An Improved Active Queue Management Algorithm for Time Fairness in Multirate 802.11 WLAN

In multirate 802.11 wireless local area network (WLAN), time unfairness is an inherent problem that slow stations occupy more time to transfer data and leave less time for fast stations, which is so called performance anomaly. The paper proposes an improved active queue management (IAQM) algorithm for fairly sharing network resources among all contending stations. Meanwhile, by setting different queue length and drop rate for each data flow with different destinations going through the access point (AP) according to their transmission rate, so that each station guarantees equal channel usage time. Therefore, the time fairness can be achieved and aggregate throughput can be improved. Both analytical and simulation results are provided to validate the effectiveness of the proposed IAQM algorithm, which can achieve good time fairness and a 30% improvement in aggregate throughput.