Impact of Additional Noise on Subjective and Objective Quality Assessement in VoIP

The main requirement in the Voice over IP technology is a good quality of received voice signal during communication between subscribers. The signal quality can be influenced by many factors such as packet loss, jitter, packet delay, noise etc. and it can be measured by number of methods. The main purpose of this paper is the investigation of an impact of different noise types and different noise levels on the quality assessment in VoIP. The artificial generated noises and real noises obtained from real telecommunications networks were used for testing. The next goal is a comparison of the results obtained by subjective listening tests and objective measuring methods. PESQ and 3SQM were used for objective testing in this paper.