QoS performance analysis for VoIP traffic in heterogeneous networks with WiMAX access

Designing a heterogeneous network including systems providing different QoS, such as the emerging WiMAX, is a difficult task. The integration of a WiMAX access system with Differentiated Services (DiffServ) enhances the overall performance of the network. This paper investigates the interworking between WiMAX and DiffServ networks, by measuring one-way delay, jitter and packet drop rate of VoIP traffic from WiMAX users in a test-bed scenario with and without DiffServ. It is shown that DiffServ in the core network solves the congestion problem in efficient way by providing service priority to delay-sensitive traffic. The results show valuable gains using DiffServ network.