Measurement of the IP Packet Delay Variation for a reliable estimation of the mean opinion score in VoIP services

In modern communication networks, Voice over IP (VoIP) users are even more interested to quantify the quality experienced in a VoIP call. This practice very often addresses the common need of rating the service of a telecommunication provider. To this aim, international standard committees have defined suitable metrics at application layer of the ISO/OSI protocol stack. Unfortunately, the evaluation of such metrics requires procedures and measurement setups very difficult to develop and, consequently, deliver to the final user. On the other hand, VoIP services performance is strongly influenced by the values assumed by the Internet Protocol Packet Delay Variation (¡PDV), also known as packet jitter. IPDV is defined at network layer and can be more easily evaluated than the cited metrics at application layer. The paper deals with the study of the correlation among measured IPDV values at network layer and those characterizing performance metrics at application layer, directly related to the quality perceived by the user in VoIP applications. The final aim is twofold: i) to design a reliable estimator able to forecast the objective quality perceived by the user on the basis of IPDV measurement results, and ii) to implement a procedure compliant with ISO-GUM for coverage interval assessment.