1 Overview of Mobile Technologies for Voice and Data Transport
1.3 EPS Architecture

Evolved UMTS networks have a clear objective to integrate all applications over a simplified and common architecture. The main components of EPS architecture are thefollowing:

The CS domain is no longer present, as all applications (including the most real-timeconstraining ones) are supported over the PS domain. This obviously requires specific gateway nodes – part of the IMS architecture – so that IP traffic is converted to PSTN circuit-switched-based transport.

As a consequence of this network simplification, specific efforts have been produced in the scope of Evolved UMTS standardization activity in order to maintain voice call continuity between old and new systems.