Upload
pedro-enriquez
View
217
Download
0
Embed Size (px)
DESCRIPTION
LTE
Citation preview
An Introduction of3GPP Long Term Evolution (LTE)
SpeakerTsung-Yin Lee
2Reference http://www.tcs.com LTE-Advanced: Future of Mobile Broadband,
TATA Consultancy Services Takehiro Nakamura ,Proposal for Candidate Radio Interface Technolo
gies for IMTAdvanced Bas d on LTE Release 10 and Beyond, 3GPP TSGRAN 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 Astly, Erik Dahlman, Anders Furuskr, Ylva Jading, Magnus
Lindstrm, and Stefan Parkvall, Ericsson Research, LTE: The Evolution of Mobile Broadband , IEEE Communications Magazine, April 2009
3Outline History of 3GPP LTE Basic Concepts of LTE Introduction of LTE Protocol Compare with LTE and LTE-Advanced Conclusion
4What 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
5Evolution of Radio Access Technologies
LTE (3.9G) : 3GPP release 8~9
LTE-Advanced :3GPP release 10+
802.16d/e
802.16m
6LTE Basic Concepts LTE employs Orthogonal Frequency
Division Multiple Access (OFDMA) for downlink data transmission and Single Carrier FDMA (SC-FDMA) for uplink transmission
7Multipath-Induced Time Delays Result in Inter-Symbol Interference (ISI)
)()()()( tnmtStSty ++= y(t) : output signalS(t) : input signalS(t-m) : delayed m time input signaln(t) : noise
y(t)
S(t-m)S(t)
8Equalizers in Receiver Against Frequency Selective Fading
Channel transform function Hc(f)
Equalizers transform function Heq(f) (Receiver)
fmjc efH pi 21)( +=
fmjc
cefHfH pi 211
)(1)(
+==
)()()( mtStSty +=
9Frequency 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 > 0.9Bc = 1 / 50 is r.m.s. delay spread
10
Cyclic Prefixes
11
FDM vs. OFDM
12
LTE-Downlink (OFDM) Improved spectral
efficiency Reduce ISI effect
by multipath Against frequency
selective fading
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
Multi-antenna techniques
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
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
LTE spectrum (bandwidth and duplex) flexibility
18
LTE Downlink Channels
Paging Channel
Paging Control Channel
Physical Downlink Shared Channel
19
LTE Uplink Channels
Random Access Channel
Physical Radio Access Channel
Physical Uplink Shared ChannelCQI report
20
LTE Release 8 Key Features (1/2) High spectral efficiency
OFDM in Downlink SingleCarrier 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
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
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
Asymmetric transmission bandwidth Symmetric transmission
voice transmission : UE to UE Asymmetric transmission
streaming video : the server to the UE (the downlink)
24
Layered OFDMA The bandwidth of basic frequency block is,
1520 MHz Layered OFDMA radio access scheme in
LTE-A will have layered transmission bandwidth, support of layered environments and control signal formats
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
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
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
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
LTE vs. LTE-Advanced
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
Backup
32
LTE Downlink Logical Channels
33
LTE Downlink Logical Channels
34
LTE Downlink Transport Channel
35
LTE Downlink Transport Channel
36
LTE Downlink Physical Channels
37
LTE Downlink Physical Channels
38
LTE Uplink Logical Channels
39
LTE Uplink Transport Channel
40
LTE Uplink Physical Channels