WLAN-UMTS integration: Architecture, seamless handoff, and simulation analysis

Providing Quality of Service (QoS) for sophisticated and QoS-constraining applications (e.g. video-based applications, multimedia services, and high speed data services) and ensuring continuous connectivity for universal mobile stations (UMS) in heterogeneous networks are important issues in the design of fourth generation (4G) networks. The latter will utilize multiple radio access technologies including cellular technologies (such as GSM, GPRS, and UNITS), satellite-based communications, and wireless local area networks, which are seamlessly integrated to form a heterogeneous wireless network. In the paper, first, an architecture for WLAN-UMTS integration is defined that makes the composing networks transparent to users and provides seamless services. Second, a novel protocol is proposed to reserve resources for handoff. Third, modeling and simulation is used to evaluate the QoS performance.