The LTE Network (LTE-->Long Term Evolution)


While LTE aims for an all-IP simplified infrastructure, in reality LTE must interwork with the 3G network, Internet Multimedia Subsystems (IMS), and other pre-existing elements. It most affects the radio access network and packet core network. The LTE Network consists of updates or replacements for many components already in the wireless network. For example:

eNodeB replaces the 3G base-station NodeB, to accommodate the change to E-UTRAN (Evolved UTRAN/RAN) from the older standard in the 2G and 3G Radio Access Networks
EPC (Evolved Packet Core, known also as SAE, System Architecture Evolution) replaces the General Packet Radio Services (GPRS) core network
The SAE Gateway is a new element that acts as a Serving Gateway and a Packet Data Network Gateway to handle traffic and data-plane aspects
Diameter signaling replaces SS7 signaling in the Home Subscriber Server (HSS), an existing element which is used by the new MME (Mobility Management Entity) node