The LTE/EPC architecture is driven by the goal to optimize the system for packet data transfer.
Remember that There are no circuit switched components in LTE/EPC.
There is a new approach in the inter-connection between radio access network and core network. The EPS architecture is made up of an EPC (Packet Core Network, also referred as EPC) and an eUTRAN LTE Radio Access Network (also referred as LTE)
The CN provides access to external packet IP networks and performs a number of CN related functions (e.g. QoS, security, mobility and terminal context management) for idle (camped) and active terminals. The RAN performs all radio interface related functions.
The LTE/EPC radio access network – Evolved UTRAN (E-UTRAN) – will only contain Node Bs. No RNC is provided anymore. This means, that the evolved Node Bs take over the radio management functionality.
This will make radio management faster and the network architecture simpler. EUTRAN exclusively uses IP as transport layer. Behind the EPC follow one or more IP networks. A major example will be IMS, that can benefit especially from the QoS awareness of LTE.
How LTE Network Architecture Works
The LTE network architecture is designed to provide high-speed, low-latency wireless communication. It is divided into two main components: the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and the Evolved Packet Core (EPC). Together, these elements support the high-performance features of LTE.
1. Evolved UMTS Terrestrial Radio Access Network (E-UTRAN)
- eNB (Evolved NodeB): The base station that connects the User Equipment (UE) to the network. It handles radio resource management, scheduling, and transmission/reception of data between the UE and EPC.
- UE (User Equipment): Devices like smartphones, tablets, and modems that connect to the network via eNB for voice and data services.
2. Evolved Packet Core (EPC)
- MME (Mobility Management Entity): Manages signaling for mobility, security, and session management. It handles tasks such as authentication and tracking of UE location.
- SGW (Serving Gateway): Routes user data packets between the eNB and the PDN Gateway (PGW). It also handles mobility between different eNBs.
- PGW (Packet Data Network Gateway): Connects the LTE network to external IP networks like the internet. It manages IP address allocation and QoS enforcement.
- HSS (Home Subscriber Server): Stores subscriber data, including authentication information, QoS profiles, and service preferences.
- PCRF (Policy and Charging Rules Function): Manages policy decisions and charging rules for data services based on the user’s subscription and usage.
The LTE network architecture combines E-UTRAN and EPC components to provide seamless, high-speed, and efficient data transmission. This structure ensures high performance, low latency, and scalability for future service demands.