03 UMTS Radio Interface Physical Layer

8/12/2019 03 UMTS Radio Interface Physical Layer

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Huawei Confidential February 23, 2006

UMTS Radio InterfacePhysical Layer


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Course Contents

Chapter 1 Physical Layer Overview

Chapter 2 Physical Channels and Channel Mapping

Chapter 3 Physical Layer Processing Procedure

Chapter 4 Physical Layer Procedure


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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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Air Interface Protocol Structure

Radio Resource Control (RRC)

Medium Access Control

Transport channels

Physical layerControl/Measurements

Layer 3

Logical channelsLayer 2

Layer 1


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Data Processing at Physical Layer

Data from MAC

LayerTB

Channel coding

and multiplexing

Spreading and

modulation


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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 CDMA 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 DLPhysical Channel

Frequency,code,phase


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Spreading Technology

Spreading consists of 2 steps

Channelization operationwhich transforms datasymbols 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 bymultiplying with OVSF code.

Scrambling operation is applied to the spreading signal .

Data

bit

OVSF

code

Scrambling

code

Chips

after

spreading


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Channelization Code

OVSF code is used as channelizaiton 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 codeGOLD sequence. Scrambling code period : 10ms ,or 38400 chips.

The code used for scrambling of the uplink

DPCCH/DPDCH may be of either long or short 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. scramblingcodes k = 0, 1, , 8191 are used.

Scrambling Code


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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

51116158192

scrambling

codes

512 sets

A primary scrambling code and 15 secondary scrambling codes are included in a set.

Primary Scrambling Code


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Group 0

Groupe1

Group 63

512 primary

scrambling codes

64 primary scrambling

code groupsEach group consists of 8

primary scrambling codes

Primary Scrambling Code Group

Primary

scramblingcodes for

downlink

physical

channels





8*63


63*87


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Course Contents






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2.1 Physical Channel

Structure and Function

2.2 Channel Mapping


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Downlink Physical Channel

Downlink Common Physical Channel

Common Control Physical Channel (CCPCH)

Synchronization Packet Channel (SCH)

Physical Downlink Shared Channel (PDSCH)

Paging Indicator Channel (PICH)

Acquisition Indicator Channel (AICH)Common Pilot Channel (CPICH)

Downlink Dedicated Physical Channel

(Downlink DPCH)

Downlink

Physical

Channel


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Uplink Physical Channel

Uplink Common Physical Channel

Physical Random Access Channel (PRACH)

Physical Common Packet Channel (PCPCH)

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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Synchronization Channel (SCH)

Used for cell search

Two sub channels: P-SCHand S-SCH.

SCH is transmitted at the first

256 chips of every time slot.

PSC is transmittedrepeatedly 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 64primary scrambling 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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Common Pilot Channel(CPICH)

Common Pilot CHannel (CPICH)

Carries pre-defined sequence.

Fixed rate 30KBPSSF=256

The CPICH uses the same channel and scrambling code but

different sequences in the case transmit diversity is used on

downlink channel

slot #1

Frame#i+1Frame#i

slot #14

A A A A A A A A A A A A A A A A A A A A A A A A

-A -A A A -A -A A A -A A -A -A A A -A -A A A -A -A A A -A -AAntenna 2

Antenna 1

slot #0

Frame Boundary


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Primary CPICH

Uses the same channel 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.

Common Pilot Channel (CPICH)


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Fixed rate30kbpsSF=256

Carry BCH transport channel

The PCCPCH is 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

Primary Common Control Physical Channel

(P-CCPCH)


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Paging Indicator Channel (PICH)

One radio frame (10 ms)

b1b0

288 bits for paging indication 12 bits (undefined)

b287b288 b299


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Paging Indicator Channel

PICH is a fixed-rate(SF=256) physical channel used

to carry the Paging Indicators (PI).

PICH is always associated with an S-CCPCH to

which a PCH transport channel is mapped.

Frame structure of PICHone frame of length 10msconsists of 300 bits of which 288 bits are used to

carry paging indicators and the remaining 12 bits are

not defined.

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 with this paging


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Secondary Common Control Physical Channel

(S-CCPCH)

Carry FACH and PCH.

Two kinds of SCCPCH: withor without TFCI. UTRAN

decides if a TFCI should be

transmitted, UE must support

TFCI.

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 be mappedto the same fame.


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

PilotNpilotbits

DataNdatabits


TFCINTFCIbits


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Physical Random Access Channel (PRACH)

The random-access transmission data

consists of two parts:

One or several preambleseach preamble is oflength 4096chips and consists of 256 repetitions

of a signature whose length is 16 chips16available signatures totally

10 or 20ms message partWhich signature is available and the length of

message part are determined by higher layer


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PRACH Access Timeslot Structure

#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14

5120 chips

radio frame: 10 ms radio frame: 10 ms

Access slot #0 Random Access Transmission

Access slot #1

Access slot #7

Access slot #14

Random Access Transmission

Random Access Transmission

Random Access TransmissionAccess slot #8


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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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Pilot

Npilotbits

Data

Ndatabits


Tslot= 2560 chips, 10*2k

bits (k=0..3)

Message part radio frame TRACH= 10 ms

Data

ControlTFCI

NTFCIbits

PRACH Message Structure


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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 20symbols(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 Dedicated Physical Channel

DPDCH and DPCCH are I/Q code multiplexed withineach radio frame

DPDCH carries data generated at Layer 2 and

higher layer

DPCCH carries control information generated at

Layer 1

Each frame is 10ms and consists of 15 time slots,

each time slot consists of 2560 chips

The spreading factor of DPDCH is from 4 to 256

The spreading factor of DPDCH and DPCCH can be

different in the same Layer 1 connection


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Frame Structure of Uplink DPDCH/DPCCH

PilotNpilotbits

TPC

NTPCbits

DataNdatabits


Tslot= 2560 chips, 10*2kbits (k=0..6)


DPDCH

DPCCHFBI

NFBIbitsTFCI

NTFCIbits


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Functions of Uplink DPDCH/DPCCH

DCHData

DPDCH

DPCCH

Provide control data

for DPDCH, such as

demodulation, powercontrol, etc

Data bearerat physical layer


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Downlink Dedicated Physical Channel

DCH consists of dedicated data and control

information.

Control information includesPilotTPC

TFCI(optional).

The spreading factor of DCH can be from 512 to 4,andcan be changed during connection

DPDCH and DPCCH is time multiplexed.

Multi-code transmission within one CCTrCH uses the

same spreading factor. In this case, the DPCH control

information is transmitted only on the first downlink

DPCH.

Different CCTrCH can use different spreading factors

F St t f D li k DPCH


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Frame Structure of Downlink DPCH

One radio frame, Tf= 10 ms


Tslot= 2560 chips, 10*2

k

bits (k=0..7)

Data2

Ndata2bits

DPDCH

TFCI

NTFCIbits

Pilot

NpilotbitsData1

Ndata1bits

DPDCH DPCCH DPCCH

TPC

NTPCbits


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Functions of Downlink DPDCH/DPCCH

DCH

dataDPDCH

DPCCH

Provide control data

for DPDCH ,such as

demodulation, power

control,etc.

Data bearerat physical layer

DCH

data


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2.1 Physical Channel

Structure and Function

2.2 Channel Mapping

Cl ifi ti f T t Ch l


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Classification of Transport Channel

Broadcast Channel (BCH)

Forward Access Channel (FACH)

Paging Channel (PCH)

ReverseRandomAccess Channel (RACH)

Common Packet Channel (CPCH)Downlink Shared Channel (DSCH)

Dedicated Channel (DCH)

DCH may be UL or DL

Common

transport channel

Dedicated

transport channel


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{XOR}

TransportChannels

(L1 CharacteristicsDependent)

PCH BCH FACH RACH DCH

S-CCPCHP-CCPCHPhysical

ChannelsPRACH DPDCH

LogicalChannels

(DataDependent)

PCCH

DCCH

DTCH

DecicatedLogicalChannel

CipherOn

BCCH CCCH CTCH

HigherLayer data

Paging SystemInfo

Signalling CellBroadcastService

Signallingand

User data

DTCHDTCH

Channel Mapping

C C t t


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Course Contents






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3.1 Coding and multiplexing

technology

3.2 Spreading technology 3.3 Modulation technology


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Transport channel multiplexing structure for downlink

102040 or 80ms

data

data

data

TrCH-i

dataCRC dataCRC dataCRC

dataCRCdataCRC dataCRCd a t aCBL CBL CBL

0816 or 24bits

Size Z

512KtailConventional code

5120KtailTurbo code

CedBL CedBL CedBLCoded data Conventional code orTurbo code

Rate matched data

Rate matched data DTXor

or

Data before 1stinterleavingData after 1stinterleaved

TrCH-1 TrCH-2 TrCH-ICCTrCHTrCH-1 TrCH-2 TrCH-I DTXCCTrCH

Ph-1 Ph-2 Ph-P

10ms

10msPh-1 Ph-2 Ph-P

TPC TFCI pilot

Spreading

Scrambling

TrCH-i+1

data1 data2 TPC TFCI pilotdata1 data2 TPC TFCI pilotdata1 data2

Radioframe

The number frames1

24 or 8Radioframe

Radioframe

Spreading

Scrambling

Spreading

Scrambling

CRC of TB


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Error detection is provided on transport blocks

through a Cyclic Redundancy Check (CRC)

CRC size is informed by higher layer signal

08121624(optional)

If no TB are input, no CRC bits should be attached.

If TB are input with TB SIZE=0,CRC bits shall be

added, i.e. all parity bits equal to zero.

CRC of TB


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TB Concatenation and Code Block Segmentation

All transport blocks in a TTI are serially

concatenated .

The maximum size of the code blocks depends on

whether convolutional coding or turbo coding is

used for the TrCH .

Convolutional code: if TBS SIZE>504,segmented to

multiple code block of the same size.

Turbo code:if TBS SIZE>5114, segmented to multiple

code block of the same size.

No coding:no segmentation

If codes cannot be segmented evenly, fill in 0 bits

at the beginning of the first code block.

If the code block length of Turbo code


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Channel coding

The following channel coding schemes can be applied

to TrCHs:

Convolutional coding, coding rates 1/3 and 1/2 are

defined

Turbo coding, The coding rate of Turbo coder is 1/3

No coding

Usage of coding

BCHPCH and RACH1/2 Convolutional coding CPCHDCHDSCH and FACH1/2or1/3

Convolutional coding ,1/3Turbo coding, no coding

Rate Matching


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Rate Matching

Rate matching means that bits on a transportchannel are repeated or punctured.

The number of bits on a transport channel can vary

between different transmission time intervals. In the

downlink the transmission is interrupted if the

number of bits is lower than maximum. When the

number of bits between different transmission time

intervals in uplink is changed, bits are repeated orpunctured to ensure that the total bit rate after TrCH

multiplexing is identical to the total channel bit rate of

the allocated dedicated physical channels.


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Interleaving

Functionreduce the influence of fast fading. Two kinds of interleaving1st interleaving and 2nd

interleaving

The length of 1st interleaving is TTI of TrCH, 1st

interleaving is a inter-frame interleaving

The length of 2nd interleaving is a physical frame , 2nd

interleaving is a intra-frame interleaving.

Radio Frame Segmentation


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Radio Frame Segmentation

When the transmission time interval is longer than 10

ms, the input bit sequence is segmented and mapped

onto consecutive Fi radio frames.

Following radio frame size equalisation in the UL the

input bit sequence length is guaranteed to be aninteger multiple of Fi.

Following rate matching in the DL the input bit

sequence length is guaranteed to be an integer

multiple of Fi.


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Multiplexing of TrCH

Every 10 ms, one radio frame from each TrCH is

delivered to the TrCH multiplexing. These radio

frames are serially multiplexed into a coded

composite transport channel (CCTrCH)

The format of CCTrCH is indicated by TFCI TrCH can have different TTI before multiplexing

2 types of CCTrCH:Common and dedicated

Common CCTrCH should be multiplexed by common

TrCH;

Dedicated CCTrCH should be multiplexed by dedicated

TrCH

There is only one CCTrCH in uplink and one or

several CCTrCH in downlink for one user

Insertion of discontinuous transmission (DTX) indication


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Insertion of discontinuous transmission (DTX) indication

bits

In the downlink, DTX is used to fill up the radio frame

with bits.

DTX indication bits only indicate when the

transmission should be turned off, they are not

transmitted. 1st insertion of DTX indication bits

This step of inserting DTX indication bits is used only if

the positions of the TrCHs in the radio frame are fixed

2nd insertion of DTX indication bits

The DTX indication bits inserted in this step shall be

placed at the end of the radio frame.


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Physical Channel Segmentation and Mapping

When multiple physical channels are used, one

CCTrCH radio frame can be divided into multiplephysical framesmulticode transmission

Each physical channel of multicode transmission must

have the same SF

DPCCH and DPDCH of uplink physical channel is code

multiplexed.

DPCCH and DPDCH of downlink physical channel is

time multiplexed Uplink physical channel must be fully filled except when

cpmpressed mode is used

In downlink, the PhCHs do not need to be completely

filled with bits that are transmitted over the air. Values


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Physical Channel Forming Before Spreading

Each TrCH can carry different service data, several TrCHs

can be multiplexed into a CCTrCH, so WCDMA support

several service share a physical connection.

CCTrCH mapping to data part of physical channel.

TFCI,TPC and pilot bits generated at physical layer mappingto control part of physical channel ,and then spreading and

scrambling, transmitting at air interface at last.

Example of Coding and Multiplexing


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The number of TrChs 3

Transport block size 81, 103, and 60 bits

CRC 12 bits (attached only to TrCh#1)

Coding CC, coding rate = 1/3 for TrCh#1, 2 coding rate =1/2 for TrCh#3

TTI 20 ms

Transport block size 148 bits

Transport block set size 148 bits

CRC 16 bits

Coding CC, coding rate = 1/3

TTI 40 ms

Parameters for

12.2kb/s AMR speech

Parameters for

3.4kb/s control channel



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TrCh#1Transport block

CRC attachment

CRC

Tail bit attachment

Convolutionalcoding R=1/3, 1/2

Rate matching

81

81

303

Tail

893

303+NRM11stinterleaving

12

Radio framese mentation

#1a

To TrCh Multiplexing

303 +NRM1

RF1= (303 +NRM1)/2

RF2= (333+ NRM2)/2

RF3= (136+ NRM3)/2

#1b

TrCh#2

103

103

333

Tail

8103

333 +NRM2

#2a

TrCh#3

60

60

136

Tail

860

136 +NRM3

#3a136 +NRM3

#3b333 +NRM2

#2bRF1 RF1 RF2 RF2 RF3 RF3

Example of Coding and Multiplexing(3.4kbps)


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Example of Coding and Multiplexing(3.4kbps)

Transport block

CRC attachment

CRC

Convolutional

coding R=1/3

Rate matching

148

148

516*B

Tail

8*B

(516+NRM)*B

1stinterleaving

16 bits

Radio framesegmentation

#1

[ (129+NRM)*B+NDI]/

4

To TrCh Multiplexing

(516+NRM)*B+NDI

#2 #4

Tail bit attachment

164*B

#3

TrBk concatination B TrBks (B =0,1)

164*B

(516+NRM)*B+NDI

Insertion of DTXindication*

[ (129+NRM)*B+NDI]/

4

[ (129+NRM)*B+NDI]/

4

[ (129+NRM)*B+NDI]/

4

* Insertion of DTX indication is used only if the position of the TrCHs in the radio frame is fixed.



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12.2 kbps data 3.4 kbps data

TrCH

multiplexing

30 ksps DPCH

2nd

interleaving

Physical channel

mapping

#1#1a #1c

1 2 15

CFN=4Nslot

Pilot symbol TPC

1 2 15

CFN=4N+1slot

1 2 15

CFN=4N+2slot

1 2 15

CFN=4N+3slot

#1b #2#2a #2c#2b #3#1a #1c#1b #4#2a #2c#2b

#1a #2a #1b #2b #1c #2c #1a #2a #1b #2b #1c #2c #1 #2 #3 #4

510 510 510 510

12.2 kbps data


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technology


Uplink DPCCH/DPDCH Spreading


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Uplink DPCCH/DPDCH Spreading

I

cd,1 d

Slong,nor Sshort,n

I+jQ

DPDCH1

Q

cd,3 d

DPDCH3

cd,5 d

DPDCH5

cd,2 d

DPDCH2

cd,4 d

DPDCH4

cd,6 d

DPDCH6

cc c

DPCCH

The DPCCH is always spread by code cc = Cch,256,0

When only 1 DPDCH exists,(Cd,1 =Cch,SF,k)k=SF/4

The code used for scrambling of the uplink

DPCCH/DPDCH may be of either long or short type

PRACH Spreading


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PRACH Spreading

Message part is shown in the following figure

the value of gain factors is the same with

DPDCH/DPCCH

ccc

cd d

Sr-msg,n

I+jQ

PRACH message

control part

PRACH message

data partI

Downlink Spreading


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p g

I

Data ofphysicalchannelexceptSCH

S

P

Cch,SF,m

Sdl,n

Q

I+jQ S

Downlink physical channel except SCH is first serial-to-parallel

converted , spread by the spreading code, and then scrambledby a complex-valued scrambling code.

The beginning chip of the scrambling code is aligned with the

frame boundary of P-CCPCH.

Each channel have different gain factor


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Downlink Spreading

Different physical

annel come from point S G1

G2

GP

GS

S-SCH

P-SCH

Ch t 3 Ph i l L P i P d


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technology


Uplink Modulation


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p

S

Im{S}

Re{S}

cos(t)

Complex-

valued

sequence

after

spreading

-sin(t)

Split

real &

imag

parts

Pulse

shaping

Pulse

shaping

The chip rate is 3.84Mbps

In the uplink, the complex-valued chip sequence generated

by the spreading process is QPSK modulated

Downlink Modulation


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The chip rate is 3.84Mbps

In the downlink, the complex-valued chip sequence

generated by the spreading process is QPSK

modulated

S

Im{S}

Re{S}

cos(t)

Complex-

valued

sequence

after

spreading

-sin(t)

Split

real &

imag

parts

Pulse

shaping

Pulseshaping

Course Contents


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Synchronization ProcedureCell Search

Slot synchronization

Frame synchronization andcode-group identification

Scrambling-code

identification

UE uses PSC to acquire slot

synchronization to a cell

UE uses SSC to find frame

synchronization and identifythe 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

Synchronization ProcedureChannel Timing


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Relationship

AICH accessslots

SecondarySCH

PrimarySCH

S-CCPCH,k

10 ms

PICH

#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4

P-CCPCH, (SFN modulo 2) = 0 P-CCPCH, (SFN modulo 2) = 1

Any CPICH

k:th S-CCPCH

PICH for k:th S-CCPCH

n:th DPCHDPCH,n

Any PDSCH

Synchronization ProcedureCommon Channel

S h i i


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Synchronization

Common Channel Synchronization

The following physical channels have the same frame timing

SCH(Primary and secondary)

CPICH(Primary and secondary)

P-CCPCH

PDSCH

P-CCPCHs radio frame timing is acquired by cell searchThe

P-CCPCH on which the cell SFN is transmitted is used as timing

reference for all the physical channels

Synchronization ProcedureDedicated Channel

S h i ti


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Synchronization

Synchronization time relations of DPCH

Different downlink DPCHs timing could be different, the

offset between the frame timing of DPCH and P-CCPCH

should be integer multiple of 256 chips, i.e,

tDPCH,n=Tn*256 chipsTn={0,1,...149} On UE side the transmitting time of uplink

DPCCH/DPDCH is T0(1024chips) after the 1st downlink

detected path All UL DPCCH/DPDCHs from one UE have the same

framing timing.

Random Access ProcedureRACH


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Physical random access procedure

1 Derive the available uplink access slots, in the next fullaccess slot set, for the set of available RACH sub-channels

within the given ASC. Randomly select one access slot

among the ones previously determined. If there is no

access slot available in the selected set, randomly select

one uplink access slot corresponding to the set of available

RACH sub-channels within the given ASC from the next

access slot set. The random function shall be such that

each of the allowed selections is chosen with equal

probability 2Randomly select a signature from the set of available

signatures within the given ASC. 3Set the Preamble Retransmission Counter to Preamble_

Retrans_ Max



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4Set the parameter Commanded Preamble Power toPreamble_Initial_Power

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

6If no positive or negative acquisition indicator (AI +1 nor1) corresponding to the selected signature is detected in the

downlink access slot corresponding to the selected uplink

access slot:

aSelect the next available access slot in the set ofavailable RACH sub-channels within the given ASC

bselect a signature cIncrease the Commanded Preamble Power dDecrease the Preamble Retransmission Counter by one.

If the Preamble Retransmission Counter > 0 then repeat

from step 6. Otherwise exit the physical random access



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7If a negative acquisition indicator corresponding tothe selected signature is detected in the downlinkaccess slot corresponding to the selected uplink

access slot, exit the physical random access procedure

Signature

8 If a positive acquisition indicator corresponding tothe selected signature is detected , Transmit the

random access message three or four uplink access

slots after the uplink access slot of the last transmitted

preamble

9exit the physical random access procedure

Transmit diversity Mode


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y

Application of Tx diversity modes on downlink physical channel

Physical channel type Open loopmode

Open loopmode

Closedloop

TSTD STTD Mode

P-CCPCH - applied -

SCH applied - -

S-CCPCH - applied -

DPCH - applied applied

PICH - applied -

PDSCH - applied applied

AICH - applied -

CSICH - applied -

Transmit Diversity-STTD


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Space time block coding based transmit antenna

diversity(STTD 4 consecutive bits b0, b1, b2, b3 using STTD coding

b0 b1 b2 b3

b0 b1 b2 b3

-b2 b3 b0 -b1

Antenna 1

Antenna 2

Channel bits

STTD encoded channel bitsfor antenna 1 and antenna 2.

T it Di it TSTD


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Transmit Diversity-TSTD

Time switching transmit diversity (TSTD) is used

only on SCH channel.

Antenna 1

Antenna 2

acs,

acp

acs,

acp

acs,

acp

Slot #0 Slot #1 Slot #14

acs,

acp

Slot #2

(Tx OFF)(Tx OFF)

(Tx OFF)(Tx OFF)

(Tx OFF)(Tx OFF)

(Tx OFF)(Tx OFF)

Transmit DiversityClosed Loop Mode


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Closed loop mode transmit diversity

Used in DPCH and PDSCH Channel coding, interleaving and spreading are done as

in non-diversity mode. The spread complex valued

signal is fed to both TX antenna branches, and

weighted with antenna specific weight factors w1 and w2.

The weight factors are determined by the UE, and

signalled to the UTRAN access point (=cell transceiver)

using the D-bits of the FBI field of uplink DPCCH.

The calculation of weight factor is the key point of

closed loop Tx diversity.there are two modes with

different calculation methods of weight factor 1mode 1 uses phase adjustmentthe dedicated pilot

symbols of two antennas are different(orthogonal)


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03 UMTS Radio Interface Physical Layer

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