This document provides an introduction to 3GPP Long Term Evolution (LTE) technology. It discusses the history and basic concepts of LTE, including the use of OFDMA for downlink and SC-FDMA for uplink transmission. It also compares LTE to LTE-Advanced, which supports larger bandwidths up to 100MHz and peak data rates of 1Gbps through techniques like carrier aggregation. The document outlines the evolution of radio access technologies and key aspects of the LTE protocol.

1. An Introduction of
3GPP Long Term Evolution (LTE)
Speaker：Tsung-Yin
Lee

2. 2
Reference
 http://www.tcs.com “LTE-Advanced: Future of Mobile Broadband,”
TATA Consultancy Services
 Takehiro Nakamura ,“Proposal for Candidate Radio Interface Technol
ogies for IMT Advanced Bas d on ‐ LTE Release 10 and Beyond,”
3GPP TSG‐RAN Chairman
 “3GPP LTE Channels and MAC Layer,” EventHelix.com Inc. 2009
 Ahmed Hamza, Network Systems Laboratory Simon Fraser
University, “Long Term Evolution (LTE) - A Tutorial,” October 13,
2009
 Jim Zyren, “Overview of the 3GPP Long Term Evolution Physical
Layer,” Document Number: 3GPP EVOLUTIONWP Rev0 07/2007
 David Astély, Erik Dahlman, Anders Furuskär, Ylva Jading, Magnus
Lindström, and Stefan Parkvall, Ericsson Research, “LTE: The
Evolution of Mobile Broadband” , IEEE Communications Magazine,
April 2009

3. 3
Outline
 History of 3GPP LTE
 Basic Concepts of LTE
 Introduction of LTE Protocol
 Compare with LTE and LTE-Advanced
 Conclusion

4. 4
What is LTE ?
 In Nov. 2004, 3GPP began a project to
define the long-term evolution (LTE) of
Universal Mobile Telecommunications
System (UMTS) cellular technology
 Higher performance
 Backwards compatible
 Wide application

5. 5
Evolution of Radio Access
Technologies
 LTE (3.9G) :
3GPP release 8~9
 LTE-Advanced :
3GPP release 10+
802.16d/e
802.16m

6. 6
LTE Basic Concepts
 LTE employs Orthogonal Frequency
Division Multiple Access (OFDMA) for
downlink data transmission and Single
Carrier FDMA (SC-FDMA) for uplink
transmission

7. 7
Multipath-Induced Time Delays Result
in Inter-Symbol Interference (ISI)
y(t) = S(t) +bS(t -m) + n(t)
y(t) : output signal
S(t) : input signal
S(t-m) : delayed m time input signal
n(t) : noise
βS(t-m)
y(t)
S(t)

8. 8
Equalizers in Receiver
 Against Frequency Selective Fading
 Channel transform function Hc(f)
j fm
c H ( f ) =1+be- 2p
 Equalizers transform function Heq(f) (Receiver)
( ) 1 + -
H f 1 b 2p
j fm
= =
c H f e
c
1
( )
y(t) = S(t) +bS(t -m)

9. 9
Frequency Selective Fading
 the coherence bandwidth of the channel is
smaller than the bandwidth of the signal
Frequency Correlation > 0.9
Bc = 1 / 50α α is r.m.s. delay spread
It may be useless for increasing transmission power

10. 10
Cyclic Prefixes

11. 11
FDM vs. OFDM

12. 12
LTE-Downlink (OFDM)
 Improved spectral
efficiency
 Reduce ISI effect
by multipath
 Against frequency
selective fading

13. 13
LTE Uplink (SC-FDMA)
 SC-FDMA is a new single carrier multiple access
technique which has similar structure and
performance to OFDMA
A salient
advantage of SC-FDMA
over
OFDM is low to
Peak to Average
Power Ratio
(PAPR) :
Increasing
battery life

14. 14
Multi-antenna techniques

15. 15
Generic Frame Structure
 Allocation of physical resource blocks
(PRBs) is handled by a scheduling function
at the 3GPP base station (eNodeB)
Frame 0 and frame 5 (always downlink)

16. 16
Resource Grid
 One frame is 10ms
 10 subframes
 One subframe is 1ms
 2 slots
 One slot is 0.5ms
 N resource blocks
[ 6 < N < 110]
 One resource block is 0.5ms
and contains 12 subcarriers
from each OFDM symbol

17. 17
LTE spectrum (bandwidth and
duplex) flexibility

18. 18
LTE Downlink Channels
Paging Control Channel
Paging Channel
Physical Downlink Shared Channel

19. 19
LTE Uplink Channels
Random Access Channel
Physical Radio Access Channel
Physical Uplink Shared Channel
CQI report

20. 20
LTE Release 8 Key Features
(1/2)
 High spectral efficiency
 OFDM in Downlink
 Single‐Carrier FDMA in Uplink
 Very low latency
 Short setup time & Short transfer delay
 Short hand over latency and interruption time
 Support of variable bandwidth
 1.4, 3, 5, 10, 15 and 20 MHz

21. 21
LTE Release 8 Key Features
(2/2)
 Compatibility and interworking with earlier
3GPP Releases
 FDD and TDD within a single radio access
technology
 Efficient Multicast/Broadcast

22. 22
Evolution of LTE-Advanced
 Asymmetric transmission bandwidth
 Layered OFDMA
 Advanced Multi-cell
Transmission/Reception Techniques
 Enhanced Multi-antenna Transmission
Techniques
 Support of Larger Bandwidth in LTE-Advanced

23. 23
Asymmetric transmission
bandwidth
 Symmetric transmission
 voice transmission : UE to UE
 Asymmetric transmission
 streaming video : the server to the UE (the downlink)

24. 24
Layered OFDMA
 The bandwidth of basic frequency block is,
15–20 MHz
 Layered OFDMA radio access scheme in
LTE-A will have layered transmission
bandwidth, support of layered environments
and control signal formats

25. 25
Advanced Multi-cell
Transmission/Reception Techniques
 In LTE-A, the advanced multi-cell
transmission/reception processes helps in
increasing frequency efficiency and cell
edge user throughput
 Estimation unit
 Calculation unit
 Determination unit
 Feedback unit

26. 26
Enhanced Multi-antenna
Transmission Techniques
 In LTE-A, the MIMO scheme has to be further improved
in the area of spectrum efficiency, average cell through put
and cell edge performances
 In LTE-A the antenna configurations of 8x8 in DL and 4x4
in UL are planned

27. 27
Enhanced Techniques to Extend
Coverage Area
 Remote Radio Requirements (RREs) using optical
fiber should be used in LTE-A as effective
technique to extend cell coverage

28. 28
Support of Larger Bandwidth in
LTE-Advanced
 Peak data rates up to 1Gbps are expected
from bandwidths of 100MHz. OFDM adds
additional sub-carrier to increase bandwidth

29. 29
LTE vs. LTE-Advanced

30. 30
Conclusion
 LTE-A helps in integrating the existing
networks, new networks, services and
terminals to suit the escalating user
demands
 LTE-Advanced will be standardized in the
3GPP specification Release 10 (LTE-A)
and will be designed to meet the 4G
requirements as defined by ITU

31. 31
Backup

32. LTE Downlink Logical Channels
32

33. LTE Downlink Logical Channels
33

34. 34
LTE Downlink Transport Channel

35. 35
LTE Downlink Transport Channel

36. 36
LTE Downlink Physical Channels

37. 37
LTE Downlink Physical Channels

38. 38
LTE Uplink Logical Channels

39. 39
LTE Uplink Transport Channel

40. 40
LTE Uplink Physical Channels