Adaptive Acknowledgment schemes of the IEEE 802.11e EDCA

The IEEE 802.11e standard adds new optional acknowledgment (ACK) schemes called block ACK and No ACK Although these two schemes offer new data transmission services, there is no description which scheme is the most efficient under the different channel environments. In this paper, we apply the three ACK schemes (including legacy 802.11 ACK scheme) to the contention-based channel; an enhanced distributed channel access (EDCA), in IEEE 802.11e and then analyze the throughput and the packet drop rate, corresponding to the different kind of ACK schemes. Link parameters such as the number of stations, physical layer (PHY) mode, bit error rate (BER) and MAC protocol data unit (MPDU) length are considered. With the numerical results, we determine the adaptive ACK scheme for the different channel environments (represented by BER) in terms of throughput and packet drop rate.