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Transcript of 2 UMTS Radio Interface Physical Layer
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Huawei Confidential. All Rights Reserved
UMTS Radio Interface Physical Layer
ISSUE 1.0
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Internal Use2
Physical layer offers data transport services
to higher layers.
The access to these services is through the
use of transport channels via the MAC sub-
layer.
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Internal Use3
ReferencesReferences
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 Acces
(HSDPA) - Iub/IurProtocol Aspects
TR 25.858 Physical layer aspects of UTRA High
Speed Downlink Packet Access
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Internal Use4
ObjectiveObjective
Upon completion this course, you will be
able to:
Understand radio interface protocolArchitecture
Understand key technology of UMTS
physical layer
Understand UMTS physical layer
procedures
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Internal Use5
Chapter 1 : Physical Layer OverviewChapter 1 : Physical Layer Overview
Chapter 2 : Physical Layer Key TechnologyChapter 2 : Physical Layer Key Technology
Chapter 3 : Physical Layer ProceduresChapter 3 : Physical Layer Procedures
Chapter 4 : Transmit Diversity on PhysicalChapter 4 : Transmit Diversity on PhysicalChannelChannel
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Internal Use6
UTRAN Protocol StructureUTRAN Protocol StructureUTRAN Protocol StructureUTRAN 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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Internal Use7
Radio Interface Protocol StructureRadio Interface Protocol StructureRadio Interface Protocol StructureRadio Interface Protocol Structure
L3
con
trol
con
trol
con
trol
con
trol
Logical
Channels
Transport
Channels
C-plane signalling U-plane information
PHY
L2/MAC
L1
RLC
DCNtGC
L2/RLC
MAC
RLCRLC
RLC
RLC
RLCRLC
RLC
Duplication avoidance
UuS boundary
BMCL2/BMC
control
PDCPPDCP L2/PDCP
DCNtGC
Radio
Bea
rers
RRC
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Internal Use8
Data Processing at Physical LayerData Processing at Physical LayerData Processing at Physical LayerData Processing at Physical Layer
Data from MAC
LayerTB
Channel coding
and multiplexing
Spreading and
modulation
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Internal Use9
Spreading TechnologySpreading TechnologySpreading TechnologySpreading Technology
Spreading consists of 2 steps
Channelization operation: Transforms data symbols into chips. Thus
increasing the bandwidth of the signal. The number of chips per data
symbol is called the Spreading FactorSF.The operation is done
through multiplication with OVSF code.
Scrambling operation is applied to the spreading signal.
Data bit
OVSF
code
Scrambling
code
Chips after
spreading
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Internal Use10
Channelization CodeChannelization CodeChannelization CodeChannelization 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 e ke 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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Internal Use11
Scrambling codeGOLD sequence.
Scrambling code period : 10ms ,or 38400 chips. The code used for scrambling of 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. Only scrambling codes k = 0, 1, , 8191 are
used.
Scrambling CodeScrambling CodeScrambling CodeScrambling Code
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Internal Use13
Group 0
Group1
Group 63
512 primary
scrambling codes
64 primary scrambling
code groupsEach group consists of8
primary scrambling codes
Primary Scrambling Code GroupPrimary Scrambling Code GroupPrimary Scrambling Code GroupPrimary Scrambling Code Group
Primary
scramblingcodes for
downlink
physical
channels
Primary
scrambling code 0
Primaryscrambling code 1
Primaryscrambling code 7
Primaryscrambling code
8*63
Primaryscrambling code
63*87
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Internal Use14
Chapter 1 : Physical Layer OverviewChapter 1 : Physical Layer Overview
Chapter 2 : Physical Layer Key TechnologyChapter 2 : Physical Layer Key Technology
Chapter 3 : Physical Layer ProceduresChapter 3 : Physical Layer Procedures
Chapter 4 : Transmit Diversity on PhysicalChapter 4 : Transmit Diversity on PhysicalChannelChannel
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Internal Use15
Chapter 2 : Physical Layer Key TechnologyChapter 2 : Physical Layer Key Technology
Section 1 Physical Channel Structure and Function
Section 2 Channel Mapping
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Internal Use17
Traffic channel
Control channel
Logical channelLogical channelLogical channelLogical channel
Dedicated traffic channel DTCH
Common traffic channel CTCH
Broadcast control channel BCCH
Paging control channel PCCH
Dedicate control channel DCCH
Common control channel (CCCH
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Internal Use18
Broadcast channel (BCH)
Forward access channel (FACH)
Paging channel (PCH)
Random access channel (RACH)
BCH, FACH & PCH are downlink channels.
Only RACH is common uplink channel
Dedicated Channel (DCH)
Dedicated Channel (DCH) exists on uplink
or downlink channel.
Common transport
channel
Dedicated transport
channel
Transport channelTransport channelTransport channelTransport channel
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Internal Use19
Physical ChannelPhysical ChannelPhysical ChannelPhysical Channel
A physical channel is defined by a specific carrier frequency, code(scrambling code, spreading code) and relative phase.
In UMTS system, the different code (scrambling code or spreading
code) can distinguish the channels.
Most channels consist of radio frames and time slots, and each radio
frame consists of 15 time slots.
Two types of physical channel: UL and DL
Physical Channel
Frequency,code,phase
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Internal Use20
Downlink Physical ChannelDownlink Physical ChannelDownlink Physical ChannelDownlink Physical Channel
Downlink Common Physical Channel
Common Pilot Channel (CPICH)
Synchronization Channel (SCH)
Common Control Physical Channel (CCPCH)
Paging Indicator Channel (PICH)
Acquisition Indicator Channel (AICH)
Downlink Dedicated Physical Channel
Downlink DPCH
Downlink
Physical
Channel
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Internal Use21
Downlink Dedicated Physical Channel (DPCH)Downlink Dedicated Physical Channel (DPCH)Downlink Dedicated Physical Channel (DPCH)Downlink Dedicated Physical Channel (DPCH)
DCH consists of dedicated data and control information.
Control information includesPilot, TPC, TFCI (optional).
SF of DCH : 512 - 4,and can be changed during connection
DPDCH and DPCCH are time multiplexed.
Multi-code transmission within one CCTrCH uses the samespreading factor. In this case, the DPCH control information is
transmitted only on the first downlink DPCH.
Different CCTrCH can use different spreading factors in the
case there are several CCTrCHs for one UE. In this case
information of only one DPCCH needs to be transmitted.
Note:
CCTrCH : Coded Composite Transport Channel
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Internal Use22
Frame Structure ofDownlink DPCHFrame Structure ofDownlink DPCHFrame Structure ofDownlink DPCHFrame Structure ofDownlink DPCH
One radio frame, Tf= 10 ms
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2kbits (k=0..7)
Data2
Ndata2 bits
DPDCH
TFCI
NTFCI bits
Pilot
Npilot bitsData1
Ndata1 bits
DPDCH DPCCH DPCCH
TPC
NTPC bits
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Internal Use23
Functions ofDownlink DPDCH/DPCCHFunctions ofDownlink DPDCH/DPCCH
DCH dataDPDCH
DPCCH
Provide control data for DPDCH ,such
as demodulation, power control,etc.
Data bearerData bearer
at physical layerat physical layer
DCH
data
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Internal Use24
Common Pilot Channel(CPICH)Common Pilot Channel(CPICH)Common Pilot Channel(CPICH)Common Pilot Channel(CPICH)
Common Pilot Channel (CPICH)
Carries pre-defined sequence.
Fixed rate 30Kbps SF=256
Can use STTD on this channel
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Internal Use25
Common Pilot Channel (CPICH)Common Pilot Channel (CPICH)Common Pilot Channel (CPICH)Common Pilot Channel (CPICH)
Primary CPICH
Uses OVSF code -Cch, 256,0 Scrambled by the primary scrambling code Only one CPICH per cell Broadcast over the entire cell The P-CPICH is a phase reference for SCH, Primary CCPCH, AICH, PICH.
By default, it is also a phase reference for downlink DPCH.
Secondary CPICH An arbitrary channel code of SF=256 is used for S-CPICH S-CPICH is scrambled by either the primary or a secondary scrambling
code There may be zero, one , or several secondary CPICH.
S-CPICH may be transmitted over part of the cell S-CPICH may be a phase reference for S-CCPCH and downlink DPCH.
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Internal Use26
Synchronization Channel (SCH)Synchronization Channel (SCH)Synchronization Channel (SCH)Synchronization Channel (SCH)
Used for cell search
Two sub channels: P-SCH and S-SCH.
SCH is transmitted at the first 256
chips of every time slot.
PSC is transmitted repeatedly in
each time slot.
SSC specifies the scrambling
code groups of the cell. SSC is chosen from a set of 16
different codes of length 256,
there are altogether64 primary
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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Internal Use27
Fixed rate30kbpsSF=256, 1
Carry BCH transport channel Not transmitted during the first 256 chips of each time slot.
Only data part
STTD transmit diversity may be used
Data18 bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips , 20 bits
1 radio frame: Tf = 10 ms
(Tx OFF)
256 chips
Primary Common Control Physical Channel (PCCPCH)Primary Common Control Physical Channel (PCCPCH)Primary Common Control Physical Channel (PCCPCH)Primary Common Control Physical Channel (PCCPCH)
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Internal Use28
Secondary Common Control Physical Channel (SCCPCH)Secondary Common Control Physical Channel (SCCPCH)Secondary Common Control Physical Channel (SCCPCH)Secondary Common Control Physical Channel (SCCPCH)
Carry FACH and PCH.
Two types of SCCPCH:with or without TFCI. UTRAN
decides if a TFCI should be
transmitted, UE must support
TFCI.
Possible rates are the same as
that of downlink DPCH
SF =256 - 4.
FACH and PCH can be mapped tothe same or separate SCCPCHs.
If mapped to the same S-CCPCH,
they can be mapped to the same
frame.
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 20*2k bits (k=0..6)
PilotNpilot bits
DataNdata bits
1 radio frame: Tf = 10 ms
TFCINTFCI bits
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Internal Use29
Paging Indicator Channel (PICH)Paging Indicator Channel (PICH)Paging Indicator Channel (PICH)Paging Indicator Channel (PICH)
One radio frame (10 ms)
b1b0
288 bits for paging indication 12 bits (undefined)
b287 b288 b299
Fixed-rate (SF=256, 3), used to carry the Paging Indicators (PI).
PICH is always associated with an S-CCPCH to which a PCH transportchannel is mapped to.
N paging indicators {PI0, , PIN-1} in each PICH frame, N=18, 36, 72, or
144.
If a paging indicator in a certain frame is set to 1, it indicates that UEs
associated with this paging indicator should read the corresponding frame of
the associated S-CCPCH.
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Internal Use30
Acquisition Indicator Channel (AICH)Acquisition Indicator Channel (AICH)Acquisition Indicator Channel (AICH)Acquisition Indicator Channel (AICH)
Frame structure of AICHtwo frames, 20 ms consists of a repeated
sequence of 15 consecutive AS, each of length 20 symbols(5120 chips).
Each time slot consists of two partsan Acquisition-Indicator(AI) and a
part of duration 1024chips with no transmission.
Acquisition-Indicator AI have 16 kinds of Signature.
CPICH is the phase reference of AICH.
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
a1 a2a0 a31 a32a30 a33 a38 a39
AI part Unused part
20 ms
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Internal Use31
Uplink Physical ChannelUplink Physical ChannelUplink Physical ChannelUplink Physical Channel
Uplink Common Physical Channel
Physical Random Access Channel (PRACH)
Uplink Dedicated Physical Channel
Uplink Dedicated Physical Data Channel
(Uplink DPDCH)
Uplink Dedicated Physical Control Channel
(Uplink DPCCH) UplinkPhysical
Channel
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Internal Use32
Uplink Dedicated Physical ChannelUplink Dedicated Physical ChannelUplink Dedicated Physical ChannelUplink Dedicated Physical Channel
DPDCH and DPCCH are 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 SF of DPDCH : 4 256
SF of DPCCH : 256 fixed
Each DPCCH time slot consists of Pilot, TFCI, FBI, TPC
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Internal Use33
Frame Structure of Uplink DPDCH/DPCCHFrame Structure of Uplink DPDCH/DPCCHFrame Structure of Uplink DPDCH/DPCCHFrame Structure of Uplink DPDCH/DPCCH
Pilot
Npilot bits
TPCNTPC bits
Data
Ndata bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2kbits (k=0..6)
1 radio frame: Tf = 10 ms
DPDCH
DPCCHFBI
NFBI bitsTFCI
NTFCI bits
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Internal Use34
Functions of Uplink DPDCH/DPCCHFunctions of Uplink DPDCH/DPCCHFunctions of Uplink DPDCH/DPCCHFunctions of Uplink DPDCH/DPCCH
DCH Data
DPDCH
DPCCH
Provide control data for DPDCH, such
as demodulation, power control, etc
Data bearerData bearerat physical layerat physical layer
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Internal Use35
Physical Random Access Channel (PRACH)Physical Random Access Channel (PRACH)Physical Random Access Channel (PRACH)Physical Random Access Channel (PRACH)
The PRACH consist of 2 parts: Preamble
>one or several preamble.
>Each preamble is of length 4096chips and consists of 256
repetitions of a signature whose length is 16 chips. Total of
16 signatures>SF : 256
Message part :
>Two type, 10 or 20ms message part
>SF : 256 - 32
Which signature is available and the length of message part are
determined by higher layer
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Internal Use36
PRACH Transmission StructurePRACH Transmission StructurePRACH Transmission StructurePRACH 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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Internal Use37
Pilot
Npilot bits
DataNdata bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2kbits (k=0..3)
Message part radio frame TRACH = 10 ms
Data
ControlTFCI
NTFCI bits
PRACH Message StructurePRACH Message StructurePRACH Message StructurePRACH Message Structure
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Internal Use38
PRACH Access Timeslot StructurePRACH Access Timeslot StructurePRACH Access Timeslot StructurePRACH Access Timeslot Structure
#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14
5120 chips
radio frame: 10 ms r adio frame: 10 ms
Acc
ess slot #0 Ra
ndom Acc
ess Tra
nsmission
Access slot #1
Access slot #7
Access slot #14
Random Access Transmission
Random Access Transmission
Random Access TransmissionAccess slot #8
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Internal Use39
Function of physical channelFunction of physical channel
Node B UE
P-CCPCH-Primary common control physical channel
SCH- Synchronisation Channel
P-CPICH-Primary common pilot channel
S-CPICH-secondary common pilot channel
Cell broadcast channels
DPDCH-dedicated physical data channel
DPCCH-dedicated physical control channel
Dedicated channels
Paging channels
PICH-paging IndicatorChannel
S-CCPCH-Secondary common control physical channel
PRACH-Physical random access channel
AICH-Acquisition Indicator Channel
Random access channels
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Internal Use40
Chapter 2 : Physical Layer Key TechnologyChapter 2 : Physical Layer Key Technology
Section 1 Physical Channel Structure and Function
Section 2 Channel Mapping
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Internal Use41
{XOR}
Transport
Channels(L1 Characteristics
Dependent)PCH BCH FACH RACH DCH
S-CCPCHP-CCPCHPhysical
ChannelsPRACH DPDCH
LogicalChannels
(DataDependent)
PCCH
DCCH
DTCH
DecicatedLogicalChannel
CipherOn
BCCH CCCH CTCH
HigherLayer data
Paging SystemInfoSignaling
CellBroadcast
Service
Signalingand
User data
DTCHDTCH
Channel MappingChannel MappingChannel MappingChannel Mapping
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Internal Use42
Chapter 1 : Physical Layer OverviewChapter 1 : Physical Layer Overview
Chapter 2 : Physical Layer Key TechnologyChapter 2 : Physical Layer Key Technology
Chapter 3 : Physical Layer ProceduresChapter 3 : Physical Layer Procedures
Chapter 4 : Transmit Diversity on PhysicalChapter 4 : Transmit Diversity on PhysicalChannelChannel
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Internal Use43
Chapter 3 : Physical Layer ProcedureChapter 3 : Physical Layer Procedure
Section 1 Synchronisation Procedure ( Cell SearcSection 1 Synchronisation Procedure ( Cell Searc
Section 2 Random Access ProcedureSection 2 Random Access Procedure
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Internal Use44
1. Synchronization Procedure1. Synchronization ProcedureCell SearchCell Search1. Synchronization Procedure1. Synchronization ProcedureCell SearchCell Search
Slot synchronization
Frame synchronization and
code-group identification
Scrambling-code
identification
UE uses PSC to acquire slot
synchronization to a cell
UE uses SSC to find frame
synchronization and identify
the code group of the cell
found in the first step
UE determines the primary scramblingcode through correlation over the
CPICH with all codes within the
identified group, and then detects the
P-CCPCH and reads BCH information
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Internal Use45
1. Synchronization Procedure1. Synchronization Procedure Channel Timing RelationshipChannel Timing Relationship1. Synchronization Procedure1. Synchronization Procedure Channel Timing RelationshipChannel Timing Relationship
AICH accessslots
SecondarySCH
Primary
SCH
XS-CCPCH,k
10 ms
XPICH
#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 DPCHXDPCH,n
AnyPDSCH
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Internal Use46
Chapter 3 : Physical Layer ProcedureChapter 3 : Physical Layer Procedure
Section 1 Synchronisation Procedure ( Cell SearcSection 1 Synchronisation Procedure ( Cell Searc
Section 2 Random Access ProcedureSection 2 Random Access Procedure
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Internal Use47
2. Random access procedure2. Random access procedure -- RACHRACH2. Random access procedure2. Random access procedure -- RACHRACH
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Internal Use48
2. Random Access Procedure2. Random Access ProcedureRACHRACH2. Random Access Procedure2. Random Access ProcedureRACHRACH
Physical random access procedure
1. UE decoded BCH to find out the available RACH sub-channel, its
scrambling code and available signature.
2. Randomly select one of the RACH sub-channels from the group its
access class allows to use. Signature also selected randomly from
among the available signatures.
3. Set Preamble Retransmission Counter to Preamble_ Retrans_ Max
4. Set Preamble Initial Power
5. Transmit a preamble using the selected uplink access slot, signature,
and preamble transmission power
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Internal Use50
2. Random Access Procedure2. Random Access ProcedureRACHRACH2. Random Access Procedure2. Random Access ProcedureRACHRACH
7. If 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
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 lasttransmitted preamble
9. Exit physical random access procedure
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Internal Use51
Chapter 1 : Physical Layer OverviewChapter 1 : Physical Layer Overview
Chapter 2 : Physical Layer Key TechnologyChapter 2 : Physical Layer Key Technology
Chapter 3 : Physical Layer ProceduresChapter 3 : Physical Layer Procedures
Chapter 4 : Transmit Diversity on PhysicalChapter 4 : Transmit Diversity on PhysicalChannelChannel
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Internal Use53
Transmit DiversityTransmit Diversity--STTDSTTDTransmit DiversityTransmit Diversity--STTDSTTD
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
forantenna 1 and antenna 2.
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Internal Use54
Transmit DiversityTransmit Diversity--TSTDTSTDTransmit DiversityTransmit Diversity--TSTDTSTD
Time switching transmit diversity (TSTD) is used only on SCH channel.
Antenna 1
Antenna 2
acsi,0
acp
acs,
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)
CCCC
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Internal Use55
Transmit DiversityTransmit DiversityClosed Loop ModeClosed Loop ModeTransmit DiversityTransmit DiversityClosed Loop ModeClosed Loop Mode
Closed loop mode transmit diversity
Used in dedicated channel, DPCH and PDSCH, to improvedownlink performance based on feedback information from UE.
Base station transmits user information using 2 antennas. UE will
send feedback bits (FB) in uplink DPCCH, for NodeB to adjust the
phase of antenna 2 (as antenna 1 taken as reference), so as tomaximize the power received by UE.
In mode 1:
>Uses phase adjustment.
>Dedicated pilot symbols of 2 antennas different.
In mode 2:
>Phase and amplitude are adjusted.
>Dedicated pilot symbols of two antennas are the same.
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Internal Use