POWER SAVE SYSTEM AND METHOD

• US 20070184870A1
• Filed: 02/06/2007
• Published: 08/09/2007
• Est. Priority Date: 02/06/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Olympus Corporation
• Inventors: Heidari-Bateni, Ghobad, Muqattash, Alaa
• Granted Patent: US 8,135,427 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

According to an embodiment of the invention, a system and method to provide alignment of hibernation and active cycles is provided. When one device receives a beacon from one of its neighbors it can be implemented to check for the neighboring device'"'"'s global cycle start countdown value and to compare it'"'"'s global cycle start countdown value with its own. If the beacon from the neighboring device contains a global cycle start countdown value that is different from the device'"'"'s own global cycle start countdown, the device can be implemented to check a predefined condition. For example, if a device'"'"'s global cycle start time falls into the first half of a neighbor'"'"'s global cycle, then the device changes its own global cycle start time to the global cycle start time of that neighbor. In another embodiment, if a device'"'"'s global cycle start time falls into the first 256/K superframes of a neighbor'"'"'s global cycle, then the device changes its own global cycle start time to the global cycle start time of that neighbor. In one embodiment, K can be the number of different global active cycle start times observed by the device.

Claims

1. A method of power management, comprising:

at a first device, receiving a beacon from a neighboring device;

getting the neighboring device'"'"'s global cycle start countdown value;

checking the neighboring device'"'"'s global cycle start countdown value and comparing the neighboring device'"'"'s global cycle start countdown to the first device'"'"'s global cycle start countdown value; and

setting the first device'"'"'s global cycle start countdown value to match the global cycle start countdown value of the neighboring device if a first condition is met.

2. The method of claim 1, wherein the first device and the neighboring device:

receive beacons from each other get each other'"'"'s global cycle start countdown value;

check the each other'"'"'s global cycle start countdown value and compare them; and

wherein a device sets its global cycle start countdown value to match the global cycle start countdown value of the neighboring device if a first condition is met.

3. The method of claim 2, wherein the first condition is generally mutually exclusive such that usually only one of the two device will met the first condition.

4. The method of claim 3, wherein the first condition comprises [GCSC_self−

GCSC_neighbor] modulo 256<

128.

5. The method of claim 3, further comprising a tie-breaking method when the condition is not mutually exclusive.

6. The method of claim 5, wherein the first condition comprises [GCSC_self−

GCSC_neighbor] modulo 256=128.

7. The method of claim 5, wherein the tie-breaking method comprises each device setting its global cycle start countdown for the next superframe to a random number within the range of possible global cycle start countdown values.

8. A network device comprising:

a memory, the memory configured to store instructions;

a processor coupled to the memory and configured to execute the instructions to perform the following steps;

at a first device, receiving a beacon from a neighboring device;

getting the neighboring device'"'"'s global cycle start countdown value;

checking the neighboring device'"'"'s global cycle start countdown value and comparing the neighboring device'"'"'s global cycle start countdown to the first device'"'"'s global cycle start countdown value; and

setting the first device'"'"'s global cycle start countdown value to match the global cycle start countdown value of the neighboring device if a first condition is met.

9. The network device of claim 8, wherein the first device and the neighboring device:

receive beacons from each other

get each other'"'"'s global cycle start countdown value;

check the each other'"'"'s global cycle start countdown value and compare them; and

wherein a device sets its global cycle start countdown value to match the global cycle start countdown value of the neighboring device if a first condition is met.

10. The network device of claim 9, wherein the first condition is generally mutually exclusive such that usually only one of the two device will met the first condition.

11. The network device of claim 10, wherein the first condition comprises [GCSC_self−

GCSC_neighbor] modulo 256<

128.

12. The network device of claim 10, further comprising a tie-breaking method when the condition is not mutually exclusive.

13. The network device of claim 12, wherein the first condition comprises [GCSC_self−

GCSC_neighbor] modulo 256=128.

14. The network device of claim 12, wherein the tie-breaking method comprises each device setting its global cycle start countdown for the next superframe to a random number within the range of possible global cycle start countdown values.

15. A method of power management, comprising:

receiving a beacon from a neighboring device;

getting the neighboring devices global cycle start countdown value;

checking the neighboring device'"'"'s global cycle start countdown value and comparing it to its own global cycle start countdown value, wherein the checking step is configured such that it can check more than two devices; and

setting its global cycle start countdown value to match the global cycle start countdown value of the neighboring device if a first condition is met.

16. The method of claim 15, further comprising a tie-breaking method.

17. The method of claim 15, wherein the first condition comprises [GCSC_self−

GCSC_k] modulo 256<

256/K.

18. The method of claim 17, further comprising repeating the getting the neighbor'"'"'s global cycle start countdown value and checking the neighbor'"'"'s global cycle start countdown value steps with a reduced value of K.

19. The method of claim 18, wherein K is reduced by 1 for each iteration of getting and checking the GCSCs.

20. The method of claim 17, further comprising repeating the getting the neighbor'"'"'s global cycle start countdown value and checking the neighbor'"'"'s global cycle start countdown value steps with a different value of K after a random number of superframes.

21. The method of claim 20, wherein the different value of K is 2.

22. The method of claim 20, wherein the random number is equal to n+r where r is a random number between 1 and k.

23. The method of claim 17, wherein K is assumed to be 2 whenever the number of devices is greater than 2.

24. A network device comprising:

a memory, the memory configured to store instructions;

a processor coupled to the memory and configured to execute the instructions to perform the following steps;

receiving a beacon from a neighboring device;

getting the neighboring devices global cycle start countdown value;

checking the neighboring device'"'"'s global cycle start countdown value to its own global cycle start countdown value, wherein the checking step is configured such that it can check more than two devices; and

setting its global cycle start countdown value to match the global cycle start countdown value of the neighboring device if a first condition is met.

25. The network device of claim 24, further comprising a tie-breaking method.

26. The network device of claim 24, wherein the first condition comprises [GCSC_self−

GCSC_k] module 256<

256/K.

27. The network device of claim 26, further comprising repeating the getting the neighbor'"'"'s global cycle start countdown value and checking the neighbor'"'"'s global cycle start countdown value steps with a reduced value of K.

28. The network device of claim 27, wherein K is reduced by 1 for each iteration of getting and checking the GCSCs.

29. The network device of claim 26, further comprising repeating the getting the neighbor'"'"'s global cycle start countdown value and checking the neighbor'"'"'s global cycle start countdown value steps with a different value of K after a random number of superframes.

30. The network device of claim 29, wherein the different value of K is 2.

31. The network device of claim 29, wherein the random number is equal to n+r where r is a random number between 1 and k.

32. The network device of claim 26, wherein K is assumed to be 2 whenever the number of devices is greater than 2.