1. An Overview on LTE

2. Contents Introduction Network Structure Protocol stack
Evolution of Cellular technology
LTE air interface capabilities
LTE standards
Network Structure
Basic components and their functions
EPC and various interfaces
Protocol stack
User plane
Control plane
EPS NAS protocols
Overview about channels
Some operations and procedures

3. Introduction

4. Evolution of Cellular technology
Rel99
WCDMA
Rel5 HSDPA
Rel6 HSUPA
Rel7
Rel8
Rel9
HSPA+
Rel8
Rel9
Rel10
LTE

5. LTE air interface capabilities
Scalable channel bandwidths
1.4Mhz to 20Mhz
TDD and FDD
Waveforms
OFDMA in DL
SC-FDMA in UL
Modulation for data channels
QPSk,16-QAM,64-QAM
MIMO support
Inter-cell interference management

6. LTE air interface capabilities (continued)
DL and UL performance is better than HSPA rel6.
Coverage
Mobility
Interworking with existing 3G and non-3G networks.

7. Radio Frame structures in LTE
Two possible radio frame structures
FDD
TDD

8. Evolved Network architecture
EPC
/P-GW
/P-GW

9. Architecture of EPC

10. Architectural differences between 3G and LTE
Centralized radio resource management
High latency
Usage of both circuit switched and packet networks.
Internetworking with 3GPP technologies only.
Distributed Radio resource management
Low latency
All IP packet core network.
Internetworking with both 3GPP and non- 3GPP technologies.

11. Protocol stack (user plane)UE
eNB
S-GW
P-GW
IP-NW

12. Protocol stack (control plane)

13. EPS – NAS protocols Two protocols for NAS Evolved Mobility Management
Evolved Session Management

14. EPS idle and active states
EMM registration\deregistration
ESM active\inactive
EMM connected\idle
RRC connected\idle

15. EPS attach procedure UE eNB MME/S-GW P-GW HSS authentication
Attach request+ PDN connectivity request
S1 signal connection
setup
authentication
Subscriber info
Default EPS bearer setup
Attach accept
EPS bearer setup accept
Attach conform

16. Access stratum channel terminology
Logical channels
Transport channels
Physical channels

17. Initial acquisition Needs two synchronization signals
PSS
SSS
Additional sys information over PBCH and PDSCH
Procedure:
Switch on the mobile
Receive the PSS signal
Receive the SSS signal
Read the PBCH for SIB and PDSCH for MIB
Register to the network

18. Handover and Cell Switching
Single communication link between eNB and UE
No more soft handover
Two types of handovers in LTE
Network based handover
Traditional handover process
UE based – Radio Link Failure handover
Triggered by RLF so need to be done by UE.

19. THANK YOU