Dynamic power mode switch in a wireless ad-hoc system

• US 9,185,655 B2
• Filed: 08/14/2013
• Issued: 11/10/2015
• Est. Priority Date: 02/12/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Panneerselvam, Sivakumar, Sathyamurthy, Dhanasekaran
• Primary Examiner(s): Chou, Albert T
• Application Number:
  US13/966,870
• Publication Number:
  US 20130329618A1
• Time in Patent Office: 818 Days
• US Class Current: 1/1
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In ad-hoc wireless networks, functionality can be implemented to dynamically enable/disable an ad-hoc power save mode depending on whether or not the WLAN device is in a continuous traffic environment. The WLAN devices in the ad-hoc wireless network can use beacon frames to transmit a power mode switch request, to respond to a received power mode switch request (to indicate acceptance or rejection of the received power mode switch request), and to indicate a power mode switch status. The WLAN devices switch the power mode if all the WLAN devices in the ad-hoc wireless network accept the power mode switch request. Changing the power mode depending on the environment can improve power savings, data throughput, and reliability.

Claims

1. A method performed by a first wireless network device of an ad-hoc wireless network, in which the first wireless network device transmits a power mode switch request to a plurality of wireless network devices of the ad-hoc wireless network in response to determining that a power mode of the first wireless network device should be changed, the method comprising:

determining whether to change the power mode of the first wireless network device based, at least in part, on power mode switch responses received from the plurality of wireless network devices responsive to the power mode switch request; and

transmitting, to the plurality of wireless network devices, a notification including a predefined value that indicates whether to change or maintain a corresponding power mode of each of the plurality of wireless network devices based, at least in part, on said determining whether to change the power mode of the first wireless network device.

2. The method of claim 1, wherein said determining whether to change the power mode of the first wireless network device further comprises:

receiving an acceptance power mode switch response at the first wireless network device from each of the plurality of wireless network devices; and

determining to change the power mode of the first wireless network device.

3. The method of claim 1, wherein said determining whether to change the power mode of the first wireless network device further comprises:

receiving a rejection power mode switch response at the first wireless network device from a second wireless network device of the plurality of wireless network devices; and

determining to maintain the power mode of the first wireless network device.

4. The method of claim 1, wherein said determining whether to change the power mode of the first wireless network device further comprises:

determining that a power mode switch response was not received at the first wireless network device from a second wireless network device of the plurality of wireless network devices; and

determining to maintain the power mode of the first wireless network device.

5. The method of claim 1, wherein said transmitting the notification further comprises:

receiving an acceptance power mode switch response at the first wireless network device from each of the plurality of wireless network devices; and

determining to transmit the notification including the predefined value indicating to change the corresponding power mode of each of the plurality of wireless network devices.

6. The method of claim 1, wherein said transmitting the notification further comprises:

receiving a rejection power mode switch response at the first wireless network device from a second wireless network device of the plurality of wireless network devices; and

determining to transmit the notification including the predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices.

7. The method of claim 1, wherein said transmitting the notification further comprises:

determining that a power mode switch response was not received at the first wireless network device from a second wireless network device of the plurality of wireless network devices; and

determining to transmit the notification including the predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices.

8. The method of claim 1, wherein said transmitting the notification comprises:

transmitting a beacon frame including a first predefined value indicating to change the corresponding power mode of each of the plurality of wireless network devices, in response to determining to change the power mode of the first wireless network device; and

transmitting the beacon frame including a second predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to determining to maintain the power mode of the first wireless network device.

9. The method of claim 1, wherein said determining that the power mode of the first wireless network device should be changed further comprises:

determining that the ad-hoc wireless network is a continuous traffic environment;

determining that an ad-hoc power save mode is enabled at the first wireless network device; and

determining that the ad-hoc power save mode can be disabled at the first wireless network device.

10. The method of claim 1, wherein said transmitting the power mode switch request comprises at least one member selected from the group consisting of:

transmitting a multicast announcement traffic indication map (ATIM) frame including a first predefined value; and

transmitting an initial beacon frame including a second predefined value.

11. The method of claim 10, wherein the first predefined value is transmitted in a power management field of the multicast ATIM frame.

12. The method of claim 10,

wherein the second predefined value is transmitted in a power management acceptance (PMA) field of an independent basic service set (IBSS) parameters field of the initial beacon frame.

13. The method of claim 1, further comprising:

initiating, by the first wireless network device, a timer associated with a tolerance time interval after transmitting the power mode switch request, wherein the tolerance time interval indicates a maximum time interval for the first wireless network device to receive the power mode switch responses.

14. The method of claim 13, further comprising:

determining the tolerance time interval based, at least in part, on a combination of a beacon interval of the first wireless network device and a number of the plurality of wireless network devices.

15. The method of claim 1, further comprising:

determining that a tolerance time interval has elapsed, wherein the tolerance time interval indicates a maximum time interval for the first wireless network device to receive the power mode switch responses; and

determining whether to change the power mode of the first wireless network device, in response to determining that a power mode switch response was received from each of the plurality of wireless network devices before the tolerance time interval elapsed.

16. The method of claim 15, comprising:

transmitting the notification including the predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to determining that the power mode switch response was not received from each of the plurality of wireless network devices before the tolerance time interval elapsed.

17. The method of claim 1, further comprising:

changing the power mode of the first wireless network device at a start of a next beacon interval after determining to change the power mode of the first wireless network device.

18. The method of claim 1, wherein the first wireless network device and the plurality of wireless network devices are configured to implement at least one wireless local area network (WLAN) protocol.

19. A method comprising:

receiving, at a first wireless network device of an ad-hoc wireless network, a power mode switch request from a second wireless network device of the ad-hoc wireless network, wherein the power mode switch request includes a request for changing a power mode of the first wireless network device;

determining whether the power mode of the first wireless network device can be changed; and

transmitting a power mode switch response from the first wireless network device to the second wireless network device, wherein the power mode switch response includes a predefined value that indicates whether the power mode of the first wireless network device can be changed in response to the power mode switch request.

20. The method of claim 19, wherein said transmitting the power mode switch response comprises:

transmitting the power mode switch response including a first predefined value in response to determining that the power mode of the first wireless network device can be changed; and

transmitting the power mode switch response including a second predefined value in response to determining that the power mode of the first wireless network device cannot be changed.

21. The method of claim 19, further comprising:

determining whether the ad-hoc wireless network is a continuous traffic environment.

22. The method of claim 19, wherein said receiving the power mode switch request comprises at least one member selected from the group consisting of:

receiving a multicast announcement traffic indication map (ATIM) frame including a first predefined value, and

receiving an initial beacon frame including a second predefined value.

23. The method of claim 19, wherein said transmitting the power mode switch response comprises:

transmitting a beacon frame including a first predefined value in response to determining that the power mode of the first wireless network device can be changed, wherein the first predefined value is transmitted in a power management acceptance (PMA) field of the beacon frame; and

transmitting the beacon frame including a second predefined value in response to determining that the power mode of the first wireless network device cannot be changed, wherein the second predefined value is transmitted in the PMA field of the beacon frame.

24. The method of claim 19, further comprising:

receiving a power mode switch status from the second wireless network device, wherein the power mode switch status indicates whether a corresponding power mode of each of a plurality of wireless network devices of the ad-hoc wireless network should be changed; and

determining whether to change or maintain the power mode of the first wireless network device based, at least in part, on the power mode switch status.

25. A first wireless network device of an ad-hoc wireless network, the first wireless network device configured to transmit a power mode switch request to a plurality of wireless network devices of the ad-hoc wireless network in response to determining that a power mode of the first wireless network device should be changed, the first wireless network device comprising:

a processor unit; and

a power management unit coupled with the processor unit, the power management unit configured to;

determine whether to change the power mode of the first wireless network device based, at least in part, on power mode switch responses received from the plurality of wireless network devices responsive to the power mode switch request; and

transmit, to the plurality of wireless network devices, a notification including a predefined value that indicates whether to change or maintain a corresponding power mode of each of the plurality of wireless network devices based, at least in part, on determining whether to change the power mode of each of the first wireless network device.

26. The first wireless network device of claim 25, wherein the power management unit is further configured to:

determine to change the power mode of the first wireless network device, in response to receiving an acceptance power mode switch response from each of the plurality of wireless network devices;

determine to maintain the power mode of the first wireless network device, in response to receiving a rejection power mode switch response from a second wireless network device of the plurality of wireless network devices; and

determine to maintain the power mode of the first wireless network device, in response to determining that a power mode switch response was not received from the second wireless network device.

27. The first wireless network device of claim 25, wherein the power management unit is further configured to:

determine to transmit the notification including a first predefined value indicating to change the corresponding power mode of each of the plurality of wireless network devices, in response to receiving an acceptance power mode switch response from each of the plurality of wireless network devices;

determine to transmit the notification including a second predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to receiving a rejection power mode switch response from a second wireless network device of the plurality of wireless network devices; and

determine to transmit the notification including the second predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to determining that a power mode switch response was not received from the second wireless network device.

28. The first wireless network device of claim 25, wherein the power management unit is further configured to:

initiate a timer associated with a tolerance time interval after transmitting the power mode switch request, wherein the tolerance time interval indicates a maximum time interval for the first wireless network device to receive the power mode switch responses.

29. The first wireless network device of claim 28, wherein the power management unit is further configured to:

determine whether to change the power mode of the first wireless network device, in response to determining that a power mode switch response was received from each of the plurality of wireless network devices before the tolerance time interval elapsed; and

transmit the notification including the predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to determining that the power mode switch response was not received from each of the plurality of wireless network devices before the tolerance time interval elapsed.

30. A first wireless network device of an ad-hoc wireless network comprising:

a processor unit; and

a power management unit coupled with the processor unit, the power management unit configured to;

receive a power mode switch request from a second wireless network device of the ad-hoc wireless network, wherein the power mode switch request includes a request for changing a power mode of the first wireless network device;

determine whether the power mode of the first wireless network device can be changed; and

transmit a power mode switch response from the first wireless network device to the second wireless network device, wherein the power mode switch response includes a predefined value that indicates whether the power mode of the first wireless network device can be changed in response to the power mode switch request.

31. The first wireless network device of claim 30, wherein the power management unit is further configured to:

transmit the power mode switch response including a first predefined value in response to determining that the power mode of the first wireless network device can be changed; and

transmit the power mode switch response including a second predefined value in response to determining that the power mode of the first wireless network device cannot be changed.

32. The first wireless network device of claim 30, wherein the power management unit is further configured to:

receive a power mode switch status from the second wireless network device, wherein the power mode switch status indicates whether a corresponding power mode of each of a plurality of wireless network devices of the ad-hoc wireless network should be changed; and

determine whether to change or maintain the power mode of the first wireless network device based, at least in part, on the power mode switch status.

33. A non-transitory machine-readable storage medium having machine executable instructions stored therein, the machine executable instructions comprising instructions to:

transmit, from a first wireless network device of an ad-hoc wireless network, a power mode switch request to a plurality of wireless network devices of the ad-hoc wireless network, in response to determining that a power mode of the first wireless network device should be changed;

determine whether to change the power mode of the first wireless network device based, at least in part, on power mode switch responses received from the plurality of wireless network devices responsive to the power mode switch request; and

transmit, to the plurality of wireless network devices, a notification including a predefined value that indicates whether to change or maintain a corresponding power mode of each of the plurality of wireless network devices based, at least in part, on determining whether to change the power mode of the first wireless network device.

34. The non-transitory machine-readable storage medium of claim 33, wherein said instructions to determine whether to change the power mode of the first wireless network device comprise instructions to:

determine to change the power mode of the first wireless network device, in response to receiving an acceptance power mode switch response from each of the plurality of wireless network devices;

determine to maintain the power mode of the first wireless network device, in response to receiving a rejection power mode switch response from a second wireless network device of the plurality of wireless network devices; and

determine to maintain the power mode of the first wireless network device, in response to determining that a power mode switch response was not received from the second wireless network device.

35. The non-transitory machine-readable storage medium of claim 33, wherein said instructions further comprise instructions to:

determine to transmit the notification including a first predefined value indicating to change the corresponding power mode of each of the plurality of wireless network devices, in response to receiving an acceptance power mode switch response at the first wireless network device from each of the plurality of wireless network devices;

determine to transmit the notification including a second predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to receiving a rejection power mode switch response at the first wireless network device from a second wireless network device of the plurality of wireless network devices; and

determine to transmit the notification including the second predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to determining that a power mode switch response was not received at the first wireless network device from the second wireless network device.

36. The non-transitory machine-readable storage medium of claim 33, wherein said instructions further comprise instructions to:

initiate a timer associated with a tolerance time interval after transmitting the power mode switch request, wherein the tolerance time interval indicates a maximum time interval for the first wireless network device to receives the power mode switch responses.

37. The non-transitory machine-readable storage medium of claim 36, wherein said instructions further comprise instructions to:

determine whether to change the power mode of the first wireless network device, in response to determining that a power mode switch response was received from each of the plurality of wireless network devices before the tolerance time interval elapsed; and

transmit the notification including the predefined value indicating to maintain the corresponding power mode of each of the plurality of wireless network devices, in response to determining that the power mode switch response was not received from each of the plurality of wireless network devices before the tolerance time interval elapsed.

38. A non-transitory machine-readable storage medium having machine executable instructions stored therein, the machine executable instructions comprising instructions to:

receive, at a first wireless network device of an ad-hoc wireless network, a power mode switch request from a second wireless network device of the ad-hoc wireless network, wherein the power mode switch request includes a request for changing a power mode of the first wireless network device;

determine whether the power mode of the first wireless network device can be changed; and

transmit a power mode switch response from the first wireless network device to the second wireless network device, wherein the power mode switch response includes a predefined value that indicates whether the power mode of the first wireless network device can be changed in response to the power mode switch request.

39. The non-transitory machine-readable storage medium of claim 38, wherein said instructions to transmit the power mode switch response comprise instructions to:

transmit the power mode switch response including a first predefined value in response to determining that the power mode of the first wireless network device can be changed; and

transmit the power mode switch response including a second predefined value in response to determining that the power mode of the first wireless network device cannot be changed.

40. The non-transitory machine-readable storage medium of claim 38, wherein said instructions further comprise instructions to:

receive a power mode switch status from the second wireless network device, wherein the power mode switch status indicates whether a corresponding power mode of each of a plurality of wireless network devices of the ad-hoc wireless network should be changed; and

determine whether to change or maintain the power mode of the first wireless network device based, at least in part, on the power mode switch status.