The next generation wireless systems will consist of heterogeneous networks from cellular, WirelessLocal Area Networks (WLANs), Worldwide Interoperability for Microwave Access (WiMAX) to other emerging access technologies and have the capability to offer various services at any time as per user requirements, anywhere with seamless interoperability. The integration of heterogeneous wireless networks poses several challenges. One of the major challenges is vertical handoff. Handoff is the process of transferring an ongoing call or data session from one access point to another in a homogeneous or heterogeneous network. Vertical handoff occurs when a mobile terminal decides to switch between networks of diverse technologies. A key issue during vertical handoff is the selection of an optimal network that maximizes end users satisfaction. This article presents a novel approach for handover decision making in the context of heterogeneous wireless network. The aim of the proposed scheme is the selection of the most suitable radio access network for each application. The performance analysis shows that the proposed approach efficiently uses the network resources by switching between LTE and WLAN to offer best connectivity to the users.It is observed that resource utilization ratio increases to (99%) and the integration of LTE with WLAN using the proposed algorithm reduces the call dropping probability (less than 0.15 for Voice over IP service when switching to LTE network) and call blocking probability (less than 0.24)
['Amina Gharsallah', 'Nouri Omheni', 'Faouzi Zarai', 'Mohammad S. Obaidat', 'Kuei-Fang Hsiao']
Network Selection in Heterogeneous Wireless System Environments