Mobility management: from GPRS to UMTS

This paper describes mobility management for the third-generation mobile networks. We focus on the evolution from General Packet Radio Service (GPRS) to Universal Mobile Telecommunication System (UMTS). In this evolution, the radio access network UTRAN has been introduced, and radio-related management is moved from the core network to UTRAN. We elaborate on how this architecture change affects the mobility management functionality, including the attach and detach procedures, location update, serving radio network controller relocation and intersystem change between GPRS and UMTS.