Responsible Editor: I.F. Akyildiz

IEEE put performance due to the high MAC overhead, such as interframe spaces (IFS) or A new mechanism is introduced as a part of the IEEE 802.11e MAC standard [1] in order to enhance the system efficiency. That is, a transmitter gains a granted time dura-There have been recent studies aimed at mathemati-cally analyzing the IEEE 802.11e block ACK scheme and evaluating its performance [2–7]. The performance of the block ACK scheme is evaluated in [2–4] via simulations and testbed implementations, while detailed mathematical analysis for the throughput and delay performance of the block ACK scheme is not provided. Simulation and analytical results in [5] present the throughput and dela