Analysis of the perceived VoIP quality under various wireless network conditions

This paper focuses on the comparative statistical analysis of the performance of VoIP calls under various situations, namely, during a handover, under different background traffic conditions (normal and heavy traffic load/saturation conditions) at a wireless access point (AP). Using empirical-based measurements, it demonstrates that various network conditions exhibit distinct statistical behaviour in terms of SNR, packet losses and end-to-end delays, and thus, impact the VoIP user quality in a different manner. The paper shows that both network conditions and codec type, as well as their interaction, have a significant effect on the PESQ MOS values. Moreover, it indicates statistically highly significant differences between the predictions of the PESQ and E-model (e.g., in the heavy packet loss scenarios, E-model underestimates quality, reporting a very low MOS value). Finally, it highlights the benefits of the packet loss concealment of the AMR 12.2Kbits/s under these network conditions.