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 astrong demand for the integration of wireless access networks for all-IP based Next GenerationNetworks (NGN). The Wireless Local Area Network (WLAN) is capable of providing high data rateat low cost. However, its services are limited to a small geographical area. Universal MobileTelecommunications System (UMTS) networks provide global coverage, however, cost is highand the provided data rate do not fulfill the requirements of bandwidth intensive applications. Byintegrating these two promising technologies; UMTS and WLAN several benefits can beachieved, 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 provideubiquitous connectivity and high data rate at low cost to wireless clients. In this paper differentintegration mechanisms of UMTS and WLAN are investigated. More precisely, an integratedmechanism for the integration of UMTS and WLAN based on two different variations of tightcoupling, i.e., interconnecting WLAN with Serving GPRS Support Node (SGSN) and GatewayGPRS Support Node (GGSN) is designed and analyzed. The simulated results reveal that theGGSN-WLAN integration performance is better than the SGSN-WLAN integration for all theapplied applications and measurement parameters.