Systems and methods for synchronization within a neighborhood aware network

Patent metadata

Field	Value
Publication number	US-9510286-B2
Application number	US-201414213017-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Mar 27, 2013
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

Methods, devices, and computer program products for synchronization of wireless devices in a peer-to-peer network are described herein. In one aspect, a method for determining at least one of a time for exiting and a time for entering a low power sleep mode to utilize a discovery window is provided. The method includes determining an earliest possible start time of a discovery window according to a clock at the first device. The method further includes transitioning from the low power sleep mode to a higher power active mode approximately at the determined earliest possible start time, wherein the determined earliest possible start time is based at least in part on a clock drift value associated with the first device and a clock drift value associated with a second device of the wireless network.

First claim

What is claimed is:

1. In a first device of a neighborhood aware network (NAN), a method of determining at least one of a time for exiting and a time for entering a low power sleep mode to utilize a discovery window comprising:
determining an earliest possible start time of the discovery window according to a clock at the first device;
transitioning from the low power sleep mode to a higher power active mode at the determined earliest possible start time, the determined earliest possible start time based at least in part on a clock drift value associated with the first device and a clock drift value associated with a second device of the network;
receiving, from the second device, a signal defining a start time of the discovery window; and
transitioning to the low power sleep mode at the end of a pre-determined time duration after receiving the signal defining the start time of the discovery window, the pre-determined time duration being independent of a time duration for the first device to transmit, wherein the pre-determined time duration is equal to a pre-determined discovery window duration plus two times the sum of the clock drift value associated with the first device and the clock drift value associated with the second device.

2. The method of claim 1 , wherein the pre-determined time duration is approximately equal to the pre-determined discovery window duration.

3. The method of claim 1 , comprising transitioning to the low power sleep mode at the end of the pre-determined time duration after transitioning from the low power sleep mode.

4. The method of claim 1 , wherein the clock drift value associated with the first device is approximately the same as the clock drift value associated with the second device.

5. The method of claim 1 , wherein the clock drift value associated with the first device is different than the clock drift value associated with the second device.

6. The method of claim 1 , wherein the determined earliest possible start time of the discovery window is equal to an expected start time of the discovery window minus the sum of the clock drift value associated with the first device and the clock drift value associated with the second device.

7. The method of claim 1 , wherein the clock drift values are based at least in part on a time duration between adjacent discovery windows.

8. A wireless communication device in a neighborhood aware network (NAN) comprising:
transceiver circuitry configured to receive, from a second device, a signal defining a start time of a discovery window;
a processor configured to:
communicate with other wireless communication devices in a wireless network during the discovery window used for timing synchronization between networked devices;
determine an earliest possible start time of a discovery window according to a clock source at the wireless communication device;
transition the wireless communication device from a low power sleep mode to a higher power active mode at the determined earliest possible start time, the determined earliest possible start time based at least in part on a maximum clock drift value associated with the wireless communication device and a maximum clock drift value associated with the second device; and
transition the wireless communication device to the low power sleep mode at the end of a pre-determined time duration after receiving the signal defining the start time of the discovery window, the pre-determined time duration being independent of a time duration for the wireless communication device to transmit, wherein the pre-determined time duration is equal to a pre-determined discovery window duration plus two times the sum of the clock drift value associated with the wireless communication device and the clock drift value associated with the second device.

9. The wireless communication device of claim 8 , wherein the pre-determined time duration is approximately equal to the pre-determined discovery window duration.

10. The wireless communication device of claim 8 , wherein the processor is configured to enter the low power sleep mode at the end of the pre-determined time duration after transitioning from the low power sleep mode.

11. The wireless communication device of claim 8 , wherein the clock drift value associated with the wireless communication device is approximately the same as the clock drift value associated with the second device.

12. The wireless communication device of claim 8 , wherein the clock drift value associated with the wireless communication device is different than the clock drift value associated with the second device.

13. The wireless communication device of claim 8 , wherein the determined earliest possible start time of the discovery window is equal to an expected start time of the discovery window minus the sum of the clock drift value associated with the wireless communication device and the clock drift value associated with the second device.

14. The wireless communication device of claim 8 , wherein the clock drift values are based at least in part on a time duration between adjacent discovery windows.

15. A non-transitory computer readable media having instructions stored thereon that cause a wireless communication device to:
communicate with other wireless communication devices in a wireless network during a discovery window used for timing synchronization between networked devices;
determine an earliest possible start time of a discovery window according to a clock source at the wireless communication device;
transition from a low power sleep mode to a higher power active mode at the determined earliest possible start time, the determined earliest possible start time based at least in part on a maximum clock drift value associated with the wireless communication device and a maximum clock drift value associated with a second wireless communication device;
receive, from the second device, a signal defining a start time of the discovery window; and
transition to the low power sleep mode at the end of a pre-determined time duration after receiving the signal defining the start time of the discovery window, the pre-determined time duration being independent of a time duration for the wireless communication device to transmit, wherein the pre-determined time duration is equal to a pre-determined discovery window duration plus two times the sum of the clock drift value associated with the wireless communication device and the clock drift value associated with the second device.

16. The media of claim 15 , wherein the pre-determined time duration is approximately equal to the pre-determined discovery window duration.

17. The media of claim 15 , wherein the instructions cause the wireless communication device to transition to the low power sleep mode at the end of the pre-determined time duration after transitioning from the low power sleep mode.

18. The media of claim 15 , wherein the determined earliest possible start time of the discovery window is equal to an expected start time of the discovery window minus the sum of the clock drift value associated with the wireless communication device and the clock drift value associated with the second device.

19. The media of claim 15 , wherein the clock drift value associated with the wireless communication device is approximately the same as the clock drift value associated with the second device.

20. The media of claim 15 , wherein the clock drift value associated with the wireless communication device is different than the clock drift value associ

Assignees

• Qualcomm Inc

Inventors

• Abraham Santosh Paul
• Cherian George
• Raissinia Alireza
• Frederiks Guido Robert

Classifications

• H04W56/0035

  detecting errors in frequency or phase · CPC title

• H04W56/002

  Mutual synchronization · CPC title

• H04W56/0015

  one node acting as a reference for the others · CPC title

• H04W52/0229

  where the received signal is a wanted signal · CPC title

• H04W8/005

  Discovery of network devices, e.g. terminals · CPC title