On the use of in-service, nonintrusive measurement devices in the performance analysis of telephone-type networks

In the paper the problem of assessing the speech quality provided by a real-life telephone-type network is considered. Two different approaches to the quoted problem are presented: subjective approach, based on customer surveys or trained operators, and objective approach, based on instrumental measurements of key transmission parameters. Advantages and drawbacks associated with the quoted approaches are summarised and briefly discussed. An objective approach based on an In-Service Nonintrusive Measurement Device (INMD) is also presented. Finally, real life experiments, which show the effectiveness of the INMD approach are reported and discussed.