What are eNB, EPC and PGW?

E-UTRAN, the radio access network part, consists of base stations which are known as evolved NodeBs (eNBs).

An eNB is responsible for reliable Radio Frequency (RF) transmission between the LTE core network and the UEs. At the data plane, eNBs are responsible for reliable delivery over the RF links, radio interface data encryption, header compression, and integrity protection through the radio protocol stack. At the control plane, eNBs are responsible for the Radio Resource Management (RRM) including admission control, radio bearer control, and scheduling through the Radio Resource Control (RRC) protocol stack.

On the other hand, EPC, the core network part, consists of Serving Gateway (S-GW), Packet Data Network (PDN) Gateway (P-GW), Mobile Management Entity (MME), Home Subscriber Server (HSS), and Policy and Charging Rules Function (PCRF) software node. S-GW, the main part of the EPC, is the anchor point between the E-UTRAN and the EPC. Moreover, it assists in interworking with other 3GPP technologies, such as GPRS or UMTS systems.

P-GW is responsible for providing IP connectivity to the UEs, UEs’ IP assignment, connecting the LTE network with other PDNs, and Quality-of-Service(QoS) provisioning insurance via the PCRF.