LTE Architecture

Above diagram represents non-roaming architecture of  LTE network. Entire architecture devided into two part Radio network part called E-UTRAN(Evolved - Universal Terrestrial radio Access Network) and Core network part called EPC(Evolved Packet Core). Both combinedly  called EPS ( Evolved Packet System).

LTE architecture is very simple in terms of accessing the packet, it is already separated Control Plane and User Plane.

Components of LTE networks are

UE(User Equipment) - End user mobile device.

E-UTRAN or eNodeB(evolved NodeB) - Radio Antenna tower or base station.

MME (Mobility Management Entity) - Main node of LTE core network.

SGW (Serving Gateway) - Pivot of LTE network and user roaming.

PGW(PDN Gateway) - Packet Data Network Gateway, connector to IP world.

HSS(Home Subscription Server)- Centralized data base of User information.

PCRF(Policy and Charging Rule Function) - QoS rule for services and their charging. 

SGSN(Serving GPRS Support Node); Main component of GPRS network.

Reference :

3GPP 23.401 TS.