The amendment IEEE 802.11aa was standardized in order to better support video multicast over Wi-Fi, or more precisely, to support real-time streaming of video from a single producer to multiple receiving clients on the same wireless local area network (LAN). This is referred to as group addressed transmission service (GATS). In particular, a very interesting medium access control (MAC) scheme is designed, so that the transmitter sends a burst of video frame packets to a group address, and then performs a per-station poll to receive acknowledgments of successfully received frames. That MAC scheme is more complex than others because a sliding window of frames has to be maintained by the transmitter and ack handling has to be done. On the other hand, that MAC scheme utilizes the wireless medium more efficiently.

The contribution of this paper is twofold: the implementation, which is made publicly available, and the evaluation of the different multicast schemes direct multicast service (DMS), unsolicited retries (UR), and block acknowledgment (BA). The results are summarized in a table showing that BA has higher complexity on the one hand, but also higher effectiveness and efficiency on the other hand, outperforming DMS and UR.

Researchers and innovators in the field of wireless communications, as well as implementers of IEEE 802.11 functionality should find the article worthwhile reading.