SIP as a unified signalling solution in a beyond 3G system

The adoption of packet-switched technologies in mobile communication systems has enabled the provision of IP-based services to mobile users. Yet, these systems, such as the UMTS network, are not flexible enough to allow the extensive deployment of IP-oriented protocols. Furthermore, they are not able to meet the stringent QoS requirements imposed by the enhanced multimedia services that are expected to be encompassed in future mobile systems. For the aforementioned reasons, an innovative beyond 3G network architecture – denoted as SIPRAN – is presented in this paper, posing an evolution to the standard UMTS network. According to the proposed concept, the GPRS Support Nodes are integrated into a single entity and the Session Initiation Protocol is adopted for performing mobility and session management, currently undertaken by the UMTS Non-Access Stratum protocols. Both modifications to the UMTS network and protocol architecture result in the smooth evolution of the UMTS Core Network towards IP, while accomplishing considerable performance improvement. In order to evaluate the target architecture and substantiate its actual effectiveness, a series of experiments was carried out, by utilizing a fully functional emulator.