Load balancing method for a wireless area network

• US 7,940,731 B2
• Filed: 01/12/2007
• Issued: 05/10/2011
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Gao, Yin, Sun, Bo, Wu, Shaohua, Ma, Fengguo, Li, Feng
• Primary Examiner(s): Hu, Jinsong
• Assistant Examiner(s): TRAN, MONG-THUY THI
• Application Number:
  US11/622,863
• Publication Number:
  US 20070115906A1
• Time in Patent Office: 1,579 Days
• Field of Search: 370/338, 370/209, 370/401, 370/329, 455/453, 455/450, 455/432.1, 4554351-4353, 455/436, 455/447, 455/448, 455/452.1, 709/241, 709/238
• US Class Current: 370/338
• CPC Class Codes: G06F 30/33 Design verification, e.g. functional simulation or model checking
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/0862 of same hierarchy level
• CPC Class Codes: H04W 48/06 based on traffic conditions
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The present invention relates to a load balancing method for a wireless local area network, which includes the following steps: initializing the load balancing group, self-organizing to select an online access point from the load balancing group as a load balancing agent center, each access point of the said balancing group managing and processing the load balance in accordance with the load level and balance optimizing policy, therefore implements the network load balance. The method of the invention improves reliability of the network load information, presents the load information from invalidly broadcasting in the wireless local area network, therefore reduces the additional overhead for managing the load balance of the wireless network, particularly in the network that having three layers switching equipment, self-organizing to select the agent center can utilize the network resource in effect, therefore managing the dynamic load balance information much more effectively, reducing the dependence on the upper server, and managing the network much more flexibly.

Claims

1. A method for implementing a load balancing system in a wireless area network, comprising:

step 1, initializing a load balancing group of online access points in the wireless area network, self-organizingly selecting one of the access points from the online access points in said load balancing group as a load balancing agent center; and

step 2, each access point of said balancing group managing and processing load balance in accordance with a load level and balance optimizing strategy, so as to implement the network load balance;

wherein the access point with a lowest current load level in the load balancing group is selected as the load balancing agent center, and after the load balancing agent center is selected, other access points in the load balancing group act as non-load-balancing agent centers, and

wherein only said load balancing agent center needs to record the load information of other access points acting as the non-load-balancing agent centers in the same load balancing group, while the access points acting as non-load-balancing agent centers just need to acknowledge the location of the load balancing agent center, wherein load information is reported to the load balancing agent center when the load of the access points acting as the non-load-balancing agent centers is changing, and the non-load-balancing agent centers obtain network load information of the load balancing group from the load balancing agent center, and load balancing management is conducted by combining with load balance information locally stored; and

wherein in step 2, a threshold strategy is used for the access points, each of which including the access points acting as the load balancing agent center and the non-load-balancing agent centers, wherein an upper load limit MAX and a lower load limit MIN are set respectively to conduct management and processing of load balance as follows;

when the load level of the access point is lower than the lower load limit MIN, the access point is under low load, allows access of a station, and does not send load change information;

when the load level of the access point waves between the upper load limit MAX and the lower load limit MIN, the access point works normally and allows station access, and dynamic load change information is sent to said load balancing agent center, once the load level of the access point changes; and

when the load level of the access point is higher than the upper load limit MAX, the access point is under high load and rejects station access.

2. The method for implementing a load balancing system in a wireless area network of claim 1, wherein during network operation of the wireless area network, another access point is self-organizingly selected from the load balancing group as a new load balancing agent center via an information exchange between devices in accordance with the load level, when the load level of the load balancing agent center exceeds an agent center threshold.

3. The method for implementing a load balancing system in a wireless area network of claim 1, wherein a processing procedure of the load balancing agent center comprises:

creating a load information table of all the online access points in said load balancing group;

monitoring the load information of other current online access points acting as non-load-balancing agent centers in said load balancing group, and receiving and saving said information;

detecting a local load level of the access point acting as said load balancing agent center, conducting load level processing by combining with the network information of said load information table, and updating the local load level of said access point acting as the load balancing agent center;

keeping on monitoring and receiving the load information of other current online access points acting as non-load-balancing agent centers in the load balancing group when a newest local load level is lower than the agent center threshold; and

communicating with the online access points in the present load balancing group, self-organizingly selecting another appropriate access point as a new load balancing agent center according to the load level, and transferring load balance information locally stored to the new balancing agent center and informing the other access points in the load balancing group of an address of the new load balancing agent center when the newest local level exceeds the agent center threshold.

4. The method for implementing a load balancing system in a wireless area network of claim 3, wherein in regard to a mobile station in a load balancing group, selectively getting access to an access point in the load balancing group, the access point having relative lower access load and being most appropriate for access of said station from the load balancing group, so that said station can get access to another access point with relative lower load in the same load balancing group when an access point rejects access of said station owing to overload.

5. The method for implementing a load balancing system in a wireless area network of claim 1, wherein a processing procedure of the non-load-balancing agent centers comprises:

detecting a local load level of the non-load-balancing agent centers;

conducting load level processing according to the current load level and updating a local record of the load level of the access points acting as non-load-balancing agent centers when the current load level is lower than the lower load limit MIN;

obtaining load information of the load balancing group from the load balancing agent center and conducting load level processing by using load balancing algorithms in combination with the local load information when the current load level is higher than the lower load level limit MIN;

updating the local load level when a newest load level of the non-load-balancing-agent-centers is lower than the lower load level limit MIN after processing; and

sending local load level information to the load balancing agent center and updating the local load level when the newest load level is higher than the lower load level limit MIN after processing.

6. The method for implementing a load balancing system in a wireless area network of claim 1, further comprising classifying the load information, wherein the load information is classified as:

Static Load Information obtained and stored by a local system resource of the access point, including frequency of CPU, capacity of memory, and capability of network connections;

Statistic Load Information obtained and stored by a historical performance data of the local system of the access points, including delay and bandwidth; and

Dynamic Load Information collected and saved by the load balancing agent center, including real-time load level information of the network.

7. The method for implementing a load balancing system in a wireless area network of claim 1, wherein when the load balancing group comprises only one access point, said access point will act as the load balancing agent center.