The LTE network architecture is that E-UTRAN removes RNC network nodes, the purpose is to simplify the network architecture and reduce the delay. in.
The E-UTRAN structure includes several eNode Bs. The eNode Bs use IP transmission at the bottom layer and are logically connected to each other through the X2 interface, that is, a mesh network structure. This design is mainly used to support the UE in the entire Mobility within the network ensures seamless handover for users. Each eNode B is connected to the Mobility Management Entity (MME) of the Evolved Packet Core (EPC) network through the S1 interface, that is, connected to the MME through the S1-MME interface and connected to the MME through S1-U and S-GW Connection, S1-MME and S1-U can be regarded as the control plane and user plane of the S1 interface, respectively.
A high-level network architecture, LTE is composed of the following three main components:
1.User equipment (UE).
2.Evolution of UMTS terrestrial radio access network (E-UTRAN).
3.Packet Core Evolution (EPC).
Similar to 3G, LTE uses a solution in which E-UTRAN and EPC functions are separated, while simplifying some network elements and merging related functions. The functional division of E-UTRAN and EPC is shown in Figure 2.
In the LTE / SAE architecture, the interface between eNode B is called X2 interface, and the interface between eNode B and EPC core network is called S1 interface.
E-UTRAN flat network architecture has the advantages of network sharing, load balancing, and robustness. In the network architecture and interface design process, the following principles are basically followed:
· Logical and data plane logical division;
· The mobility of RRC connection is completely controlled by E-UTRAN;
· When defining an E-UTRAN interface, the number of options for interface function division should be minimized;
An interface should be designed based on the physical logic model controlled by this interface;
· A physical network element can contain multiple logical nodes.
