Method for balancing the load of a wireless local area network

• US 7,558,208 B2
• Filed: 02/04/2004
• Issued: 07/07/2009
• Est. Priority Date: 04/04/2003
• Status: Active Grant

• Current Assignee: Infineon Technologies Taiwan Co. Ltd. (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Taiwan Co. Ltd. (Infineon Technologies AG)
• Inventors: Kuo, Chi-Chih, Lin, Ying-Chien
• Primary Examiner(s): Nguyen; Duc
• Assistant Examiner(s): Yun; Eugene
• Application Number:
  US10/772,650
• Publication Number:
  US 20040199668A1
• Time in Patent Office: 1,980 Days
• Field of Search: 370/238, 370/238.1, 370/124, 370/236.1, 370/237, 370/338, 370400-408, 370/389, 370/392, 370/466, 370/468, 370/399, 370/395.5, 455/453
• US Class Current: 370/238
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

The method of the present invention selects an access point with the lowest load, which will reply to the probe-request packet sent by a station, and then constructs an association between the station and the access point with the lowest load so as to balance the load of the plurality of access points. To select the access point with the lowest load, a master access point sends a load collection packet, and the access points with the same service set identifier send a load index packet when receiving the load collection packet. Afterward each access point performs a load comparison procedure to select the access point with the lowest load. The access point with the lowest load will turn on the probe-response function, and the other access point will turn off the probe-response function.

Claims

1. A method for balancing the load of a wireless local area network, the wireless local area network comprising a plurality of access points forming a service set, the method comprising the steps of:

sending a probe-request frame for association with said service set from a station to said plurality of access points;

selecting an access point with the lowest load;

sending a probe-response frame from the access point with the lowest load to the station; and

constructing an association between the station and the access point with the lowest load for balancing the load of said plurality of access points.

2. The method for balancing the load of a wireless local area network of claim 1, wherein the step of selecting an access point with the lowest load access point includes the substeps of:

selecting an access point as a master access point and assigning the other access points as slave access points;

sending a load collection packet from the master access point to the slave access points;

returning load index packets with load information from the slave access points; and

performing a load comparison procedure to select an access point with the lowest load according to the load index packets.

3. The method for balancing the load of a wireless local area network of claim 2, wherein the load comparison procedure comprises the substeps of:

collecting the load index packets sent from the other access points by each access point;

comparing its own load by each access point with the loads of the 5 other access points; and

turning on a probe-response function of the access point with the lowest load, and turning off the probe-response function of the other access points.

4. The method for balancing the load of a wireless local area network of claim 2, wherein the master access point is the access point booted first.

5. The method for balancing the load of a wireless local area network of claim 2, further comprising a group reconstruction procedure for selecting the access point with the lowest load as the master access point.

6. The method for balancing the load of a wireless local area network of claim 5, wherein the group reconstruction procedure comprises the substeps of:

sending group reconstruction packets with load information from said 20 plurality of access points;

comparing its own load by each access point with the loads of the other access points; and

setting the access point with the lowest load as the master access point.

7. The method for balancing the load of a wireless local area network of claim 1, wherein the plurality of access points have the same basic service set identifier.

8. The method for balancing the load of a wireless local area network of claim 1, wherein the access point with the lowest load replies a probe-response frame to the station and the other access points do not reply.

9. A wireless local area network system comprising:

a plurality of access points forming a service set; and

at least one station configured to send to said plurality of access points a probe-request frame for association with said service set,

wherein the system is configured to select an access point with the lowest load and to send a probe-response from the access point wit the lowest load to said station and wherein the system is further configured to construct an association between the station and the access point with the lowest load.