Handover and class-based Call Admission Control policy for 4G-heterogeneous mobile networks

In this paper we propose a handover and class-based Call Admission Control algorithm for UMTS/WLAN heterogeneous networks. Its main objective is to limit the occurrence of hard WLAN-UMTS handovers to mobile nodes moving across cells and using real time applications. Our mechanism is based on the service class differentiation, the call origination point, and a vertical handoff decision function as well. It aims at maximizing the utilization of the resources available at the WLAN cells, and meeting the QoS requirement of higher priority users as much as possible while maintaining the minimum requirements of lower priority users, especially when the UMTS and the WLAN networks suffer from congestion. The new CAC policy achieves a good performance and capacity gain.