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 IPbased services to mobile users. Yet, these systems, such as the UMTS network, are unable to meet the stringent delay requirements imposed by the enhanced multimedia services due to the anchor point that introduce into the user’s data path. Moreover, such applications will rely on IP-based control protocols for session and mobility management, resulting in duplication of functionality in the network at both the bearer and the application level. For the above reasons, the SAILOR network architecture is presented in this paper, proposing an evolution to the standard UMTS network, where GSNs are integrated into a single entity. Furthermore, the SIP protocol is adopted, for performing mobility and session management procedures 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 as well as accomplish a significant performance gain.