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. In the context of UMTS (Universal Mobile Telecommunications System), Uu stands for the interface between UTRAN (UMTS Terrestrial Radio Access Network) and the UE (User Equipment).