Integration of WLAN, UMTS and WiMAX in 4G

Since broadband network connectionsare becoming ubiquitous, people expect access to multimedia content anywhere at anytime. This new demand results in a need to create and develop a new platform which will be able to support all type of traffic at the same time. In this paper we demonstrate how we can integrate WLAN, UMTS and WiMAX in this new concept of networks NGN by studying vertical handover´s system. We introduce our paper by an overview of network access, then we focus on an existing vertical handover decision strategy in literature and we give details after our approach which is based on user profile, scoring and network information system for providing the appropriate time and the most suitable access network to perform a handover.