Performance Evaluation of QoS of VoIP over WiMAX Networks

Abstract

Due to its large coverage area, low cost of deployment and high speed data rates, WiMAX is a promising technology for providing wireless last-mile connectivity. Voice over Internet Protocol (VoIP) is one of the rapidly growing technologies and is expected to replace the conventional circuit switched voice services. VoIP is also considered as one of the applications of WiMAX which requires careful design of QoS configurations. As real-time application VoIP requires packet delivery with low latency, jitter, packet loss, and sufficient bandwidth. WiMAX technology defines 5 different service classes that can be used in order to satisfy QoS requirements of different applications. This research evaluates the performance of VoIP traffic over WiMAX networks. This has been done through the study and evaluation of several aspects related to the WiMAX network and VoIP configurations such as: WiMAX service classes, number of nodes and VoIP Codecs. The investigated parameters include: throughput, mean opinion score (MOS), jitter delay and end-to-end delay. The results were obtained through the design and simulation of different WiMAX network scenarios using OPNET Modeler. Results showed that UGS service class has the best performance parameters serving VoIP. It is also observed that the G.711 codec has lower end-to-end delay, higher MOS and higher throughput.