UMTS Architecture

According to TS 23.101 :"General UTMS Architecture"

UTMS architecture are split to user equipment domain and infrastructure domain.

User Equipment Domain
In layman's term, user equipment is a mobile phone which is to access the infrastructure through the air interface. Air interface is the air space between the mobile phone and the base station.

Infrastructure Domain
It consist of UMTS Terrestial Radio Access network (UTRAN) and core network.

UTRAN
UTRAN is the access network where the user equipment interact with Node B trough the air interface. "The Access Network Domain consists of the physical entities which manage the resources of the access network and provides the user with a mechanism to access the core network domain." The Technical document explained that Access Network Domain which also known as UTRAN consist of the physical entities. Physical entities in UTRAN are the Node B and Radio Network Controller (RNC).

Core Network
"The Core Network Domain consists of the physical entities which provide support for the network features and telecommunication services. The support provided includes functionality such as the management of user location information, control of network features and services, the transfer (switching and transmission) mechanisms for signalling and for user generated information."