Objective Assessment Methodology for Estimating Conversational Quality in VoIP

Abstract

Voice over IP (VoIP) is becoming one of key technologies for telecommunications. Since IP networks generally do not guarantee transmission quality, it is extremely important to design and manage quality of service (QoS) properly. To do this, it is desirable to develop an objective quality assessment method that estimates subjective quality based on physical characteristics of VoIP system. This paper first proposes a framework of objective models that can be applied not only to quality planning, which is an intended application of existing standard methodology known as International Telecommunication Union - Telecommunication Standardization Sector (ITU-T) Recommendation G.107, the E-model, but also to quality benchmarking and management. Then, it proposes a model that complies with proposed framework. Experimental results show that proposed model has sufficient accuracy in evaluation of practical VoIP systems. In addition, we attempt to integrate opinion model with other objective quality measures, such as perceptual evaluation of speech quality (PESQ), standardized in Recommendation P.862 in ITU-T. Finally, we examine task dependence of performance of proposed model