E-UTRAN, which stands for Evolved UMTS Terrestrial Radio Access Network, is a fundamental component of the LTE (Long-Term Evolution) system, often referred to as 4G LTE. It represents the radio access portion of the LTE architecture.
Here are the main points about E-UTRAN:
- eNodeBs: E-UTRAN is made up of eNodeBs, commonly just termed as “nodes”. These eNodeBs are the equivalent of base stations in other cellular networks. They handle the radio communications with the mobile device, specifically the Radio Resource Management (RRM) functionalities like handover decisions, selection of the MIMO (Multiple Input, Multiple Output) profile, scheduling, and more.
- No More RNCs: In previous UMTS systems, there were Radio Network Controllers (RNCs) that controlled multiple base stations. With E-UTRAN and eNodeBs, there’s no longer a need for a separate RNC layer. The eNodeB takes over many of the functionalities that were previously performed by RNCs.
- Simplified Architecture: Because E-UTRAN does away with the RNC layer and has high-capacity eNodeBs, the architecture is simpler and more efficient than its predecessors. This means lower latency and more direct communication between the mobile device and the core network.
- Connectivity: eNodeBs connect to the user equipment (UE, such as smartphones and tablets) and also to the Evolved Packet Core (EPC), which is the next part of the LTE system after E-UTRAN. The EPC handles data routing, mobility, and sessions, among other things.
- Protocols: The main protocol stack used on the air interface between the UE and the eNodeB in E-UTRAN is called the LTE-Uu interface. This interface uses a set of protocols to handle different layers of communication, including the Physical layer, MAC (Medium Access Control) layer, RLC (Radio Link Control) layer, and PDCP (Packet Data Convergence Protocol) layer.
- Frequency: E-UTRAN operates over a range of different frequency bands, depending on the region and specific LTE deployment. The flexibility in frequency band usage allows for LTE to be deployed in various regions around the world.
- MIMO Technology: E-UTRAN uses MIMO technology, which employs multiple antennas both at the source (transmitter) and the destination (receiver). This enhances data throughput and link reliability.
In summary, E-UTRAN represents a key advancement in mobile radio access network technology, simplifying the architecture while delivering faster and more efficient communication for LTE systems.