Support of multimedia broadcast/multicast service in UMTS networks

This paper describes two basic approaches to implementation of MBMS support in UMTS network. The main idea of both approaches is to overcome the gap between the current service support in UMTS network on one side and the current support for multicasting in IP networks on the other. One approach modifies already implemented procedures in UMTS network and defines new ones to support IP multicasting within the UMTS. Second approach uses existing functionality provided by UMTS network to bring current IP multicasting support from IP networks, as close as possible to the end-users. Focus of this paper is to examine and compare two important issues of MBMS support in both approaches, which are usage of network resources and service continuity and mobility. Packet services, currently provided by UMTS network, are based on point-to-point communication and designed for individual users. The packet switched part of the UMTS network, presented in this paper, enables its end- users to access external packet data networks, especially the Internet. With every new release, UMTS network enhances the quality and the service spectrum, but so far everything is based on the single-user services. At the same time, packet data networks, based on IP