Formal model of the MBMS multicast support in the UMTS network

This paper describes formal model of the MBMS (multimedia broadcast/multicast service) support in UMTS (universal mobile telecommunication system). The formal model is based on the reference architecture and implementation suggestion, which was proposed by 3GPP (third generation partnership project) specification TS23.246. The main goal was to build the formal model, which supports basic signalization scenarios that are introduced by MBMS. For the MBMS architecture and functionality the UML (Universal Modeling Language) model is used. Furthermore, SDL (Specification and Description Language) is used to specify the exact behavior of the nodes within the packet switched part of the UMTS network. The SDL model was built using the SICAT (SDL integrated computer aided toolset) tool. Verification of the formal model was done through simulation of the basic signalization scenarios for which the MSC (message sequence charts) diagrams were created dynamically. The MSC diagrams are compared to the corresponding call flows from 3GPP TS23.246.