eNB – Evolved Node B or eNodeB

What is eNB?

The eNB (eNodeB) is the 4G LTE base station. Unlike 3G where the NodeB and Radio Network Controller (RNC) were separate, the eNB is a self-contained node that integrates both radio functions and radio resource management, connecting directly to the EPC. It is the most widely deployed mobile base station in the world.

How Does eNB Work?

The eNB manages radio resource scheduling, OFDMA/SC-FDMA physical layer processing, MIMO, handover decisions, and RRC (Radio Resource Control) protocol. It connects to the EPC via the S1 interface (S1-MME for control, S1-U for user plane) and to neighbouring eNBs via the X2 interface for coordinated handovers. In 5G NSA deployments, the eNB acts as the Master Node in EN-DC.

Use Cases

4G LTE macro and small cell coverage, voice (VoLTE) and data service delivery, anchor Master Node for 5G NSA (EN-DC Option 3x) deployments.

3GPP / Standards Reference

3GPP TS 36.300 (E-UTRAN Overall Description), TS 36.413 (S1AP Protocol)

Related Terms

4G  |  EPC  |  EN-DC  |  gNB  |  LTE  |  NSA

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