Impact of retransmissions on the quality of experience in VoIP systems

In recent years, structure of communication systems is changed due to increasing usage of internet. Voice is started to transmit over IP (Internet Protocol) that is named as Voice over IP (VoIP), instead of conventional voice transmission public switched telephone network (PSTN). The voice quality that is perceived by the end user is showed numerically by the value of Quality of Experiene (QoE) which is depend on many variable parameters. In this work, the impact of retransmission on the QoE is examined. VoIP packets are simulated. For the QoE value, E-model methodology is used with assuming the voice packets are created by ITU-T's G.711 codec. In simulation progress it is shown that increasing number of retransmissions initially enhance the value of QoE. However, QoE value begins to decrease after a number of transmission because of the increment on delay time.