A Novel QoE-Aware Multicast Mechanism for Video Communications over IEEE 802.11 WLANs

During the past few years, the development of video services over wireless networks has been driven by Quality of Service (QoS) parameters and service level agreements. Even though QoS parameters, such as packet losses, jitter and delays are good indicators of the service provided by the underlying network services to the applications, they fall short on providing a better measure of the Quality of Experience (QoE) to the end-user. In order to gain a better understanding of the benefits in terms of the QoE guarantees, it is essential to evaluate the effectiveness of the enabling protocol mechanisms. In this paper, we introduce a novel multicast service for the IEEE 802.11 WLAN standard. The proposed service combines a novel MAC scheme and layered video, guaranteeing a minimum acceptable video quality to all the members of the multicast group through the base layer. To avoid penalizing the users capable of receiving data at higher rates and the performance of an IEEE 802.11 WLAN, the enhancement layers are transmitted using a higher transmission rate. We show that by properly coupling the video and multicast control mechanisms, the QoS as well as the QoE requirements of the end-user can be guaranteed. The performance of the proposed system architecture is extensively investigated by simulations and through numerical evaluation of relevant QoS and QoE metrics. Furthermore, our results show that the real-time video streaming quality of the total system can be greatly improved while keeping downward compatibility with the IEEE 802.11 multicast mechanism.