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What is E-UTRAN?
E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) is the radio access network of the 4G LTE system, consisting of a network of interconnected eNodeBs (eNBs) that provide the air interface to user equipment. Introduced by 3GPP in Release 8 (2008), E-UTRAN represented a fundamental redesign of the RAN architecture — eliminating the Radio Network Controller (RNC) of 3G UTRAN and moving its functions into the eNB, creating a flatter, lower-latency architecture. E-UTRAN remains an active component of 5G NSA deployments.
How Does E-UTRAN Work?
E-UTRAN is a single-node RAN architecture where each eNB handles all radio access functions: radio resource management, scheduling, handover execution, mobility management, and IP header compression. eNBs connect to the EPC via the S1 interface (S1-MME for control, S1-U for user data) and interconnect with each other via the X2 interface for handover and inter-cell interference coordination. The air interface uses OFDMA in the downlink and SC-FDMA in the uplink with MIMO support. In 5G NSA (EN-DC) configurations, the E-UTRAN eNB serves as the master node and connects to the en-gNB via X2.
Use Cases
4G LTE mobile broadband radio access, 5G NSA anchor RAN for EN-DC deployments, VoLTE radio bearer delivery, LTE-M and NB-IoT radio access for IoT devices, and carrier aggregation across multiple frequency bands.
3GPP / Standards Reference
3GPP TS 36.300 (E-UTRA and E-UTRAN overall description), 3GPP TS 36.401 (E-UTRAN architecture description)
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This glossary entry is part of the 5GWorldPro Complete 5G Glossary. To go deeper into 5G architecture and technology, explore our 5G Training courses.
