LTE Architecture Overview
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The document provides an overview of LTE network architecture, detailing its three main components: User Equipment (UE), Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), and Evolved Packet Core (EPC). It outlines the functions of various modules and interfaces within these components, including user data management, signaling, and roaming architecture. The document serves as a comprehensive guide for understanding the structure and operations of LTE networks.
LTE Architecture Overview
- 3. VoIP Solutions Provider Since 2005 3
- 4. History 4
- 5. LTE Network Architecture 5 •Three main components: The User Equipment (UE) The Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) The Evolved Packet Core (EPC) UE
- 6. LTE Network Architecture (Cont.) 6 • The User Equipment (UE), comprised of the following important modules: o Mobile Termination (MT) : handles all the communication functions o Terminal Equipment (TE) : terminates the data streams o Universal Integrated Circuit Card (UICC) : known as the SIM card for LTE equipment's. It runs an application known as the Universal Subscriber Identity Module (USIM)
- 7. LTE Network Architecture (Cont.) 7 • The E-UTRAN (access network): o Handles the radio communications between the mobile and the evolved packet core o Just one component, the evolved base stations, called eNodeB or eNB o Each eBN connects with the EPC by means of the S1 interface o It can also be connected to nearby base stations by the X2 interface, which is mainly used for signalling and packet forwarding during handover
- 8. LTE Network Architecture (Cont.) 8 • The E-UTRAN: UE
- 9. LTE Network Architecture (Cont.) 9 • The Evolved Packet Core (EPC): core network, is included some components: o The Home Subscriber Server (HSS): a central database that contains information about all the network operator's subscribers o The Packet Data Network (PDN) Gateway (P-GW): communicates with the packet data networks PDN, using SGi interface o The serving gateway (S-GW): acts as a router, and forwards data between the base station and the PDN gateway
- 10. LTE Network Architecture (Cont.) 10 o The mobility management entity (MME): controls the high-level operation of the mobile by means of signaling messages and HSS o The Policy Control and Charging Rules Function (PCRF): is responsible for policy control decision- making, as well as for controlling the flow-based charging functionalities in the Policy Control Enforcement Function (PCEF), which resides in the P-GW
- 11. LTE Network Architecture (Cont.) 11 • The Evolved Packet Core (EPC): EPC
- 14. 14 LTE Components Protocol Stack & Interface USERPlaneControlPlane
- 15. 15 eNodeB X2 Interface User PlaneControl Plane • The X2 interface main function is to provide an E- UTRAN handover without the involvement of the Core network • The control plan is based on SCTP and User plane is based on UDP
- 16. 16 MME Interfaces • The MME provides the main roaming architecture • It provides session management through S1- MME interface to eNodeB • The MME controls the user data plane through S11 interface • The MME provides the mobility management function through S10 interface • It does user authentication through S6a interface that is connected to HSS • The MME provides an integration point with 2G/3G core SGSN via S3 interface
- 17. 17 MME Protocol Stack • The MME mobility and session management functionalities is implemented on NAS (Non- Access-Stratum)
- 18. 18 MME S1-AP Interface • It provides a Control interface to the eNodeB • It’s based on SCTP • It’s transport for NAS • It’s a many to many interface eNodeB
- 19. 19 MME S11 Interface • It provides a Control interface between MME and SGW (SAE GW) • The protocol is GTP-C • It’s many to many
- 20. 20 MME S10 Interface • The main functionality is to connect the MME with the neighbor MME • It supports only control plane • The protocol is GTP-C
- 21. 21 MME S6a Interface • The main functionality is to provide access to the HSS, enables transfer of subscription and authentication data • The connection is purely control plane • The connection is based on SCTP and is using Diameter protocol
- 22. 22 MME S3 Interface • Enables user and bearer information exchange for inter 3GPP access network mobility • The protocol is GTP-C MME
- 23. 23 S-GW Interfaces • The SGW acts as a user plane anchor where it manages the user data path through the S1-U and S5/S8 interface by forwarding the packets and buffering the data packets • The SGW is controlled by one or more MME through the S11 interface • Mobility anchoring for inter-3GPP mobility via S4 Interface
- 24. 24 SGW S1-U Interface • Provide user plane interface to the eNodeB • All user traffic are forwarded using this interface • The user plan is based on GTP tunnels • Multiple S1-U connectivity is supported
- 25. 25 SGW S5/S8 Interface • The main functionality is to forward traffic between S –GW and P-GW • S5 is standardized for local network and S8 is standardized for roaming • Control and user plane are under two different protocol stacks GTP and PMIPv6
- 26. 26 SGW S4 Interface • It provides related control and anchoring for inter-3GPP mobility • The Protocol is GTP-C
- 27. 27 SGW SGi Interface • The SGi interface connects the PGW to a external network (PDN) • Packet data network may be an operator external public or private packet data network or an intra operator packet data network, IMS, …
- 28. 28 PCRF Interfaces • The PCRF controls the main policies assigned per subscriber • Provide a QoS policy and charging rules through the Gx interface • Provide a Data Network interface through the Rx+ • Connection between local and roaming PCRF through S9 interface • It’s based on Diameter protocol