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
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)
)
(
)
(
)
(
)
( t
n
m
t
S
t
S
t
y
y(t) : output signal
S(t) : input signal
S(t-m) : delayed m time input signal
n(t) : noise
y(t)
βS(t-m)
S(t)
8. 8
Equalizers in Receiver
Against Frequency Selective Fading
Channel transform function Hc(f)
Equalizers transform function Heq(f) (Receiver)
fm
j
c e
f
H
2
1
)
(
fm
j
c
c
e
f
H
f
H
2
1
1
)
(
1
)
(
)
(
)
(
)
( m
t
S
t
S
t
y
9. 9
Frequency Selective Fading
the coherence bandwidth of the channel is
smaller than the bandwidth of the signal
It may be useless for increasing transmission power
Frequency Correlation > 0.9
Bc = 1 / 50α α is r.m.s. delay spread
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
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
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
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 throughput
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
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
