| Summary: | 碩士 === 國立交通大學 === 網路工程研究所 === 102 === There are many different specifications of transmission rate which are set by IEEE 802.11 standards. Under the infrastructure mode, mobile stations which are far away from the AP, will suffer much more signal interference. In this circumance, those stations will change their transmission rate to a lower value. It has been known that, the existence of the low rate stations will affect the other high rate stations severely. In the related research work of IEEE 802.11, we often refer it as performance anomaly.
Since the IEEE 802.11n standard had been released in 2009, it has been widely applied among many products around the world. The purpose of our work is to solve the performance anomaly problem by tuning the minimum contetion window size(CW_min), under the 802.11n specifications.
First, we prove that the self-developed simulation program can simulate the abnormal phenomenon mentioned above. Second, we make experiments with different parameters such as transmission rate, traffic arrival rate, CW_min and number of contending stations. And observe the variations of throughput, mean delay and delay jitter.
Throughout our experiments, we show that when the number of contending stations are large enough, maximizing the CW_min of the low rate stations and minimizing the CW_min of the high rate stations highly improved the performance of the high rate stations.
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