Evolving from GSM/GPRS to UMTS - Paths for safe and secure migration

GSM and GPRS, the so-called second-generation mobile technologies, offer the combination of mobile voice and mobile Internet access at convenient data transmission speeds that will be comparable to the PSTN and ISDN. GSM ensures the necessary voice service quality based on classical circuit-switching principles, whereas GPRS maintains efficient packet transport for best-effort data communication with the Internet. UMTS will introduce a new air interface that enables much higher data transmission rates over specifically allocated UMTS frequency bands. The UMTS network transports any traffic packetised in order to cope efficiently with the traffic dynamics of multirate-coded speech and data streams at different transmission speeds. The UMTS core network in its first implementation follows the same hybrid architecture for circuit voice and packet data. As the majority of future UMTS operators already have 2G networks in operation, this article gives an overview of different core network migration scenarios from 2G GSM/GPRS to the first phase of UMTS.