1. LTE Architecture
KANNAN M
JTO(3G)

2. LTE System Architecture-EPS
EPC
E-UTRAN
eNode B
HSS
MME
P-GW
Every Mobile telecommunication system will have 3 element structure.
A Radio air iterface
A Radio access network
And a core network.
Here also the structure is same The air interface which connects the Mobile to Radio access network is called Evolved UTRA or E-UTRA. This equivalent Um interface of UMTS.
The Radio Access network is called Evolved UTRAN or E- UTRAN . This is equivalent of UTRAN in UMTS
The core network is called Evolved packet Core. This an all IP packet core NW. The CN provides access to external packet IP networks
The E-UTRAN and EPC is together known as Evolved Packet system EPS. EPS is also called System architecture for Evolution SAE.
S-GW
eNode B
Evolved Packet Core (EPC)
E UTRA

3. LTE System Architecture-EPS
Internet & Operator services
EPC
This is simplified architecture, consists of E-UTRA, E-UTRAN and EPC. EPC interfaces internet and other services. Now we will see the detailed architecture.
E-UTRAN

4. Evolved Packet Core (EPC)
2G/3G UTRAN
HSS
MME
E- UTRAN
Trusted IP NWs
P-GW
This is the the detailed EPC architecture. It consists of
An MME, S-GW , P-GW ePDG and an HSS. You can see that MME and S-GW inter faces the EPC with Radio access network.
P-GW and ePDG interfaces EPC with other Packet or operator services like internet.
HSS is the data base centre. We will see each and every element in detail.
There is no circuit switched core network for services like Voice. This different from 2G / 3G.
S-GW
Operator Services
ePDG
Non-Trusted IP NWs

5. EPC –Home Subscriber Server
Master subscriber database
Stores user related information like, subscription parameters, user identification, service profile, user location etc
Generates security related information
It can be treated as an “upgraded HLR” with GSM, GPRS, LTE and IMS information
Master subscriber database
Stores user related information like, subscription parameters, user identification, service profile, user location etc
Generates security related information ie it carries the functionality of AuC
It can be treated as an “upgraded HLR” with GSM, GPRS, LTE and IMS information

6. EPC –Mobility Management Entity
Main control node
Handles the control plane signaling
Idle mode UE tracking
Bearer activation / de-activation
Choice of SGW and PGW for a UE
Mobility anchoring
Interacting with HSS to authenticate user
Provides temporary identities for UEs
Paging procedure
Coordinating LI
MME is the main control element in EPC.
It Handles the control plane signaling – From R4 onwards control and bearer switching parts are separated in core NWs. In UMTS this introduced MSC servers and MGWs. Where the MSC server handles the control functionality and MGW will do the switching functionality. Here MME is handling the control functionality.. So it terminates the control messages from E-UTRAN.
Idle mode UE tracking - location of the UE in idle mode as done by the MSC in legacy systems.
Bearer activation / de-activation – Call control or call set up
Choice of SGW and PGW for a UE – This is because sevral SGW and PGW may be connected to same MME for different services.
Mobility anchoring- It will coordinate Handovers in certain cases.
Interacting with HSS to authenticate user
Provides temporary identities for UEs – like TMSI in GSM
Paging procedure will be cordited
Coordinating LI
Now it seems that is almost similar to our MSC server in UMTS. But MSC server in Circuitswitched core NW. But MME is Packet core element. We can treat MME as the cotrol part of SGSN.
One MME can be connected to more than one S-GWs.

7. EPC –Serving GateWay SGW is the data plane interface of EPC.
A data plane element
An interface for the data packet network at the E-UTRAN.
The SGW maintains the data paths between the eNodeBs and the PDN Gateways
Routes user data packets between E-UTRAN and P-GW
When UEs move across areas served by different eNodeBs, the SGW serves as a mobility anchor ensuring that the data path is maintained
SGW is the data plane interface of EPC.
Forms an interface for the data packet network at the E-UTRAN.
The SGW maintains the data paths between the eNodeBs and the PDN Gateways
Routes user data packets between E-UTRAN and P-GW
When UEs move across areas served by different eNodeBs, the SGW serves as a mobility anchor ensuring that the data path is maintained. Also it will handle the data path when a handover to other RATs happens.
Can be treated as the data part of the SGSN or MGW of circuit core.
It supports LI

8. EPC –Packet Data Network GateWay
A data plane element
provides connectivity for the UE to external packet data networks
The UE may have connectivity with more than one PGW for accessing multiple PDNs
Charging
QoS control
IP address allocation
This is a data plane element
provides connectivity for the UE to external packet data networks
The UE may have connectivity with more than one PGW for accessing multiple PDNs
Charging
QoS control
IP address allocation
This is some what similar to GGSN

9. EPC – evolved PDG (ePDG)
Gateway used for Interworking with non trusted non 3GPP IP access systems
Provides some additional security mechanisms
Gateway used for Interworking with non trusted non 3GPP IP access systems
Provides some additional security mechanisms

10. Evolved UTRAN Architecture
S1 -MME X2
MME X2
This is the E-UTRAN architecture
As u can see, there only one element in E-UTRAN , the eNodeB. No RNC is there .
All eNodeBs are directly connected to core network.
Now there are two interfaces towards core network from eNodeB. One is towards MME and other is towards S-GW.
In addition to that neighboring NodeBs are interconnected by X2 interface.
S1- U X2
S-GW
E-UTRAN
E-PC

11. eNode B The lone NE in the E-UTRAN
Functionality of RNC moved to Node B, which reduces the number of nodes and there by complexity and latency of the network
It does the RRM functionality
Controls the scheduling
Transmission of paging & Broadcast information
Selection of MME during registration
Measurement configuration
Routing of user data to the S-GW
The lone NE in the E-UTRAN
Functionality of RNC moved to Node B, which reduces the number of nodes and there by complexity and latency of the network
It does the RRM functionality- In UMTS it was done by RNC
Controls the scheduling data
Transmission of paging & Broadcast information
Selection of MME during registration- One E-Node B may be connected to different vendors and so different MMEs. In that case eNodeBs will rote the signaling messages to the corresponding MMEs
Measurement configuration- What to measure, when to measure etc.
Routing of user data to the S-GW

12. eNode B Interfaces S1 MME Connects eNodeBs with MME
It is control / signaling plane interface
S1 U
Connects eNodeBs with S-GW
It is user plane interface
It transports actual user data /packets
3 types of interfaces are there in eNodeB. S1MME, S1U and X2
S1 MME
Connects eNodeBs with MME
It is control / signaling plane interface
S1 U
Connects eNodeBs with S-GW
It is user plane interface
It transports actual user data /packets towards the core network.

13. eNode B Interfaces X2 Connects eNodeBs with neighboring e-NodeBs
e Node Bs communicate directly with each other for cell reselection, intra LTE handover procedures, inter cell interference coordination etc through this X2 interface.
This is some what similar to Iur interface of UMTS UTRAN
Connects eNodeBs with neighboring e-NodeBs
e Node Bs communicate directly with each other for cell reselection, intra LTE handover procedures, inter cell interference coordination etc through this X2 interface.
This is some what similar to Iur interface of UMTS UTRAN
LTE is termed as SON self optimizing network. I.e. it will adjust the frequency and power in consultation with adjacent network. For this communication it uses this interface
ICIC

14. One RAN, Simplify your Network
Disadvantages
High CAPEX
Buy systems separately
Deploy systems separately
High OPEX
Operate systems separately
Maintain systems separately
Performance Down
Bad intersystem coordination
High intersystem interference
Reliability Down
- Fault point & risk increasing
- Hard for trouble shooting
Advantages
Reduce Capax and Opex
Reduce Investment Risk
Quick responses to market opportunities
Improve users’ experience
GSM Expansion
Core Network
SingleRAN
GSM / UMTS / HSPA / LTE
Backhaul
UMTS/HSPA Introduced
Legacy GSM Network
LTE in the coming future
Convergence
Equipment Level
Site Level
Operation Level 14

15. REFERENCES www.3gpp.org www.radio-electronics.com

16. Thank You