QoE Enhancement of Audio-Video Reliable Groupcast with IEEE 802.11aa

This paper enhances the QoE of audio and video multicast transmission over a wireless LAN by means of reliable groupcast schemes. We use GCR (GroupCast with Retries) Unsolicited Retry and GCR Block ACK as reliable groupcast schemes; they are standardized by IEEE 802.11aa. We assume that a wireless access point transmits audio and video streams to several terminals connected to the access point by groupcast. We compare three schemes: Groupcast with EDCA (Enhanced Distributed ChannelAccess), GCRUnsolicited Retry and GCR BlockACK. We perform computer simulations under various network conditions to assess application-level QoS and evaluate QoE by a subjective experiment. As a result, we find that the most effective scheme depends on network conditions.