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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
Primaryscrambling code 0
Primaryscrambling code 1
Primaryscrambling code 7
Primaryscrambling code
8*63
Primaryscrambling code
63*87
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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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Chapter 2 Physical Channels and Channel Mapping
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.
Slot #0 Slot #1 Slot #i Slot #14
Tslot= 2560 chips, 20*2kbits (k=0..6)
PilotNpilotbits
DataNdatabits
1 radio frame: Tf= 10 ms
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
Slot #0 Slot #1 Slot #i Slot #14
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
Slot #0 Slot #1 Slot #i Slot #14
Tslot= 2560 chips, 10*2kbits (k=0..6)
1 radio frame: Tf= 10 ms
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
Slot #0 Slot #1 Slot #i Slot #14
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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Chapter 2 Physical Channels and Channel Mapping
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
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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Chapter 3 Physical Layer Processing Procedure
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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Example of Coding and Multiplexing
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
Example of Coding and Multiplexing
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Example of Coding and Multiplexing
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.
Example of Coding and Multiplexing
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Example of Coding and Multiplexing
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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Chapter 3 Physical Layer Processing Procedure
3.1 Coding and multiplexing
technology
3.2 Spreading technology 3.3 Modulation 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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Chapter 3 Physical Layer Processing Procedure
3.1 Coding and multiplexing
technology
3.2 Spreading technology 3.3 Modulation 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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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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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
Random Access ProcedureRACH
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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
Random Access ProcedureRACH
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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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Thank You