Tight Coupling internetworking between UMTS and WLAN: challenges, design architectures and simulation analysis

To provide seamless internet connectivity anywhere at any time to the mobile users, there is a strong demand for the integration of wireless access networks for all-IP based Next Generation Networks (NGN). The Wireless Local Area Network (WLAN) is capable of providing high data rate at low cost. However, its services are limited to a small geographical area. Universal Mobile Telecommunications System (UMTS) networks provide global coverage, however, cost is high and the provided data rate do not fulfill the requirements of bandwidth intensive applications. By integrating these two promising technologies; UMTS and WLAN several benefits can be achieved, i.e., load balancing, extension of coverage area, better Quality of Service (QoS), improved security features, etc. Therefore, the integration of these two technologies can provide ubiquitous connectivity and high data rate at low cost to wireless clients. In this paper different integration mechanisms of UMTS and WLAN are investigated. More precisely, an integrated mechanism for the integration of UMTS and WLAN based on two different variations of tight coupling, i.e., interconnecting WLAN with Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN) is designed and analyzed. The simulated results reveal that the