Résumé:
—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.
