Analysis of QoS VoIP applications on mobile devices based on PESQ MOS score

Abstract

This paper aims to compare the QoS of two VoIP applications, Whatsapp and SOMAapp, in scenarios in which factors of variation of network conditions were used such as delay, packet loss and jitter and also a configuration of the transmission rate limited at 10Mbps. The applications were submitted to all scenarios and in each scenario a call is made by Whatsapp and another by SOMAapp, which are made between two smartphones and transmitted a pre-recorded audio. The audio captured on the smartphone that received the call is the audio that suffered network degradation and is used for analysis using the tool available by the objective PESQ method which generates a MOS equivalent score between 1 (poor) and 5 (excellent). The evaluation was carried out in two stages. During the first stage, named preliminary tests, we checked how much applications’ QoS is affected by each factor. During the second stage, named evaluation scenarios, all factors were combined. To create the scenarios, the Core 4.8 network condition emulation tool was used. Finally, with the experiments it could be concluded that the SOMAapp application had mostly better performance than Whatsapp, because, in the preliminary scenarios, in 06 of the 09 scenarios it obtained higher average PESQ MOS scores. In its worst scenario, the difference was of 0.5 score. Another observation from the preliminary tests is that both were more affected by the jitter factor. In the second stage, in which the factors were combined, the application SOMAapp also presented better PESQ MOS grades, but presented a larger grade range, while whatsapp was more stable. Overall, out of the 37 scenarios, in 91.0% of cases the SOMAapp application scored higher.