Abstract:

In WLAN, the performance anomaly of wireless channels and the greedy closed loop control nature of TCP congestion control lead to the congestion problem and significant unfair bandwidth distribution among TCP flows. An explicit congestion notification (ECN)based congestion control scheme called (access point congestion control) APCC is proposed. The main properties of APCC are: Using both wireless channel load and buffer length as congestion indicators, APCC brings low loss rate and low queue delay while keeping high network goodput; APCC achieves the up/down TCP fairness by marking the ECN bit to TCP DATA and ACK packets; and taking into account the wireless channel rate of each TCP flow, APCC sets different ECN marking probability for each flow to guarantee the time fairness of each flow and higher total network goodput.