WCDMA RAN Fudamental

Primary Scrambling Code Group Primary scrambling codes for downlink physical channels Group 0 … Primary scrambling code 0 …… Primary scrambling code 8*63 …… Primary scrambling [r]

(1)

www.huawei.com

(2)

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

(3)

Contents

1

3G Overview

CDMA Principle

(4)

Contents

1.

3G Overview

2

CDMA Principle

(5)

Different Service, Different

Technology

AMPS

TACS

NMT

Others

1G 1980s

Analog

GSM

CDMA

IS-95

TDMA

IS-136

PDC

2G 1990s

Digital

Technologies

drive

3G

IMT-2000

UMTS

WCDMA

cdma

2000

Demands

drive

TD-SCDMA

(6)

3G Evolution



Proposal of 3G



IMT-2000: the general name of third generation mobile commu

nication system



The third generation mobile communication was first proposed i

n 1985 ， and was renamed as IMT-2000 in the year of 1996

Commercialization: around the year of 2000



Work band : around 2000MHz

(7)

(8)

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 frequency×5, for main ba

nd:

(9)

3G Application Service

Time Delay

BER

background

conversational

streaming

(10)

The Core technology of 3G: CDMA

CDMA

WCDMA

CN: based on MAP and GPRS

RTT: WCDMA - FDD/TDD

TD-SCDMA

CN: based on MAP

RTT: TD-SCDMA

cdma2000

CN: based on ANSI 41 and MIP

(11)

WCDMA Protocol Version Evolution

3GPP Rel99

3GPP Rel4

3GPP Rel5

2000

2001

2002

GSM/GPRS CN

WCDMA RTT

IMS

HSDPA

3GPP Rel6

MBMS

HSUPA

2005

CS domain change to

NGN

(12)

WCDMA System Architecture

RNS

RNC

RNS

RNC

Core Network

Node B

Iu-CS

Iu-PS

Iur

Iub

CN

UTRAN

UE

Uu

(13)

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 Stre

am(s)

ALCAP(s)

Transport

Network

Layer

Signalling

Bearer(s)

Control Plane

User Plane

(14)

Contents

1

3G Overview

2.

CDMA Principle

(15)

Multiple Access and Duplex

Technology



Multiple Access Technology



Frequency division multiple access (FDMA)

Time division multiple access (TDMA)

(16)

Multiple Access Technology

frequ ency time

power

FDMA

frequ ency

time power

TDMA

power

time

CDMA

(17)

Multiple Access and Duplex

Technology



Duplex Technology

(18)

Duplex Technology

Time

Frequency Power

TDD

USER 2

USER 1

DL

UL

DL

UL

FDD

Time

Frequency Power

UL

DL

USER 2

(19)

Contents

1

3G Overview

CDMA Principle

(20)

Processing Procedure of WCDMA

System

Sourc

e

Codin

g

Chann

el

Coding

Spreading

Modulation

Source

Decodin

g

Channel

Decodin

g

Despreadi

ng

Demodulati

on

Transmission

Reception

chip

modulated

signal

(21)

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.

)

rate

bit

rate

chip

log(

10

Gain

ocess

(22)

WCDMA Source Coding



AMR (Adaptive Multi-Rate) Speech



A integrated speech codec with

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_12.2

0

12.2 (GSM

EFR)

AMR_10.2

0

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

(23)

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 Convolutional

Coding 1/3 Convolutional

Coding

(24)

WCDMA Interleaving



Effect



Interleaving is used to reduce the probability of

consecutive

bits error

Longer interleaving periods have better data protection with more delay

                1 1 0 0 0

0 0 0 1 1

            0 0

0 … … 0 … … 1

Inter-column

permutation

Output bits

Input bits

(25)

Correlation



Correlation measures similarity between any two arbitrary

signals



Identical and Orthogonal signals:

Correlation = 0

Orthogonal signals

-1 -1 1



-1 -1 1

1 1 1

+1 -1 +1 -1 +1 -1 +1 -1

Correlation = 1

Identical signals

-1 -1 1



1 1 1

-1 -1 1

C

1

C

2

+1

C

1

(26)

Page27

Orthogonal Code Usage - Coding

UE1:

＋ 1

－

UE2:

－ 1

＋

C

:

－＋－＋－＋－

1 ＋ 1

C

:

＋＋＋＋＋＋＋

1 ＋

UE1×c1 ：

－＋－＋＋－＋

1 － 1

UE2×c2 ：

－－－－＋＋＋

1 ＋

UE1:

＋ 1

－

UE2:

－ 1

＋ 1

C1 :

－＋－＋－＋－

1

＋ 1

C

:

＋＋＋＋＋＋＋

1 ＋ 1

UE1×c1 ：

－＋－＋＋－＋

1

－ 1

UE2×c2 ：

－－－－＋＋＋

(27)

Orthogonal Code Usage -

Decoding

UE1×C

＋ UE2×C

:

－－＋＋

0

UE1 Dispreading by c1: －＋－＋－＋－＋ 1

Dispreading result:

＋＋－－

0

Integral judgment: ＋ (means ＋ 1) － (means － 1)

UE2 Dispreading by c2: ＋＋＋＋＋＋＋＋

Dispreading result:

－－＋＋

UE1×C

＋ UE2×C

:

－－＋＋

0

UE1 Dispreading by c1: －＋－＋－＋－ 1

＋ 1

Dispreading result:

＋＋－－

0

Integral judgment: ＋ (means ＋ 1) － (means － 1)

UE2 Dispreading by c2: ＋＋＋＋＋＋＋＋

Dispreading result:

－－＋＋

(28)

Spectrum Analysis of Spreading &

Dispreading

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)

(29)

Spectrum Analysis of Spreading &

Dispreading

Max allowed interference

Eb/No Requir ement

Powe r

Max interference caused by UE

Processing Gain

E

Interference from other UE

E

(30)

Spreading Technology



Spreading consists of steps



Channelization operation, which transforms data symbols into chips

Scrambling operation is applied to the spreading signal

Data bit

OVSF

code

Scrambling

code

(31)

WCDMA Channelization Code



OVSF Code (Orthogonal Variable Spreading Factor) is used

as channelization code

SF = 8

SF = 1

SF = 2

SF = 4

C

= (1)

C

= (1,1)

C

= (1, -1)

C

= (1,1,1,1)

C

= (1,1,-1,-1)

C

= (1,-1,1,-1)

C

= (1,-1,-1,1)

C

= (1,1,1,1,1,1,1,1)

C

= (1,1,1,1,-1,-1,-1,-1)

C

= (1,1,-1,-1,1,1,-1,-1)

C

= (1,1,-1,-1,-1,-1,1,1)

C

= (1,-1,1,-1,1,-1,1,-1)

C

= (1,-1,1,-1,-1,1,-1,1)

C

= (1,-1,-1,1,1,-1,-1,1)

C

= (1,-1,-1,1,-1,1,1,-1)

(32)

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

12

8

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

Data 128 kbps UL

8

Data 128 kbps DL

16

Data 144 kbps UL

8

Data 144 kbps DL

16

(33)

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 sep

arate different physical channels of one cell



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

(34)

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

(35)

Scrambling Code



Scrambling code: GOLD sequence.



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

.



There are 2

long uplink scrambling codes which are used for scra

mbling of the uplink DPCCH/DPDCH Uplink scrambling codes are

assigned by higher layers.

(36)

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

Primary

scrambling

code 0

……

Secondary

scrambling code

1

Secondary

scrambling code

15

Primary

scrambling

code 511*16

……

Secondary

scrambling

code

511*16+15

8192 scramblin

g codes

512 sets

…

(37)

Primary Scrambling Code Group

Primary

scrambling

codes for

downlink

physical

channels

Group 0

…

Primary

scrambling

code 0

……

Primary

scrambling

code 8*63

……

Primary

scrambling

code 8*63 +7

512 primary sc

rambling codes

…

Group 1

Group

63

Primary

scrambling

code 1

Primary

scrambling

code 8

64 primary scrambl

(38)

Code Multiplexing



Downlink Transmission on a Cell Level

Scrambling code

Channelization code 1

User signal

(39)

Code Multiplexing



Uplink Transmission on a Cell Level

NodeB

Scrambling code 3

User signal

Channelization code

User signal

Channelization code

(40)

Modulation Overview

1

0

1

0

time

Basic steady radio

wave:

carrier = A.cos(2



Ft+



)

Amplitude Shift

Keying:

A

.cos(2



Ft+



)

Frequency Shift

Keying:

A.cos(2



F

t+



)

Phase Shift Keying:

A.cos(2



Ft+



)

Data to be transmitted:

(41)

Modulation Overview



Digital Modulation - BPSK

1

t

1 0 1

1

t

-1

NRZ coding

f

o

BPSK Modulated

BPSK Carrier Information

signal

=0 = =0

1 2 3 4 5 6 7 8 9 10

Digital Input

High Frequency Carrier

(42)

Modulation

Over

view



Digital Modulation - QPSK

-1 -1

1

2

3

4

5

6

7

8

9

10

NRZ Input

I di-Bit Stream

Q di-Bit Stream

I

Component

Q

Component

QPSK Waveform

1

-1

1

-1

1

-1

(43)

Modulation

Over

view

NRZ

coding

90o

NRZ

coding

QPSK

Q(t)

I(t)

f

o

±A

±Acos(



o

t)

±Acos(



o

t

+



/2)



1



/4

1

-1

7



/4

-1 1

3



/4

)

cos(

2

:

A



o





(44)

Demodulation



QPSK Constellation Diagram

1

2

3

4

5

6

7

8

9

10

QPSK Waveform

1,1

-1,-1 -1,1

1,-1

1

-1

1

-1

1

-1

-1,1

(45)

WCDMA Modulation



Different modulation methods corresponding to

different transmitting abilities in air interface

(46)

Wireless Propagation

Received

Signal

Transmitted

Signal

Transmission Loss:

Path Loss + Multi-path Fading

(47)

Propagation of Radio Signal

Signal at Transmitter

Signal at Receiver

(48)

Fading Categories



Fading Categories

(49)

Diversity Technique



Diversity technique is used to obtain uncorrelated

signals for combining



Reduce the effects of fading



Fast fading caused by multi-path

Slow fading caused by shadowing

(50)

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

(51)

Principle of RAKE Receiver

Receive set

Correlator 1

Correlator 2

Correlator 3

Searcher

correlator

Calculate the

time delay and

signal strength

Combiner

The

combined

signal

t

s(t)

(52)

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

(53)

Thank you