VoIP Voice and Fax Signal Processing

13.13 VoIP SPEECH QUALITY TESTS BY THE ETSI

The European Telecommunications Standards Institute (ETSI) conducts VoIP speech quality test events (SQTEs) in different regions. Vendors participate with their VoIP equipment to test speech quality during scheduled events [URL (ETSI-news)]. The goal of taking the products through a Plugtests event is interoperability and voice quality. Plugtests increase the probability of achieving interoperability by debugging the standard and the companies' implementations at an early stage.

All conversational aspects like speech quality, echo measurements, double talk performance, and transmission quality in the presence of background noise are considered for the speech quality test. The coder test under different packet loss rates and jitter conditions, detailed analysis of packet loss concealment (PLC), and jitter buffer implementations are also investigated in the SQTE. These test events provide important hints for the optimization of speech quality and allow for a benchmark comparison of the products. Moreover, the results of the ETSI VoIP SQTEs have become an important marketing tool for the participating manufacturers because the test methods used for the SQTE have practically developed into a standard for speech quality evaluation of VoIP equipment. The ETSI also provides the Plugtests service, which is a professional unit of ETSI specialized in running interoperability test events for a wide range of telecommunications, Internet, broadcasting, ...