Admission Control Based on Channel Time Classification for EDCA in IEEE 802.11e Networks

Admission control is an important QoS (quality of service) provision component for EDCA mechanism in IEEE 802.11e wireless LAN. Since EDCA is a contention-based random access mechanism and channel usage is hard to predict, lack of accuracy and adaptability is a common shortcoming of the existing admission control schemes. To overcome this we analyze the channel status in detail and find out that not all the channel idle time is available to the new flow. Then we further divide the channel occupation of the new flow into extra backoff time, collision time and transmission time, and give the prediction method of each kind of time. These analyses lay the foundation for an accurate admission control scheme. Simulation results show that the new scheme makes more reasonable admission decisions and has greater flexibility