An Adaptive Modulation Method with IEEE 802.11aa GCR Block Ack for QoE Enhancement of Audio-Video Reliable Groupcast

In this paper, we propose an adaptive modulation method for IEEE 802.11aa GCR Block Ack. The method is based on AARF to reduce the transfer delay of all receiver terminals. Generally, in order to enable all receiver terminals to receive data, communication speed and the number of retransmissions are adjusted to a receiver terminal with the worst communication state. However, with such the simple strategy, the receiver terminal with the best communication state may suffer delay. We conduct a computer simulation of audio and video transmission. We then perform a subjective experiment to show that adaptive communication speed and the number of retransmissions can enhance QoE under the situation in which the receiver terminals have different distances from the access point.