Dynamic power mode switch in a wireless ad-hoc system

• US 8,537,733 B1
• Filed: 02/12/2010
• Issued: 09/17/2013
• 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:
  US12/705,267
• Time in Patent Office: 1,313 Days
• Field of Search: 370/311
• US Class Current: 370/311
• 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 comprising:

determining that a current power mode in a first of a plurality of wireless network devices in an ad-hoc wireless network should be changed;

transmitting a power mode switch request to one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network in response to determining that the current power mode in the first of the plurality of wireless network devices in the ad-hoc wireless network should be changed;

determining whether to transmit, to the one or more additional wireless network devices in the ad-hoc wireless network, a notification in a beacon frame to change the current power mode based, at least in part, on one or more responses to the power mode switch request received from the one or more additional wireless network devices;

transmitting a first predefined value in the beacon frame to the one or more additional wireless network devices to change the current power mode of the one or more additional wireless network devices, in response to determining that the notification to change the current power mode should be transmitted; and

transmitting a second predefined value in the beacon frame to the one or more additional wireless network devices to maintain the current power mode of the one or more additional wireless network devices, in response to determining that the notification to change the current power mode should not be transmitted.

2. The method of claim 1, wherein said determining whether to transmit the notification in the beacon frame to change the current power mode further comprises detecting a successful power mode switch and determining to transmit the notification in the beacon frame to change the current power mode in the one or more additional wireless network devices in response to receiving an acceptance response to the power mode switch request from each of the one or more additional wireless network devices.

3. The method of claim 1, wherein said determining whether to transmit the notification in the beacon frame to change the current power mode further comprises detecting a failed power mode switch and determining to transmit a notification in the beacon frame to maintain the current power mode in the one or more additional wireless network devices, in response to receiving at least one rejection response to the power mode switch request from at least one of the one or more additional wireless network devices.

4. The method of claim 1, further comprising:

changing the current power mode in the first of the plurality of wireless network devices in response to receiving an acceptance response from each of the one or more additional wireless network devices; and

maintaining the current power mode in the first of the plurality of wireless network devices in response to receiving at least one rejection response from at least one of the one or more additional wireless network devices.

5. The method of claim 1, wherein said determining that the current power mode in the first of the plurality of wireless network devices in the ad-hoc wireless network should be changed further comprises:

determining that the ad-hoc wireless network comprising the plurality of wireless network devices is a continuous traffic environment;

determining that an ad-hoc power save mode is enabled in the first of the plurality of wireless network devices; and

determining that the ad-hoc power save mode can be disabled in the first of the plurality of wireless network devices.

6. The method of claim 1, wherein said transmitting the power mode switch request to the one or more additional wireless network devices of the plurality of wireless network devices comprises transmitting a first predefined value in a multicast announcement traffic indication map (ATIM) frame and transmitting a third predefined value in an initial beacon frame.

7. The method of claim 6, wherein said transmitting the first predefined value in the multicast ATIM frame further comprises transmitting the first predefined value in a power management flag in the ATIM frame.

8. The method of claim 6, wherein said transmitting the third predefined value in the initial beacon frame further comprises transmitting the third predefined value in a power management acceptance field in an independent basic service set (IBSS) parameters field in the beacon frame.

9. The method of claim 1, further comprising starting a tolerance interval in response to transmitting the power mode switch request to the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network, wherein the tolerance interval indicates a maximum time interval during which the responses to the power mode switch request are to be received from the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network.

10. The method of claim 9, further comprising determining the tolerance interval based on a product of a beacon interval and a number of the plurality of the wireless network devices in the ad-hoc wireless network.

11. The method of claim 1, further comprising:

determining that a tolerance interval has expired;

determining whether responses to the power mode switch request are received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired;

determining whether the notification to change the current power mode should be transmitted to the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network in response to determining that the responses to the power mode switch request are received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired; and

transmitting the second predefined value in the beacon frame to the one or more additional wireless network devices in response to determining that the responses to the power mode switch request are not received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired.

12. The method of claim 1, wherein said transmitting the first predefined value in the beacon frame to the one or more additional wireless network devices to change the current power mode of the one or more additional wireless network devices further comprises switching the current power mode beginning at a next beacon interval.

13. The method of claim 1, wherein the plurality of network devices are wireless local area network (WLAN) devices.

14. A wireless network device comprising:

a processor unit; and

a power management unit coupled to the processor unit and the network interface, the power management unit configured to;

determine that a current power mode in the wireless network device of a plurality of wireless network devices in an ad-hoc wireless network should be changed;

transmit a power mode switch request to one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network in response to the power management unit determining that the current power mode in the wireless network device of the plurality of wireless network devices in the ad-hoc wireless network should be changed;

determine whether to transmit, to the one or more additional wireless network devices in the ad-hoc wireless network, a notification in a beacon frame to change the current power mode based, at least in part, on one or more responses to the power mode switch request received from the one or more additional wireless network devices;

transmit a first predefined value in a beacon frame to the one or more additional wireless network devices to change the current power mode of the one or more additional wireless network devices, in response to the power management unit determining that the notification to change the current power mode should be transmitted; and

transmit a second predefined value in the beacon frame to the one or more additional wireless network devices to maintain the current power mode of the one or more additional wireless network devices, in response to the power management unit determining that the notification to change the current power mode should not be transmitted.

15. The wireless network device of claim 14, wherein the power management unit configured to determine whether to transmit the notification in the beacon frame to change the current power mode further comprises the power management unit configured to detect a successful power mode switch and to determine to transmit the notification in the beacon frame to change the current power mode in the one or more additional wireless network devices in response to the power management unit receiving an acceptance response to the power mode switch request from each of the one or more additional wireless network devices.

16. The wireless network device of claim 14, wherein the power management unit configured to determine whether to transmit the notification in the beacon frame to change the current power mode further comprises the power management unit configured to detect a failed power mode switch and to determine to transmit a notification in the beacon frame to maintain the current power mode in the one or more additional wireless network devices, in response to the power management unit receiving at least one rejection response to the power mode switch request from at least one of the one or more additional wireless network devices.

17. The wireless network device of claim 14, further comprising the power management unit configured to start a tolerance interval in response to the power management unit transmitting the power mode switch request to the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network, wherein the tolerance interval indicates a maximum time interval during which the responses to the power mode switch request are to be received from the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network.

18. The wireless network device of claim 14, wherein the power management unit is further configured to:

determine that a tolerance interval has expired;

determine whether responses to the power mode switch request are received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired;

determine whether the notification to change the current power mode should be transmitted to the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network in response to the power management unit determining that the responses to the power mode switch request are received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired; and

transmit the second predefined value in the beacon frame to the one or more additional wireless network devices in response to the power management unit determining that the responses to the power mode switch request are not received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired.

19. The wireless network device of claim 14, wherein the power management unit is further configured to:

receive, at the wireless network device of the plurality of wireless network devices, a second power mode switch request from a second of the plurality of wireless network devices;

determine whether to accept the second power mode switch request;

transmit a third predefined value in a second beacon frame in response to the power management unit determining that the second power mode switch request should be accepted; and

transmitting a fourth predefined value in the second beacon frame in response to the power management unit determining that the second power mode switch request should not be accepted.

20. One or more non-transitory machine-readable storage media having instructions stored therein, which when executed by one or more processors causes the one or more processors to perform operations that comprise:

determining that a current power mode in a first of a plurality of wireless network devices in an ad-hoc wireless network should be changed;

transmitting a power mode switch request to one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network in response to determining that the current power mode in the first of the plurality of wireless network devices in the ad-hoc wireless network should be changed;

determining whether to transmit, to the one or more additional wireless network devices in the ad-hoc wireless network, a notification in a beacon frame to change the current power mode based, at least in part, on one or more responses to the power mode switch request received from the one or more additional wireless network devices;

transmitting a first predefined value in the beacon frame to the one or more additional wireless network devices to change the current power mode of the one or more additional wireless network devices, in response to determining that the notification to change the current power mode should be transmitted; and

transmitting a second predefined value in the beacon frame to the one or more additional wireless network devices to maintain the current power mode of the one or more additional wireless network devices, in response to determining that the notification to change the current power mode should not be transmitted.

21. The machine-readable storage media of claim 20, wherein said determining whether to transmit the notification in the beacon frame to change the current power mode further comprises detecting a successful power mode switch and determining to transmit the notification in the beacon frame to change the current power mode in the one or more additional wireless network devices in response to receiving an acceptance response to the power mode switch request from each of the one or more additional wireless network devices.

22. The machine-readable storage media of claim 20, wherein said determining whether to transmit the notification in the beacon frame to change the current power mode further comprises detecting a failed power mode switch and determining to transmit a notification in the beacon frame to maintain the current power mode in the one or more additional wireless network devices, in response to receiving at least one rejection response to the power mode switch request from at least one of the one or more additional wireless network devices.

23. The machine-readable storage media of claim 20, further comprising starting a tolerance interval in response to transmitting the power mode switch request to the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network, wherein the tolerance interval indicates a maximum time interval during which the responses to the power mode switch request are to be received from the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network.

24. The machine-readable storage media of claim 20, wherein the power management unit is further configured to:

determining that a tolerance interval has expired;

determining whether responses to the power mode switch request are received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired;

determining whether the notification to change the current power mode should be transmitted to the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network in response to determining that the responses to the power mode switch request are received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired; and

transmitting the second predefined value in the beacon frame to the one or more additional wireless network devices in response to determining that the responses to the power mode switch request are not received from each of the one or more additional wireless network devices of the plurality of wireless network devices in the ad-hoc wireless network before the tolerance interval expired.