The Research Of Load-balancing Mechanism About Ieee802.11

Due to the rapid development of wireless communication technology, the wireless networks have a very wide range of applications. As an authority of the wireless local area network, IEEE 802 Working Groups get some success on the dominance of the wireless local area network area. AS wireless local area network became more popularity and the different applications appearing continually, the high level of network put forward higher requirements to the underlying network that uses the IEEE802.11 standard as the basis for building the wireless network. The IEEE802.11 standard shows out of its shortcoming. Because of the mobility and channel characteristics of wireless networks, the 802.11 standard should have some improvement. In practical applications, the workstation will be relatively concentrated in a certain area, forming the so-called hot zone. A large number of workstations are located in the same area. In accordance with IEEE802.11 standard, the station will compare the location of each AP's signal strength, and then select the maximum of signal strength of AP to establishing a connection. It may make the AP connected to a large number of workstations to providing data transmission services. When the amount of data exceeds the AP's throughput, it will cause end-to-end delay, network congestion and the application disruption. At this point, other APs in the vicinity of the AP maybe connected with a small number of workstations because the weak signal strength. This is an instance of uneven distribution of network load. It will waste the network resources. Load balancing mechanism is proposed in this case.The existing load-balancing mechanisms based on the chooser were divided into two broad categories. The one is the AP selection mechanism, and the other one is station selection mechanism. AP selection mechanism can redistribute the global load, but this mechanism is difficult to collect information on the station. If the switching time is too long, it may form invalid load redistribution. The station selection mechanism can select AP quickly and redistribute the load, but its effects are not global but local. According to the existing load balancing mechanism, this paper presents the self-control AP load balancing mechanism. This mechanism has some improvement in a traditional AP selection mechanism. It establish the location information table that access to the entire network physical topology information. The mechanism compared the network load of current time with load threshold, and then determined whether the load balancing mechanism needs to be triggered. Load balancing mechanism used the location information to redistribute the load. We put up the physical environment of 802.11b by the OPNET simulation software, use the existing 802.11b module and to simulate the mechanism. By comparing the network performance parameters, we can validate whether the load balancing mechanism to improve network quality of service.