POWER SAVINGS FOR WIRELESS LOCAL AREA NETWORKS

• US 20100002610A1
• Filed: 07/03/2008
• Published: 01/07/2010
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bowser, Robert, Jones, Chad, Metsker, Corey, Carty, Clark
• Granted Patent: US 8,023,444 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: G06F 1/3253 Power saving in bus
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Described in example embodiments herein are techniques for implementing power savings in a wireless local area network (WLAN). In accordance with an example embodiment, a centralized controller can be employed to gather data about network activity and select access points to switch to power save mode. Optionally, the controller may designate certain access points to remain active so as to monitor for clients attempting to access the WLAN. An aspect of an example embodiment is that it allows the controller to configure and manage power consumption based on demands on the overall system. In an example embodiment, techniques for implementing power savings within individual hardware components, such as access points, are disclosed. An aspect of a technique described in an example embodiment is that it provides flexibility to balance power savings and performance.

Claims

1. An apparatus, comprising:

a plurality of ports configured to be coupled to a plurality of access points; and

control logic configured to communicate with the plurality of access points via the plurality of ports and to control operation of the plurality of access points;

wherein the control logic is configured to receive data from the plurality of access points representative of network activity; and

wherein the control logic is configured to select at least one of the plurality of access points to switch to a power save mode based on the data representative of network activity.

2. The apparatus of claim 1, wherein the control logic is further configured to select a single access point from the plurality of access points to remain operational;

and

wherein the control logic is further configured to signal all of the other access points belonging to the plurality of access points to switch to a power save mode.

3. The apparatus of claim 1, wherein the control logic is further configured to select a plurality of access points from the plurality of access points to remain operational;

and

wherein the control logic is further configured to signal all of the other access points belonging to the multiplicity of access points to switch to a power save mode.

4. The apparatus of claim 1, wherein the control logic is further configured to select a first single access point from the plurality of access points to remain operational during a first time period, wherein the control logic is further configured to signal all of the other access points belonging to the plurality of access points to switch to a power save mode;

and

wherein the control logic is further configured to select a second single access point from the plurality of access points to remain operational during a second time period, wherein the control logic is further configured to signal all of the other access points belonging to the plurality of access points to switch to a power save mode.

5. The apparatus of claim 1, wherein the control logic is further configured to select a first multiplicity of access points from the plurality of access points to remain operational during a first time period, wherein the control logic is further configured to signal all of the other access points belonging to the plurality of access points to switch to a power save mode;

and

wherein the control logic is further configured to select a second multiplicity of access points from the plurality of access points to remain operational during a second time period, wherein the control logic is further configured to signal all of the other access points belonging to the plurality of access points to switch to a power save mode.

6. The apparatus of claim 1, wherein the control logic is further configured to signal at least one access point from the plurality of access points that are not in a power save mode to adjust transmit power, clear channel assessment threshold, and start of packet threshold to provide coverage for an area normally covered by the at least one of the plurality of access points switched to power save mode.

7. The apparatus of claim 1, wherein the control logic selects the at least one of the plurality of access points to switch to power save mode responsive to a load on the plurality of access points decreasing.

8. The apparatus of claim 1, wherein the control logic is further configured to select a second of the plurality of access points to exit from power save mode responsive to a load on the plurality of access points increasing.

9. The apparatus of claim 1, wherein the control logic selects access points that do not have clients associated therewith to switch to the power save mode.

10. The apparatus of claim 1, wherein the control logic selects access points that do not have clients associated therewith and adjacent access points that do not have associated clients to switch to power save mode.

11. The apparatus of claim 1, wherein the control logic switches an access point from a power save mode to an operational mode responsive to a mobile device associating with an adjacent access point.

12. The apparatus of claim 1, wherein the control logic is configured to group mobile devices to a selected access point in order to increase access points in power save mode;

and

wherein the control logic is configured to have a signal sent to mobile devices not already associated with the selected access points to roam to the selected access point.

13. The apparatus of claim 1, wherein the control logic is further configured to activate each neighboring access point adjacent to an access point that associated with a new client one at a time in a round robin manner;

wherein the control logic determines whether the new client has roamed to one of the neighboring access points; and

wherein the control logic maintains the neighboring access point the new client has roamed to in an active state while switching the remaining neighboring access points to a power save mode.

14. The apparatus of claim 1, wherein the control logic is further configured to activate all neighboring access points adjacent to an access point that associated with a new client concurrently;

wherein the control logic determines whether the new client has roamed to one of the neighboring access points; and

wherein the control logic maintains the neighboring access point the new client has roamed to in an active state while switching the remaining neighboring access points to a power save mode.

15. An apparatus, comprising:

processing logic; and

at least one wireless transceiver in communication with the processing logic;

wherein the processing logic is configured to communicate with an associated wireless controller; and

wherein at least one of the processing logic and the at least one wireless transceiver is configured to switch to a power save mode responsive to a signal received from the associated controller to switch to a power save mode.

16. The apparatus of claim 15, wherein the processing logic switches to power save mode.

17. The apparatus of claim 16, wherein the at least one wireless transceiver sends a wakeup signal to the processing logic responsive to receiving a wireless signal;

and

wherein the processing logic is responsive to the wakeup signal to leave the power save mode.

18. The apparatus of claim 15, wherein the at least one wireless transceiver switches to power save mode.

19. The apparatus of claim 18, wherein the processing logic is responsive to receiving a signal from the associated controller to send a wakeup signal to the at least one wireless transceiver;

and

wherein the at least one wireless transceiver is responsive to the wakeup signal to leave power save mode.

20. The apparatus of claim 15, wherein the at least one wireless transceiver comprises two wireless transceivers;

and

wherein one wireless transceiver enters the power save mode while the other wireless transceiver remains operational.

21. The system of claim 15, wherein the associated controller comprises an interface for communicating with the processing logic and control logic for controlling the operation of the interface, processing logic, and at least one wireless transceiver switches to a power save state responsive to a signal from the control logic.

22. A method, comprising:

receiving data from a plurality of associated access points representative of network activity;

determining which of the plurality of access points have associated clients;

determining a set of access points selecting from the plurality of access points to switch to a power save mode based on the data; and

signaling the set of access points to switch to a power save mode;

wherein the set of access points does not include access points having associated clients.

23. The method of claim 22, further comprising:

selecting at least one monitor access point from the plurality of access points;

wherein the set of access points does not include the at least one monitor access point.

24. The method of claim 22, wherein the selecting at least one monitor access point further comprises periodically selecting at least one new access point for the monitor access point.

25. The method of claim 24, further comprising:

switching the at least one new access point into an operational mode; and

signaling access points that are no longer a monitor access point to switch to a power save mode.

26. The method of claim 22, wherein the set of access points does not include access points adjacent to access points having associated clients.

27. The method of claim 26, further comprising:

determining a client has roamed from a first access point to a second access point;

powering on access points adjacent to the second access point that were in power save mode prior to the roam;

determining whether any of the access points adjacent to the first access point are adjacent to a cell having an associated client; and

switching access points adjacent to the first access point that are not adjacent to a cell having an associated client to a power save mode.

28. The method of claim 26, further comprising:

determining a new client has associated with a second access point adjacent to a first access point having a first client associated therewith;

determining whether the new client is capable of associating with the first access point; and

forcing the client to roam to the first access point responsive to determining that the new client is capable of associating with the first access point.

29. The method of claim 28, further comprising:

switching access points adjacent to the second access point into an operational mode responsive to the new client associating with the second access point; and

switching access points adjacent to the second access point that are not adjacent to an access point with an associated client to power save mode after the new client has roamed to the first access point.

30. The method of claim 22, further comprising:

selecting at least one monitor access point from the plurality of access points;

configuring the monitor access point to change cell size to cover cells belonging to the set of access points;

wherein the set of access points does not include the at least one monitor access point.

31. The method of claim 30, wherein the cell size is changed by one of a group consisting of increasing transmit power, decreasing clear channel assessment threshold, and decreasing start of packet threshold.

32. The method of claim 30, further comprising:

determining that a load on one of the monitor access points has exceeded a threshold;

activating an access point adjacent to the monitor access point from the set of access points responsive to the load exceeding the threshold; and

changing the cell size of the monitor access point to balance the load between the monitor access point and the access point adjacent to the monitor access point.

33. The method of claim 32, further comprising:

determining that the load on the monitor access point has decreased below a second threshold;

de-activating the adjacent access point responsive to the load decreasing below the second threshold; and

changing the cell size of the monitor access point to cover at least a portion of a cell covered by the adjacent access point.

34. The method of claim 22, further comprising:

selecting a monitor access point from the plurality of access points, wherein the set of access points does not include the at least one monitor access point;

determining that a new client has associated with the monitor access point;

activating every access point adjacent to the monitor access point, one at a time in a round robin manner;

determining whether the new client has associated with one of the adjacent access points;

switching adjacent access points that are not associated with the client to power save mode; and

maintaining the adjacent access point associated with the new client in operational mode.

35. The method of claim 22, further comprising:

selecting a monitor access point from the plurality of access points, wherein the set of access points does not include the at least one monitor access point;

determining that a new client has associated with the monitor access point;

activating all access points adjacent to the monitor access point concurrently;

determining whether the new client has associated with one of the adjacent access points;

switching adjacent access points that are not associated with the client to power save mode; and

maintaining the adjacent access point associated with the new client in operational mode.

36. The method of claim 22, further comprising:

selecting a monitor access point from the plurality of access points, wherein the set of access points does not include the at least one monitor access point;

determining that a new client has associated with the monitor access point;

determining a location for the new client; and

activating an access point with a cell area covering the location where the new client is located.

37. A method, comprising:

receiving a signal from an associated controller to enter into a power save mode;

selecting one of a group consisting of a digital section and a radio section to place into a low power state responsive to the signal; and

placing the selected one of a group consisting of a digital section and a radio section into the low power state.

38. The method of claim 37, wherein the radio section is placed in power save mode.

39. The method of claim 38, wherein the digital section receives a signal from the associated controller to exit the power save mode;

wherein the digital controller is responsive to the signal to send a command to the radio section to exit the lower power mode; and

wherein the radio section is responsive to the command to exit the lower power mode.

40. The method of claim 37, wherein the radio section comprises two radios;

and

wherein one radio is placed into the low power state.

41. The method of claim 40, wherein both radios are placed into the low power state.

42. The method of claim 37, wherein the digital section and radio section are placed into a low power state.

43. The method of claim 37, wherein the digital section, radio section, and communication port of the associated controller are placed into a low power state.

44. The method of claim 37, wherein the digital section is placed into the low power state.

45. The method of claim 44, wherein the radio section is responsive to receiving a packet to signal the digital section to exit the low power state;

and

wherein the digital section is responsive to the signal to exit the low power state.