Training Program Day1

8/10/2019 Training Program Day1

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Training Module for 3 G (WCDMA)

Day :1WCDMA principle and overview.

WCDMA Radio Interface Physical Layer

Day :2WCDMA Handover PrincipleWCDMA Power Control Principle

WCDMA RF Optimization Basic


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WCDMA Principles

DAY - 1


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Chapter 1 Introduction

Chapter 2 WCDMA Network Structure

Chapter 3 WCDMA Technologies

Chapter 4 WCDMA RNC Area


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Mobile Network Evolution

1G

Analogue

2G

Digital

2.5GPacket Data

2.75G

Enhanc ed Data

NMT

TACS

AMPS

GSM

CDMA

TDMA

PDC

GPRS

EDGE

CDMA 1X

WCDMA

TD-SCDMA

cdma20001X EV-DO

2M, 14M

2M

2.4M

384K

144K

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

115K


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Target 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


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WCDMA FDD

WCDMA FDD

Multiple access method DS-CDMA

Duplex Method Frequency Division

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

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 4.75kb12.2kbps


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WCDMA 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


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Data 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


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WCDMA Network Structure

GSM /GPRS BSS

BTS

BSC

PCUSS7

SCP

SMS

SCE

PSTN/other PLMN

Internet,Intranet

MSC/VLR GMSC

HLR/AUC

SGSN

CGBG

GGSN

PS backbone

Other PLMN

CS domain

PSdomain

NodeB

RNC

UTRAN

Iu-CS

Iu-PS

A

Gb


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WCDMA Interfaces

A Interface

A-bis

Um

MSC

BSC

BTS

UE

SGSN

Gb

GSM

Iub

Uu

MSC

RNC

NodeB

UE

SGSN

Iu-PSIu-CS

Iub

Uu

RNC

NodeB

UE

Iur

WCDMA

UTRANBSS


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Section 1- Correlation Function- OVSF and PN code

- Information Spreading & Recovery- Rake Receiver

Section 2- WCDMA Transmission Block Diagram

Section 3- Power Control- Handover- Diversity


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Correlation Function

Correlation is a measure of similarity 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

+10

-1

+1

0

-1

+1

0

-1

+1

0

-1


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Orthogonal Function

Orthogonal functions have zero correlation. Two binary sequences are orthogonal if their XOR

output contains equal number of 1s and 0s

0000

0101

0101

EXAMPLE:

1010

0101

1111


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OVSF & 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)


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SF 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;


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Scrambling 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 scrambling

codes.

The first scrambling code of each group is called primary scrambling code

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


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OVSF and PN Code Usage

OVSF Code PN Code

Usage Uplink :Separate physical data

(DPDCH) & control channels

(DPCCH) from the sameterminal

Downlink :Separate downlink

connections to different UEs

within the cell

Uplink :Separation of UEs

Downlink :Separation of cells

Length Uplink : 4256 chips

Downlink : 4512 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 transmissionbandwidth No change in transmissionbandwidth


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Information 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


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Information 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


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Spreading 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.

f

Sf

The spectrum before spreading

information

f0

The spectrum before despreading

information

Interference/noise

S

f

f0 f f0

The spectrum after despreading

information

Interference/noise

S

f

f

The spectrum after spreading

information

f0

Sf

f


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Principle 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 correlatorCalculate the

time delay and

signal strength

Combiner The combined

signal

tt

s(t) s(t)


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Section 1- Correlation Function

- OVSF and PN code- Information Spreading & Recovery- Rake Receiver


Section 3

- Power Control- Handover- Diversity


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Block Diagram of WCDMA

SystemSourcecoding

Channel

codingSpreading Modulation

Sourcedecoding

Channel

decodingDespreading Demodulation

Radio channel


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Common 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


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WCDMA System

Source Coding

Voice : Adaptive multirate technique with rate 4.75kbps12.2kbps

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


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WCDMA System

Spreading

Spreading (OVSF code)

SF 4512, depends on data rate

Scrambling (Gold Code)

Modulation

QPSK


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Section 1- Correlation Function

- OVSF and PN code- Information Spreading & Recovery- Rake Receiver


Section 3

- Power Control- Handover- Diversity


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Power 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


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Open Loop Power Control

Controlled by UE.

Determine UE initial transmission power for random access procedure.

Not in use when inner loop power control running.

UE obtain information from network on:

CPICH power

Uplink interference level

Constant value (Default = 2dB)

UE Initial Power = CPICH power CPICH_RSCP + UL interference +

Constant

System information :CPICH power, UL interference & constant

PRACH Tx power


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Inner Closed Loop Power

Control

Power Control Bit

Located in UE & NodeB

Controls power of dedicated physical channels

Power controls occurs at 1500Hz, thus known as

fast power control

NodeB and UE continuously measure and compare

SIRmeasuredwith SIRthresholdvalue, and inform each

other to increase /reduce its power accordingly.

UE1 UE2 UE3 UE4

With Optimum Power Control

UE1

UE2

UE3

UE4

Without Power Control

ceivedp

oweratNodeB

ceivedp

oweratNodeB

(SIR)measured

NodeB

UE2

UE3

UE1

UE4

SIR threshold


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Outer Closed Loop Power

Control Adjust SIR for every user

Needed to keep track of changes in radio environment

Aims to provide required quality

If SIRthresholdreaches its maximum, system has to perform

- inter-frequency/inter-system handover

- RRC connection release

BER/BLER Value

Change in (SIR)threshold

RNCSIR threshold


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Handover

Softer 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 handover- Handover between intra-frequency cells under the control of the differentBTSs

Hard handover

- Condition of hard handover:

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

Inter-frequency handover

Inter-system handover

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


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Soft/Softer Handover

Combine all the

power from each

sector

Power received from

a single sector

Selection combination in the RNC during soft handoff

Maximum ratio combination in the NodeB during softer handoffs


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Transmission Diversity :

STTD

Space Time transmit Diversity (STTD)

Transmissiondiversity

processing

Restoring data stream

Antenna 2

Antenna 1

B0 B1 B2 B3

B2 B3 B0 B1

B0 B1 B2 B3

B0 B1 B2 B3


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Transmission Diversity :

TSTD

Transmission

diversity

processing

Data stream 1

Data stream 2

Data stream Restoring data stream

Antenna 2

Antenna 1

Time Switch transmit Diversity (TSTD)

Used in synchronization physical channel ( SCH)


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UMTS Radio Interface Physical Layer


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Chapter 1 : Physical Layer Overview

Chapter 2 : Physical Layer Key Technology

Chapter 3 : Physical Layer Procedures

Chapter 4 : Transmit Diversity on PhysicalChannel


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UTRAN Protocol Structure

RNS

RNC

RNS

RNC

Core Network

Node B Node B Node B Node B

Iu Iu

Iur

Iub IubIub Iub


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Spreading Technology

Spreading consists of 2 steps

Channelization operation: Transforms data symbols into chips. Thus

increasing the bandwidth of the signal. The number of chips per data symbol

is called the Spreading FactorSF.The operation is done through

multiplication with OVSF code.

Scrambling operation is applied to the spreading signal.

Data bit

OVSF

code

Scrambling

code

Chips afterspreading


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Channelization Code

OVSF code is used as channelization code

The channelization codes are uniquely described as Cch,SF,k, where SF is

the spreading factor of the code and kis the code number, 0 k SF-1.

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)


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Scrambling Code

Scrambling codeGOLD sequence.

Scrambling code period : 10ms ,or 38400 chips.

The code used for scrambling of uplink DPCCH/DPDCH may be of either long orshort type, There are 224long and 224short uplink scrambling codes. Uplink

scrambling codes are assigned by higher layers.

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.


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Primary Scrambling Code

Scrambling

codes for

downlink

physical

channels

Set 0

Set 1

Set 511

Primaryscrambling code 0

Secondaryscrambling code 1

Secondaryscrambling code

15

Primaryscrambling code

51116

Secondaryscrambling code

51116

15

8192

scramblingcodes

512 sets


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Primary Scrambling Code Group

Group 0

Group1

Group 63

512 primary

scrambling codes

64 primary scrambling

code groups Each group consists of 8primary scrambling codes

Primary

scrambling

codes for

downlink

physical

channels





8*63


63*87


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Chapter 4 : Transmit Diversity on PhysicalChannel


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Section 1 Physical Channel Structure and Function

Section 2 Channel Mapping


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WCDMA Radio Interface

3GPP protocol defined WCDMA radio interface into three channels:

Physical channel, transport channel and logical channel.

Logical channel: Carrying user services. Divided into 2 types,based on services it carried: Control channel and service channel.

Transport channel: Between radio interface layer 2 and physicallayer. Services provided by physical layer for MAC layer. Based on

information transported, can be divided into dedicated channel

and common channel.

Physical channel: It is the ultimate embodiment of all kinds ofinformation when they are transmitted on radio interfaces. Each

channel that uses dedicated carrier frequency, code (spreading

code and scramble) and carrier phase can be regarded as adedicated channel.


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Logical channel

Traffic channel

Control channel

Dedicated traffic channel DTCH

Common traffic channel CTCH

Broadcast control channel BCCH

Paging control channel PCCH

Dedicate control channel DCCH

Common control channel (CCCH


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Transport channel

Broadcast channel (BCH)

Forward access channel (FACH)

Paging channel (PCH)

Random access channel (RACH)

BCH, FACH & PCH are down link channels.

Only RACH is comm on u pl ink channel

Dedicated Channel (DCH)

Dedicated Channel (DCH) exists on up link

or dow nl ink channel.

Dedicated transport

channel


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Physical Channel

A physical channel is defined by a specific carrier frequency, code (scrambling

code, spreading code) and relative phase.

In UMTS system, the different code (scrambling code or spreading code) can

distinguish the channels. Most channels consist of radio frames and time slots, and each radio frame

consists of 15 time slots.

Two types of physical channel: UL and DL

Physical Channel

Frequency,code,phase


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Downlink Physical Channel

Downlink Common Physical Channel

Common Pilot Channel (CPICH)

Synchronization Channel (SCH)Common Control Physical Channel (CCPCH)

Paging Indicator Channel (PICH)

Acquisition Indicator Channel (AICH)

Downlink Dedicated Physical Channel

Downlink DPCH

Downlink

Physical

Channel


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Functions of Downlink DPDCH/DPCCH

DCH data

DPDCH

DPCCH

Provide control data for DPDCH ,such

as demodulation, power control,etc.

Data bearer

at physical layer

DCH

data


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Common Pilot

Channel(CPICH) Common Pilot Channel (CPICH)

Carries pre-defined sequence.

Fixed rate 30KbpsSF=256

Can use STTD on this channel


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Common Pilot Channel

(CPICH) Primary CPICH

Uses OVSF code -Cch, 256,0

Scrambled by the primary scrambling code

Only one CPICH per cell Broadcast over the entire cell

The P-CPICH is a phase reference for SCH, Primary CCPCH, AICH,

PICH. By default, it is also a phase reference for downlink DPCH.

Secondary CPICH

An arbitrary channel code of SF=256 is used for S-CPICH

S-CPICH is scrambled by either the primary or a secondary scrambling

code

There may be zero, one , or several secondary CPICH.

S-CPICH may be transmitted over part of the cell

S-CPICH may be a phase reference for S-CCPCH and downlink DPCH.


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Synchronization Channel (SCH)

Used for cell search

Two sub channels: P-SCH and S-

SCH.

SCH is transmitted at the first

256 chips of every time slot. PSC is transmitted repeatedly in

each time slot.

SSC specifies the scrambling

code groups of the cell.

SSC is chosen from a set of 16

different codes of length 256,

there are altogether 64 primaryscrambling code groups.

PrimarySCH

SecondarySCH

256 chips

2560 chips

One 10 ms SCH radio frame

acs,

acp

acs,

acp

acs,

acp

Slot #0 Slot #1 Slot #14


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Primary Common Control PhysicalChannel (PCCPCH)

Fixed rate30kbpsSF=256, 1

Carry BCH transport channel

Not transmitted during the first 256 chips of each time slot.

Only data part

STTD transmit diversity may be used

Data18 bits

Slot #0 Slot #1 Slot #i Slot #14

Tslot= 2560 chips , 20 bits

1 radio frame: Tf= 10 ms

(Tx OFF)

256 chips


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Secondary Common Control Physical

Channel (SCCPCH) Carry FACH and PCH.

Two types of SCCPCH:

with or without TFCI. UTRAN

decides if a TFCI should be

transmitted, UE must supportTFCI.

Possible rates are the same as

that of downlink DPCH

SF =256 - 4.

FACH and PCH can be mapped

to the same or separate

SCCPCHs. If mapped to the

same S-CCPCH, they can bemapped to the same frame.

Slot #0 Slot #1 Slot #i Slot #14

Tslot= 2560 chips, 20*2kbits (k=0..6)

Pilot

Npilotbits

Data

Ndatabits

1 radio frame: Tf= 10 ms

TFCI

NTFCIbits


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Paging Indicator Channel (PICH)

One radio frame (10 ms)

b1b0

288 bits for paging indication 12 bits (undefined)

b287b288 b299

Fixed-rate (SF=256, 3), used to carry the Paging Indicators (PI).

PICH is always associated with an S-CCPCH to which a PCH transport channel is

mapped to.

N paging indicators {PI0, , PIN-1} in each PICH frame, N=18, 36, 72, or 144.

If a paging indicator in a certain frame is set to 1, it indicates that UEs associated withthis paging indicator should read the corresponding frame of the associated S-CCPCH.


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Acquisition Indicator Channel

(AICH) Frame structure of AICHtwo frames, 20 msconsists of a repeated

sequence of 15 consecutive AS, each of length 20 symbols(5120 chips).

Each time slot consists of two partsan Acquisition-Indicator(AI) and a

part of duration 1024chips with no transmission.

Acquisition-Indicator AI have 16 kinds of Signature.

CPICH is the phase reference of AICH.

AS #14 AS #0 AS #1 AS #i AS #14 AS #0

a1 a2a0 a31 a32a30 a33 a38 a39

AI part Unused part

20 ms


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Uplink Physical Channel

Uplink Common Physical Channel

Physical Random Access Channel (PRACH)

Uplink Dedicated Physical Channel

Uplink Dedicated Physical Data Channel

(Uplink DPDCH)

Uplink Dedicated Physical Control Channel

(Uplink DPCCH) Uplink

Physical

Channel


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Physical Random Access Channel(PRACH)

The PRACH consist of 2 parts:

Preamble

one or several preamble.

Each preamble is of length 4096chips and consists of 256 repetitions of asignature whose length is 16 chips. Total of 16 signatures

SF : 256

Message part :

Two type, 10 or 20ms message part

SF : 256 - 32

Which signature is available and the length of message part are determined by

higher layer


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PRACH Transmission Structure

Message partPreamble

4096 chips10 ms (one radio frame)

Preamble Preamble

Message partPreamble

4096 chips 20 ms (two radio frames)

Preamble Preamble


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Function of physical channel

P-CCPCH-Primary common control physical channel

SCH- Synchronisation Channel

P-CPICH-Primary common pilot channel

S-CPICH-secondary common pilot channel

Cell broadcast channels

DPDCH-dedicated physical data channel

DPCCH-dedicated physical control channel

Dedicated channels

Paging channels

PICH-paging Indicator Channel

S-CCPCH-Secondary common control physical channel

PRACH-Physical random access channel

AICH-Acquisition Indicator Channel

Random access channels


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Section 1 Physical Channel Structure and Function

Section 2 Channel Mapping


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Channel Mapping

{XOR}

TransportChannels

(L1 CharacteristicsDependent)

PCH BCH FACH RACH DCH

S-CCPCHP-CCPCHPhysical

Channels PRACH DPDCH

LogicalChannels

(DataDependent)

PCCH

DCCH

DTCH

DecicatedLogicalChannel

CipherOn

BCCH CCCH CTCH

HigherLayer data

PagingSystem

InfoSignaling

CellBroadcast

Service

Signalingand

User data

DTCHDTCH


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Chapter 4 : Transmit Diversity on Physical

Channel


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Chapter 3 : Physical Layer Procedure

Section 1 Synchronisation Procedure ( Cell Search)

Section 2 Random Access Procedure


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1. Synchronization ProcedureCell Search

Slot synchronization

Frame synchronization and

code-group identification

Scrambling-code

identification

UE uses PSC to acquire slot

synchronization to a cell

UE uses SSC to find frame

synchronization and identify

the code group of the cell

found in the first step

UE determines the primary scrambling

code through correlation over the

CPICH with all codes within the

identified group, and then detects the

P-CCPCH and reads BCH information


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Chapter 3 : Physical Layer Procedure

Section 1 Synchronisation Procedure ( Cell Search)

Section 2 Random Access Procedure


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2. Random Access ProcedureRACH

Physical random access procedure

1. UE decoded BCH to find out the available RACH sub-channel, its scrambling

code and available signature.

2. Randomly select one of the RACH sub-channels from the group its access class

allows to use. Signature also selected randomly from among the available

signatures.

3. Set Preamble Retransmission Counter to Preamble_ Retrans_ Max

4. Set Preamble Initial Power

5. Transmit a preamble using the selected uplink access slot, signature, and

preamble transmission power


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2. Random Access ProcedureRACH

6. If no Acquisition Indicator received for the corresponding signature in the

downlink access slot :

Select the next available access slot in the set of available RACH sub-channels within the given access service class (ASC)

Select a signature

Increase the Commanded Preamble Power

Decrease the Preamble Retransmission Counter by one. If the Preamble

Retransmission Counter > 0 then repeat from step 6. Otherwise exit the

physical random access procedure.


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Thank You

Documents

Training Program Day1