or reference time.

22. The apparatus of claim 21, wherein:

the means for receiving is further configured to receive information about the calibrated clock from a Global Positioning System (GPS) based device comprising the external source device.

23. The apparatus of claim 21, wherein:

the means for receiving is further configured to receive information about the calibrated clock from the external source device associated with a Code Division Multiple Access (CDMA) wireless communications system.

24. The apparatus of claim 21, wherein:

the means for receiving is further configured to receive information about the calibrated clock from the external source device associated with a Universal Mobile Telecommunications System (UMTS) wireless communications system.

25. The apparatus of claim 18, further comprising:

means for discovering the one or more other apparatuses for communication during the wake mode of the apparatus.

26. A computer program product for wireless communications, comprising a computer-readable medium comprising instructions executable to:

alternate an apparatus between a sleep mode and a wake mode at similar time periods as one or more other apparatuses,

wherein the apparatus alternates between the sleep mode and the wake mode with a frequency similar to one or more frequencies of alternating between sleep and wake modes of the one or more other apparatuses.

27. A wireless terminal, comprising:

at least one antenna;

a first circuit configured to alternate the wireless terminal between a sleep mode and a wake mode at similar time periods as one or more other wireless terminals,

wherein the wireless terminal alternates between the sleep mode and the wake mode with a frequency similar to one or more frequencies of alternating between sleep and wake modes of the one or more other wireless terminals; and

a transceiver configured to communicate with the one or more other wireless terminals via the at least one antenna upon discovering the one or more other wireless terminals during the wake mode.