An analytic and experimental study on the impact of jitter playout buffer on the E-model in VoIP quality measurement

Abstract

—Over the years, the quality in Voice over IP (VoIP) applications has been defined from the perspective of VoIP service providers but not necessarily from the perspective of end-users. Conversational quality as perceived by endusers is affected by a wide variety of factors that are not exclusive to network performance. While service providers focus their efforts on Quality of Service (QoS) in VoIP, endusers expect improvement in Quality of Experience (QoE). The measurement of QoE is significantly challenging due to the diverse nature of factors that collectively determine QoE. It is highly desired to have a more comprehensive and accurate quality measurement model that can provide objective measurement of QoS in real-time while simultaneously offering QoE measurement as well. Thus, unveiling the relevance of various factors in a quality measurement model is crucial. In this paper, we study a commonly used ITU-T recommended quality measurement model: the E-model with a focus on how an important but ignored parameter jitter playout buffer affects the measurement accuracy by conducting an analytical and experimental approach. Our study shows that adaptive jitter playout buffering does affect the measurement of end user perceived VoIP quality. Thus, the E-Model that excludes the impact of the dynamic jitter playout buffer cannot provide accurate measurement on how an user perceives conversational quality in VoIP application.