Dynamic channel assignment for WLAN deployments with IEEE 802.11ac access points

• US 9,060,352 B2
• Filed: 08/14/2012
• Issued: 06/16/2015
• Est. Priority Date: 08/14/2012
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Chan, Douglas, Ahmed, Mansoor, Hedayat, Ahmadreza, Hart, Brian D.
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): CASTANEYRA, RICARDO H
• Application Number:
  US13/584,881
• Publication Number:
  US 20140050156A1
• Time in Patent Office: 1,036 Days
• Field of Search: 370/329, 370/335, 370/343, 370/252, 370/338, 370/310, 370/310.2, 370/330, 370/331, 370/332, 370/334, 370/341, 370/350, 370/443, 370/503, 370/431, 370/328, 370/336, 370/346
• US Class Current: 1/1
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/27 between access points
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 76/15 Setup of multiple wireless link connections
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Techniques are provided for selecting channels for use by access points operating in a wireless local area network. Metrics are computed for at least one set of radio frequency (RF) channels, wherein the set of RF channels comprises at least two RF channels in a frequency band that are available for use by a wireless network for a wider bandwidth mode that combines bandwidth of two or more RF channels. Alignment of individual primary and secondary RF channels is determined in the set of RF channels for operation of at least first and second wireless networks. A bias is applied to the metrics for each RF channel that is a member of the set of RF channels for the primary channel depending on alignment of the primary and secondary channels of the respective first and second wireless networks to produce adjusted metrics, based on which RF channels are assigned.

Claims

1. A method comprising:

computing metrics for at least one set of radio frequency (RF) channels, wherein the set of RF channels comprises at least two RF channels in a frequency band that are available for use by a wireless network for a wider bandwidth mode of operation that combines bandwidth of two or more RF channels, wherein the metrics are based on activity from devices in the set of RF channels;

determining alignment of individual primary and secondary RF channels in the set of RF channels for operation of at least first and second wireless networks, at least one of which operates in a wider bandwidth mode, wherein a primary channel is a set of one or more RF channels that is a smaller denomination of RF channels used by a wireless network when it is not operating in a wider bandwidth mode and a secondary channel is one or more RF channels used in conjunction with a primary channel when a wireless network is operating in a wider bandwidth mode;

applying to the metrics a bias for each RF channel that is a member of the set of RF channels for a primary channel depending on alignment of primary and secondary channels of the respective first wireless network and second wireless network to produce adjusted metrics, wherein the bias for each RF channel is computed from a receive signal strength of the first wireless network relative to a clear channel access threshold of a secondary channel of the second wireless network based on a piecewise linear transfer function; and

assigning RF channels to a primary channel and at least two secondary channels for the first wireless network or the second wireless network based on the adjusted metrics.

2. The method of claim 1, wherein applying comprises applying a first bias value in order to bias against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a secondary channel of the second wireless network and a secondary channel of the first wireless network coinciding with a primary channel of the second wireless network.

3. The method of claim 2, wherein applying comprises applying a second bias value in order to bias against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a secondary channel of the second wireless network, which secondary channel of the second wireless network comprises two or more RF channels aggregated together, wherein the first bias value is greater than the second bias value.

4. The method of claim 3, wherein applying comprises applying a third bias value against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a primary channel of the second wireless network and a secondary channel of the first wireless network coinciding with a secondary channel of the second wireless network, wherein the third bias value is less than or equal to the second bias value.

5. The method of claim 4, wherein the first wireless network and the second wireless network are managed by the same management entity.

6. The method of claim 4, wherein the second wireless network is managed by a different management entity than that used to manage the first wireless network.

7. The method of claim 4, wherein computing the first, second and third bias values is based on a curve having an elongated peak value region.

8. The method of claim 1, wherein applying comprises applying bias values to channel assignments depending on adjacency of primary and secondary channels of the first wireless network with respect to primary and secondary channels of the second wireless network.

9. The method of claim 8, wherein applying comprises applying a first bias value against assignment of a secondary channel of the first wireless network to an RF channel that is adjacent to a secondary channel of the second wireless network that is operating in a wider bandwidth mode, and applying a second bias value against assignment of either a primary channel of the first wireless network that is adjacent to a secondary channel of the second wireless network or a primary channel of the second wireless network that is adjacent to a secondary channel of the first wireless network.

10. The method of claim 9, wherein the second bias value is less than or equal to the first bias value, and the first wireless network is an IEEE 802.11n wireless network and the second wireless network is an IEEE 802.11ac wireless network.

11. The method of claim 9, wherein the first wireless network and the second wireless network are managed networks.

12. The method of claim 9, wherein either of the first wireless network or the second wireless networks is managed by a different management entity.

13. The method of claim 1, further comprising normalizing the adjusted metrics by applying weights to the adjusted metrics to emphasize selection of primary channels.

14. The method of claim 13, wherein normalizing comprises computing a weighted average of primary and secondary channels by applying a greater weight for selection of a primary channel over secondary channels and such that secondary channels are given progressively less weight as their bandwidth increases.

15. The method of claim 1, wherein assigning comprises assigning multiple RF channels to wireless networks so as to allow a bandwidth needed to support the highest data rates capable by a wireless network.

16. The method of claim 1, wherein applying comprises applying a bias to assign the first wireless network to an RF channel not required for dynamic frequency selection when the second wireless network neighboring the first wireless network is operating on an RF channel that is required for dynamic frequency selection.

17. The method of claim 16, wherein applying comprises applying a bias with a greater value in assigning the first wireless network to an RF channel not required for dynamic frequency selection if the second wireless network and one or more additional wireless networks neighboring the first wireless network are operating on RF channels requiring dynamic frequency selection.

18. The method of claim 1, wherein computing metrics comprises computing, for each individual channel in the set of channels, a metric based on one or more of:

ambient noise floor, receive signal strength from other wireless networks, receive signal strength that would be contributed to the set of channels, and receive signal strength associated with activity of unidentified RF signals.

19. The method of claim 1, wherein applying comprises applying the bias so as to bias against channel assignments based on resulting relative interference level.

20. One or more non-transitory computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to:

compute metrics for at least one set of radio frequency (RF) channels, wherein the set of RF channels comprises at least two RF channels in a frequency band that are available for use by a wireless network for a wider bandwidth mode of operation that combines bandwidth of two or more RF channels, wherein the metrics are based on activity from devices in the set of RF channels;

determine alignment of individual primary and secondary RF channels in the set of RF channels for operation of at least first and second wireless networks, at least one of which operates in a wider bandwidth mode, wherein a primary channel is a set of one or more RF channels that is a smaller denomination of RF channels used by a wireless network when it is not operating in a wider bandwidth mode and a secondary channel is one or more RF channels used in conjunction with a primary channel when a wireless network is operating in a wider bandwidth mode;

apply to the metrics a bias for each RF channel that is a member of the set of RF channels for a primary channel depending on alignment of primary and secondary channels of the respective first wireless network and second wireless network to produce adjusted metrics, wherein the bias for each RF channel is computed from a receive signal strength of the first wireless network relative to a clear channel access threshold of a secondary channel of the second wireless network based on a piecewise linear transfer function; and

assign RF channels to a primary and at least two secondary channels for the first wireless network or the second wireless network based on the adjusted metrics.

21. The computer readable storage media of claim 20, wherein the instructions for applying comprise instructions operable to:

apply a first bias value in order to bias against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a secondary channel of the second wireless network and a secondary channel of the first wireless network coinciding with a primary channel of the second wireless network;

apply a second bias value in order to bias against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a secondary channel of the second wireless network, which secondary channel of the second wireless network comprises two or more RF channels aggregated together, wherein the first bias value is greater than the second bias value; and

apply a third bias value against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a primary channel of the second wireless network and a secondary channel of the first wireless network coinciding with a secondary channel of the second wireless network, wherein the third bias value is less than or equal to the second bias value.

22. The computer readable storage media of claim 20, wherein the instructions operable to apply comprise instructions operable to apply bias values to channel assignments depending on adjacency of primary and secondary channels of the first wireless network with respect to primary and secondary channels of the second wireless network.

23. The computer readable storage media of claim 22, wherein the instructions operable to apply comprise instructions operable to apply a first bias value against assignment of a secondary channel of the first wireless network to an RF channel that is adjacent to a secondary channel of the second wireless network that is operating in a wider bandwidth mode, and applying a second bias value against assignment of either a primary channel of the first wireless network that is adjacent to a secondary channel of the second wireless network or a primary channel of the second wireless network that is adjacent to a secondary channel of the first wireless network.

24. The computer readable storage media of claim 20, further comprising instructions operable to normalize the adjusted metrics by applying weights to the adjusted metrics to emphasize selection of primary channels.

25. The computer readable storage media of claim 20, wherein the instructions operable to assign comprise instructions operable to assign multiple RF channels to wireless networks so as to allow a bandwidth needed to support the highest data rates capable by a wireless network.

26. The computer readable storage media of claim 20, wherein the instructions operable to apply comprise instructions operable to apply the bias so as to bias against channel assignments based on resulting relative interference level.

27. An apparatus comprising:

a network interface unit configured to enable communications over a network;

a processor coupled to the network interface unit, wherein the processor is configured to;

compute metrics for at least one set of radio frequency (RF) channels, wherein the set of RF channels comprises at least two RF channels in a frequency band that are available for use by a wireless network for a wider bandwidth mode of operation that combines bandwidth of two or more RF channels, wherein the metrics are based on activity from devices in the set of RF channels;

determine alignment of individual primary and secondary RF channels in the set of RF channels for operation of at least first and second wireless networks, at least one of which operates in a wider bandwidth mode, wherein a primary channel is a set of one or more RF channels that is a smaller denomination of RF channels used by a wireless network when it is not operating in a wider bandwidth mode and a secondary channel is one or more RF channels used in conjunction with a primary channel when a wireless network is operating in a wider bandwidth mode;

apply to the metrics a bias for each RF channel that is a member of the set of RF channels for a primary channel depending on alignment of primary and secondary channels of the respective first wireless network and second wireless network to produce adjusted metrics, wherein the bias for each RF channel is computed from a receive signal strength of the first wireless network relative to a clear channel access threshold of a secondary channel of the second wireless network based on a piecewise linear transfer function; and

assign RF channels to a primary channel and at least two secondary channels for the first wireless network or the second wireless network based on the adjusted metrics.

28. The apparatus of claim 27, wherein the processor operable to:

apply a first bias value in order to bias against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a secondary channel of the second wireless network and a secondary channel of the first wireless network coinciding with a primary channel of the second wireless network;

apply a second bias value in order to bias against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a secondary channel of the second wireless network, which secondary channel of the second wireless network comprises two or more RF channels aggregated together, wherein the first bias value is greater than the second bias value; and

apply a third bias value against assignment of primary and secondary channels for the first wireless network that would result in a primary channel of the first wireless network coinciding with a primary channel of the second wireless network and a secondary channel of the first wireless network coinciding with a secondary channel of the second wireless network, wherein the third bias value is less than or equal to the second bias value.

29. The apparatus of claim 27, wherein the processor is operable to apply bias values to channel assignments depending on adjacency of primary and secondary channels of the first wireless network with respect to primary and secondary channels of the second wireless network.

30. The apparatus of claim 29, wherein the processor is operable to apply a first bias value against assignment of a secondary channel of the first wireless network to an RF channel that is adjacent to a secondary channel of the second wireless network that is operating in a wider bandwidth mode, and apply a second bias value against assignment of either a primary channel of the first wireless network that is adjacent to a secondary channel of the second wireless network or a primary channel of the second wireless network that is adjacent to a secondary channel of the first wireless network.

31. The apparatus of claim 27, wherein the processor is further operable to normalize the adjusted metrics by applying weights to the adjusted metrics to emphasize selection of primary channels.

32. The apparatus of claim 27, wherein the processor is operable to assign multiple RF channels to wireless networks so as to allow a bandwidth needed to support the highest data rates capable by a wireless network.

33. The apparatus of claim 27, wherein the processor is operable to apply the bias so as to bias against channel assignments based on resulting relative interference level.

34. A method comprising:

computing metrics for at least one set of radio frequency (RF) channels, wherein the set of RF channels comprises at least two RF channels in a frequency band that are available for use by a wireless network for a wider bandwidth mode of operation that combines bandwidth of two or more RF channels, wherein the metrics are based on activity from devices in the set of RF channels;

determining alignment of individual primary and secondary RF channels in the set of RF channels for operation of at least first and second wireless networks, at least one of which operates in a wider bandwidth mode, wherein a primary channel is a set of one or more RF channels that is a smaller denomination of RF channels used by a wireless network when it is not operating in a wider bandwidth mode and a secondary channel is one or more RF channels used in conjunction with a primary channel when a wireless network is operating in a wider bandwidth mode;

applying to the metrics a bias for each RF channel that is a member of the set of RF channels for a primary channel depending on alignment of primary and secondary channels of the respective first wireless network and second wireless network to produce adjusted metrics;

assigning RF channels to a primary channel and at least two secondary channels for the first wireless network or the second wireless network based on the adjusted metrics;

normalizing the adjusted metrics by applying weights to the adjusted metrics to emphasize selection of primary channels, wherein normalizing comprises computing a weighted average of primary and secondary channels by applying a greater weight for selection of a primary channel over secondary channels and such that the secondary channels are given progressively less weight as the bandwidth increases.

35. The method of claim 34, wherein the first wireless network and the second wireless network are managed by a single management entity.

36. The method of claim 34, wherein the second wireless network is managed by a different management entity than that used to manage the first wireless network.