QoS Provisioning in Vertical Handover of WiMAX/WLAN Overlay Network for Fixed and Mobile Users

The integration of WiMAX and WLAN has been seenan important goal towards the enhancement of fourth generation(4G). Vertical handoff plays important role while integration ofWiMAX and WLAN heterogeneous overlay systems. Verticalhandoff is preformed on the basis of Quality of Service (QoS) metricsof the two heterogeneous networks. We addresses a tightly coupledarchitecture executed with seamless handoff By using the ad-hoc ondemand multipath distance vector protocol and channel aware adhocon demand multipath distance vector a simple evaluation algorithmis used to measure the QoS metrics such as available bandwidth andpacket delay of both mobile and fixed users respectively. Wheneverthe criteria is not satisfied the vertical handoff occurs. The proposedscheme can keep the users always being best connected to networkavailable (WiMAX OR WLAN).