2 wcdma ran principle

Huawei Confidential. All Rights Reserved

WCDMA Principles

2 Internal Use

Chapter 1 IntroductionChapter 1 IntroductionChapter 2 WCDMA Network StructureCDMA Network Structure

Chapter 3 WCDMA TechnologiesChapter 3 WCDMA Technologies

Chapter 4 WCDMA RNC AreaChapter 4 WCDMA RNC Area

3 Internal Use

Mobile Network EvolutionMobile Network Evolution

1G

Analogue

2G

Digital

2.5G

Packet Data

2.75G

Enhanced Data

NMTNMT

TACSTACS

AMPSAMPS

GSMGSM

CDMACDMA

TDMATDMA

PDCPDC

GPRSGPRS

EDGEEDGE

CDMA 1XCDMA 1X

WCDMAWCDMA

TD-SCDMATD-SCDMA

cdma2000 1X EV-DO

cdma2000 1X EV-DO

2M, 14M

2M

2.4M

384K

144K

1982-1996+ 1992-2002+ 2001+ 2004+ 2002-2004+

115K

4 Internal Use

Standardization Course of ITU IMT-2000Standardization Course of ITU IMT-2000

1985: ITU-T form FPLMTS. Later renamed as IMT-2000 in 1996

1992: 230MHz spectrum was allocated in WARC92

Standardization organizations such as 3GPP(1998.12), 3GPP2(1999) were established

2000: All the network standards of IMT2000 were completed

“Family concept ” was adopted in network part

ITU-MC

CDMA2000

ITU-DS

WCDMA

ITU-TC

UMTSTDD

ITU-SC

UWC-136

ITU-FT

DECT

IMT2000

3GPP 3GPP2 CWTS ETSI

5 Internal Use

Main CDMA 3G ProposalsMain CDMA 3G Proposals

Regional Standard Organization(RSO)

Radio Transmission Technology(RTT)

U.S. TIA(TR 45.5) cdma2000

T1 WCDMA

Korea TTA TTA1(~WCDMA)

TTA2(~cdma2000)

Japan ARIB WCDMA

Europe ETSI(SMG 2) WCDMA

China CWTS TD-SCDMA

6 Internal Use

Target of IMT2000Target of IMT2000

Global uniform frequency band and standard, global seamless coverage

High efficient spectrum utility

High quality of service, high security

Easy for evolution from 2G system

Providing multimedia service Car speed environment: 144kbps Walk speed environment: 384kbps Indoor environment: 2048kbps

7 Internal Use

QoS Requirements of Different ServicesQoS Requirements of Different Services

Sensitivity of delay

Sensitivity of error

background

conversational

streaming

interactive

8 Internal Use

WCDMA FDD WCDMA FDD

WCDMA FDD

Multiple access method DS-CDMA

Duplex Method Frequency Division

Frequency Band Uplink : 1920-1980MHz, Downlink : 2110-2170MHz

Carrier 5MHz, with 190MHz frequency spacing

Base Station Synchronization Asynchronous/Synchronous operation

Chip Rate 3.84Mcps

Frame Length 10ms

Service multiplexing Multiple Services with different QoS are multiplexed on a single connection

Multi-user detection, smart antennas Supported by standard, optional in implementation

Power Control Fast Power Control, 1.5KHz

Handover Softer, Soft & Hard Handover

Transmit Diversity Open & Closed Loop

Voice Coding AMR Voice Coding, rate 4.75kbps – 12.2kbps

9 Internal Use

WCDMA Voice EvolutionWCDMA Voice EvolutionWCDMA Voice EvolutionWCDMA Voice Evolution

Adopt AMR voice coding, and support voice quality of 4.75Kbps ~ 12.2Kbps

Adopt soft handover and transmit diversity to improve system capacity

Provide high fidelity voice mode

Fast power control

10 Internal Use

Data Service Evolution of WCDMAData Service Evolution of WCDMAData Service Evolution of WCDMAData Service Evolution of WCDMA

Support maximum 2Mbps data service

Support packet switch

Adopt ATM platform currently

Provide QoS

Common Packet Channel(CPCH) and Downlink Share Channel(DSCH) can support Internet packet services better

Provide high-quality support for uplink-downlink symmetric data service, such as voice, video phone, conference TV

11 Internal Use

Chapter 1 IntroductionChapter 1 IntroductionChapter 2 WCDMA Network StructureCDMA Network StructureChapter 3 WCDMA TechnologiesChapter 3 WCDMA Technologies


12 Internal Use

WCDMA Network StructureWCDMA Network Structure

GSM /GPRS BSS

BTS

BSC

PCU

SS7

SCP

SMS

SCE

PSTN/other PLMN

Internet,Intranet

MSC/VLR GMSC

HLR/AUC

SGSN

CG BG

GGSN

PS backbone

Other PLMN

CS domain

PS domain

NodeB

RNC

UTRAN

Iu-CS

Iu-PS

A

Gb

13 Internal Use

WCDMA InterfacesWCDMA Interfaces

A Interface

A-bis

Um

MSCMSC

BSCBSC

BTSBTS

UE

SGSNSGSN

Gb

GSM

Iub

Uu

MSCMSC

RNCRNC

NodeBNodeB

UE

SGSNSGSN

Iu-PS

Iu-CS

Iub

Uu

RNCRNC

NodeBNodeB

UE

Iur

WCDMA

UTRANBSS

14 Internal Use


Chapter 3 WCDMA TechnologiesChapter 3 WCDMA TechnologiesChapter 4 WCDMA RNC AreaChapter 4 WCDMA RNC Area

15 Internal Use

Section 1Section 1 - - Correlation FunctionCorrelation Function - OVSF and PN code- OVSF and PN code - Information Spreading & Recovery- Information Spreading & Recovery - Rake Receiver- Rake Receiver

Section 2Section 2 - WCDMA Transmission Block Diagram- WCDMA Transmission Block Diagram

Section 3Section 3 - Power Control- Power Control - Handover- Handover - Diversity- Diversity


16 Internal Use

Correlation FunctionCorrelation FunctionCorrelation FunctionCorrelation Function

Correlation is a measure of similarity of between any two arbitrary signals.

EXAMPLE:

-1 1 -1 1 1 1 1 1 -1 1 -1 1 Zero correlation Orthogonal signals

-1 1 -1 1 -1 1 -1 1 1 1 1 1 1 correlation Identical signals

+1 0-1+1 0-1

+1 0-1

+1 0-1

17 Internal Use

Orthogonal Function Orthogonal Function

Orthogonal functions have zero correlation. Two binary sequences are orthogonal if their “XOR” output contains equal number of 1’s and 0’s

0000

0101

0101

EXAMPLE:

1010

0101

1111

18 Internal Use

OVSF & Walsh CodeOVSF & Walsh Code

SF = 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)

19 Internal Use

SF and Service RateSF and Service Rate

Symbol Rate*SF=Chip Rate In WCDMA system, if chip rate=3.84MHz, SF=4, then symbol

rate=960Kbps;

Symbol Rate=(Service Rate + Checking Code)*Channel Coding Rate* Repeat or Puncture Rate In WCDMA system, if service rate=384Kbps, channel coding=1/3 Turbo

coding, then symbol rate=960Kbps;

20 Internal Use

Scrambling CodeScrambling Code

Scrambling codes GOLD sequence.

Uplink scrambling codes Uplink scrambling codes are used to distinguish different UEs

Downlink scrambling codes For downlink physical channels, a total of 218-1 = 262,143 scrambling

codes can be generated. Only scrambling codes k = 0, 1, …, 8191 are used. 8192 codes are divided into 512 groups, each of which contains 16 scra

mbling codes. The first scrambling code of each group is called primary scrambling co

de (PSC), and the other 15 ones are secondary scrambling codes (SSC).

21 Internal Use

OVSF and Scrambling Code UsageOVSF and Scrambling Code Usage

OVSF Code PN Code

Usage Uplink : Separate physical data (DPDCH) & control channels (DPCCH) from the same terminal

Downlink : Separate downlink connections to different UEs within the cell

Uplink : Separation of UEs

Downlink : Separation of cells

Length Uplink : 4 – 256 chips

Downlink : 4 – 512 chips

Uplink/Downlink :

10ms = 38400 chips

Number of codes Number of codes under one scrambling factor = spreading factor

Uplink : Several Million

Downlink : 512

Code Family Orthogonal Variable Spreading Factor (OVSF)

Gold code

Bandwidth Spreading increase transmission bandwidth

No change in transmission bandwidth

22 Internal Use

Information spreading over orthogonal codesInformation spreading over orthogonal codes

1 0 0 1 1

0110 0110 0110 0110 0110

1001 0110 0110 1001 1001

User Input

Orthogonal Sequence

Tx Data

+1

-1

+1

-1

23 Internal Use

Information recoveryInformation recovery

1 0 0 1 1+1

-1

Rx Data 1001 0110 0110 1001 10010110 0110 0110 0110 01101111 0000 0000 1111 1111

Correct Function

? ? ? ? ?

Rx Data 1001 0110 0110 1001 10010101 0101 0101 0101 01011100 0011 0011 1100 1100

Incorrect Function

24 Internal Use

Spreading and De-spreadingSpreading and De-spreading

information pulse interference White noise

The improvement of time-domain information rate means that the bandwidth of spectrum-domain

information is spread.

S(f) is the energy density.

f

S （ f ）

The spectrum before spreading

information

f0

The spectrum before despreading

informationInterference/noise

S （ f ）

f0 f f0

The spectrum after despreading

information

Interference/noise

S （ f ）

f

The spectrum after spreading

information

f0

S （ f ）

f

25 Internal Use

Principle of RAKE ReceiverPrinciple of RAKE ReceiverPrinciple of RAKE ReceiverPrinciple of RAKE Receiver

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

the receive performance of the system

Receive set

Correlator 1

Correlator 2

Correlator 3

Searcher correlator Calculate the time delay and signal strength

Combiner The combined signal

tt

s(t) s(t)

26 Internal Use





27 Internal Use

Block Diagram of WCDMA SystemBlock Diagram of WCDMA SystemBlock Diagram of WCDMA SystemBlock Diagram of WCDMA System

Source coding

Channel coding

Spreading

Modulation

Source decoding

Channel decoding

Despreading Demodulation

Radio channel

28 Internal Use

Common Technical TermsCommon Technical Terms

Bit, Symbol, Chip: A bit is the input data which contain information A symbol is the output of the convolution, encoder, and the

block interleaving A chip is the output of spreading

Processing Gain: Processing gain is the ratio of chip rate to the bit rate. Closely related to spreading factor, SF.

Forward direction/ Downlink : Information path from base station to mobile station

Reverse direction/ Uplink : Information path from mobile station to base station

29 Internal Use

WCDMA SystemWCDMA System

Source Coding Voice : Adaptive multirate technique with rate 4.75kbps – 12.2kbps

Channel Coding CRC Attachment.

Check for error during transmission. Voice : CRC check returns error, discard information Data : CRC check returns error; ask for retransmission

Convolutional or Turbo Coding Convolution coding for voice and low speed signaling Turbo Coding for large data transmission. Better performance than convolutional

coding

Interleaving Distribute error over data transmitted

Rate Matching Match symbol rate to that accepted by spreading Rate matching technique : Repeat or puncturing

30 Internal Use

WCDMA SystemWCDMA System

Spreading Spreading (OVSF code)

SF 4 – 512, depends on data rate

Scrambling (Gold Code)

Modulation QPSK

31 Internal Use





32 Internal Use

Power ControlPower Control

Open Loop Power Control Set initial power for transmission of PRACH

Closed Loop Power Control

Inner Loop Power Control Uplink : Controls power of NodeB. Downlink : Ensures all power received at NodeB are just enough to

maintain satisfactory connection Fast Power Control : 1.5khz

Outer Loop Power Control Set SIRthreshold based on BER/BLER

33 Internal Use

Open Loop Power ControlOpen Loop Power Control

• Used in setting initial transmission power of UE.

• Not in use when inner loop power control running.

• UE obtain information on uplink interference level, NodeB transmit

power (CPICH power) and constant from system information which is

broadcast by cell.

Initial Power = CPICH downlink transmit power – CPICH_RSCP + UL

interference + Constant

System information :CPICH Transmit power, UL interference & constant

PRACH Tx power

34 Internal Use

Closed Loop Power ControlClosed Loop Power Control

Power Control Bit

(Eb/Nt)measured

BER/BLER Value

Inner Loop Power Control

Outer Loop Power Control

Change in (Eb/Nt)threshold

RNC

NodeB

35 Internal Use

HandoverHandover

Softer handoverSofter handover- Handover between intra-frequency cells under the control of the same BTS- Radio link connection to new target cell is created before existing connection being deleted.

Soft handoverSoft handover- Handover between intra-frequency cells under the control of the different BTSs

Hard handoverHard handover- Condition of hard handover:

Intra-frequency handover, cells controlled by different RNCs and no Iur interface between them

Inter-frequency handover Inter-system handover

Interruption in voice or data communication occurs but this interruption does not effect the user communication

36 Internal Use

Soft/Softer HandoverSoft/Softer Handover

• Selection combination in the RNC during soft handoff

• Maximum ratio combination in the NodeB during softer handoffs

Combine all the power from each

sector

Power received from a single sector

37 Internal Use

Transmission Diversity : STTDTransmission Diversity : STTD

Space Time transmit Diversity (STTD)

Transmission diversity

processing

Restoring data stream

Path 1

Path 2

Antenna 2

Antenna 1

B0 B1 B2 B3

B2 B3 B0 B1

B0 B1 B2 B3

B0 B1 B2 B3

38 Internal Use

Transmission Diversity : TSTDTransmission Diversity : TSTD

Time Switch transmit Diversity (TSTD)Used in synchronization physical channel ( SCH)

Transmission diversity

processing

Data stream 1

Data stream 2

Data stream Restoring data stream

Path 1

Path 2

Antenna 2

Antenna 1

39 Internal Use




40 Internal Use

WCDMA RNC AreaWCDMA RNC Area

Service Area: - An area where a mobile station can obtain services, namely, the area where the users in different communication networks (PLMN, PSTN or ISDN) can communicate with a mobile station without knowing its actual location

PLMN Area - geographic area where a PLMN provides communication services

LAC : Location Area Code - Area where a mobile station can move without any location update in MSC - Define MSC paging area

RAC : Routing Area Code - Area where a mobile station can move without any location update in SGSN - Define SGSN paging area

URA : UTRAN registration Area - Performed when UE in URA-PCH mode. - UE only perform location update when cells URA ID changes

Cell : Defines a coverage area

41 Internal Use

2 wcdma ran principle

Documents