A demonstrator for real-time multimedia sessions over 3rd generation wireless networks

This paper presents a simulation tool used to demonstrate the effects of 3^rd generation wireless network access on IP-based multimedia applications. In 3^rd generation wireless networks like, e,g., the Universal Mobile Telecommunications System (UMTS), complex control and transport mechanisms influence the link quality for a given application, while the application itself influences the control mechanisms by generating load on the wireless link. To study the effects of such a dynamic system on the user-perceived quality of service (QoS) of a real-time multimedia application it is necessary to simulate the wireless link in real-time. Our tool allows to interface standard IP-based multimedia applications with an UMTS-specific link simulator. The system comprises essential layer 2 and 3 protocol functionality of the UMTS Terrestrial Radio Access Network (UTRAN) for terminal equipment (TE) and base station (BS). We motivate and describe the concept, system architecture and implementation in terms of timing, QoS mapping, packet- and circuit-switched (CS) services integration, and physical link parameters