METHODS AND APPARATUS FOR SUPPORTING SYNCHRONIZATION BETWEEN GROUPS OF DEVICES

• US 20110222515A1
• Filed: 03/12/2010
• Published: 09/15/2011
• Est. Priority Date: 03/12/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wang, Hua, Jovicic, Aleksandar, Wu, Xinzhou, Li, Junyi, Shakkottai, Sanjay
• Granted Patent: US 8,483,196 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

Methods and apparatus related to supporting rapid synchronization between groups of wireless communications devices are described. Described methods and apparatus are well suited for use in peer to peer wireless communications systems in which a plurality of ad hoc peer to peer networks may be formed, each ad hoc network operating with its own notion of time. As two groups of devices, having different notions of time, come within proximity of one another, a wireless communications device of a first group detects the presence of a member of a second group. The wireless device determines that network timing re-synchronization is to be performed by one of the first and second groups and transmits a re-synchronization alert signal on a dedicated resource. Subsequently, the wireless device transmits a timing synchronization signal in accordance with new timing. Intended devices, which detect the alert signal and timing synchronization signal, adjust their internal timing.

Claims

1. A method of operating a wireless communications device, the method comprising:

determining that a network timing re-synchronization is to be performed; and

transmitting a re-synchronization alert signal indicating that devices receiving the re-synchronization alert signal should perform a network timing re-synchronization operation.

2. The method of claim 1, wherein transmitting said re-synchronization alert signal includes using a dedicated communications resource, said dedicated communications resource being dedicated to communicating network re-synchronization alert signals.

3. The method of claim 2, further comprising:

transmitting a timing synchronization signal following transmission of said re-synchronization alert signal.

4. The method of claim 3, wherein said wireless communications device is synchronized to the timing of a first ad hoc communications network and is within timing synchronization signal range of a second ad hoc communications network, said timing synchronization signal propagating timing information from the second ad hoc communications network to the first ad hoc communications network.

5. The method of claim 3, wherein said wireless communications device is synchronized to the timing of a first ad hoc communications network and is within timing synchronization signal range of a second ad hoc communications network, said timing synchronization signal propagating timing information from the first ad hoc communications network to the second ad hoc communications network.

6. The method of claim 1, further comprising:

receiving a re-synchronization alert signal transmitted by another wireless communications device;

refraining from further transmissions until a timing synchronization signal is received; and

updating first ad hoc communications network wireless communications device timing based on the received timing synchronization signal.

7. The method of claim 6 further comprising:

returning to normal network communication operation using said updated wireless communications device timing.

8. A wireless communications device comprising:

means for determining that a network timing re-synchronization is to be performed; and

means for transmitting a re-synchronization alert signal indicating that devices receiving the re-synchronization alert signal should perform a network timing re-synchronization operation.

9. The wireless communications device of claim 8, wherein means for transmitting said re-synchronization alert signal includes means for using a dedicated communications resource, said dedicated communications resource being dedicated to communicating network re-synchronization alert signals.

10. The wireless communications device of claim 9, further comprising:

means for transmitting a timing synchronization signal following transmission of said re-synchronization alert signal.

11. The wireless communications device of claim 10, wherein said wireless communications device is synchronized to the timing of a first ad hoc communications network and is within timing synchronization signal range of a second ad hoc communications network, said timing synchronization signal propagating timing information from the second ad hoc communications network to the first ad hoc communications network.

12. The wireless communications device of claim 10, wherein said wireless communications device is synchronized to the timing of a first ad hoc communications network and is within timing synchronization signal range of a second ad hoc communications network, said timing synchronization signal propagating timing information from the first ad hoc communications network to the second ad hoc communications network.

13. The wireless communications device of claim 8, further comprising:

means for receiving a re-synchronization alert signal transmitted by another wireless communications device;

means for refraining from further transmissions until a timing synchronization signal is received; and

means for updating first ad hoc communications network wireless communications device timing based on the received timing synchronization signal.

14. The wireless communications device of claim 13 further comprising:

means for returning to normal network communication operation using said updated wireless communications device timing.

15. A computer program product for use in a wireless communications device, the computer program product comprising:

a computer readable medium comprising;

code for causing at least one computer to determine that a network timing re-synchronization is to be performed; and

code for causing said at least one computer to transmit a re-synchronization alert signal indicating that devices receiving the re-synchronization alert signal should perform a network timing re-synchronization operation.

16. A wireless communications device comprising:

at least one processor configured to;

determine that a network timing re-synchronization is to be performed; and

transmit a re-synchronization alert signal indicating that devices receiving the re-synchronization alert signal should perform a network timing re-synchronization operation;

and memory coupled to said at least one processor.

17. The wireless communications device of claim 16, wherein said at least one processor is configured to include using a dedicated communications resource, as part of being configured to transmit said re-synchronization alert signal, said dedicated communications resource being dedicated to communicating network re-synchronization alert signals.

18. The wireless communications device of claim 17, wherein said at least one processor is further configured to:

transmit a timing synchronization signal following transmission of said re-synchronization alert signal.

19. The wireless communications device of claim 18, wherein said wireless communications device is synchronized to the timing of a first ad hoc communications network and is within timing synchronization signal range of a second ad hoc communications network, said timing synchronization signal propagating timing information from the second ad hoc communications network to the first ad hoc communications network.

20. The wireless communications device of claim 18, wherein said wireless communications device is synchronized to the timing of a first ad hoc communications network and is within timing synchronization signal range of a second ad hoc communications network, said timing synchronization signal propagating timing information from the first ad hoc communications network to the second ad hoc communications network.