User equipment
In the Universal Mobile Telecommunications System (UMTS) and 3GPP Long Term Evolution (LTE), user equipment (UE) is any device used directly by an end-user to communicate. It can be a hand-held telephone, a laptop computer equipped with a mobile broadband adapter, or any other device. It connects to the base station Node B/eNodeB as specified in the ETSI 125/136-series and 3GPP 25/36-series of specifications. It roughly corresponds to the mobile station (MS) in GSM systems.
The radio interface between the UE and the Node B is called Uu. The radio interface between the UE and the eNodeB is called LTE-Uu.
Functionality
UE handles the following tasks towards the core network:
- Mobility management
- Call control
- Session management
- Identity management
The corresponding protocols are transmitted transparently via a Node B, that is, Node B does not change, use or understand the information. These protocols are also referred to as Non Access Stratum protocols.
The UE is a device which initiates all the calls and it is the terminal device in a network.