PICKING AN OPTIMAL CHANNEL FOR AN ACCESS POINT IN A WIRELESS NETWORK

• US 20100067379A1
• Filed: 09/15/2008
• Published: 03/18/2010
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: Trapeze Networks Incorporated (Juniper Networks Incorporated)
• Original Assignee: Trapeze Networks Incorporated (Juniper Networks Incorporated)
• Inventors: Zhao, Shiwei, Gast, Matthew S.
• Granted Patent: US 8,238,298 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 41/147 for predicting network behaviour
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A novel technique involves evaluating a real-time environment of a channel based on a nonlinear function of the number of neighbor radios and channel utilization requirements. The technique can be used to pick a channel for an AP that is added to a wireless network or to tune a channel for an existing AP. The technique can be applied to, for example, a relatively new wideband option in the 802.11n standard.

Claims

1. A method comprising:

selecting a first narrowband channel;

determining first one or more channel loading indicators associated with respective one or more neighboring access points (APs) on the first narrowband channel;

deriving a first channel load metric from the channel loading indicators;

selecting a second narrowband channel;

determining second one or more channel loading indicators associated with respective one or more neighboring APs on the second narrowband channel;

deriving a second channel load metric from the second channel loading indicators;

combining the first channel load metric and the second channel load metric to obtain a wideband channel load metric.

2. The method of claim 1, wherein the wideband channel load metric is a first wideband channel load metric, further comprising:

predicting a lower channel load on a first wideband channel associated with the first wideband channel load metric than on a second wideband channel associated with a second wideband channel load metric;

picking the first wideband channel for use by an AP.

3. The method of claim 1, wherein the wideband channel load metric is a first wideband channel load metric, further comprising:

predicting a lower channel load on a first wideband channel associated with the first wideband channel load metric than on a second wideband channel associated with a second wideband channel load metric;

auto-tuning an AP to the first wideband channel.

4. The method of claim 1 further comprising providing a stations database that includes data associated with APs.

5. The method of claim 1 further comprising providing a stations database that includes data associated with client stations.

6. The method of claim 1, further comprising:

obtaining a relative signal strength indicator (RSSI) associated with a first AP;

generating a first channel loading indicator of the first channel loading indicators from a function of the RSSI associated with the first AP;

obtaining an RSSI associated with a second AP;

generating a second channel loading indicator of the second channel loading indicators from a function of the RSSI associated with the second AP.

7. The method of claim 1, further comprising:

obtaining a signal-to-noise ratio (SNR) associated with a first AP;

generating a first channel loading indicator of the first channel loading indicators from a function of the SNR associated with the first AP;

obtaining an SNR associated with a second AP;

generating a second channel loading indicator of the second channel loading indicators from a function of the SNR associated with the second AP.

8. The method of claim 1, wherein the wideband channel load metric is a first wideband channel load metric, further comprising:

selecting a third narrowband channel;

determining third one or more channel loading indicators associated with respective one or more neighboring access points (APs) on the third narrowband channel;

deriving a third channel load metric from the channel loading indicators;

selecting a fourth narrowband channel;

determining fourth one or more channel loading indicators associated with respective one or more neighboring APs on the fourth narrowband channel;

deriving a fourth channel load metric from the fourth channel loading indicators;

combining the third channel load metric and the fourth channel load metric to obtain a second wideband channel load metric.

9. The method of claim 1, further comprising:

calculating an index from a function of each channel loading indicator associated with respective one or more neighboring APs on the first narrowband channel;

combining the indices to derive the first channel load metric;

calculating an index from a function of each channel loading indicator associated with respective one or more neighboring APs on the second narrowband channel;

combining the indices to derive the second channel load metric.

10. The method of claim 1, further comprising:

adding a tuning threshold to the wideband channel load metric;

determining that the wideband channel load metric plus the tuning threshold have a lower value than a current channel load metric;

switching channels for an AP from a channel associated with the current channel load metric to a channel associated with the wideband channel load metric.

11. A system comprising:

a wireless network environment monitoring engine coupled to a wireless network;

a stations database coupled to the wireless network environment monitoring engine;

a wideband channel selection engine coupled to the stations database;

an access point (AP) coupled to the wideband channel selection engine;

wherein, in operation;

the wireless network environment monitoring engine obtains data associated with stations in the wireless network;

the wireless network environment monitoring engine stores the data in the stations database;

the wideband channel selection engine uses the data associated with stations neighboring the AP to calculate narrowband channel load metrics for narrowband channels;

the wideband channel selection engine combines the narrowband channel load metrics to obtain wideband channel load metrics for one or more wideband channels available to the AP.

12. The system of claim 11, wherein, in operation:

the wideband channel selection engine determines a best narrowband channel load metric from the narrowband channel load metrics;

the wideband channel selection engine weights the best narrowband channel load metric to obtain a weighted best narrowband channel load metric;

the wideband channel selection engine determines a best wideband channel load metric from the wideband channel load metrics;

the wideband channel selection engine selects a channel associated with the best wideband channel load metric when the weighted best narrowband channel load metric is greater than the best wideband channel load metric.

13. The system of claim 11, wherein, in operation:

the wideband channel selection engine determines a best narrowband channel load metric from the narrowband channel load metrics;

the wideband channel selection engine weights the best narrowband channel load metric to obtain a weighted best narrowband channel load metric;

the wideband channel selection engine determines a best wideband channel load metric from the wideband channel load metrics;

the wideband channel selection engine selects a channel associated with the best narrowband channel load metric when the best wideband channel load metric is greater than the weighted best narrowband channel load metric.

14. The system of claim 11, wherein, in operation:

the wideband channel selection engine determines a best narrowband channel load metric from the narrowband channel load metrics;

the wideband channel selection engine weights the best narrowband channel load metric to obtain a weighted best narrowband channel load metric;

the wideband channel selection engine determines a best wideband channel load metric from the wideband channel load metrics;

the wideband channel selection engine tunes the AP to a channel associated with the best wideband channel load metric when the weighted best narrowband channel load metric is greater than the best wideband channel load metric.

15. The system of claim 11, wherein, in operation:

the wideband channel selection engine determines a best narrowband channel load metric from the narrowband channel load metrics;

the wideband channel selection engine weights the best narrowband channel load metric to obtain a weighted best narrowband channel load metric;

the wideband channel selection engine determines a best wideband channel load metric from the wideband channel load metrics;

the wideband channel selection engine tunes the AP to a channel associated with the best narrowband channel load metric when the best wideband channel load metric is greater than the weighted best narrowband channel load metric.

16. The system of claim 11, further comprising:

a plurality of function blocks having inputs and an output;

an N-to-1 multiplexor coupled to the plurality of function blocks;

an adder coupled to the N-to-1 multiplexor;

an auto-tuning engine coupled to the adder and the AP;

wherein, in operation;

a first function block of the plurality of function blocks receives a channel loading indicator for each relevant neighboring AP on a first channel as inputs and provides a first channel load metric for the first channel as output;

a second function block of the plurality of function blocks receives a channel loading indicator for each relevant neighboring AP on a second channel as inputs and provides a second channel load metric for the second channel as output;

the N-to-1 multiplexor receives at least the first channel load metric and the second channel load metric as inputs and outputs a best channel load metric;

the adder combines the best channel load metric and a tuning threshold;

the auto-tuning engine;

receives the combined best channel load metric and tuning threshold and a current channel load metric associated with the AP;

tunes the AP to a channel associated with the best channel load metric when the combined best channel load metric and tuning threshold is indicative of better channel characteristics than the current channel load metric.

17. A method comprising:

providing a stations database associated with a wireless network;

determining a channel load metric for each available channel by;

determining channel loading indicators for a plurality of neighboring APs;

computing a function for each of the channel loading indicators;

combining the function for each of the channel loading indicators;

combining a first sub-plurality of load metrics of the channel load metric for each available channel to obtain a wideband channel load metric;

picking a channel to optimize throughput for the wireless network using the channel load metric associated with at least one available channel.

18. The method of claim 17, wherein picking a channel includes picking a wideband channel associated with the wideband channel load metric.

19. The method of claim 17, wherein picking a channel includes picking a narrowband channel associated with a narrowband channel load metric, wherein the narrowband channel load metric is one of the channel load metric for each available channel.

20. The method of claim 17, further comprising:

selecting a narrowband channel load metric from the channel load metric for each available channel;

weighting the narrowband channel load metric;

comparing the weighted narrowband channel load metric with the wideband channel load metric;

wherein picking a channel includes picking a wideband channel associated with the wideband channel load metric if the wideband channel load metric is less than the weighted narrowband channel load metric.