Towards VoIP quality testing with real-life devices and degradations

The paper presents mediated conversation test results for narrowband, wideband and super-wideband connections, where different end-user terminals were used by the test participants, and different impairment types typical to Voice over Internet Protocol (VoIP) were simulated. For the purpose of testing, a setup for real-time voice communication has been built enabling a control of many impairments such as echo, noise and packet loss. The overall goal of our research work is to assess the contributions to perceived listening and conversational quality stemming from terminal equipment characteristics and respective signal processing such as noise suppression and echo cancellation on the one hand, and network transmission conditions on the other hand. The experiment presented in this paper serves as a core test for the following tests planned by the authors, and already provides a range of relevant results.