Improving the VoIP performances during vertical handovers between WiMAX and WLAN

In this paper we analyze the vertical handover latency for real time service VoIP G.711 using IEEE 802.21 standard during the vertical handover process between WiMAX and WLAN. We make comparison between MIPv6 and PMIPv6 protocols for different MN velocity and conclude that PMIPv6 reduces the vertical handover latency, so we obtain better VoIP performances during vertical handovers between WiMAX and WLAN networks.