Multi Constraint Load Balancing Based on Cell Breathing in WLAN
In WLAN,load imbalance incurs two problems: lower network throughput and longer transmission delay. To realize load balancing,researchers introduced the concept of cell breathing in Code Division Multiple Access (CDMA) networks into wireless local area networks (WLANs) due to requiring no special modification of clients. Cell breathing technique adjusts APs' coverage area through adjusting their beacon power to control the load of APs. Most of existing load balancing methods based on cell breathing did not care two key problems: the tradeoff between load balancing on APs and data power loss of users,as well as the service availability of APs (including AP service cheating and AP service loophole) In this paper,these two problems are viewed as constraints when using cell breathing method to realize load balancing. Firstly the problem of multi constraint load balancing is formulated,and then some analytical models are proposed to solve key parameters such as the load gap of two neighboring APs,the average data power loss cost and the condition of AP full coverage. At last,the genetic algorithm is employed to solve the problem of multi constraint load balancing,and test the proposed scheme and the similar scheme in terms of AP load,throughput and the average successful transmission probability under different user density. The simulation shows the proposed scheme realizes optimization.