Date Added: Aug 2012
In wireless communication new technologies emerges regularly with faster data rates and larger coverage area. Therefore, the forthcoming challenge is to make the best possible use of the available heterogeneous network. For connecting mobile between heterogeneous networks vertical handoff is mandatory. IP Multimedia Subsystem is an emerging architecture for interworking of heterogeneous networks. In this paper, the authors used WLAN/WiMAX/LTE heterogeneous networks. Coupling architectures such as tight coupling and loose coupling are considered. In order to reduce the latency two mechanisms such as neighbour bandwidth reservation and gateway relocation are employed.