1-owa200002 wcdma ran fudamental

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

WCDMA RANFundamental


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Page2Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

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, DifferentTechnology

AMPS

TACS

NMT

Others

1G 1980sAnalog

GSMGSM

CDMACDMAIS-95IS-95

TDMATDMAIS-136IS-136

PDCPDC

2G 1990sDigital

Technologiesdrive

3GIMT-2000

UMTSUMTS

WCDMAWCDMA

cdmacdma20002000

Demandsdrive

TD-

SCDMA

TD-

SCDMA

3G provides compositive services for both operators and subscribers


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Different Service, DifferentTechnology

AMPS

TACS

NMT

Others

1G 1980sAnalog

GSMGSM

CDMACDMAIS-95IS-95

TDMATDMAIS-136IS-136

PDCPDC

2G 1990sDigital

Technologiesdrive

3GIMT-2000

UMTSUMTS

WCDMAWCDMA

cdmacdma20002000

Demandsdrive

TD-

SCDMA

TD-

SCDMA

3G provides compositive services for both operators and subscribers


7/54Page7Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

3G Evolution

Proposal of 3G

IMT-2000: the general name of third generation mobile

communication system

The third generation mobile communication was firstproposed in 1985 and 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 number central frequency5, formain band:

UL frequency channel number

9612

9888 DL frequency channel number : 10562 10838


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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

WCDMAWCDMACN: based on MAP and GPRS

RTT: WCDMA - FDD/TDD

TD-SCDMACN: based on MAP

RTT: TD-SCDMA

cdma2000CN: based on ANSI 41 and

MIPRTT: 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 TerrestrialInterface

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)

Transport

Network

Layer

Physical Layer

Signalling

Bearer(s)

Control Plane User Plane

Transport Network

User Plane

Transport Network

Control Plane

Radio

Network

Layer

Signalling

Bearer(s)

Data

Bearer(s)

Transport Network

User Plane


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Contents

1. 3G Overview

2. CDMA Principle



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Multiple Access and DuplexTechnology Multiple Access Technology

Frequency division multiple access (FDMA)

Time division multiple access (TDMA)

Code division multiple access (CDMA)


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Multiple Access and DuplexTechnology 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

DL

DL

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 WCDMASystem

SourceCoding

Channel

Coding

Spreading Modulation

SourceDecodin

g

ChannelDecodin

g

Despreading

Demodulation

Transmission

Reception

chipmodulated

signalbit symbo

l

Service

Signal

RadioChannel

Service

Signal

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.324 is 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 Block

of N Bits

No Coding

1/2 ConvolutionalCoding

1/3 Convolutional

Coding

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 = 0

Orthogonal 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

1 1

C2: 1 1 1 1 1 1

1 1UE1c1 1 1 1 1 1 1

1 1

UE2c2 1 1 1 1 1 1

1 1


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Orthogonal Code Usage -Decoding

UE1C1 UE2C2: 2 0 2 0 2

0 2 0

UE1 Dispreading by c1: 1 1 1 1 1 1 1 1

Dispreading result: 2 0 2 0 2

0 2 0

Integral judgment: 4 (means 1) 4

(means 1)

UE2 Dispreading by c2: 1 1 1 1 1 1

1 1


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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 allowedinterference

Eb/NoRequirement

Power

Max interferencecaused by UE

Processing Gain

Ebit

Interferencefrom other 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

OVSF

codeScrambling

code

Chips after

spreading


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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 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.

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

15Primary

scramblingcode 511*16

Secondaryscrambling

code511*16+15

8192scrambling

codes512 sets


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Code Multiplexing

Downlink Transmission on a Cell Level

Scrambling codeScrambling code

Channelization code 1Channelization 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 radio

wave:

carrier =A.cos(2 Ft+ )Amplitude Shift

Keying:

A.cos(2 Ft+ )Frequency Shift

Keying:

A.cos(2 Ft+ )Phase Shift Keying:

A.cos(2 Ft+ )

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

=0 = =0

1 102 3 4 9875 6

1 102 3 4 9875 6

Digital Input

High Frequency

Carrier

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

I

Component

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 + /2)

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

)cos(2: +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

different transmitting abilities in air interface

HSDPA: adopt 16QAMR99/R4: adopt QPSK


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Wireless Propagation

Received

Signal

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

0dB

m

-20-15

-10

-5

5

10

15

2

0

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 uncorrelatedsignals for combining

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 the

time delay and

signal strength

CombinerThe

combined

signal

tt

s(t) s(t)

RAKE receiver help to overcome on the multi-path fading and enhance the receive

performance 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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