Widespread deployment of wireless local area networks (WLANs) and a gradual increase in streaming applications have brought about a demand for improved Quality of Service (QoS) in wireless networks. The IEEE 802.11e standard was proposed to provide QoS mechanisms for assigning high priority to delay-sensitive applications. However, Internet traffic is still dominated by TCP based applications, and the negative effects of the IEEE 802.11e service differentiation scheme on TCP performance in the presence of high priority traffic are becoming a challenging issue. TCP has been found to perform poorly in wireless networks, including IEEE 802.11e; more applications with higher QoS demands use UDP in the transport layer than TCP. Therefore, the QoS of low priority traffic in 802.11e is not guaranteed in networks highly loaded with high priority traffic. This is aggravated by the class differentiation introduced in current QoS protocols, which results in TCP applications being starved during high traffic load. The motivation of this work is to enhance the interaction between the TCP and MAC protocols in order to improve TCP performance in WLANs.