| Summary: | 碩士 === 國立雲林科技大學 === 電機工程系碩士班 === 93 === A key issue in Wireless Local Area Networks (WLANs) is user congestion at popular areas called Hot Spots. In these areas where several access points (APs) are deployed with overlapped coverage, network load is usually unevenly distributed among them. One major reason is that current IEEE 802.11 standards do not provide any mechanism to distribute stations, while stations select APs to associate with the received signal quality. As a consequence, some APs are likely to become heavily populated by stations, whereas others are lightly loaded. This impairs network utilization and degrades network thought. In view of such deficiencies, we propose an approach to dynamically balancing the load among APs. We let a station first determine its prospective AP by evaluating a weighted function that parameterizes both the received signal quality and affordable bandwidth by APs. In this manner, the station can avoid (re) associating with an overloaded AP even though the AP provides the best wireless link. Next we keep monitoring the system dynamics to detect whether a considerable discrepancy of load among APs has occurred. If so, in light of our transfer policy, a suitable station will be selected to switch from an overloaded AP to another lightly loaded AP.
Experimental result show that our scheme can maintain the system to be at least 95% balanced and improve overall network throughput by 5.5%
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