VoIP Quality of Experience (QoE)

Abstract

Quality of Experience (QoE) is a term used to describe user perceived experience for a provided service, e.g. VoIP. This term is also referred to as User Perceived Quality of Service (PQoS) in order to differentiate with Network Quality of Service (QoS) which reflects network performance. Network QoS metrics generally include packet loss, delay and jitter which are the main impairments affecting voice and video quality in VoIP applications. The key QoE metric is Mean Opinion Score (MOS), an overall voice/video quality metric. In this chapter, the definition of QoS and QoS metrics will be introduced first. Then the characteristics of these metrics and how to obtain them in a practical way will be discussed. Further, the QoE concept and an overview of QoE measurement for VoIP applications will be presented. Finally, the most commonly used subjective and objective QoE measurement for voice and video will be presented in detail, including Perceptual Evaluation of Speech Quality (PESQ) and E-model for voice quality assessment, and Full-Reference (FR), Reduced-Reference (RR) and No-Reference (NR) models for video quality assessment.