01-Owa200002 Wcdma Ran Fudamental

8/2/2019 01-Owa200002 Wcdma Ran Fudamental

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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

WCDMA RAN

Fundamental


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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved. Page1

Objectives

Upon completion of this course, you will be able to:

Know the development of 3G

Outline the advantage of CDMA principle

Characterize code sequence

Outline the fundamentals of RAN

Describe feature of wireless propagation


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Contents

1. 3G Overview

2. CDMA Principle

3. WCDMA Fundamental


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Contents

1. 3G Overview

2. CDMA Principle



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Different Service, Different Technology

AMPS

TACS

NMT

Others

1G 1980sAnalog

GSM

CDMA

IS-95

TDMAIS-136

PDC

2G 1990sDigital

Technologiesdrive

3GIMT-2000

UMTS

WCDMA

cdma2000

Demandsdrive

TD-

SCDMA

3G provides compositive services for both operators and subscribers


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3G Evolution

Proposal of 3G

IMT-2000: the general name of third generation mobile

communication system

The third generation mobile communication was first proposedin 1985and was renamed as IMT-2000 in the year of 1996

Commercialization: around the year of 2000

Work band : around 2000MHz

The highest service rate :up to 2000Kbps


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3G Spectrum Allocation


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Bands WCDMA Used

Main bands 1920 ~ 1980MHz / 2110 ~ 2170MHz

Supplementary bands: different country maybe different

1850 ~ 1910 MHz / 1930 MHz ~ 1990 MHz (USA)

1710 ~ 1785MHz / 1805 ~ 1880MHz (Japan)

890 ~ 915MHz / 935 ~ 960MHz (Australia)

Frequency channel numbercentral frequency5, for mainband:

UL frequency channel number96129888

DL frequency channel number : 1056210838


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3G Application Service

Time Delay

BER

background

conversational

streaming

interactive


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The Core technology of 3G: CDMA

CDMA

WCDMA

CN: based on MAP and GPRS

RTT: WCDMA - FDD/TDD

TD-SCDMACN: based on MAP

RTT: TD-SCDMA

cdma2000CN: based on ANSI 41 and MIP

RTT: cdma2000


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WCDMA Protocol Version Evolution

3GPP Rel993GPP Rel4

3GPP Rel5

2000 2001 2002

GSM/GPRS CN

WCDMA RTT

IMS

HSDPA 3GPP Rel6

MBMS

HSUPA

2005

CS domain change toNGN

WCDMA RTT


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WCDMA System Architecture

RNS

RNC

RNS

RNC

Core Network

Node B Node B Node B Node B

Iu-CS Iu-PS

Iur

Iub IubIub Iub

CN

UTRAN

UEUu

CS PS


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Protocol Mode for UTRAN Terrestrial Interface

The structure is based on the principle that the layers and planes

are logically independent of each other.

Application

Protocol

Data

Stream(s)

ALCAP(s)

TransportNetwork

Layer

Physical Layer

SignallingBearer(s)

Control Plane User Plane

Transport NetworkUser Plane

Transport NetworkControl Plane

RadioNetwork

Layer

SignallingBearer(s)

DataBearer(s)

Transport NetworkUser Plane


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Contents

1. 3G Overview

2. CDMA Principle



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Multiple Access and Duplex Technology

Multiple Access Technology

Frequency division multiple access (FDMA)

Time division multiple access (TDMA)

Code division multiple access (CDMA)


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Multiple Access Technology

power

FDMA

power

TDMA

power

CDMA


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Multiple Access and Duplex

Technology

Duplex Technology

Frequency division duplex (FDD)

Time division duplex (TDD)


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Duplex Technology

Time

Frequency

Power

TDD

USER 2

USER 1

DL

UL

DLDL

UL

FDD

Time

Frequency

Power

UL DL

USER 2

USER 1


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Contents

1. 3G Overview

2. CDMA Principle



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Processing Procedure of WCDMA System

SourceCoding

ChannelCoding

Spreading Modulation

SourceDecoding

ChannelDecoding

Despreading Demodulation

Transmission

Reception

chipmodulated

signalbit symbol

ServiceSignal

RadioChannel

ServiceSignal

Transmitter

Receiver


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Process Gain

Process Gain

Process gain differs for each service.

If the service bit rate is greater, the process gain is smaller, UE

needs more power for this service, then the coverage of this

service will be smaller, vice versa.

)ratebit

ratechiplog(10GainocessPr


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WCDMA Source Coding

AMR (Adaptive Multi-Rate) Speech A integrated speech codec with 8 source

rates.

The AMR bit rates can be controlled by the

RAN depending on the system load and

quality of the speech connections.

Video Phone Service

H.324is used for VP Service in CS domain.

Includes: video codec, speech codec, data

protocols, multiplexing and etc.

CODEC Bit Rate (kbps)

AMR_12.20 12.2 (GSM EFR)

AMR_10.20 10.2

AMR_7.95 7.95

AMR_7.40 7.4 (CDMA EFR)

AMR_6.70 6.7 (PDC EFR)

AMR_5.90 5.9

AMR_5.15 5.15

AMR_4.75 4.75


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WCDMA Channel Coding

Effect Enhance the correlation among symbols so as to recover the signal when

interference occurs

Provides better error correction at receiver, but brings increment of the delay

Types No Coding

Convolutional Coding (1/2, 1/3)

Turbo Coding (1/3)

Code Blockof N Bits

No Coding

1/2 ConvolutionalCoding

1/3 ConvolutionalCoding

1/3 Turbo Coding

Uncoded N bits

Coded 2N+16 bits

Coded 3N+24 bits

Coded 3N+12 bits


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WCDMA Interleaving

Effect Interleaving is used to reduce the probability of consecutive bits error

Longer interleaving periods have better data protection with more delay

1110

1.........

............

...000

0100

0 0 1 0 0 0 0 . . . 1 0 1 1 1

1110

1.........

.. ..........

.. .000

00100 0 0 1 0 1 0 0 1 0 1 1

Inter-columnpermutation

Output bits

Input bits

Interleaving periods:

10, 20, 40, or 80 ms


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Correlation

Correlation measures similarity between any two arbitrary signals.

Identical and Orthogonal signals:

Correlation = 0Orthogonal signals

-1 1 -1 1

-1 1 -1 11 1 1 1

+1

-1

+1

-1

+1

-1

+1

-1

Correlation = 1Identical signals

-1 1 -1 11 1 1 1

-1 1 -1 1

C1

C2+1

+1

C1

C2


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Orthogonal Code Usage - Coding

UE1: 1 1

UE2: 1 1

C1 : 1 1 1 1 1 1 11C2 : 1111 1111UE1c1 1 1 1 1 1 1 11

UE2c2 1111 1111

UE1c1 UE2c2 2 02 0 2 0 2 0


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Orthogonal Code Usage - Decoding

UE1C1 UE2C2: 2 02 0 2 0 20

UE1 Dispreading by c1: 1 1 1 1 1 1 11Dispreading result: 2 02 0 2 0 2 0Integral judgment: 4 (means1) 4 (means1)

UE2 Dispreading by c2: 11 11 11 11Dispreading result: 2 0 2 0 2 0 2 0Integral judgment: 4 (means1) 4 (means1)


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Spectrum Analysis of Spreading & Dispreading

Spreading code

Spreading code

Signal

Combination

Narrowband signal

f

P(f)

Broadband signal

P(f)

f

Noise & Other Signal

P(f)

f

Noise+Broadband signal

P(f)

f

Recovered signal

P(f)

f


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Spectrum Analysis of Spreading & Dispreading

Max allowed interference

Eb/NoRequirement

Power

Max interference causedby UE

Processing Gain

Ebit

Interference fromother UE Echip

Eb / No = Ec / Io PG


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Spreading Technology

Spreading consists of 2 steps

Channelization operation, which transforms data symbols into chips

Scrambling operation is applied to the spreading signal

Data bit

OVSFcode

Scrambling

code

Chips after

spreading


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WCDMA Channelization Code

OVSF Code (Orthogonal Variable Spreading Factor) is used as

channelization code

SF = 8SF = 1 SF = 2 SF = 4

Cch,1,0 = (1)

Cch,2,0 = (1,1)

Cch,2,1 = (1, -1)

Cch,4,0 = (1,1,1,1)

Cch,4,1 = (1,1,-1,-1)

Cch,4,2 = (1,-1,1,-1)

Cch,4,3 = (1,-1,-1,1)

Cch,8,0 = (1,1,1,1,1,1,1,1)

Cch,8,1 = (1,1,1,1,-1,-1,-1,-1)

Cch,8,2 = (1,1,-1,-1,1,1,-1,-1)

Cch,8,3 = (1,1,-1,-1,-1,-1,1,1)

Cch,8,4 = (1,-1,1,-1,1,-1,1,-1)

Cch,8,5 = (1,-1,1,-1,-1,1,-1,1)

Cch,8,6 = (1,-1,-1,1,1,-1,-1,1)

Cch,8,7 = (1,-1,-1,1,-1,1,1,-1)


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WCDMA Channelization Code

SF = chip rate / symbol rate

High data rates low SF code

Low data rates high SF code

Radio bearer SF Radio bearer SF

Speech 4.75 UL 128 Speech 4.75 DL 256

Speech 12.2 UL 64 Speech 12.2 DL 128

Data 64 kbps UL 16 Data 64 kbps DL 32





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Purpose of Channelization Code

Channelization code is used to distinguish different physical

channels of one transmitter

For downlink, channelization code ( OVSF code ) is used to

separate different physical channels of one cell

For uplink, channelization code ( OVSF code ) is used to

separate different physical channels of one UE


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Purpose of Scrambling Code

Scrambling code is used to distinguish different transmitters

For downlink, Scrambling code is used to separate different

cells

For uplink, scrambling code is used to separate different UE


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Scrambling Code

Scrambling code: GOLD sequence.

In UMTS, Gold codes were chosen for their very low peak cross-

correlation.

There are 224 long uplink scrambling codes which are used for

scrambling of the uplink DPCCH/DPDCH. Uplink scrambling

codes are assigned by higher layers.

For downlink physical channels, 8192 scrambling codes are used.


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Downlink Scrambling Code

A primary scrambling code and 15 secondary scrambling codes are

included in a set.

Scrambling

codes for

downlink

physical

channels

Set 0

Set 1

Set 511

Primaryscrambling code 0

Secondaryscrambling code 1

Secondaryscrambling code 15

Primaryscrambling code

511*16

Secondaryscrambling code

511*16+15

8192scrambling

codes

512 sets


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Primary Scrambling Code Group

Primaryscramblingcodes fordownlink

physicalchannels

Group 0

Primary

scrambling code 0


8*63


8*63 +7512 primaryscrambling

codes

Group 1

Group 63



64 primaryscrambling code

groups

Each group consists of 8primary scrambling codes


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Code Multiplexing

Downlink Transmission on a Cell Level

Scrambling code

Channelization code 1



User 1 signal

User 2 signal

User 3 signal

NodeB


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Code Multiplexing

Uplink Transmission on a Cell Level

NodeB

Scrambling code 3

User 3 signal

Channelization code

Scrambling code 2

User 2 signal

Channelization code

Scrambling code 1

User 1 signal

Channelization code


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Modulation Overview

1 00 1

time

Basic steady radiowave:

carrier = A.cos(2pFt+f)Amplitude Shift

Keying:

A.cos(2pFt+f)Frequency Shift

Keying:

A.cos(2pFt+f)Phase Shift Keying:

A.cos(2pFt+f)

Data to be transmitted:Digital Input


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Modulation Overview

Digital Modulation - BPSK

1

t

1 10

1

t-1

NRZ coding

fo

BPSK

Modulated

BPSKsignal

Carrier

Informationsignal

f=0 f=p f=0

1 102 3 4 9875 6

1 102 3 4 9875 6

Digital Input

High FrequencyCarrier

BPSK Waveform


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Modulation Overview

Digital Modulation - QPSK

-1 -1

1 102 3 4 9875 6

1 102 3 4 9875 6

NRZ Input

I di-Bit Stream

Q di-Bit Stream

IComponent

Q

Component

QPSK Waveform

1

1

-1

1

-1

1

1

-1

-1

-1

1 1 -1 1 -1 1 1 -1


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Modulation Overview

NRZcoding

90o

NRZcoding

QPSK

Q(t)

I(t)

fo

A

A Acos(ot)

Acos(ot + p/2)

f1 1 p/41 -1 7p/4-1 1 3p/4-1 -1 5p/4

)cos(2: f oAQPSK


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Demodulation

QPSK Constellation Diagram

1 102 3 4 9875 6

QPSK Waveform

1,1

-1,-1

-1,1

1,-1

1 -11 -1 1 -1-11-1 1

-1,1

NRZ Output


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WCDMA Modulation

Different modulation methods corresponding to differenttransmitting abilities in air interface

HSDPA: adopt 16QAMR99/R4: adopt QPSK


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Wireless Propagation

ReceivedSignal

TransmittedSignal

Transmission Loss:Path Loss + Multi-path Fading

Time

Amplitude


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Propagation of Radio SignalSignal at Transmitter

Signal at Receiver

-40

-35

-30

-25

-20

-15

-10

-5

dB

0

0dBm

-20-15

-10

-5

5

10

15

20

Fading


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Fading Categories

Fading Categories Slow Fading

Fast Fading


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Diversity Technique

Diversity technique is used to obtain uncorrelated signals forcombining

Reduce the effects of fading

Fast fading caused by multi-path

Slow fading caused by shadowing

Improve the reliability of communication

Increase the coverage and capacity


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Diversity

Time diversity Channel coding, Block interleaving

Frequency diversity

The user signal is distributed on the whole bandwidth frequency spectrum

Space diversity Receive space diversity

Transmit space diversity

Polarization diversity

Vertical polarization

Horizontal polarization


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Principle of RAKE Receiver

Receive set

Correlator 1

Correlator 2

Correlator 3

Searcher correlator Calculate thetime delay andsignal strength

CombinerThe

combinedsignal

tt

s(t) s(t)

RAKE receiver help to overcome on the multi-path fading and enhance the receiveperformance of the system


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Summary

In this course, we have discussed basic concepts of WCDMA:

Spreading / Despreading principle

UTRAN Voice Coding

UTRAN Channel Coding

UTRAN Spreading Code

UTRAN Scrambling Code

UTRAN Modulation

UTRAN Transmission/Receiving


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01-Owa200002 Wcdma Ran Fudamental

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