Method and system for dynamically assigning channels across multiple radios in a wireless LAN

• US 9,185,714 B2
• Filed: 06/14/2013
• Issued: 11/10/2015
• Est. Priority Date: 06/25/2002
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Friday, Robert J., Hills, Alexander H., Dietrich, Paul F., Calhoun, Patrice R., O'Hara, Robert B. Jr.
• Primary Examiner(s): Kim, Wesley
• Assistant Examiner(s): Chan, Richard
• Application Number:
  US13/918,668
• Publication Number:
  US 20140029526A1
• Time in Patent Office: 879 Days
• Field of Search: 455/440, 455/452.1, 455/13.1, 455/423, 370/328, 370/252, 370/338, 370/230
• US Class Current: 1/1
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04W 72/52 based on load
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

According to one embodiment, a method includes monitoring, at one or more wireless network access elements, signal strength of signals transmitted by respective neighboring wireless network access elements. Information is collected from said wireless network access elements and converted into reportable data about signal strength observed during the monitoring. The method further includes identifying, based at least in part on interference associated with concurrent signal transmissions of the wireless network access elements, a combination of channel assignments for the one or more wireless network access elements from a plurality of possible combinations of channel assignments and assigning channels for concurrent, respective use by said wireless network access elements based on the identified combination of channel assignments.

Claims

1. A method, comprising:

monitoring, at one or more wireless network access elements, signal strength of signals transmitted by respective neighboring wireless network access elements;

collecting information from said wireless network access elements and converting said information into reportable data about signal strength observed during the monitoring the signal strength of signals by the one or more wireless network access elements and about access element load, wherein the reportable data about access element load comprises;

data regarding wireless network traffic load corresponding to each of said wireless network access elements over a period of time; and

physical interference;

creating a signal strength matrix describing the signal strength observed between each of the access elements;

creating a utilization matrix describing the load observed at each access element over a given time interval;

combining the signal strength matrix and the utilization matrix to create an average signal strength matrix describing the average signal strength observed between each of the access elements;

creating a first interference matrix by matrix-multiplying the average signal strength matrix by a channel assignment matrix describing a plurality of possible combinations of channel assignments of the physical channels across the access elements; and

identifying, based at least in part, on said physical interference associated with concurrent signal transmissions of the wireless network access elements, a combination of channel assignments for the one or more wireless network access elements from the plurality of possible combinations of channel assignments and assigning channels for concurrent, respective use by said wireless network access elements based on the identified combination of channel assignments.

2. The method of claim 1 further comprising constructing, from said physical interference, a physical interference matrix that represents noise power within each said physical channel.

3. The method of claim 1 wherein the reportable data about access element load further comprises recognizable interference, the method further comprising constructing, from said recognizable interference, a recognizable interference matrix.

4. The method of claim 2 wherein said identifying is further based on, at least in part, said physical interference matrix.

5. The method of claim 3 wherein said identifying is further based on, at least in part, said recognizable interference matrix.

6. The method of claim 2 wherein said constructing step includes:

prioritizing wireless network access elements according to information derived from said interference matrix to obtain priorities;

assigning channels according to said information derived from said first interference matrix to access elements according to said priorities from highest to least until all access elements have channels assigned thereto.

7. The method of claim 1 further comprising causing one or more wireless network access elements to probe for neighboring wireless network access elements and to observe and detect signal strength of signals transmitted by the neighboring wireless network access elements by transmitting a probe request, receiving one or more probe responses to the probe request, and detecting strength of the signals carrying the one or more probe responses.

8. A system for dynamically assigning said physical channels to a set of wireless network access elements, comprising:

a first resource management module associated with each access element for collecting physical layer information from said wireless network access elements and converting said physical layer information into reportable data about signal strength observed during the monitoring the signal strength of signals by the one or more wireless network access elements and about access element load, wherein the reportable data about access element load comprises;

data regarding wireless network traffic load corresponding to each of said wireless network access elements over a period of time; and

physical interference; and

a second resource management module associated with said central control element, said second resource management module in communication via a packetized communication path with said first resource management module, for processing said reportable data to;

cause one or more access elements to monitor signal strength of signals transmitted by respective neighboring wireless network access elements;

create a signal strength matrix describing the signal strength observed between each of the access elements;

create a utilization matrix describing the load observed at each access element over a given time interval;

combine the signal strength matrix and the utilization matrix to create an average signal strength matrix describing the average signal strength observed between each of the access elements;

create a first interference matrix by matrix-multiplying the average signal strength matrix by a channel assignment matrix describing a plurality of possible combinations of channel assignments of the physical channels across the access elements; and

identify a combination of channel assignments for the one or more wireless network access elements from the plurality of possible combinations of channel assignments and assign channels for concurrent, respective use by said wireless network access elements based on the identified combination of channel assignments; and

select the identified combination of channel assignments based at least in part on the physical interference associated with concurrent signal transmissions of the wireless network access clients.

9. The system of claim 8 further including front-end signal reception means for detecting presence of potential physical interference comprising narrowband sensors and further including a selector for selecting between a wideband sensor and a narrowband sensor.

10. The system of claim 9 wherein said wideband sensor includes a wideband filter and said narrowband sensor includes a narrowband filter.

11. The system of claim 8 wherein said central control element further includes high speed dataflow counters for quick update of interference and load data.

12. The system of claim 8 wherein, in said packetized communication path, every data packet has a header with physical layer information appended to said packet.

13. The system of claim 8 wherein the second resource management module is operative to cause one or more access elements to transmit a probe request, receive one or more probe responses to the probe request, and detect strength of the signals carrying the one or more probe responses.

14. An apparatus, comprising:

means for monitoring, at one or more wireless network access elements, signal strength of signals transmitted by respective neighboring wireless network access elements;

means for collecting physical layer information from said wireless network access elements and converting said physical layer information into reportable data about signal strength observed during the monitoring the signal strength of signals by the one or more wireless network access elements and about access element load, wherein the reportable data about access element load comprises;

data regarding wireless network traffic load corresponding to each of said wireless network access elements over a period of time; and

physical interference;

means for creating a signal strength matrix describing the signal strength observed between each of the access elements;

means for creating a utilization matrix describing the load observed at each access element over a given time interval;

means for combining the signal strength matrix and the utilization matrix to create an average signal strength matrix describing the average signal strength observed between each of the access elements;

means for creating a first interference matrix by matrix-multiplying the average signal strength matrix by a channel assignment matrix describing a plurality of possible combinations of channel assignments of the physical channels across the access elements; and

means for identifying a combination of channel assignments for the one or more wireless network access elements from the plurality of possible combinations of channel assignments and assigning channels for concurrent, respective use by said wireless network access elements based on the identified combination of channel assignments, wherein the identified combination of channel assignments is selected based at least in part on the physical interference associated with concurrent signal transmissions of the wireless network access clients.