WLAN中一种基于AP选择的负载均衡机制

A Load Balancing Mechanism Based on AP Selection in WLAN

基于IEEE 802.11的WLAN中,终端通常根据各自接收到的信号强度来连接或切换AP,但由于终端不知道AP的负载状态,容易聚集到信号强度最好的AP,造成AP间的负载分布不均,导致网络的整体性能下降,在高密度场景下尤为显著。为此,本文提出一种基于AP选择的负载均衡机制,该机制的研究重点在于判定AP超载后,综合STA切换后对全局AP负载状态的影响以及该STA从周围轻载AP收到的信号强度两方面来选择需要卸载的STA,并且依据周围AP的平均吞吐量和信号强度来为卸载的STA选择目标迁移AP,以达到全网负载均衡的目的。仿真实验证明,该机制能使各AP的负载达到均衡状态,并且相比较于其他负载均衡机制,网络的系统吞吐量得到明显提升。

In an IEEE 802.11-based wireless local area network,terminals usually connect or handover to an access point according to their individual received signal strength.As loads of access points are not invisible to terminals,AP with the best signal strength is easy to get overloaded,resulting in uneven load distribution between APs.This unevenness causes overall performance deterioration,especially in high-density scenarios.This paper proposes a load balancing mechanism based on AP selection.When an AP is considered as overloaded,a handoff candidate STA is selected among STAs connecting to that AP.The selection process takes both global AP load impact caused by STA handoff and the signal strengths of surrounding light-load AP received by the candidate into account.Then the target AP is selected for the offloaded STAs based on the average throughput and signal strength of the surrounding APs to achieve load balancing of the entire network.Simulation experiments prove that proposed mechanism can achieve load balance.Compared with other load balancing mechanisms,the network system throughput is significantly improved.