This paper presents a unique approach for a model-based admission control algorithm for the IEEE 802.11e Enhanced Distributed Channel Access (EDCA) standard. The analytical model used as the foundation for the algorithm covers both non-saturation and saturation conditions. This allows us to keep the system out of saturation by monitoring several variables. Since the medium access delay represents the service time of the system, it is used as the threshold condition to ensure that the queuing delay is within reasonable bounds. The paper describes the admission control algorithm and several simulation results are presented and discussed.