QoE-based MAC Layer Optimization for Video Teleconferencing over WiFi
This work addresses video quality issues for users in WiFi-based teleconferencing, but it is incremental as it builds on existing IEEE 802.11 standards.
The paper tackles the problem of video teleconferencing quality degradation over WiFi by dynamically adjusting packet retry limits based on video frame types and network loss events, resulting in significant performance gains without harming cross traffic.
In IEEE 802.11, the retry limit is set the same value for all packets. In this paper, we dynamically classify video teleconferencing packets based on the type of the video frame that a packet carries and the packet loss events that have happened in the network, and assign them different retry limits. We consider the IPPP video encoding structure with instantaneous decoder refresh (IDR) frame insertion based on packet loss feedback. The loss of a single frame causes error propagation for a period of time equal to the packet loss feedback delay. To optimize the video quality, we propose a method to concentrate the packet losses to small segments of the entire video sequence, and study the performance by an analytic model. Our proposed method is implemented only on the stations interested in enhanced video quality, and is compatible with unmodified IEEE 802.11 stations and access points in terms of performance. Simulation results show that the performance gain can be significant compared to the IEEE 802.11 standard without negatively affecting cross traffic.