Oea000050 Lte-tdd System Overview Issue 1.00

7/27/2019 Oea000050 Lte-tdd System Overview Issue 1.00

1/97

www.huawei.com

Copyright 2010 Huawei Technologies Co., Ltd. All rights reserved.

LTE-TDD SystemOverview


2/97

Copyright 2010 Huawei Technologies Co., Ltd. All rights reserved. Page2

Contents

1. Network Architecture

2. LTE Key Technology

3. LTE Air Interface

4. Technical Comparison Between LTE-TDD and LTE-FDD

5. LTE Deployment


3/97


4/97


Contents

1 Network Architecture

1.1 Evolution of Cellular Networks

1.2 3GPP Releases

1.3 E-UTRAN Network Architecture and protocol structure


5/97


Evolution of Cellular Networks

1G (FirstGeneration)

2G (SecondGeneration)

3G (ThirdGeneration)

4G (FourthGeneration)


6/97


7/97


Second Generation Mobile

Systems

GSM

cdmaOne

(IS-95)

D-AMPS

(IS-136)

Other

2G (Second

Generation)


8/97


2.5G and 2.75G GSM/GPRS

Systems

System Service Theoretical DataRate

Typical Data Rate

2G GSM Circuit SwitchedData Service

9.6kbit/s or14.4kbit/s

9.6kbit/s or14.4kbit/s

2.5G GPRS Packet Switched

Data171.2kbit/s 4kbit/s to 50kbit/s

2.75G EDGE Packet SwitchedData

473.6kbit/s 120kbit/s


9/97


Third Generation Mobile Systems

3G (Third

Generation)UMTS

W-CDMA

UMTS

TD-CDMA

TD-SCDMA

CDMA2000

Other


10/97


Fourth Generation Mobile Systems

Key IMT Advanced Features

A high degree of commonality of functionality worldwide while retaining the flexibility to

support a wide range of services and applications in a cost efficient manner.

Compatibility of services within IMT and with fixed networks.

Capability of interworking with other radio access systems.

High quality mobile services.

User equipment suitable for worldwide use.

User-friendly applications, services and equipment.

Worldwide roaming capability.

Enhanced peak data rates to support advanced services and applications (100Mbit/s for high

and 1Gbit/s for low mobility were identified as targets).


11/97


Fourth Generation Mobile Systems

4G (Fourth

Generation)

LTE

Advanced

WiMAX

802.16m

UMB

(EV-DO Rev C)


12/97


Contents



1.2 3GPP Releases



13/97


14/97


LTE Protocol Roadmap

3GPP Rel8 was functional freezing in March 2009

LTE FDD and LTE TDD keep the same schedule

SAE Rel 8

(Approval)

SAE Rel 8

Enhancement and Improvement

LTE Rel8

(Approval)

2008 2009 2010

SAE Rel 8

(Functionally

Freezing)

LTE Rel8

(Functionally

Freezing )

LTE Rel8

(Enhancement and Improvement )


15/97


LTE Evolution

TD-HSDPA TD-HSUPA

WCDMA HSDPAHSDPA

HSUPA

LTE

Advanced

LTE TDD1

LTE TDD2

LTE TDD

TD-HSPA+

EV-DO Rel. 0cdma2000 1x D0 Rel. A

LTE FDD

GSM EDGE GSM GERAN

TD-SCDMA

Do Rev B(Multi Carrier DO)

HSPA+


16/97


Contents



1.2 3GPP Releases



17/97


18/97


E-UTRAN Interfaces and Protocols

E-UTRAN

X2

Uu

eNB

eNB

EPC

S-GW

MME

S1-MME

S1-MMES1-U

S1-U


19/97


Uu Interface

eNBUE

Uu

RLC

MAC

PHY

PDCP

RRC

Control Plane

RLC

MAC

PHY

PDCP

IP

User Plane


20/97


X2 Interface

eNB eNB

X2

IP

Layer 2

Layer 1

SCTP

X2AP

Control Plane

IP

Layer 2

Layer 1

UDP

GTP-U

User Plane


21/97


S1 Interface

eNB

IP

Layer 2

Layer 1

SCTP

S1APControl Plane

S1-MME

MME

IP

Layer 2

Layer 1

UDP

GTP-UUser Plane

eNB

S1-U

S-GW


22/97


Questions

Which release of the 3GPP specifications includes the initial

release of LTE?

a. Release 6.

b. Release 7.

c. Release 8.

d. Release 9.


23/97


Questions

Which network elements form part of the E-UTRAN?

a. UE.

b. eNB.

c. MME.

d. S-GW.

e. PDN-GW.

f. HSS.


24/97


Questions

Which interface links the eNB to the MME?

a. Uu.

b. S1.

c. X2

d. S5.


25/97


Contents





5. LTE Deployment


26/97


Contents

2 LTE Key Technology

2.1DownlinkOFDMA

2.2 Uplink SC_FDMA

2.3 MIMO

2.4 Higher-Order Modulation

2.5 HARQ

2.6 SON


27/97


Frequency Division Multiplexing

Frequency

Guard Band

Channel

Bandwidth

Subcarrier


28/97


OFDM Subcarriers

Frequency

Channel

Bandwidth

Orthogonal

SubcarriersCentre Subcarrier

Not Orthogonal


29/97


Inverse Fast Fourier Transform

Coded

Bits

Serial

to

Parallel

Subcarrier

Modulation

IFFT

Inverse Fast

Fourier

Transform

RF

Complex

Waveform


30/97


FFT

Fast Fourier

Transform

Page34

Fast Fourier Transform

Receiver

Subcarrier

Demodulation

Coded

Bits

Parallelto

Serial


31/97


LTE Channel and FFT Sizes

ChannelBandwidth

FFT Size SubcarrierBandwidth

Sampling Rate

1.4MHz 128

15kHz

1.92MHz

3MHz 256 3.84MHz

5MHz 512 7.68MHz

10MHz 1024 15.36MHz

15MHz 1536 23.04MHz

20MHz 2048 30.72MHz


32/97


OFDM Symbol Mapping

Time

Frequency

Amplitude

OFDM

Symbol

Cyclic

Prefix

Modulated

OFDM

Symbol


33/97


Frequency

PowerTime

Page37

Orthogonal Frequency Division

Multiple Access

OFDMA

Each user allocated a

different resourcewhich can vary in

time and frequency.


34/97


35/97


Time Domain Interference

Energy

Time

Delay Spread


36/97


37/97


Cyclic Prefix

CP

CP

CP

CP

CP

CP

CP

CP

CP

CP

CP

CP

Frequency

Time

Symbol Period T(s)T(g)

Symbol Period T(s)

Bit Period T(b)Cyclic Prefix


38/97


OFDMA Features

Benefit High frequency spectrum efficiency

CP is used to resist multi-paths interference

Easy channel estimation and balance

Be good at resist frequency selection fading

Disadvantage

Be sensitive to frequency tolerance

Doppler shift impacts subcarrier orthogonality

High PAPR ( Peak Average Power Ratio) , affect the efficiency of PA


39/97


Contents


2.1 Downlink OFDMA

2.2 Uplink SC_FDMA

2.3 MIMO


2.5 HARQ

2.6 SON


40/97


Time Domain

CP

Insertion

Subcarrier

Mapping

Frequency Domain

Page44

SC-FDMA Subcarrier Mapping

Concept

DFTSymbols

Time Domain

IDFT

0

0

0

0

0

0

0


41/97


SC-FDMA Signal Generation

DFT

N symbols sequenceproduces N subcarriers

Different input sequence

produces different output

First N Symbols

DFT Output

Modulated andCoded Symbols

DFT

Second N Symbols


42/97


SC-FDMA and the eNB

N Subcarriers

Time

Power

Cyclic

Prefix

IDFT

IDFT

First N Symbols

Second N Symbols


43/97


44/97


SC-FDMA Verses OFDMA

Feature SC-FDMA OFDMA

Low PAPR Y X

Performance X Y

Uplink MIMO X Y


45/97


46/97


47/97

S ti l M lti l i I t f


48/97


Spatial Multiplexing Interference

Issues

eNB

UE

Port 0

Port 1TB

TB

MIMO

TB

TB

Interference

causes twice

as may errors

Interference

MIMO S Ti C di


49/97


MIMO Space Time Coding

Concept

eNB

UE

Port 0

Port 1

MIMO TB

Interference

TB

1 2 3 4 5 6

1 2 3 4 5 6

123 456

Form of

STC

TB Still

Recoverable

Increased

Robustness


50/97


Adaptive MIMO Switching

Space Time

Coding

Spatial

Multiplexing

High SNRLow SNR

E

fficiency

UE

eNB

AMS Point


51/97


Contents


2.1 Downlink OFDMA

2.2 Uplink SC_FDMA

2.3 MIMO


2.5 HARQ

2.6 SON


52/97


Higher-Order Modulation

64QAM allows more bits per

Symbol to be transmitted

Higher peak rate achieved in

good channel condition


53/97


Higher-Order Modulation

Benefits Provide higher-data-rate services

Significantly improve the system throughput

Improve users experience

Features

6 information bits can be modulated by one symbol

Large transport blocks supported

Used with excellent channel condition


54/97


Contents


2.1 Downlink OFDMA

2.2 Uplink SC_FDMA

2.3 MIMO


2.5 HARQ

2.6 SON


55/97


HARQ

FEC

ARQ

+ =

HARQ


56/97


Contents


2.1 Downlink OFDMA

2.2 Uplink SC_FDMA

2.3 MIMO


2.5 HARQ

2.6 SON


57/97


58/97


Questions

LTE supports which FTT sizes?

a. 64. e. 1024.

b. 128. f. 1536.

c. 256. g. 2048.

d. 512. h. 3072.

i. 4048.


59/97


Questions

True / False. A cyclic prefix is used to combat multipathdelays.

a. True.

b. False.


60/97


Questions

How many symbols are there in a slot when a normal CP isused?

a. 5.

b. 6.c. 7.

d. 8.


61/97


Questions

True / False. Spatial multiplexing is a technique used inMIMO.

a. True.

b. False.


62/97


63/97


Contents

3 LTE Air Interface Principles

3.1 LTE Channel Structures

3.2 LTE Frame Structure


64/97


LTE Channels

LogicalChannels

TransportChannels

PhysicalChannels

RadioChannels


65/97


Logical Channels

RLC

MAC

PHY

Logical

ChannelsTransport

Channels

Physical

Channels Radio

Channel


66/97


Control Logical Channels

BCCHeNBUE

PCCH

System InformationMessages

Paging

Devices


67/97


68/97


Traffic Logical Channels

eNBUE

DTCHDRB

Carries AM or UM

RLC Traffic


69/97


70/97


Downlink Physical Channels

PBCH (Physical Broadcast Channel)

PCFICH (Physical Control Format Indicator Channel)

PDCCH (Physical Downlink Control Channel)

PHICH (Physical Hybrid ARQ Indicator Channel)

PDSCH (Physical Downlink Shared Channel)


71/97


Uplink Physical Channels

PRACH (Physical Random Access Channel)

PUCCH (Physical Uplink Control Channel)

PUSCH (Physical Uplink Shared Channel)


72/97


73/97


Downlink Channel Mapping

DL-SCH

Physical Layer

MAC Layer

RLC Layer

PDCP Layer

RRC Layer

Physical

Channels

TransportChannels

Logical

Channels

PDSCHPDCCHPHICHPCFICHPBCH

BCH PCH

BCCH PCCH CCCH DCCH DTCH

TM TM TM UM/AM UM/AM

Ciphering

Integrity

Ciphering

ROHC

RRC

ESM EMM IPNAS Layer


74/97


Uplink Channel Mapping

Physical Layer

MAC Layer

RLC Layer

PDCP Layer

RRC Layer

PhysicalChannels

TransportChannels

LogicalChannels

PUSCHPUCCHPRACH

RACH

CCCH

TM UM/AM UM/AM

CipheringIntegrity

CipheringROHC

RRC

ESM EMM IPNAS Layer

UL-SCH

DCCH DTCH


75/97


Contents

3 LTE Air Interface Principles

3.1 LTE Channel Structures

3.2 LTE Frame Structure


76/97


Frame Structure

Frame Structure

Type 1: FDD frame Type 2: TDD frame

Transmission Modes


77/97


Transmission Modes

Frequency Division Duplex

Uplink Downlink

Duplex Spacing

Frequency

Channel

Bandwidth

Channel

Bandwidth

Transmission Modes


78/97


Transmission Modes

Time Division Duplex

TDDFrequency

Downlink

and Uplink

Downlink Uplink Downlink Uplink

TDD Frame TDD Frame

Time

AsymmetricAllocation

FDD F


79/97


FDD FrameSlot (0.5ms)

Radio Frame Tf= 307200 x Ts = 10ms

Subframe (1ms)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Ts = 1/(15000x2048)= 32.552083ns

Tslot

= 15360 x Ts

Normal CP

Extended CP

TDD F


80/97


TDD Frame

In one TDD frame it contains one or two special subframes, which can be

divided into 3 parts:

DwPTSDL pilot slot

UpPTS: UL pilot slot

GP: Guard protect slot

Type 2 Radio Frame Tf= 307200 x Ts = 10ms

0

Special

Subframe

2 3 4 5 7 8 9

DwPTS (Downlink

Pilot Time Slot)

GP (Guard Period)

UpPTS (Uplink

Pilot Time Slot)

Special Subframe DwPTS &


81/97


Special Subframe DwPTS &

UpPTS1ms 1ms 3ms 1ms 1ms 1ms2ms

2 210

14 OFDM symbols

Special-subframe configuration DwPTS GP UpPTS

0 3 10 1

1 9 4 1

2 10 3 1

3 11 2 1

4 12 1 1

5 3 9 2

6 9 3 2

7 10 2 2

8 11 1 2

S i l S bf GP


82/97


Special Subframe GP

Guarantee that uplink signals from different UEs which are far away

from the eNBs antenna are aligned on the air interface of eNodeB

Provide an uplink-and-downlink conversion time (There is a very

short conversion time Tud (less than 20 s) in the conversion from

the uplink to the downlink of eNodeB)

The length of GP determines the eNBs cell radius. The maximum

cell radius supported by LTE-TDD is 100 km

Avoid uplink/downlink interference between eNodeBs

Adjustable Subframe Configuration for


83/97


Adjustable Subframe Configuration for

LTE-TDD

Confi

gurat

ion

Switch-

point

periodi

city

Subframe number

0 1 2 3 4 5 6 7 8 9

0 5 ms D S U U U D S U U U

1 5 ms D S U U D D S U U D

2 5 ms D S U D D D S U D D

3 10 ms D S U U U D D D D D

4 10 ms D S U U D D D D D D

5 10 ms D S U D D D D D D D

6 5 ms D S U U U D S U U D

90

50

70

10

50

30

0

10

20

30

40

50

60

70

80

90

100

Download Video Call Online Game

Throughput(%)

DL

UL


84/97

C t t


85/97


Contents




4. Technical Comparison Between LTE-TDD and LTE-

FDD

5. LTE Deployment

Similar technologies Between LTE-


86/97


Similar technologies Between LTE

TDD and LTE-FDD

Item LTE-TDD LTE-FDD

Scalable bandwidth

configuration

1.4 MHz, 3 MHz, 5 MHz, 10

MHz, 15 MHz, and 20 MHz

1.4 MHz, 3 MHz, 5 MHz, 10 MHz,15

MHz, and 20MHz

Multiple access

scheme

DL: OFDM DL: OFDM

UL: SC-FDMA UL: SC-FDMA

Coding scheme

Convolutional code and

turbo code Convolutional code and turbo code

Modulation scheme QPSK, 16QAM, and 64QAM QPSK, 16QAM, and 64QAM

Power control scheme

Combination of open-loop

power control and closed-

loop power control

Combination of open-loop power

control and closed-loop power control

AMC Supported Supported

Congestion control Supported Supported

Different Technologies Between LTE-


87/97


g

TDD and LTE-FDDItem LTE-TDD LTE-FDD

Duplex mode TDD FDD

Frame structure Type 2 Type 1

Uplink and downlink

subframe configuration

According to different UL-DL subframe configuration,

the number of subframes allocated to uplink and

downlink can be adjusted flexibility

All subframes can be allocated only for the

uplink or downlink

HARQ process

The number of processes and the delay vary with

the proportions of subframes configured for the

uplink and downlink The number of processes and delay are fixed

Beamforming

Supported (exchangeability based on uplink and

downlink channel)

Not supported (no exchangeability based on

uplink and downlink channels)

MIMO Mode Modes 18 are supported Mode 16 are supported.

Network Interference

Strict synchronization is required in the whole

network

When different spectrum are used , the guard

bandwidth can avoid the interference, while

using the same spectrum among the adjacent

cells,synchronization requirement is not strict

Diff t O ti B d


88/97


Different Operating BandsE-UTRA Band Uplink Downlink Duplex Mode

1 1920MHz1980MHz 2110MHz2170MHz FDD








9 1749.9MHz1784.9MHz 1844.9MHz1879.9MHz FDD


11 1427.9MHz1452.9MHz 1475.9MHz1500.9MHz FDD





Diff t O ti B d


89/97


Different Operating Bands

E-UTRA Band Uplink DownlinkDuplex

Mode

33 1900 MHz 1920 MHz 1900 MHz 1920 MHz TDD








Networking Comparison


90/97


Networking Comparison

The networking differences mainly lie in network planning: LTE-FDD: Only frequency planning is involved and frequency

planning is completed in combination with ICIC

LTE-TDD: Frequency planning and timeslot planning are

involved. Frequency planning is completed in combination

with ICIC, while timeslot planning is completed in

consideration of the service distribution and interference

isolation

Networking Modes of LTE-TDD:


91/97


g

Thare are two networking modes of LTE-TDD: Intra-frequency networking:

All cells in the whole network use the same frequency

Inter-frequency networking:

No sub-carrier collision can happen between adjacent cells of

one eNodeB

Intra-frequency networking Inter-frequency networking

Contents


92/97


Contents





5. LTE Deployment

Frequency Bands Issued


93/97


Frequency Bands Issued

Norway

2.6GHz (11-2007)

Sweden [1]

2.6GHz (Q1-2008)

Finland1800MHz (04-2009), 2.6GHz (12-2009)

USA [5]

700MHz auction 73 (03-2008)

Japan

1.5GHz, 1800MHz, 2.1GHz [2]

(06-2009)

Hong-Kong [3]

2.6GHz (01-2009)

Singapore

2.6GHz (2005)

Saudi Arabia

2.6GHz (~2010)Chile

2.6GHz (~2010)

Europe

800M/2.6GHz (~2010)

New Zealand

2.6GHz

E2E Solutions


94/97


E2E Solutions

End-to-End transport solution

Complete e-NodeB portfolio

Distributed BTS

DBS3900 Indoor

BTS3900

OutdoorBTS3900A

Macro BTS

2008 20102009

PDA

PhoneUSB Modem

Router

2011

Test Prototype

USN (Unified Serving Node) for MME

Convergence SAE solution

Unified platform incl. TDM, IP, ATM

Smooth evolution to all IP

Pico/Femto

UGW (Unified packet Gateway) for SGW and PGW

Terminals


95/97

Application Scenario


96/97


Application Scenario

Consecutive

Coverage

Marco BTS

Outdoor

Coverage

Femto

Family

Applicaiton

Pico

Indoor

Coverage

DBS

Outdoor

Coverage

eNodeB

Solution

BBU

RRU

RRUL

T

E

H

S

P

A

W

iM

AX

D

O

r

A

R

F

U

R

F

U

R

F

U

R

F

U

R

F

U

R

F

U

BBU

H

S

P

A

L

T

E

Wi

MA

X

H

S

P

A

L

T

E

L

T

E

L

T

E

W

i

MA

X

H

S

P

A

BBU RRU RFUBBU RRUR

F

U

Module

Design

W

i

F

i


97/97

Thank youwww.huawei.com

Oea000050 Lte-tdd System Overview Issue 1.00

Documents