MEASURING SPEECH QUALITY OVER A COMMUNICATIONS NETWORK

摘要

When the PESQ and similar algorithms are used to measure speech quality, a particular voice call is set up to transmit only test voice signals over a communications network. This enables the test voice signals to be easily identified and provides a means of determining the amount of degradation that occurs as a result of transmission of the test voice signals. However, one problem is that in packet switched networks the transmission characteristics change with time. Thus the estimated MOS score obtained cannot be assumed to give an accurate speech quality measure for a voice call later made between the same two points. By adding test voice information to an ongoing voice call and transmitting that test voice information integrally with the ongoing voice call these problems are addressed. The test voice information is sent in packets during silent periods in the voice call such that the voice call is not affected by the test voice information. An identifier is used to identify or label the packets comprising test voice information. In the case that real-time transport protocol is used, the identifier is preferably a payload type value.