Improving the vertical handover latency for VoIP between WLAN and WiMAX networks

In this paper we study the optimization of the parameter Link Going Down that affects the vertical handover performance when mobile node moves with different speed from WLAN to WiMAX network. We show here that optimizing the Link Going Down parameter for VoIP traffic can appreciably improve the vertical handover latency. This is very important for real time services like VoIP, where minimal handover disruption and service continuity are the primary requirements. We also verified our simulation results theoretically with an equation that relates the optimized link going down factor with the speed of the mobile node.