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Introduction to Third Generation Communications (3G) Technology
Wideband Code Division Multiple Access
www.3gpp.org
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Outline
• Background
• Key concepts
– Code multiplexing
– Spreading
• Introduction to Wideband Code Division Multiple Access (WCDMA)
• WCDMA Performance Enhancements
– High Speed Packet Access (HSDPA/HSUPA)
– Advanced features for HSDPA
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Background
• Why new radio access system
• Frequency Allocations
• Standardization
• WCDMA background and evolution
• Evolution of Mobile standards
• Current WCDMA markets
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Why new radio access system
• Need for universal standard (Universal Mobile Telecommunication System)
• Support for packet data services
– IP data in core network
– Wireless IP
• New services in mobile multimedia need faster data transmission and flexible utilization of the spectrum
• FDMA and TDMA are not efficient enough
– TDMA wastes time resources
– FDMA wastes frequency resources
• CDMA can exploit the whole bandwidth constantly
• Wideband CDMA was selected for a radio access system for UMTS (1997)
– (Actually the superiority of OFDM was not fully understood by then)
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Frequency allocations for UMTS
• Frequency plans of Europe, Japan and Korea are harmonized
• US plan is incompatible, the spectrum reserved for 3G elsewhere is
currently used for the US 2G standards
• IMT-2000 band in Europe:
– FDD 2x60MHz
Expected air interfaces and spectrums, source: “WCDMA for UMTS”
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Standardization
• WCDMA was studied in various research programs in the industry and
universities
• WCDMA was chosen besides ETSI also in other forums like ARIB
(Japan) as 3G technology in late 1997/early 1998.
• During 1998 parallel work proceeded in ETSI and ARIB (mainly), with
commonalities but also differences
– Work was also on-going in USA and Korea
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Standardization
• At end of 1998 different standardization organizations got together and created 3GPP, 3rd Generation Partnership Project.
– 5 Founding members: ETSI, ARIB+TTC (Japan), TTA (Korea), T1P1 (USA)
– CWTS (China) joined later.
• Different companies are members through their respective standardization organization.
ETSI Members
ETSI
ARIB Members
ARIB
TTA Members
TTA
T1P1 Members
T1P1
TTC Members
TTC
CWTS Members
CWTS
3GPP
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
WCDMA Background and Evolution
• First major milestone was Release „99, 12/99– Full set of specifications by 3GPP
– Targeted mainly on access part of the network
• Release 4, 03/01 – Core network was extended
– markets jumped over Rel 4
• Release 5, 03/02– High Speed Downlink Packet Access (HSDPA)
• Release 6, end of 04/beginning of 05– High Speed Uplink Packet Access (HSUPA)
• Release 7, 06/07– Continuous Packet connectivity (improvement for e.g. VoIP), advanced features for HSDPA
(MIMO, higher order modulation)
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WCDMA Background and Evolution
2000 2002 2004 2006 2007200520032001
3GPP Rel -99
12/99
3GPP Rel 4
03/01
3GPP Rel 5
(HSDPA)
03/02
3GPP Rel 6
(HSUPA)
2H/04
3GPP Rel 7
HSPA+
06/07Further Releases
JapanEurope
(pre-commercial)Europe
(commercial)
HSDPA
(commercial)HSUPA
(commercial)
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Evolution of Mobile standards
EDGE
GPRSGSM
HSCSD
cdmaOne(IS-95)
WCDMA FDD
HSDPA/HSUPA
cdma2000
TD-SCDMA TDD LCR
cdma20001XEV - DO
cdma20001XEV - DV
TD-CDMATDD HCR
HSDPA/HSUPA
LTE
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
WCDMA markets• Graph of the technologies adopted by the wireless users worldwide:
• Over 3.5 billion wireless users worldwide
• GSM+WCDMA share currently over 88 % (www.umts-forum.org)
• CDMA share is decreasing every year
GSM (80.9%)
CDMA (12%)
WCDMA (4.6%)
iDEN (0.9%)
PDC (0.8%)
US TDMA (0.8%)
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
WCDMA markets
• Over 200 million WCDMA subscribers globally (04/08) (www.umts-forum.org)
– 10 % HSDPA/HSUPA users
• Number of subscribers is constantly increasing
Millio
n s
ub
scri
bers
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Key concepts
• CDMA
• Spread Spectrum
• Direct Sequence spreading
• Spreading and Processing gain
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Multiple Access Schemes
• Frequency Division Multiple Access (FDMA), different frequencies for different users– example Nordic Mobile Terminal (NMT) systems
• Time Division Multiple Access (TDMA), same frequency but different timeslots for different users, – example Global System for Mobile Communication (GSM)
– GSM also uses FDMA
• Code Division Multiple Access (CDMA), same frequency and time but users are separated from each other with orthogonal codes
Code
Frequency
Time
12
N…
TDMAFDMA CDMA
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Spread Spectrum
• Means that the transmission bandwidth is much larger than the information
bandwidth i.e. transmitted signal is spread to a wider bandwidth
– Bandwidth is not dependent on the information signal
• Benefits
– More secure communication
– Reduces the impact of interference (and jamming) due to processing gain
• Classification
– Direct Sequence (spreading with pseudo noise (PN) sequence)
– Frequency hopping (rapidly changing frequency)
– Time Hopping (large frequency, short transmission bursts)
• Direct Sequence is currently commercially most viable
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Spread Spectrum
• Where does spread spectrum come from
– First publications, late 40s
– First applications: Military from the 50s
– Rake receiver patent 1956
– Cellular applications proposed late 70s
– Investigations for cellular use 80s
– IS-95 standard 1993 (2G)
– 1997/1998 3G technology choice
– 2001/2002 Commercial launch of WCDMA technology
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Direct Sequence
• In direct sequence (DS) user bits are coded with unique binary
sequence i.e. with spreading/channelization code
– The bits of the spreading code are called chips
– Chip rate (W) is typically much higher than bit rate (R)
– Codes need to be in some respect orthogonal to each other (cocktail party
effect)
• Length of a spreading code code
– defines how many chips are used to spread a single information bit and thus
determines the end bit rate
– Shorter code equals to higher bit rate but better Signal to Interference and
Noise Ratio (SINR) is required
• Also the shorter the code, the fewer number of codes are available
– Different bit rates have different geographical areas covered based on the
interference levels
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Direct Sequence
• Transmission (Tx) side with DS
– Information signal is multiplied with spreading code => spread signal
• Receiving (Rx) side with DS
– Spread signal is multiplied with spreading code
– Multiplied signal (spread signal x code) is then integrated (i.e. summed
together)
• If the integration results in adequately high (or low) values, the signal is meant for
the receiver
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Direct Sequence
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Direct Sequence
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Spread Spectrum
Frequency
Despread narrowband signal
Spread wideband signal
W
R
Po
we
r d
en
sit
y (
Wa
tts
/Hz)
Po
we
r d
en
sit
y (
Wa
tts
/Hz)
Frequency
Transmitted signalbefore spreading
Received signalbefore despreading
Interference for the part we are interested in
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Spread Spectrum
Frequency
Po
we
r d
en
sit
y (
Wa
tts
/Hz)
Po
we
r d
en
sit
y (
Wa
tts
/Hz)
Frequency
Received signalafter despreading butbefore filtering
Received signalafter despreading andafter filtering
Transmitted signal
Interference
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Introduction to Wideband Code Division Multiple Access (WCDMA)
• Overview
• Codes in WCDMA
• QoS support
• Network Architecture
• Radio propagation and fading
• RAKE receiver
• Power Control in WCDMA
• Diversity
• Capacity and coverage
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WCDMA System
• WCDMA is the most common radio interface for UMTS systems
• Wide bandwidth, 3.84 Mcps (Megachips per second)
– Maps to 5 MHz due to pulse shaping and small guard bands between the
carriers
• Users share the same 5 MHz frequency band and time
– UL and DL have separate 5 MHz frequency bands
• High bit rates
– With Release ‟99 theoretically 2 Mbps both UL and DL
– 384 kbps highest implemented
• Fast power control (PC)
=> Reduces the impact of channel fading and minimizes the interference
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
WCDMA System
• Soft handover
– Improves coverage, decreases interference
• Robust and low complexity RAKE receiver
– Introduces multipath diversity
• Variable spreading factor
– Support for flexible bit rates
• Multiplexing of different services on a single physical connection
– Simultaneous support of services with different QoS requirements:
• real-time
– E.g. voice, video telephony
• streaming
– streaming video and audio
• interactive
– web-browsing
• background
– e-mail download
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Codes in WCDMA
• Channelization Codes (=short code)
– Codes from different branches of the code tree are orthogonal
– Length is dependent on the spreading factor
– Used for
• channel separation from the single source in downlink
• separation of data and control channels from each other in the uplink
– Same channelization codes in every cell / mobiles and therefore the additional
scrambling code is needed
• Scrambling codes (=long code)
– Very long (38400 chips = 10 ms =1 radio frame), many codes available
– Does not spread the signal
– Uplink: to separate different mobiles
– Downlink: to separate different cells
– The correlation between two codes (two mobiles/NodeBs) is low
• Not fully orthogonal
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UMTS Terrestrial Radio Access Network (UTRAN) Architecture
• New Radio Access network
needed mainly due to new
radio access technology
• Core Network (CN) is based
on GSM/GPRS
• Radio Network Controller
(RNC) corresponds roughly
to the Base Station
Controller (BSC) in GSM
• Node B corresponds
roughly to the Base Station
in GSM
– Term “Node B” is a relic from
the first 3GPP releases
RNC
NodeB
NodeB
NodeB
UE
CN
RNC
UE
Uu interface Iub interface
Iur interface
UTRAN
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UMTS Terrestrial Radio Access Network (UTRAN) Architecture
• Radio network controller (RNC)
– Owns and controls the radio resources in its domain
– Radio resource management (RRM) tasks include e.g. the following
• Mapping of QoS Parameters into the air interface
• Air interface scheduling
• Handover control
• Outer loop power control
• Call Admission Control
• Setting of initial powers and SIR targets
• Radio resource reservation
• Code allocation
• Load Control
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UMTS Terrestrial Radio Access Network (UTRAN) Architecture
• Node B
– Main function to convert the data flow between Uu and Iub interfaces
– Some RRM tasks:
• Measurements
• Inner loop power control
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Radio propagation and fading
• A transmitted radio signal goes
through several changes while
traveling via air interface to the
receiver
– reflections, diffractions, phase
shifts and attenuation
• Due to length difference of the
signal paths, multipath
components of the signal arrive
at different times to the receiver
and can be combined either
destructively or constructively
– Depends on the phases of the
multipath components
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Radio propagation and fading
• Example of the fast fading
channel of a function of time
• Opposite phases of two
random multipath components
arriving at the same time
cancel each other out
– Results in a fade
• Coherent phases are
combined constructively
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Diversity
• Transmitting on a single path only can lead to serious performance
degradation due to fading
• As fading is independent between different times and spaces it is reasonable
to use the available diversity of them to decrease the probability of a deep
fade
– The more there are paths to choose from, the less likely it is that all of them have a
poor energy level
• There exists different types of diversity which can be used to improve the
quality, e.g.:
– Multipath
• RAKE receiver exploits taps arriving at different times
– Macro
• Different Node Bs send the same information
– Site Selection Transmit Diversity (SSTD)
• Maintain a list of available base stations and choose the best one, from which the transmission
is received and tell the others not to transmit
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Diversity
– Time
• Same information is transmitted in different times
– Receive antenna
• Transmission is received with multiple antennas
• Power gain and diversity gain
– Transmit antenna
• Transmission is sent with multiple antennas
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WCDMA evolution
•High Speed Downlink Packet Access (HSDPA)
•High Speed Uplink Packet Access (HSUPA)
•Advanced receivers with HSDPA
•Advanced HSDPA scheduling
•Femto cells with HSDPA
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High Speed Downlink Packet Access (HSDPA)
• The High Speed Downlink Packet Access (HSDPA) concept was
added to Release 5 to support higher downlink data rates
• It is mainly intended for non-real time traffic, but can also be used for
traffic with tighter delay requirements.
• Peak data rates up to 10 Mbit/s (theoretical data rate 14.4 Mbit/s)
• Reduced retransmission delays
• Improved QoS control (Node B based packet scheduler)
• Spectrally and code efficient solution
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
HSDPA features
• Agreed features in Release 5– Adaptive Modulation and Coding (AMC)
• QPSK or 16QAM
– Multicode operation
• Support of 1-15 code channels (SF=16)
– Short frame size
– Fast retransmissions using Hybrid Automatic Repeat Request (HARQ)
• Chase Combining
• Incremental Redundancy
– Fast packet scheduling at Node B
• E.g. Round robin, Proportional fair
• Features agreed in Release 7– Higher order modulation (64QAM)
– Multiple Input Multiple Output (MIMO)
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
HSDPA - general principle
• Fast scheduling is done directly in Node-B based on feedback information from UE and knowledge of current traffic state.
Channel quality(CQI, Ack/Nack)
Data
Users may be time and/or code multiplexed
New base station functions
• HARQ retransmissions
• Modulation/coding selection
• Packet data scheduling (short TTI)
UE
0 20 40 60 80 100 120 140 160-2
02468
10121416
Time [number of TTIs]
QPSK1/4
QPSK2/4
QPSK3/4
16QAM2/4
16QAM3/4
Inst
anta
neo
us
EsN
o [
dB
]
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
HSDPA functionality• UE informs the Node B regularly of its channel quality by CQI messages
(Channel Quality Indicator)
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
HSDPA functionality
• Node B can use channel state information for several purposes
– In transport format (TFRC) selection
• Modulation and coding scheme
– Scheduling decisions
• Non-blind scheduling algorithms can be utilized
– HS-SCCH power control
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
High Speed Uplink Packet Access (HSUPA)
• Peak data rates increased to significantly higher than 2 Mbps; Theoretically reaching 5.8 Mbps
• Packet data throughput increased, though not as high throughput as with HSDPA
• Reduced delay from retransmissions.
• Solutions
– Layer1 hybrid ARQ
– NodeB based scheduling for uplink
– Frame sizes 2ms & 10 ms
• Schedule in 3GPP
– Part of Release 6
– First specifications version completed 12/04
– In 3GPP specs with the name Enhanced uplink DCH (E-DCH)
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Performance of advanced HSDPA features
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Advanced receivers with HSDPA
• UE receiver experiences significant interference from different sources
– In a reflective environment the signal interferes itself
– Neigboring base station signals interfere each other
– One solution to decrease mainly own base station signal interference is to
use an equalizer before despreading
Own cell interference
Other cell interference
Own signal
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Advanced receivers with HSDPA
• In a frequency-selective channel there is a significant amount of
interfering multipaths
• Linear Minimum Mean Squared Error (LMMSE) equalizer can be used
to make an estimate of the original transmitted chip sequence before
despreading
– The interfering multipath components are removed
– The channel becomes flat again
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Advanced receivers with HSDPA
• LMMSE equalizer (Equ in the
figure) offers a very good
performance for the user
especially near the base station
• Using antenna diversity (1x2) the
throughput can be doubled
compared to a single antenna
• Both techniques increase the
cost of a mobile unit
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Timo Nihtilä , TLT-5606 Spread Spectrum Techniques www.tut.fi
Femtocells
• More and more consumers want to use their mobile devices at home,
even when there‟s a fixed line available
– Providing full or even adequate mobile residential coverage is a significant
challenge for operators
– Mobile operators need to seize residential minutes from fixed line providers,
and compete with fixed and emerging VoIP and WiFi services
=> There is trend in discussing very small indoor, home and campus NodeB
layouts
• Femtocells are cellular access points (for limited access group) that
connect to a mobile operator‟s network using residential DSL (digital
subscriber line) or cable broadband connections
• Femtocells enable capacity equivalent to a full 3G network sector at
very low transmit powers, dramatically increasing battery life of
existing phones
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Zhong Zheng noppa.aalto.fi
Why femtocells?
• Low manufacturing cost, short radio coverage home base station
operates in licensed spectrum
• Radio traffic is backhauled by premises broadband connection (DSL)
to mobile network
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Zhong Zheng noppa.aalto.fi
Why femtocells?
• Macrocell base station covers up to a few hundred square meters
area and Signal quality decays along with transmit distance in the form
of
• Under non-line-of-sight condition, signal is blocked by large
shadowing or building wall at 2GHz band
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Zhong Zheng noppa.aalto.fi
Why femtocells?
• Technical motivation
• Reduced separation distance between transmitter and
receiver
• Interference is isolated by building structure
• Limited number of users
• Business motivation
• Half of voice calls and a majority of data traffic originate
indoor
• Operators expand network capacity and coverage
without much investments on infrastructure.
• Subscribers get better radio service at low price
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Zhong Zheng noppa.aalto.fi
3GPP standardization on femtocells
• New interface Iuh is created between femto base station and HNB-
GW (home node B gateway)
• HNB-GW utilizes standard Iu interface to mobile network
• Iuh traffic is tunneled through public Internet
• In 3GPP Release 8, femtocell access is granted to Close Subscriber
Group (CSG). Handover between femtocells is not allowed.
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Zhong Zheng noppa.aalto.fi
More about WCDMA
– WCDMA for UMTS – Harri Holma, Antti Toskala
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Zhong Zheng noppa.aalto.fi
END
Thanks for your attention!
arusu[@]comm.pub.ro
![Page 52: Introduction to Third Generation Communications (3G ...comm.pub.ro/soc/Ch1_3G_LTE_introduction.pdfTimo Nihtilä , TLT-5606 Spread Spectrum Techniques Outline •Background •Key concepts](https://reader031.vdocuments.us/reader031/viewer/2022021821/5b065ddc7f8b9a58148cbd46/html5/thumbnails/52.jpg)
An Introduction to
3GPP Long Term Evolution (LTE)
www.3gpp.org
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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Outline
History of 3GPP LTE
Basic Concepts of LTE
Introduction to LTE Protocol
Compare with LTE and LTE-Advanced
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
![Page 54: Introduction to Third Generation Communications (3G ...comm.pub.ro/soc/Ch1_3G_LTE_introduction.pdfTimo Nihtilä , TLT-5606 Spread Spectrum Techniques Outline •Background •Key concepts](https://reader031.vdocuments.us/reader031/viewer/2022021821/5b065ddc7f8b9a58148cbd46/html5/thumbnails/54.jpg)
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
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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Evolution of Radio Access
Technologies
LTE (3.9G) :
3GPP release 8~9
LTE-Advanced :
3GPP release 10+
802.16d/e
802.16m
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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LTE Basic Concepts
LTE employs Orthogonal Frequency
Division Multiple Access (OFDMA) for
downlink data transmission and Single
Carrier FDMA (SC-FDMA) with Discrete
Fourier Transform for uplink transmission
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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LTE network architecture: Evolved Packet System
Geert Heijenk http://wwwhome.cs.utwente.nl
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Multipath-Induced Time Delays Result
in Inter-Symbol Interference (ISI)
)()()()( tnmtStSty
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)
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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FDM vs. OFDM
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
![Page 60: Introduction to Third Generation Communications (3G ...comm.pub.ro/soc/Ch1_3G_LTE_introduction.pdfTimo Nihtilä , TLT-5606 Spread Spectrum Techniques Outline •Background •Key concepts](https://reader031.vdocuments.us/reader031/viewer/2022021821/5b065ddc7f8b9a58148cbd46/html5/thumbnails/60.jpg)
Frequency Selective Fading
the coherence bandwidth of the channel is
smaller than the bandwidth of the signal
It may be useless to increase the
transmission powerTsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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OFDM transmission scheme
![Page 62: Introduction to Third Generation Communications (3G ...comm.pub.ro/soc/Ch1_3G_LTE_introduction.pdfTimo Nihtilä , TLT-5606 Spread Spectrum Techniques Outline •Background •Key concepts](https://reader031.vdocuments.us/reader031/viewer/2022021821/5b065ddc7f8b9a58148cbd46/html5/thumbnails/62.jpg)
Cyclic Prefix
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
Is a repetition of the last part of the symbol, placed at the beginning of the symbol
![Page 63: Introduction to Third Generation Communications (3G ...comm.pub.ro/soc/Ch1_3G_LTE_introduction.pdfTimo Nihtilä , TLT-5606 Spread Spectrum Techniques Outline •Background •Key concepts](https://reader031.vdocuments.us/reader031/viewer/2022021821/5b065ddc7f8b9a58148cbd46/html5/thumbnails/63.jpg)
LTE-Downlink (OFDM)
Improved spectral
efficiency
Reduce ISI effect
by multipath
Against frequency
selective fading
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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LTE Uplink (SC-FDMA)
SC-FDMA is a new single carrier multiple access technique which has similar structure and performance to OFDMA
An advantage of
SC-FDMA over
OFDM is low to
Peak to Average
Power Ratio
(PAPR) :
Increasing
battery life
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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Multi-antenna techniques
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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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 MHzTsung-Yin Lee
http://ants.iis.sinica.edu.tw/ants_70/
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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
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_
70/
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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
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_
70/
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Enhanced Multi-antenna
Transmission Techniques
In LTE-A, the MIMO scheme is further improved in the area of spectrum efficiency, average cell throughput and cell edge performances
For LTE-A the antenna configurations of 8x8 in DL and 4x4 in UL are planned
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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LTE vs. LTE-Advanced
Tsung-Yin Lee http://ants.iis.sinica.edu.tw/ants_70/
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END
Thanks for your attention!