A Solution For Load Congestion In Centralized WLAN

Wireless LAN technology has been widely used in recent years. As hot-spots constantly increase and WLAN's utilization becomes larger, traditional autonomous WLAN can not meet increasingly service requirements in aspect of cost, operation and management. However, centralized WLAN which is a new network configuration and has been popular recently is considered as an effective and reasonable solution in large-scale deployment for it is well compatible with VoIP even though it has not been mature yet. The new network configuration need appropriate radio resource management (RRM) technology to be proposed. The proper RRM method should make use of the predominance of centralized WLAN in aspect of holistic information collecting, centralized management and control to obtain better performance.Hot-spot congestion gets worse as users increases. Most of current wireless stations select APs exclusively based on the received signal quality, but this method will result in unbalance usage of wireless resources and performance degradation. Several approaches have been suggested to solve this problem. Some of them are based on the modification or enhancement of the MAC layer which implies that all deployed stations should be changed. Some others are based on adding QoS support to the standard. These solutions require that stations and APs cooperate, which makes its deployment difficult in existing WLANs. This paper represents a load balancing algorithm which applies to centralized WLAN and bases on received signal strength indicatior (RSSI), loads of APs and balance index in the point of load balancing and increasing throughputs of whole network. This algorithm is simple to implement and do not need modification of protocol and cooperation of stations and APs.Matlab is selected as simulation circumstance to model network configuration and realize the algorithm. The simulation results show that usages of wireless resource in whole network achieve nearly balance, furthermore, APs'capacity and network throughput increases obviously. The improvement indicates the new algorithm is effective.