IEEE 802. lie has a new coordination function, which has both contention-based and contention-free medium access methods, in order to support applications with Quality of Service (QoS) requirements. The contention-based MAC protocol, Enhanced Distributed Channel Access (EDCA) supports QoS; however, it cannot guarantee strict QoS required by real-time applications without proper tuning of QoS parameters and network control mechanisms. In this paper we adjust QoS parameters trading off between call admission control and rate control to enhance the EDCA access mechanism of IEEE 802.11e wireless LAN. Performance of the proposed scheme is analyzed using an OPNET modeler 12.0.