Our objective is to propose an effective call admission control (CAC) scheme for Quality of service provisioning in heterogeneous networks (Integration of WLAN hotspots in 3G cell) .With the ubiquitous coverage of the cellular network and the disjoint deployment of WLANs in the hot-spot areas, the integrated system has a two-tier overlaying structure. The parameters have been taken into consideration is service type of user i.e. real and non-real service and also velocity of the user. For real time services which require higher Qos, has given preference to UMTS network and for non-real services , priority is given to WLAN network. The analytical model has been proposed for Priority based Call Admission Control (CAC) scheme and authenticates with simulation results followed by comparison with existing scheme. It is observed that there is an increase in the capacity of overall network marked by minimizing of two performance metrics – dropping probability of handoff calls and blocking probability of new calls. The importance of heterogeneous wireless network is essential to integrate 4G with WLAN to provide seamless roaming and user service connectivity. 4G is expected to provide high throughput, high data rate, low handoff Latency and reduce the power consumption of the mobile Node. © 2015 Praise Worthy Prize S.r.l. - All rights reserved.