The increasing amount of audio and video data transmitted over Wi-Fi networks raises a problem of parametrized Quality of Service (QoS) provisioning, which is challenging even for point-to-point transmission. QoS provisioning is much more complicated when a wireless access point (AP) streams IPTV or another multimedia flow to a group of receiving stations. This scenario is a typical use case for IEEE 802.11aa, a recently approved amendment to the Wi-Fi standard. To improve performance of multicast transmission, the amendment defines several approaches. In the paper, we study their efficiency in the case, when deterministic channel access with periodic reservations is used to improve reliability of multicast transmission. For that we develop a mathematical model and use the model both to compare efficiency of the approaches and to select the best parameters for channel reservation1.