A QoE-Centric Modeling of End-to-End Packet Loss Impact in Skype/SILK Call Quality

Satisfying users has been an important issue for all application service providers, and all service providers shall understand how their users react to the services they provide. For real-time speech delivery services such as the most popular voice over IP (VoIP) service, Skype, packet loss is one of the major impairment to user satisfaction. However, there still lacks investigation and model of how users perceive the quality of speech with different packet loss conditions for Skype calls. A well-known perceptual objective model POLQA (Perceptual Objective Listening Quality Assessment) has its limitation to measure user experience for real-time data transmission, and hence, an alternative parametric model should be constructed for VoIP calls. Motivated by the existing model deficiency and lack of research concerning packet loss conditions, this study conducts a large-scale subjective experiment with more than 3000 participants involved on crowdsourcing platform to rate the perceived quality under different packet loss schemes. In the end, we propose a quality of experience (QoE) model with respect to measurable quality of service (QoS) parameters that are the indicators of network system performance including bitrate, loss rate and average burst length. The result shows that the goodness of fit of our proposed model is 94.28%, and we test the goodness of fit with 2 more independent datasets that obtain the goodness of fit being 92.16% and 89%, respectively. As our proposed model is compared to the POLQA, the proposed model outperforms POLQA modeling the perceived quality of Skype calls.