Download - OWA200003 WCDMA Radio Interface Physical Layer

8/2/2019 OWA200003 WCDMA Radio Interface Physical Layer

1/55

HUAWEI TECHNOLOGIES CO., LTD. All rights reserved

www.huawei.com

Internal

WCDMA Radio Interface

Physical Layer

ISSUE 1.0

CHAPTER 1


2/55

HUAWEI TECHNOLOGIES CO., LTD. All rights reserved Page 1

The physical layer offers data transport

services to higher layers.

In order to provide the data transport service,

the physical layer is expected to perform the

following functions

Modulation and demodulation

Spreading and despreading

Inner - loop power control

etc.


3/55


References

TS 25.104 UTRA (BS) FDD Radio Transmission and

Reception

TS 25.201 Physical layer-general description

TS 25.211 Physical channels and mapping of

transport channels onto physical channels (FDD)

TS 25.212 Multiplexing and channel coding (FDD)

TS 25.213 Spreading and modulation (FDD)

TS 25.214 Physical layer procedures (FDD)

TS 25.308 UTRA High Speed Downlink Packet Access

(HSDPA); Overall description; Stage 2

TR 25.877 High Speed Downlink Packet Access (HSDPA)

- Iub/Iur Protocol Aspects

TR 25.858 Physical layer aspects of UTRA High Speed

Downlink Packet Access


4/55


Upon completion of this course, you will be

able to:

Understand radio interface protocol

Architecture

Understand key technology of UMTS

physical layer

Understand UMTS physical layer

procedures


5/55


Chapter 1 Physical Layer Overview

Chapter 2 Physical layer key technology

Charter 3 Physical Layer Procedures


6/55


UTRAN Protocol Structure

RNS

RNC

RNS

RNC

Core Network

Node B Node B Node B Node B

Iu Iu

Iur

Iub IubIub Iub


7/55HUAWEI TECHNOLOGIES CO., LTD. All rights reserved Page 6

Radio Interface Protocol Structure

L3

control

control

control

control

Logical

Channels

TransportChannels

C-plane signaling U-plane information

PHY

L2/MAC

L1

RLC L2/RLC

MAC

RLCRLC

RLCRLC

RLCRLC

RLC

BMC L2/BMC

control

PDCPPDCP L2/PDCP

RadioBearers

RRC


8/55


Spreading Technology

Spreading consists of 2 steps Channelization operationwhich transforms data symbols into chips.

Thus increasing the bandwidth of the signal, The number of chips per datasymbol is called the Spreading Factor (SF). The operation is done bymultiplying with OVSF code.

Scrambling operation is applied to the spreading signal .

Data bit

OVSFcode

Scrambling

code

Chips after

spreading


9/55


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 k is 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)


10/55


Scrambling Code

Scrambling codeGOLD sequence.

Scrambling code period10ms, or 38400 chips.

The code used for scrambling of the uplink

DPCCH/DPDCH may be of either long or short type,

There are 224 long and 224 short 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.

scrambling codes k = 0, 1, , 8191 are used.


11/55


Scrambling

codes for

downlink

physical

channels

Set 0

Set 1

Set 511

Primary

scrambling code 0

Secondaryscrambling code 1

Secondary

scrambling code 15

Primaryscrambling code

51116

Secondaryscrambling code

51116158192 scrambling

codes512 sets

Primary Scrambling Code

A primary scrambling code and 15 secondary scrambling codes are

included in a set.


12/55


Primary Scrambling Code Group

Primaryscramblingcodes fordownlink

physicalchannels

Group 0

Primaryscrambling code 0


8*63


63*87512 primary

scrambling codes

Group 1

Group 63

Primaryscrambling code 1

Primary scrambling

code 7

64 primary scramblingcode groups

Each group consists of 8primary scrambling codes


13/55






14/55



Section 1 Physical ChannelStructure and Functions

Section 2 Channel Mapping


15/55


WCDMA radio interface has three kinds of channels

In terms of protocol layer, the WCDMA radio interface has three typesof channel: Physical channel, transport channel and logical channel.

Logical channel: Carrying user services directly. According to the

types of the carried services, it is divided into two types: Control

channel and service channel.

Transport channel: It is the interface of radio interface layer 2 and

physical layer, and is the service provided for MAC layer by the

physical layer. According to whether the information transported is

dedicated information for a user or common information for all users, it

is divided into dedicated channel and common channel.

Physical channel: It is the ultimate embodiment of all kinds of

information when they are transmitted on radio interfaces. Each kind ofchannel which uses dedicated carrier frequency, code (spreading code

and scramble) and carrier phase (I or Q) can be regarded as a physical

channel.


16/55


Control channel

Traffic 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

Logical channel


17/55


Dedicated Channel (DCH)

-The Dedicated Channel (DCH) is an

uplink or downlink channel.

Broadcast channel (BCH)

Forward access channel (FACH)

Paging channel (PCH)Random access channel (RACH)

High-speed downlink shared channel

(HS-DSCH)

Common transport

channel

Dedicated transportchannel

Transport channel


18/55


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


19/55


Downlink Physical Channel

Downlink Dedicated Physical Channel

(Downlink DPCH)

Downlink Common Physical Channel

Common Control Physical Channel (CCPCH)

Synchronization Channel (SCH)

Paging Indicator Channel (PICH)

Acquisition Indicator Channel (AICH)

Common Pilot Channel (CPICH)High-Speed Physical Downlink Shared

Channel (HS-PDSCH)

High-Speed Shared Control Channel (HS-SCCH)

DownlinkPhysical Channel


20/55


Uplink Physical Channel

Uplink Dedicated Physical Channel

Uplink Dedicated Physical Data Channel

(Uplink DPDCH)

Uplink Dedicated Physical Control Channel

(Uplink DPCCH)

High-Speed Dedicated Physical Control

Channel (HS-DPCCH)

Uplink Common Physical Channel Physical Random Access Channel (PRACH)

Uplink PhysicalChannel


21/55


Function of physical channel

Node B UE

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

HS-DPCCH-High speed dedicated physical control channel

HS-SCCH-High speed share control channel

HS-PDSCH-High speed physical downlink share channel

High speed downlink share channels

P-CPICH-Primary common pilot channelS-CPICH-Secondary common pilot channel

Cell broadcast channels

P-CCPCH-Primary common control physical channel

SCH- Synchronisation Channel


22/55


Primary Synchronization Channel (P-SCH)

Used for cell search Two sub channels: P-SCH and S-SCH.

SCH is transmitted at the first 256 chipsof every time slot.

PSC is transmitted repeatedly in eachtime slot.

SSC specifies the scrambling codegroups of the cell.

SSC is chosen from a set of 16different codes of length 256, thereare altogether 64 primary scramblingcode groups.

PrimarySCH

SecondarySCH

Slot #0 Slot #1 Slot #14

acsi,0

pac pac pac

acsi,1 acsi,14

256 chips

2560 chips

One 10 ms SCH radio frame


23/55


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

Group 0 1 1 2 8 9 10 15 8 10 16 2 7 15 7 16

Group 1 1 1 5 16 7 3 14 16 3 10 5 12 14 12 10

Group 2 1 2 1 15 5 5 12 16 6 11 2 16 11 15 12

Group 3 1 2 3 1 8 6 5 2 5 8 4 4 6 3 7

Group 4 1 2 16 6 6 11 15 5 12 1 15 12 16 11 2

Group 61 9 10 13 10 11 15 15 9 16 12 14 13 16 14 11

Group 62 9 11 12 15 12 9 13 13 11 14 10 16 15 14 16

Group 63 9 12 10 15 13 14 9 14 15 11 11 13 12 16 10

Secondary Synchronization Channel (S-SCH)

..

2560 chips

acp

Slot # ?P-SCH acp

Slot #?

16 6S-SCHacp

Slot #?

11 Group 2Slot 7, 8, 9

256 chips


24/55


Common Pilot Channel (CPICH)

Common Pilot Channel (CPICH)

Carries pre-defined sequence.

Fixed rate 30Kbps SF=256

Primary CPICH

Uses the fixed 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 other physical channels

Pre-defined symbol sequence

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

Tslot= 2560 chips, 20 bits

1 radio frame: Tr = 10 ms

P i C C l Ph i l Ch l (PCCPCH)


25/55


Primary Common Control Physical Channel (PCCPCH)

Fixed rate, fixed OVSF code30kbpsCch,256,1

Carry BCH transport channel The PCCPCH is not transmitted during the first 256 chips of each time slot.

STTD transmit diversity may be used

PCCPCH Data

18 bits


1 radio frame: Tf

= 10 ms

256 chips

Tslot

= 2560 chips, 20 bits

SCH

P i I di Ch l (PICH)


26/55


Paging Indicator Channel (PICH)

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 10ms consists 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

indicator should read the corresponding frame of the associated S-CCPCH.

One radio frame (10 ms)

b1b0

288 bits for paging indication 12 bits (undefined)

b287 b288 b299

S d C C t l Ph i l Ch l (SCCPCH)


27/55


Secondary Common Control Physical Channel (SCCPCH)

Carry FACH and PCH.

Two kinds of SCCPCH: with or 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 thesame or separate SCCPCHs. Ifmapped to the same S-CCPCH, theycan be mapped to the same fame.

DataN bits


1 radio frame: T f = 10 ms

T slot = 2560 chips,

Data

PilotN bitsPilotN bits

TFCITFCI

20*2 k bits (k=0..6)

Ph i l R d A Ch l (PRACH)


28/55


Physical Random Access Channel (PRACH)

The random-access transmission data consists

of two parts:

One or several preambleseach preamble

is of length 4096chips and consists of 256

repetitions of a signature whose length is

16 chips16 available signatures totally

10 or 20ms message part

Which signature is available and the length

of message part are determined by higher

layer

PRACH T i i St t


29/55


PRACH Transmission Structure

Message partPreamble

4096 chips10 ms (one radio frame)

Preamble Preamble

Message partPreamble

4096 chips 20 ms (two radio frames)

Preamble Preamble

PRACH A Ti l t St t


30/55


PRACH Access Timeslot Structure

#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

PRACH M St t


31/55


PRACH Message Structure

Pilot

N bits

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

Message part radio frame TRACH = 10 ms

Tslot = 2560 chips, 10*2

Pilot

TFCI

N bitsTFCI

Data

Ndata

bitsData

Control

kbits (k=0..3)

A i iti I di t Ch l (AICH)


32/55


Acquisition Indicator Channel (AICH)

Frame structure of AICH

two frames, 20 ms, consists of a repeatedsequence 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

Uplink Dedicated Ph sical Channel (DPDCH&DPCCH)


33/55


Uplink Dedicated Physical Channel (DPDCH&DPCCH)

DPDCH and DPCCH are I/Q code multiplexed within each 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

Each DPCCH time slot consists of Pilot, TFCIFBITPC

Frame Structure of Uplink DPDCH/DPCCH


34/55


Frame Structure of Uplink DPDCH/DPCCH

Pilot

Npilot

bits

TPCNTPC bits

DataNdatabits


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

1 radio frame: Tf = 10 ms

DPDCH

DPCCHFBI

NFBI bitsTFCI

NTFCI bits

Downlink Dedicated Physical Channel (DPDCH DPCCH)


35/55


Downlink Dedicated Physical Channel (DPDCH+DPCCH)

DCH consists of dedicated data and control information.

Control information includesPilotTPCTFCI.

The spreading factor of DCH can be from 512 to 4,and can be

changed during connection

DPDCH and DPCCH is time multiplexed.

Frame Structure of Downlink DPCH


36/55


Frame Structure of Downlink DPCH

One radio frame, Tf = 10 ms


Tslot = 2560 chips, 10*2k bits (k=0..7)

Data2

Ndata2 bits

DPDCH

TFCI

NTFCI bits

Pilot

Npilot bitsData1

Ndata1 bits

DPDCH DPCCH DPCCH

TPC

NTPC bits

High Speed Physical Downlink Shared Channel (HS PDSCH)


37/55


High-Speed Physical Downlink Shared Channel (HS-PDSCH)

Bear service data and layer2 overhead bits mapped from the transportchannel

SF=16, can be configured several channels to increase data service

Slot #0 Slot#1 Slot #2

Tslot= 2560 chips, M*10*2k

bits (k=4)

Data

Ndata1bits

1 subframe: Tf= 2 ms

High Speed Shared Control Channel (HS SCCH)


38/55


High-Speed Shared Control Channel (HS-SCCH)

HS-SCCH is a fixed rate (60 kbps, SF=128) downlink physicalchannel used to carry downlink signalling related to HS-DSCH

transmission

Slot #0 Slot#1 Slot #2

Tslot= 2560 chips, 40bits

Data

Ndata1bits

1 subframe: Tf= 2 ms

High Speed Dedicated Physical Control Channel (HS DPCCH )


39/55


High-Speed Dedicated Physical Control Channel (HS-DPCCH )

HS-DPCCH carries information to acknowledge downlink transport

blocks and feedback information to the system for scheduling and link

adaptation of transport block

CQI and ACK/NACK

Physical Channel, Uplink, SF=256, power control

Subframe #0 Subframe #i Subframe #4

HARQ-ACK CQI

One radio frame Tf= 10 ms

One HS-DPCCH subframe (2 ms)

2Tslot= 5120 chipsTslot= 2560 chips


40/55



Section 1 Physical Channel Structure and Functions

Section 2 Channel Mapping

Mapping Between Channels


41/55


Mapping Between Channels

Logical channels Transport channels Physical channels

BCCH BCH P-CCPCH

FACH S-CCPCH

PCCH PCH S-CCPCH

CCCH RACH PRACH

FACH S-CCPCH

CTCH FACH S-CCPCH

DCCH, DTCH DCH DPDCH

HS-DSCH HS-PDSCH

RACH, FACH PRACH, S-CCPCH


42/55





Synchronization Procedure - Cell Search


43/55


Synchronization Procedure - Cell Search

Frame synchronization andcode-group identification

Scrambling-codeidentification

UE uses SSC to find framesynchronization and identify thecode group of the cell found inthe first step

UE determines the primary scramblingcode through correlation over theCPICH with all codes within theidentified group, and then detects theP-CCPCH and reads BCH information

Slot synchronization

UE uses PSC to acquire slotsynchronization to a cell

Synchronization Procedure - Channel Timing Relationship


44/55


Synchronization Procedure Channel Timing Relationship

AICH accessslots

SecondarySCH

PrimarySCH

tS

-CCPCH,k

10 ms

tPICH

#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 DPCHtDPCH,n

Random access procedure


45/55


Random access procedureSTART

Choose a RACH sub channel fromavailable ones

Get available signatures

Set Preamble Retrans Max

Set Preamble _ Initial _ Power

Send a preamble

Check the corresponding AI

Increase message part power by p-m based on preamble power

Set physical status to be RACHmessage transmitted Set physical status to be Nack

on AICH received

Choose a access slot again

Counter> 0

Choose a signature andincrease preamble transmit power

Set physical status to be Nackon AICH received

Get negative AI

No AI

Report the physical status to MAC

END

Get positive AI

The counter of preamble retransmit

Subtract-1, Commanded preamble powerincreased by Power Ramp Step

N

Y

Send the corresponding message part

Random Access Procedure - RACH


46/55


Random Access Procedure RACH

Physical random access procedure1. Derive the available uplink access slots, in the next full access

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 correspondingto 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

2. Randomly select a signature from the set of available signatures

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

Retrans_ Max



47/55



4. Set the parameter Commanded Preamble Power toPreamble_Initial_Power

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

signature, and preamble transmission power.

6. If no positive or negative acquisition indicator (AI +1 nor1)

corresponding to the selected signature is detected in the downlinkaccess slot corresponding to the selected uplink access slot:

A: Select the next available access slot in the set of available

RACH sub-channels within the given ASC;

B: select a signature;

C: Increase the Commanded Preamble Power; D: 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.



48/55



7. If a negative acquisition indicator corresponding to the

selected signature is detected in the downlink access slot

corresponding to the selected uplink access slot, exit the

physical random access procedure Signature

8. If a positive acquisition indicator corresponding to the

selected signature is detected , Transmit the random

access message three or four uplink access slots after the

uplink access slot of the last transmitted preamble9. exit the physical random access procedure

Transmit Diversity Mode


49/55


Transmit Diversity Mode

Application of Tx diversity modes on downlink physical channel

Physical channel type Open loop mode Closed loop mode

TSTD STTD Mode 1 Mode 2

P-CCPCH applied

SCH applied

S-CCPCH applied

DPCH applied applied applied

PICH applied

HS-PDSCH applied applied

HS-SCCH applied

AICH applied

Transmit Diversity - STTD


50/55


Transmit Diversity STTD

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 bits

for antenna 1 and antenna 2.

Transmit Diversity - TSTD


51/55


Transmit Diversity TSTD

Time switching transmit diversity (TSTD) is used only on SCH channel.

Antenna 1

Antenna 2

acsi,0

acp

acsi,1

acp

acsi,14

acp

Slot #0 Slot #1 Slot #14

acsi,2

acp

Slot #2

(Tx OFF) (Tx OFF)(Tx OFF)

(Tx OFF)

(Tx OFF)

(Tx OFF)(Tx OFF)(Tx OFF)

Closed Loop Mode


52/55


Closed Loop Mode

Transmit Diversity - Closed Loop Mode


53/55


y p

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 FBIfield 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 pilotsymbols of two antennas are different (orthogonal)

2mode 2 uses phase/amplitude adjustment the dedicated

pilot symbols of two antennas are the same.

Summary


54/55


Su a y

This chapter mainly explained:

Uu Interface structure

Different physical channels function and

structure

Summary


55/55

www.huawei.com

Thank You