Wcdmaphysicallayer 111120031701-phpapp02

WCDMA Physical Layer Design
A. Chockalingam
Assistant Professor
Indian Institute of Science, Bangalore-12
achockal@ece.iisc.ernet.in
http://ece.iisc.ernet.in/~achockal

Dr. A. Chockalingam Dept of ECE, IISc, Bangalore 2
Outline
WCDMA Network ArchitectureWCDMA Network Architecture
WCDMA Physical LayerWCDMA Physical Layer
– Physical / Transport / Logical ChannelsPhysical / Transport / Logical Channels
– UplinkUplink
» Spreading - Channelisation / ScramblingSpreading - Channelisation / Scrambling
» Transport Formats and ConfigurationTransport Formats and Configuration
» Multiplexing and Channel CodingMultiplexing and Channel Coding
– DownlinkDownlink
» Spreading / Scrambling / ChannelisationSpreading / Scrambling / Channelisation
» Multiplexing and Channel CodingMultiplexing and Channel Coding

2G to 3G Evolution
IS-95AIS-95A IS-95BIS-95B cdma2000cdma2000
IMT2000IMT2000
IMT2000: ITU’s Standardization Effort towards 3GIMT2000: ITU’s Standardization Effort towards 3G
(IMT-2000 previously termed as FPLMTS)
UMTS:UMTS: European Effort (Specified by 3G Partnership Project 3GPP)
GSMGSM GPRSGPRS
WCDMAWCDMA
EDGEEDGE
DD
AA
TT
AA
II
SS
99
99

UMTS NW Model
USIM
Mobile
Equipment
Access
Network
Serving
Network
PS/CS
Transit
Network
CuCu UuUu IuIu YuYu
User EquipmentUser Equipment Access NetworkAccess Network Core NetworkCore Network
InfrastructureInfrastructure
Home
Network
Access StratumAccess Stratum
(Protocols between UE and Access NW)
Non-access StratumNon-access Stratum
(Protocols between UE and Core NW)
ZuZu
Stratum:Stratum: Refers to a way of
grouping protocols handling activities

UMTS NW Architecture
Node B
UE
UE
UE
Node B
Node B
Node B
RNC
RNC
UTRAN
RNS
RNS
CN
CN (CS Domain)
CN (PS Domain)
SGSN GGSN
Registers
HLR/AuC/EIR
(Home Network)
3G MSC
/ VLR
3G
GMSC
UuUu IuIu
IurIur
IubIub

WCDMA System Features
UTRA FDD mode and TDD modeUTRA FDD mode and TDD mode
UTRA FDD featuresUTRA FDD features
– Multiple Access:Multiple Access: CDMACDMA
– Channel Spacing:Channel Spacing: 5 MHz5 MHz
– Chip Rate:Chip Rate: 3.84 Mcps3.84 Mcps
– Frame Length:Frame Length: 10 msec10 msec
– Time Slots:Time Slots: 15 slots per 10 msec frame15 slots per 10 msec frame
– Spreading Factor:Spreading Factor: 4 to 5124 to 512
– Multi-rate:Multi-rate: Through Multi-code orThrough Multi-code or
Orthogonal Variable SpreadingOrthogonal Variable Spreading

UTRA FDD Features
– FEC Codes:FEC Codes: Rate 1/2, 1/3 convolutional codeRate 1/2, 1/3 convolutional code
with constraint length K = 9with constraint length K = 9
Rate 1/3, 8-state Turbo codingRate 1/3, 8-state Turbo coding
– Interleaving:Interleaving: Intra- or Inter-frame interleavingIntra- or Inter-frame interleaving
(10, 20 40, 80 msec)(10, 20 40, 80 msec)
– Modulation:Modulation: QPSKQPSK
– Detection:Detection: Coherent based on pilot symbolsCoherent based on pilot symbols
– Micro diversity:Micro diversity: RAKE in BS and UERAKE in BS and UE
– Power Control:Power Control: Fast closed-loop at 1500 Hz rateFast closed-loop at 1500 Hz rate
– Intra-frequency HO: Soft / Softer HandoverIntra-frequency HO: Soft / Softer Handover
– Inter-frequency HO: Hard HandoverInter-frequency HO: Hard Handover
– Interference Cancellation: Support for multiuser detectionInterference Cancellation: Support for multiuser detection

Radio Interface Protocol Model
PHYPHY
MACMAC
RLCRLC
Transport ChannelsTransport Channels
Logical ChannelsLogical Channels
User PlaneUser Plane
Radio BearersRadio Bearers
SignallingSignalling
Radio BearersRadio Bearers
PDCPPDCP
BMCBMC
RRCRRC
USER PLANEUSER PLANECONTROL PLANECONTROL PLANE
ControlControl
L1L1
(Radio Physical Layer)(Radio Physical Layer)
L2L2
(Radio Link Layer)(Radio Link Layer)
L3L3
(Radio Network Layer)(Radio Network Layer)U-Plane Radio BearersU-Plane Radio Bearers

WCDMA Radio Channels
Physical ChannelsPhysical Channels
– Transmission media.Transmission media.
– Two types of physical channels defined in L1; FDD and TDD.Two types of physical channels defined in L1; FDD and TDD.
– FDD is characterized by frequency, code, I/Q phaseFDD is characterized by frequency, code, I/Q phase
– Follow a layered structure of “radio frames” and “time slots”Follow a layered structure of “radio frames” and “time slots”
– describes the way information is transferred over the radio interfacedescribes the way information is transferred over the radio interface
– the type of information transferred characterizes a logical channelthe type of information transferred characterizes a logical channel
UE BS RNC
Physical ChannelsPhysical Channels

Physical Channels
Corresponds to a specific carrier frequency,Corresponds to a specific carrier frequency,
code, relative phase in I and Q branchescode, relative phase in I and Q branches
Dedicated and Common Physical ChannelsDedicated and Common Physical Channels
Layered structure of radio frames and time slotsLayered structure of radio frames and time slots
A radio frame = 10 msec = 15 slots/frameA radio frame = 10 msec = 15 slots/frame
1 frame = 38400 chips, 1 slot = 2560 chips1 frame = 38400 chips, 1 slot = 2560 chips
Slot configuration varies depending on theSlot configuration varies depending on the
channel bit rate of the physical channelchannel bit rate of the physical channel
– # bits/slot different for different physical channels# bits/slot different for different physical channels
– may vary with time (on a frame by frame basis)may vary with time (on a frame by frame basis)

U/L Physical Channels
Dedicated U/L ChannelsDedicated U/L Channels
– DPDCHDPDCH
– DPCCHDPCCH
Common U/L ChannelsCommon U/L Channels
– PRACHPRACH
» Preamble partPreamble part
» Message partMessage part
– PCPCHPCPCH
» Preamble partPreamble part
» Message partMessage part

Dedicated U/L Physical Channels
Two typesTwo types
– Dedicated Physical Data CHannel (DPDCH)Dedicated Physical Data CHannel (DPDCH)
– Dedicated Physical Control CHannel (DPCCH)Dedicated Physical Control CHannel (DPCCH)
– Both are I/Q code multiplexed within each radio frameBoth are I/Q code multiplexed within each radio frame
U/L DPDCH carries the DCH transport channelU/L DPDCH carries the DCH transport channel
U/L DPCCH carries L1 control bits such asU/L DPCCH carries L1 control bits such as
– Pilot bitsPilot bits (to enable channel estimation for coherent detection at BS)(to enable channel estimation for coherent detection at BS)
– Transmit power control (TPC)Transmit power control (TPC) commandscommands
– Feedback Information (FBI)Feedback Information (FBI)
» used for CL transmit diversity and Site Selection Diversityused for CL transmit diversity and Site Selection Diversity
Transmission (SDTC)Transmission (SDTC)
– Transport Format Combination Indicator (TFCI)Transport Format Combination Indicator (TFCI)
» for several simultaneous services. Informs the rx of the transportfor several simultaneous services. Informs the rx of the transport
format combination of the transport channels mapped to DPDCHformat combination of the transport channels mapped to DPDCH

U/L Frame Structure
There is only one U/L DPCCH on each radio linkThere is only one U/L DPCCH on each radio link
There can be 0, 1, or several DPDCHs on each radio linkThere can be 0, 1, or several DPDCHs on each radio link
10 msec frames divided into 15 slots10 msec frames divided into 15 slots
S0S0 S1S1 S2S2 S3S3 S13S13 S14S14
1 Frame = 15 slots = 10 msec1 Frame = 15 slots = 10 msec
DATADATA
1 time slot = 2/3 msec1 time slot = 2/3 msec
DPDCHDPDCH
(on I-Chl)(on I-Chl)
PilotPilotDPCCHDPCCH
(on Q-Chl)(on Q-Chl)
TFCITFCI FBIFBI TPCTPC
10 bits = 2560 chips => SF = 25610 bits = 2560 chips => SF = 256
(N(Ndatadata bits)bits)

I, Q Spreading for DPDCH, DPCCH
DPDCH-1DPDCH-1
∑
DPDCH-3DPDCH-3
CCd,1d,1
CCd,3d,3 BBdd
BBdd
II
DPDCH-2DPDCH-2
∑
DPCCH-2DPCCH-2
CCd,2d,2
CCcc BBcc
BBdd
QQ
I+jQI+jQ
SSdpch,ndpch,n
CCc,c, CCd,n:d,n: Channelization codesChannelization codes
Sdpch,n: Scrambling codeSdpch,n: Scrambling code
BBd,d, BBc:c: Gain factorsGain factors
Up to 6 DPDCHs in parallelUp to 6 DPDCHs in parallel
jj

WCDMA Transmission Rates (U/L)
System Chip Rate : 3.84 McpsSystem Chip Rate : 3.84 Mcps
Symbol Rates on UplinkSymbol Rates on Uplink
– Chl Symb RateChl Symb Rate Chl Bit RateChl Bit Rate SF Bits/frame NSF Bits/frame Ndatadata
15 Ks/s15 Ks/s 15 Kb/s 25615 Kb/s 256 150150 1010
30 Ks/s30 Ks/s 30 Kb/s 12830 Kb/s 128 300 20300 20
60 Ks/s 60 Kb/s60 Ks/s 60 Kb/s 64 600 4064 600 40
120 Ks/s 120 Kb/s120 Ks/s 120 Kb/s 32 1200 8032 1200 80
240 Ks/s 240 Kb/s240 Ks/s 240 Kb/s 16 2400 16016 2400 160
480 Ks/s 480 Kb/s480 Ks/s 480 Kb/s 8 4800 3208 4800 320
960 Ks/s 960 Kb/s 4 9600 640960 Ks/s 960 Kb/s 4 9600 640

WCDMA Channelisation Codes
Orthogonal codesOrthogonal codes
Used for channel separation both in U/L and D/LUsed for channel separation both in U/L and D/L
directionsdirections
Can have different spreading factor values (thusCan have different spreading factor values (thus
support different symbol rates)support different symbol rates)
CCch,SF,kch,SF,k : SF - Spreading Factor, k is the code: SF - Spreading Factor, k is the code
number 0<=k<= SF-1number 0<=k<= SF-1
Spreading factor value indicates how many bits ofSpreading factor value indicates how many bits of
those codes are used in a connectionthose codes are used in a connection

U/L Channelization Codes
Orthogonal Variable Spreading Factor (OVSF)Orthogonal Variable Spreading Factor (OVSF)
channelization codeschannelization codes
Separates data / control channels from same UESeparates data / control channels from same UE
Preserves orthogonality between these channelsPreserves orthogonality between these channels
(1)(1)
(1,1)(1,1)
(1,-1)(1,-1)
(1,1,1,1)(1,1,1,1)
(1,1,-1,-1)(1,1,-1,-1)
(1,-1,1,-1)(1,-1,1,-1)
(1,-1,-1,1)(1,-1,-1,1)
SF=1SF=1
SF=2SF=2
SF=4SF=4
C(SF,k)C(SF,k)
SF: Spreading FactorSF: Spreading Factor
k: code number 0<k<=SF-1k: code number 0<k<=SF-1

U/L Scrambling Codes
Use complex valued scrambling codeUse complex valued scrambling code
Long scrambling sequences (2^24)Long scrambling sequences (2^24)
– Gold sequences (linear combination of two m-sequences)Gold sequences (linear combination of two m-sequences)
Short scrambling sequences (2^24)Short scrambling sequences (2^24)
– from a family sequence of periodically extended S(2)from a family sequence of periodically extended S(2)
codescodes
Long or short sequences for DPCCH / DPDCHLong or short sequences for DPCCH / DPDCH
Only long sequences for message parts of PRACHOnly long sequences for message parts of PRACH
and PCPCHand PCPCH

WCDMA Code Types
Scrambling Codes, Channelisation CodesScrambling Codes, Channelisation Codes
UplinkUplink DownlinkDownlink
Scrambling codesScrambling codes User separationUser separation Cell separationCell separation
ChannelisationChannelisation Data and ControlData and Control Users within aUsers within a
codescodes channels from thechannels from the cellcell
same terminalsame terminal
Spreading code = Scrambling code x Channelisation codeSpreading code = Scrambling code x Channelisation code

Common U/L Physical Channels
Two TypesTwo Types
– Physical Random Access CHannel (PRACH)Physical Random Access CHannel (PRACH)
– Physical Common Packet CHannel (PCPCH)Physical Common Packet CHannel (PCPCH)
Physical Random Access CHannel (PRACH)Physical Random Access CHannel (PRACH)
– carries RACHcarries RACH
– Uses S-ALOHA technique with fast Acquisition IndicationUses S-ALOHA technique with fast Acquisition Indication
– Access slots (15 access slots per 2 frames)Access slots (15 access slots per 2 frames)
– RA transmission consists ofRA transmission consists of
» several 4096 chip preambles (uses 256 repetitions of 16 chipsseveral 4096 chip preambles (uses 256 repetitions of 16 chips
signature sequence) and 1or 2 frame messagesignature sequence) and 1or 2 frame message
PreamblePreamble Message Part (1 or 2 frames)Message Part (1 or 2 frames)
4096 Chips4096 Chips
PreamblePreamble

Random Access
UEUE BSBS
PRACH: Preamble sent (initial access)PRACH: Preamble sent (initial access)
No detection on AICHNo detection on AICH
PRACH: Preamble sent (initial access)PRACH: Preamble sent (initial access)
AICH: Preamble sent detectedAICH: Preamble sent detected
PRACH: Random Access Info sentPRACH: Random Access Info sent

Common U/L Physical Channels
Physical Common Packet CHannel (PCPCH)Physical Common Packet CHannel (PCPCH)
– Carries CPCHCarries CPCH
– CPCH is based on DSMA-CD technique with fastCPCH is based on DSMA-CD technique with fast
Acquisition IndicationAcquisition Indication
– Access slot timing and structure are identical to thoseAccess slot timing and structure are identical to those
defined for RACHdefined for RACH
– Transmission consists ofTransmission consists of
» Access preamble(s) - one or several each 4096 chipsAccess preamble(s) - one or several each 4096 chips
» Collision Detection preambleCollision Detection preamble
» DPCCH Power Control Preamble (0 or 8 slots)DPCCH Power Control Preamble (0 or 8 slots)
» Message of variable length (Nx10 msec)Message of variable length (Nx10 msec)
– PCPCH good for carrying small sized bursty dataPCPCH good for carrying small sized bursty data

Transport Formats / Configurations
Transport BlockTransport Block (TB)(TB)
» Basic unit of data exchanged between L1 & MAC for L1Basic unit of data exchanged between L1 & MAC for L1
processingprocessing
Transport Block Size:Transport Block Size: Number of bits in a TB.Number of bits in a TB.
Transport Block SetTransport Block Set (TBS)(TBS)
» A set of TBs exchanged between L1 and MAC at the sameA set of TBs exchanged between L1 and MAC at the same
time instant using the same transport channeltime instant using the same transport channel
Transport Block Set Size:Transport Block Set Size: Number of bits in a TBSNumber of bits in a TBS
Transmission Time IntervalTransmission Time Interval (TTI)(TTI)
» Periodicity at which a TBS is transferred by the physical layerPeriodicity at which a TBS is transferred by the physical layer
on to the radio interface - {10, 20, 40, 80 ms}on to the radio interface - {10, 20, 40, 80 ms}
» MAC delivers one TBS to the physical layer every TTIMAC delivers one TBS to the physical layer every TTI

Transport FormatTransport Format (TF)(TF)
– Format offered by L1 to MAC (and vice versa) for the delivery of aFormat offered by L1 to MAC (and vice versa) for the delivery of a
TBS during a TTI on a given transport channel (TrCH)TBS during a TTI on a given transport channel (TrCH)
– Dynamic part (TB size, TBS size)Dynamic part (TB size, TBS size)
– Semi-static part (TTI, type/rate of coding,size of CRC)Semi-static part (TTI, type/rate of coding,size of CRC)
– TB size, TBS size, TTI define the TrCH bit rateTB size, TBS size, TTI define the TrCH bit rate before L1 processingbefore L1 processing
» e.g., TB size = 336 bits (320 bit payload + 16 bits RLC header)e.g., TB size = 336 bits (320 bit payload + 16 bits RLC header)
» TBS size = 2 TBs per TTI, TTI = 10 msTBS size = 2 TBs per TTI, TTI = 10 ms
» DCH Bit rate (with RLC header) = 336*2/10 = 67.2 KbpsDCH Bit rate (with RLC header) = 336*2/10 = 67.2 Kbps
» User Bit rate (without RLC header) = 320*2/10 = 64 KbpsUser Bit rate (without RLC header) = 320*2/10 = 64 Kbps
– Variable bit rate can be achieved by changing (Variable bit rate can be achieved by changing (between TTIsbetween TTIs))
either the TBS size only, or both the TB size and TBS Sizeeither the TBS size only, or both the TB size and TBS Size
Transport Format SetTransport Format Set (TFS)(TFS)
– a set of TFs associated with a TrCHa set of TFs associated with a TrCH
– semi-static part of all TFs in a TFS is the samesemi-static part of all TFs in a TFS is the same

Transport Format CombinationTransport Format Combination (TFC)(TFC)
» Multiple TrCHs each having a TFMultiple TrCHs each having a TF
» Authorized combination of the currently valid TFs that can beAuthorized combination of the currently valid TFs that can be
submitted to L1 on asubmitted to L1 on a CCTrCHCCTrCH, containing one TF from each TrCH, containing one TF from each TrCH
Transport Format Combination SetTransport Format Combination Set (TFCS)(TFCS)
» A set of TFCs on a CCTrCH. Produced by RNCA set of TFCs on a CCTrCH. Produced by RNC
» TFCS is given to MAC by L3 for controlTFCS is given to MAC by L3 for control
» MAC chooses between the different TFCs specified in the TFCSMAC chooses between the different TFCs specified in the TFCS
» MAC has control over only the dynamic part of the TFs. Semi-static partMAC has control over only the dynamic part of the TFs. Semi-static part
relates to QoS (e.g., quality) and is controlled by RNC admission controlrelates to QoS (e.g., quality) and is controlled by RNC admission control
» Bit rate can be changed quickly by MAC with no need to L3 signalingBit rate can be changed quickly by MAC with no need to L3 signaling
Transport Format IndicatorTransport Format Indicator (TFI)(TFI)
» A label for a specific TF within a TFS. Used between MAC and L1A label for a specific TF within a TFS. Used between MAC and L1
Transport Format Combination IndicatorTransport Format Combination Indicator (TFCI)(TFCI)
» Used to inform the receiving side of the currently valid TFCUsed to inform the receiving side of the currently valid TFC

TTITTI TTITTI TTITTI
TTITTI TTITTI TTITTI
TBTB
DCH1DCH1
DCH2DCH2
TBTB TBTB
TBTB TBTB TBTB
TBTB
Transport Block SetTransport Block Set
(TBS)(TBS)
TBTB
TBTB
Transport Format (TF)Transport Format (TF)
Transport FormatTransport Format
Set (TFS)Set (TFS)
Combination (TFC)Combination (TFC)
Combination SetCombination Set
(TFCS)(TFCS)

TFI and TFCI (Transmitter)
Transport Chl 1Transport Chl 1 Transport Chl 2Transport Chl 2
TransportTransport
BlockBlock
TransportTransport
BlockBlock
TransportTransport
BlockBlock
TransportTransport
BlockBlockTFITFI TFITFI
TFCITFCI
Coding andCoding and
MultiplexingMultiplexing
PhysicalPhysical
LayerLayer
HigherHigher
LayerLayer
DPCCH (Q-Chl)DPCCH (Q-Chl) DPDCH (I-Chl)DPDCH (I-Chl)
PhysicalPhysical
Control ChlControl Chl
PhysicalPhysical
Data ChlData Chl
E.g: Two transport channels mapped to a single physical channelE.g: Two transport channels mapped to a single physical channel
This dotted lineThis dotted line
represents the Iur interfacerepresents the Iur interface
in case of NW sidein case of NW side

TFI and TFCI (Receiver)
Transport Chl 1Transport Chl 1 Transport Chl 2Transport Chl 2
TransportTransport
Block & EIBlock & EI
TransportTransport
TransportTransport
TransportTransport
Block & EIBlock & EITFITFI TFITFI
TFCITFCI
DecodeDecode
Decoding andDecoding and
DemultiplexingDemultiplexing
PhysicalPhysical
LayerLayer
HigherHigher
LayerLayer
DPCCH (Q-Chl)DPCCH (Q-Chl) DPDCH (I-Chl)DPDCH (I-Chl)
EI: ErrorEI: Error
IndicationIndication
PhysicalPhysical
Control ChlControl Chl
PhysicalPhysical
Data ChlData Chl

TFI and TFCI
Each transport channel is accompanied by aEach transport channel is accompanied by a TFITFI at eachat each
time event at which data is expected to arrive from HLtime event at which data is expected to arrive from HL
Physical layer combines the TFI info from differentPhysical layer combines the TFI info from different
transport channels to the TFCItransport channels to the TFCI
TFCI is sent on the DPCCH to inform the receiver aboutTFCI is sent on the DPCCH to inform the receiver about
the instantaneousthe instantaneous transport format combinationtransport format combination of theof the
transport channels mapped to the U/L DPDCHtransport channels mapped to the U/L DPDCH
transmitted simultaneouslytransmitted simultaneously

Transport Format (e.g., Speech)
Conversational Speech (12 Kbps)Conversational Speech (12 Kbps)
– 12.2 Kbps max.12.2 Kbps max.
– TTI: 20 msecTTI: 20 msec
– Transport Formats (TF) available:Transport Formats (TF) available:
TF RAB1 RAB2 RAB3TF RAB1 RAB2 RAB3
TF0v 0 x 81 0 x 103 0 x 60 (e.g., silence)TF0v 0 x 81 0 x 103 0 x 60 (e.g., silence)
TF1v 1 x 81 1 x 103 1 x 60 (e.g, active voice)TF1v 1 x 81 1 x 103 1 x 60 (e.g, active voice)
two other formats too (see Stds. Doc.)two other formats too (see Stds. Doc.)
– TFC: (TF0, TF0, TF0) e.g., during silenceTFC: (TF0, TF0, TF0) e.g., during silence
(TF1, TF1, TF1) e.g., during active voice periods(TF1, TF1, TF1) e.g., during active voice periods

Transport Format (e.g., Data)
Interactive/Background Data (64 Kbps)Interactive/Background Data (64 Kbps)
– 64 Kbps max.64 Kbps max.
– TTI: 20 msecTTI: 20 msec
– Transport Block (TB) size = 336 bitsTransport Block (TB) size = 336 bits
– Transport Formats (TF) available:Transport Formats (TF) available:
» TF0 - 0 x 336TF0 - 0 x 336
» TF1 - 1 x 336TF1 - 1 x 336
» TF2 - 2 x 336TF2 - 2 x 336
» TF3 - 3 x 336TF3 - 3 x 336
» TF4 - 4 x 336TF4 - 4 x 336

Transport Format (Speech + Data)
Conversational speech (12 Kbps) +Conversational speech (12 Kbps) +
Interactive/Background Data (64 Kbps)Interactive/Background Data (64 Kbps)
Voice TrCH Data TrCHVoice TrCH Data TrCH
TFC1: (TF0v, TF0v, TF0v) TF0dTFC1: (TF0v, TF0v, TF0v) TF0d

Multiplexing & Channel Coding
Data arrives at the coding/mux unit in transport block sets,Data arrives at the coding/mux unit in transport block sets,
once every transmission time interval (TTI)once every transmission time interval (TTI)
TTI depends on the transport channel; {10, 20, 40, 80 ms})TTI depends on the transport channel; {10, 20, 40, 80 ms})
Main stepsMain steps
– Add CRC to each blockAdd CRC to each block
– transport block concatenation and block segmentationtransport block concatenation and block segmentation
– channel codingchannel coding
– first interleaving (per TTI)first interleaving (per TTI)
– radio frame segmentation (when TTI > 10 ms)radio frame segmentation (when TTI > 10 ms)
– rate matching (repetition or puncturing)rate matching (repetition or puncturing)
– multiplexing of transport channels (CCTrCH)multiplexing of transport channels (CCTrCH)
– insertion of DTX indication bitsinsertion of DTX indication bits
– physical channel segmentationphysical channel segmentation
– second interleaving (per radio frame, ie., among bits in 1 radio frame)second interleaving (per radio frame, ie., among bits in 1 radio frame)
– mapping to physical channelmapping to physical channel

Multiplexing & Channel Coding (U/L)
CRC Attachment
TrBk Concatenation/
Code Block Segmentation
Channel Coding
Radio Frame Equalization
1st Interleaving
Radio Frame Segmentation
Rate Matching
CCTrCHCCTrCH
CRC Attachment
TrBk Concatenation/
Channel Coding
Radio Frame Equalization
1st Interleaving
Rate Matching
TrCH-2TrCH-2
TrCH Multiplexing
Physical Channel Segmentation
2nd interleaving
TrCH-1TrCH-1
Physical Channel Mapping
PhCH#2PhCH#2PhCH#1PhCH#1

Multiplexing & Channel Coding (..cntd)
Applicable to DCH, RACH, CPCH, DSCH, BCH,Applicable to DCH, RACH, CPCH, DSCH, BCH,
FACH, PCHFACH, PCH
CRCCRC
– add CRC to each transport block for error detectionadd CRC to each transport block for error detection
– CRC calculated on entire transport blockCRC calculated on entire transport block
– Size of CRC: 24, 16, 12, 8, 0 bitsSize of CRC: 24, 16, 12, 8, 0 bits
– what CRC size is used for each TrCH is signaled fromwhat CRC size is used for each TrCH is signaled from
higher layershigher layers

TrBk Concatenation & Code Block SegmentationTrBk Concatenation & Code Block Segmentation
– all transport blocks in a TTI are concatenatedall transport blocks in a TTI are concatenated
– if no. of bits in a TTI after concatenation (X) is greater thanif no. of bits in a TTI after concatenation (X) is greater than
the maximum size of the code block (in the channel codingthe maximum size of the code block (in the channel coding
block), then code block segmentation is doneblock), then code block segmentation is done
– max. size of the code block (Z) depends on whethermax. size of the code block (Z) depends on whether
» Convolutional code ( Z = 504 bits) orConvolutional code ( Z = 504 bits) or
» Turbo code ( Z = 5114 bits) is used for the TrCHTurbo code ( Z = 5114 bits) is used for the TrCH
– Code blocks after segmentation are of the same sizeCode blocks after segmentation are of the same size
– Filler bits (zeros) added to 1st coded block toFiller bits (zeros) added to 1st coded block to
» to make integer number of code blocks, orto make integer number of code blocks, or
» if X < 40 bits when Turbo code is usedif X < 40 bits when Turbo code is used

Channel CodingChannel Coding
Coding SchemeCoding Scheme Coding RateCoding RateType of TrCHType of TrCH
BCHBCH
PCHPCH
RACHRACH
DPCH, DCH,DPCH, DCH,
DSCH, FACHDSCH, FACH
ConvolutionalConvolutional
CodingCoding
(constraint(constraint
length = 9)length = 9)
Turbo CodingTurbo Coding 1/31/3
1/3, 1/21/3, 1/2
1/21/2
If number of coded blocks is greater than 1, they areIf number of coded blocks is greater than 1, they are
serially concatenatedserially concatenated

Radio Frame EqualizationRadio Frame Equalization
– padding the input bit sequence in order to ensure thatpadding the input bit sequence in order to ensure that
the output can be segmented into data segments ofthe output can be segmented into data segments of
equal sizeequal size
– I.e., number of bits per segment is same after radioI.e., number of bits per segment is same after radio
frame equalizationframe equalization
– performed only on the U/Lperformed only on the U/L
1st Interleaving1st Interleaving
– block interleaverblock interleaver
– among bits in a TTIamong bits in a TTI

Radio Frame SegmentationRadio Frame Segmentation
– when TTI > 10 msec, input bit sequence is segmentedwhen TTI > 10 msec, input bit sequence is segmented
and mapped on to Fi consecutive radio framesand mapped on to Fi consecutive radio frames
Rate MatchingRate Matching
– means that bits on a transport channel are repeated ormeans that bits on a transport channel are repeated or
puncturedpunctured to ensure that the total bit rate after TrCHto ensure that the total bit rate after TrCH
multiplexing is identical to the total channelmultiplexing is identical to the total channel bit ratebit rate
of the allocated dedicated physical channelsof the allocated dedicated physical channels
– higher layers assign a rate-matching (semi-static)higher layers assign a rate-matching (semi-static)
attribute for each transport channelattribute for each transport channel
– this attribute is used to calculate the number of bits tothis attribute is used to calculate the number of bits to
repeat or puncture, spreading factor, number of PhCHsrepeat or puncture, spreading factor, number of PhCHs
needed, rate matching patternneeded, rate matching pattern

TrCH MultiplexingTrCH Multiplexing
– every 10 msec, one radio frame from each TrCH isevery 10 msec, one radio frame from each TrCH is
delivered to the TrCH multiplexingdelivered to the TrCH multiplexing
– these radio frames are serially concatenated into athese radio frames are serially concatenated into a
coded composite transport channelcoded composite transport channel (CCTrCH)(CCTrCH)
Physical Channel SegmentationPhysical Channel Segmentation
– when more than once PhCH is used, the physicalwhen more than once PhCH is used, the physical
channel segmentation divides the bits among differentchannel segmentation divides the bits among different
PhCHsPhCHs
2nd Interleaving2nd Interleaving
– among bits within a radio frameamong bits within a radio frame

Insertion of Discontinuous Transmission (DTX)Insertion of Discontinuous Transmission (DTX)
Indication BitsIndication Bits
– only on the D/Lonly on the D/L
– used to fill up the radio frame with bitsused to fill up the radio frame with bits
– insertion point depends on whetherinsertion point depends on whether fixed positionsfixed positions (1st(1st
Insertion)Insertion) oror flexible positionsflexible positions (2nd Insertion)(2nd Insertion) of theof the
TrCHs in the radio frame are usedTrCHs in the radio frame are used
– During connection setup, NW decides if fixed or flexibleDuring connection setup, NW decides if fixed or flexible
position is used for each CCTrCHposition is used for each CCTrCH
– DTX Indication bits are not transmitted; they only tellDTX Indication bits are not transmitted; they only tell
when the Tx must be turned offwhen the Tx must be turned off

Transport Format DetectionTransport Format Detection
– TFCI Based DetectionTFCI Based Detection
– Explicit Blind DetectionExplicit Blind Detection
» using receive power ratiousing receive power ratio
» by use of channel decoding and CRC checkby use of channel decoding and CRC check
– Guided DetectionGuided Detection
» Explicit blind detection used on Guiding TrCHExplicit blind detection used on Guiding TrCH
» Guiding TrCH has the same TTI as the TrCH underGuiding TrCH has the same TTI as the TrCH under
considerationconsideration

Blind Transport Format DetectionBlind Transport Format Detection
– Using Received Power Ratio (for the case of 2 TFs)Using Received Power Ratio (for the case of 2 TFs)
» Ratio of the power received on DPDCH (Pd) and DPCCH (Pc)Ratio of the power received on DPDCH (Pd) and DPCCH (Pc)
» Full Rate TF: if ratio Pd/Pc > thresholdFull Rate TF: if ratio Pd/Pc > threshold
» Zero rate TF: if ratio Pd/Pc < thresholdZero rate TF: if ratio Pd/Pc < threshold
– Using CRC (for the case of multiple TFs)Using CRC (for the case of multiple TFs)
» Receiver knows only the possible TFs or end bit (thru’ L3 signaling)Receiver knows only the possible TFs or end bit (thru’ L3 signaling)
» Receiver performs FEC (Viterbi) decodingReceiver performs FEC (Viterbi) decoding
» path metric selection among the surviving paths in the decodingpath metric selection among the surviving paths in the decoding

D/L Physical Channels
Dedicated D/L ChannelsDedicated D/L Channels
– DPDCHDPDCH
– DPCCHDPCCH
Common D/L ChannelsCommon D/L Channels
– Common PIlot CHannel (CPICH)Common PIlot CHannel (CPICH)
» Primary CPICHPrimary CPICH
» Secondary CPICHSecondary CPICH
– Common Control Physical CHannel (CCPCH)Common Control Physical CHannel (CCPCH)
» Primary CCPCH,Primary CCPCH,
» Secondary CCPCHSecondary CCPCH
– Synchronization CHannel (SCH)Synchronization CHannel (SCH)
» Primary SCH,Primary SCH,
» Secondary SCHSecondary SCH

Dedicated D/L Physical Channels
Dedicated Physical CHannel (D/L DPCH)Dedicated Physical CHannel (D/L DPCH)
– transmits dedicated data generated at L2 and abovetransmits dedicated data generated at L2 and above
– time-multiplexes with L1 control bits (Pilot, TPC,time-multiplexes with L1 control bits (Pilot, TPC,
TFCI)TFCI)
D/L DPCHD/L DPCH
– Time-multiplex of a D/L DPDCH and a D/L DPCCHTime-multiplex of a D/L DPDCH and a D/L DPCCH

DL Frame Structure
S0S0
10 msec frames divided into 15 slots10 msec frames divided into 15 slots
No. of bits in different DPDCH field (Npilot, Ntpc, Ntfci, Ndata1,No. of bits in different DPDCH field (Npilot, Ntpc, Ntfci, Ndata1,
Ndata2) are given in tablesNdata2) are given in tables
Which slot format to use is configured (and reconfigured) byWhich slot format to use is configured (and reconfigured) by
higher layershigher layers
S1S1 S2S2 S3S3 S13S13 S14S14
1 Frame = 15 slots = 10 msec1 Frame = 15 slots = 10 msec
DATA 1DATA 1
1 time slot = 2/3 msec1 time slot = 2/3 msec
DPDCHDPDCH
PilotPilot
DPCCHDPCCH
TFCITFCITPCTPC DATA 2DATA 2
DPDCHDPDCH DPCCHDPCCH

D/L Transmission
Multicode Transmission on D/LMulticode Transmission on D/L
– Multicode transmission can be employed on the D/LMulticode transmission can be employed on the D/L
– I.e., CCTrCH is mapped on to several parallel D/LI.e., CCTrCH is mapped on to several parallel D/L
DPCHs using the same spreading factorDPCHs using the same spreading factor
– In this case, L1 control information is sent only on theIn this case, L1 control information is sent only on the
first downlink DPCHfirst downlink DPCH
Multiple CCTrCHsMultiple CCTrCHs
– In case there are several CCTrCHs mapped to differentIn case there are several CCTrCHs mapped to different
DPCHs transmitted to the same UE, different spreadingDPCHs transmitted to the same UE, different spreading
factors can be used on DPCHsfactors can be used on DPCHs
– multiple CCTrCHs feature for future releasemultiple CCTrCHs feature for future release

WCDMA Transmission Rates (D/L)
System Chip Rate : 3.84 McpsSystem Chip Rate : 3.84 Mcps
Symbol Rates on DownlinkSymbol Rates on Downlink
– Symb RateSymb Rate Chl bit rateChl bit rate SFSF
7.5 Ks/s7.5 Ks/s 15 Kb/s 51215 Kb/s 512
15 Ks/s15 Ks/s 30 Kb/s 25630 Kb/s 256
30 Ks/s30 Ks/s 60 Kb/s 12860 Kb/s 128
60 Ks/s 120 Kb/s 6460 Ks/s 120 Kb/s 64
120 Ks/s 240 Kb/s 32120 Ks/s 240 Kb/s 32
240 Ks/s 480 Kb/s 16240 Ks/s 480 Kb/s 16
480 Ks/s 960 Kb/s 8480 Ks/s 960 Kb/s 8
960 Ks/s 1920 Kb/s 4960 Ks/s 1920 Kb/s 4

Common D/L Physical Channels
Common Pilot CHannel (CPICH)Common Pilot CHannel (CPICH)
– 30 Kbps fixed rate channel (SF = 256)30 Kbps fixed rate channel (SF = 256)
– Primary CPICHPrimary CPICH
» Always uses the same channelization codeAlways uses the same channelization code
» Scrambled by primary scrambling codeScrambled by primary scrambling code
» There is one and only one P-CPICH per cellThere is one and only one P-CPICH per cell
» Broadcast over the entire cellBroadcast over the entire cell
» Provides a phase reference for several D/L channelsProvides a phase reference for several D/L channels
– Secondary CPICHSecondary CPICH
» Uses an arbitrary channelization code of SF=256Uses an arbitrary channelization code of SF=256
» Scrambled either by the primary or a secondary scrambling codeScrambled either by the primary or a secondary scrambling code
» A cell may contain 0,1, or several S-CPICHA cell may contain 0,1, or several S-CPICH
» Broadcast over entire OR part of a cellBroadcast over entire OR part of a cell
» A S-CPICH can be a phase reference to some D/L channelsA S-CPICH can be a phase reference to some D/L channels
(which is communicated to the UE thru’ higher layer signaling)(which is communicated to the UE thru’ higher layer signaling)

Common Control Physical CHannel (CCPCH)Common Control Physical CHannel (CCPCH)
– Primary CCPCH (P-CCPCH)Primary CCPCH (P-CCPCH)
» 30 Kbps fixed rate channel with SF=25630 Kbps fixed rate channel with SF=256
» Carries BCH transport channelCarries BCH transport channel
» No TPC, TFCI, pilot bits are sentNo TPC, TFCI, pilot bits are sent
» the transport channel mapped to P-CCPCH (I.e., BCH) canthe transport channel mapped to P-CCPCH (I.e., BCH) can
only have a fixed predefined TFConly have a fixed predefined TFC
– Secondary CCPCH (S-CCPCH)Secondary CCPCH (S-CCPCH)
» Carries FACH and PCHCarries FACH and PCH
» S-CCPCH can be with TFCI and without TFCIS-CCPCH can be with TFCI and without TFCI
» NW decides if TFCI has to be sentNW decides if TFCI has to be sent
» So UE should be (mandatory) capable of receiving with orSo UE should be (mandatory) capable of receiving with or
without TFCI (i.e., blind)without TFCI (i.e., blind)
» S-CCPCH can support multiple TFCs using TFCIS-CCPCH can support multiple TFCs using TFCI
– Main difference between CCPCHs and Dedicated PhysicalMain difference between CCPCHs and Dedicated Physical
Channels : a CCPCH is NOT inner loop Power ControlledChannels : a CCPCH is NOT inner loop Power Controlled

Synchronization CHannel (SCH)Synchronization CHannel (SCH)
– Downlink signal used for cell searchDownlink signal used for cell search
– Consists of Primary and Secondary subchannelsConsists of Primary and Secondary subchannels
– Primary SCHPrimary SCH
» Uses Primary Sychronization Code (PSC), TXUses Primary Sychronization Code (PSC), TX
once every slotonce every slot
» PSC is the same for every cell in the systemPSC is the same for every cell in the system
– Secondary SCHSecondary SCH
» Tx in parallel with Primary SCHTx in parallel with Primary SCH
» SSC indicates which of the code groups (64SSC indicates which of the code groups (64
groups) the cell’s DL scrambling code belongs togroups) the cell’s DL scrambling code belongs to

D/L Spreading
DL PhysicalDL Physical
Channel dataChannel data CCd,SF,md,SF,m
Serial toSerial to
ParallelParallel
Conv.Conv.
II
QQ
I+jQI+jQ
SSdl,ndl,n
jj
Channelisation code: - Differentiate users in a cellChannelisation code: - Differentiate users in a cell
- OVSF- OVSF
- UTRAN assigns channelisation codes to diff. phy. chls- UTRAN assigns channelisation codes to diff. phy. chls
Scrambling Code: Differentiate cellsScrambling Code: Differentiate cells

Scrambling Codes
# possible D/L scrambling codes = 2**18 -1 = 262143# possible D/L scrambling codes = 2**18 -1 = 262143
Scrambling codes divided into 512 setsScrambling codes divided into 512 sets
– 1 primary scrambling code and 15 secondary scrambling codes1 primary scrambling code and 15 secondary scrambling codes
– So, there are 512 x 16 = 8192 codesSo, there are 512 x 16 = 8192 codes
Each cell is allocated one and only primary scrambling codeEach cell is allocated one and only primary scrambling code
– The primary CCPCH (Common Control Physical CHannel) is TxThe primary CCPCH (Common Control Physical CHannel) is Tx
always using this primary scrambling codealways using this primary scrambling code
– Other D/L physical channels can be Tx with either the PSC or SSCOther D/L physical channels can be Tx with either the PSC or SSC
from the set associated with the PSC of the cellfrom the set associated with the PSC of the cell

Multiplexing & Channel Coding (D/L)
CRC Attachment
TrBk Concatenation/
Channel Coding
Rate Matching
1st Insertion of DTX Indication
1st Interleaving
CCTrCHCCTrCH
CRC Attachment
TrBk Concatenation/
Channel Coding
Rate Matching
1st Insertion of DTX Indication
1st Interleaving
TrCH-2TrCH-2
TrCH Multiplexing
Physical Channel Segmentation
2nd interleaving
TrCH-1TrCH-1
Physical Channel Mapping
PhCH#2PhCH#2PhCH#1PhCH#1
2nd Insertion of DTX Indication

Physical Channel MappingPhysical Channel Mapping
– on U/L: PhCHs are either completely filled or noton U/L: PhCHs are either completely filled or not
used at allused at all
– on D/L: No bits in locations with DTX indicationon D/L: No bits in locations with DTX indication
» in compressed mode, no bits are mapped to certain slotsin compressed mode, no bits are mapped to certain slots
in a PhCH. Reducing the SF by a factor of 2, 7.5 slotsin a PhCH. Reducing the SF by a factor of 2, 7.5 slots
per frame is used in compressed modeper frame is used in compressed mode

Insertion of Discontinuous Transmission (DTX)Insertion of Discontinuous Transmission (DTX)
Indication BitsIndication Bits
– only on the D/Lonly on the D/L
– used to fill up the radio frame with bitsused to fill up the radio frame with bits
– insertion point depends on whetherinsertion point depends on whether fixed positionsfixed positions (1st(1st
Insertion)Insertion) oror flexible positionsflexible positions (2nd Insertion)(2nd Insertion) of theof the
TrCHs in the radio frame are usedTrCHs in the radio frame are used
– During connection setup, NW decides if fixed or flexibleDuring connection setup, NW decides if fixed or flexible
position is used for each CCTrCHposition is used for each CCTrCH
– DTX Indication bits are not transmitted; they only tellDTX Indication bits are not transmitted; they only tell
when the Tx must be turned offwhen the Tx must be turned off

WCDMA Physical Channels
P-CCPCHP-CCPCH
S-CCPCHS-CCPCH
DPDCHDPDCH
DPCCHDPCCH
PDSCHPDSCH
PCPCHPCPCH
PRACHPRACH BSBSUEUE
AICHAICH
P-SCHP-SCH
S-SCHS-SCH
CSICHCSICH
CPICHCPICH
PICHPICH
CD/CA-ICHCD/CA-ICH

Channel Mapping on the U/L
CCCH DTCH DCCH
RACH DCH CPCH
PRACH DPDCH DPCCH PCPCH
LogicalLogical
ChannelsChannels
TransportTransport
ChannelsChannels
PhysicalPhysical
ChannelsChannels

Channel Mapping on the D/L
BCCH PCCH CTCH CCCH DCCH DTCH
BCH PCH FACH DCH DSCH
P-CCPCH S-CCPCH DPDCH DPCCH PDSCH
LogicalLogical
ChannelsChannels
TransportTransport
ChannelsChannels
PhysicalPhysical
ChannelsChannels

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