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HUAWEI TECHNOLOGIES CO., LTD.
All rights reserved
www.huawei.com
Internal
WCDMA Radio Interface WCDMA Radio Interface Physical LayerPhysical Layer
ISSUE 1.0ISSUE 1.0
HUAWEI TECHNOLOGIES CO., LTD. Page 2All rights reserved
The physical layer offers data transport services to
higher layers (MAC sub-layer)
The access to these services is through the use of
transport channels via the MAC sub-layer
The physical layer is expected to perform the following
functions in order to provide the data transport service,
for example modulation/demodulation and
spreading/despreading, Inner - loop power control
HUAWEI TECHNOLOGIES CO., LTD. Page 3All rights reserved
References
TS 25.104 UTRA (BS) FDD Radio Transmission and
Reception
TS 25.201 Physical layer-general description
TS 25.211 Physical channels and mapping of
transport channels onto physical channels (FDD)
TS 25.212 Multiplexing and channel coding (FDD)
TS 25.213 Spreading and modulation (FDD)
TS 25.214 Physical layer procedures (FDD)
TS 25.308 UTRA High Speed Downlink Packet Access
(HSDPA); Overall description; Stage 2
TR 25.877 High Speed Downlink Packet Access (HSDPA) -
Iub/Iur Protocol Aspects
TR 25.858 Physical layer aspects of UTRA High Speed
Downlink Packet Access
HUAWEI TECHNOLOGIES CO., LTD. Page 4All rights reserved
Upon completion of this course, we will be able to:
Outline radio interface protocol stack
architecture
Describe key technology of UMTS physical
layer
Describe UMTS physical layer procedures
HUAWEI TECHNOLOGIES CO., LTD. Page 5All rights reserved
Chapter 1 Physical Layer OverviewChapter 1 Physical Layer Overview
Chapter 2 Physical Layer Key Technology Chapter 2 Physical Layer Key Technology
Chapter 3 Physical Layer ProceduresChapter 3 Physical Layer Procedures
HUAWEI TECHNOLOGIES CO., LTD. Page 6All rights reserved
UTRAN Protocol Structure
RNS
RNCRNC
RNS
RNCRNC
Core Network
NodeBNodeB NodeBNodeB NodeBNodeB NodeBNodeB
IuIu IuIu
IurIur
IubIub IubIubIubIub IubIub
UTRAN
User Equipment
HUAWEI TECHNOLOGIES CO., LTD. Page 7All rights reserved
Radio Interface Protocol Structure
L3
con
tro
l
con
tro
l
con
tro
l
con
tro
l
Logical Channels
Transport Channels
C-plane signaling U-plane information
PHY
L2/MAC
L1
RLC
DCNtGC
L2/RLC
MAC
RLCRLC
RLCRLC
RLCRLCRLC
Duplication avoidance
UuS boundary
BMC L2/BMC
control
PDCPPDCP L2/PDCP
DCNtGC
Radio Bearers
RRC
HUAWEI TECHNOLOGIES CO., LTD. Page 11All rights reserved
Spreading Technology Spreading consists of 2 steps :
Channelization operation, which transforms data symbols into chips. Thus increasing the bandwidth of the signal, The number of chips per data symbol is called the Spreading Factor ( SF ) .The operation is done by multiplying with OVSF code
Scrambling operation is applied to the spreading signal
Data bit
OVSF code
Scrambling code
Chips after spreading
HUAWEI TECHNOLOGIES CO., LTD. Page 12All rights reserved
Channelization Code
OVSF code is used as channelization code
The channelization codes are uniquely described as Cch,SF,k, where SF is the
spreading factor of the code and k is the code number, 0 k SF-1
SF = 1 SF = 2 SF = 4
Cch,1,0 = (1)
Cch,2,0 = (1,1)
Cch,2,1 = (1,-1)
Cch,4,0 =(1,1,1,1)
Cch,4,1 = (1,1,-1,-1)
Cch,4,2 = (1,-1,1,-1)
Cch,4,3 = (1,-1,-1,1)
HUAWEI TECHNOLOGIES CO., LTD. Page 13All rights reserved
Scrambling Code
Scrambling code: GOLD 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 224 long and 224 short uplink
scrambling codes. Uplink scrambling codes are assigned by higher
layers
For downlink physical channels, a total of 218-1 = 262,143 scrambling
codes can be generated. scrambling codes k = 0, 1, …, 8191 are used
HUAWEI TECHNOLOGIES CO., LTD. Page 14All rights reserved
Scrambling codes for downlink physical channels
Set 0
Set 1
…
Set 511
Primary scrambling code 0
……
Secondary scrambling code 1
Secondary scrambling code 15
Primary scrambling code
511×16
……
Secondary scrambling code
511×16 + 15
8192 scrambling codes
512 sets
Primary Scrambling Code
……
A primary scrambling code and 15 secondary scrambling codes are
included in a set.
HUAWEI TECHNOLOGIES CO., LTD. Page 15All rights reserved
Primary Scrambling Code Group
Primary scrambling codes for downlink physical channels
Group 0
…
Primary scrambling code 0
……
Primary scrambling code
63 × 8
……
Primary scrambling code
63×8 + 7
512 primary scrambling codes
……
Group 1
Group 63
Primary scrambling code 1
Primary scrambling code 7
64 primary scrambling code groups
Each group consists of 8 primary scrambling codes
HUAWEI TECHNOLOGIES CO., LTD. Page 16All rights reserved
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
HUAWEI TECHNOLOGIES CO., LTD. Page 17All rights reserved
Chapter 2 Physical Layer Key TechnologyChapter 2 Physical Layer Key Technology
Section 1 Physical ChannelSection 1 Physical Channel Structure and FunctionsStructure and Functions
Section 2 Channel MappingSection 2 Channel Mapping
HUAWEI TECHNOLOGIES CO., LTD. Page 18All rights reserved
WCDMA radio interface has three kinds of channels
In terms of protocol layer, the WCDMA radio interface has three channels: Physical channel, transport channel and logical channel.
Logical channel: Carrying user services directly. According to the types of the carried services, it is divided into two types: Control channel and traffic channel
Transport channel: It is the interface of radio interface layer 2 and physical layer, and is the service provided for MAC layer by the physical layer. According to whether the information transported is dedicated information for a user or common information for all users, it is divided into dedicated channel and common channel
Physical channel: It is the ultimate embodiment of all kinds of information when they are transmitted on radio interfaces. Each kind of channel which uses dedicated carrier frequency, code (spreading code and scrambling code) and carrier phase (I or Q) can be regarded as a dedicated channel
HUAWEI TECHNOLOGIES CO., LTD. Page 19All rights reserved
Control channelControl channel
Traffic channelTraffic channel
Dedicated traffic channelDedicated traffic channel (DTCH) (DTCH)
Common traffic channelCommon traffic channel (CTCH) (CTCH)
Broadcast control channelBroadcast control channel (BCCH) (BCCH)
Paging control channelPaging control channel (PCCH) (PCCH)
Dedicate control channelDedicate control channel (DCCH) (DCCH)
Common control channelCommon control channel (CCCH) (CCCH)
Logical Channel
HUAWEI TECHNOLOGIES CO., LTD. Page 21All rights reserved
Dedicated Channel (DCH)
DCH is an uplink or downlink channel
Broadcast channel (BCH)
Forward access channel (FACH)
Paging channel (PCH)
Random access channel (RACH)
High-speed downlink shared channel (HS-
DSCH)
Common transport channel
Dedicated transport channel
Transport Channel
HUAWEI TECHNOLOGIES CO., LTD. Page 22All rights reserved
Physical Channel
A physical channel is defined by a specific carrier frequency, code
(scrambling code, spreading code) and relative phase
In UMTS system, the different code (scrambling code or spreading
code) can distinguish the channels
Most channels consist of radio frames and time slots, and each radio
frame consists of 15 time slots
Two types of physical channel: UL and DL
Physical Channel
Frequency, Code, Phase
HUAWEI TECHNOLOGIES CO., LTD. Page 23All rights reserved
Downlink Physical Channel
Downlink Dedicated Physical Channel
(Downlink DPCH)
Downlink Physical Channel
Downlink Common Physical Channel
Common Control Physical Channel (CCPCH)
Synchronization Channel (SCH)
Paging Indicator Channel (PICH)
Acquisition Indicator Channel (AICH)
Common Pilot Channel (CPICH)
High-Speed Physical Downlink Shared Channel (HS-PDSCH)
High-Speed Shared Control Channel
(HS-SCCH)
HUAWEI TECHNOLOGIES CO., LTD. Page 24All rights reserved
Uplink Physical Channel
Uplink Dedicated Physical Channel
Uplink Dedicated Physical Data Channel (Uplink DPDCH)
Uplink Dedicated Physical Control Channel (Uplink DPCCH)
High-Speed Dedicated Physical Control Channel (HS-DPCCH)
Uplink Common Physical Channel
Physical Random Access Channel (PRACH)
Uplink Physical Channel
HUAWEI TECHNOLOGIES CO., LTD. Page 25All rights reserved
Function of physical channel
Node B UE
P-CCPCH-Primary Common Control Physical ChannelSCH- Synchronisation Channel
P-CCPCH-Primary Common Control Physical ChannelSCH- Synchronisation Channel
P-CPICH-Primary Common Pilot Channel S-CPICH-Secondary Common Pilot ChannelP-CPICH-Primary Common Pilot Channel S-CPICH-Secondary Common Pilot Channel
Cell broadcast channels
DPDCH-Dedicated Physical Data ChannelDPDCH-Dedicated Physical Data Channel
DPCCH-Dedicated Physical Control ChannelDPCCH-Dedicated Physical Control Channel
Dedicated channels
Paging channels
PICH-Paging Indicator ChannelPICH-Paging Indicator Channel
S-CCPCH-Secondary Common Control Physical ChannelS-CCPCH-Secondary Common Control Physical Channel
PRACH-Physical Random Access ChannelPRACH-Physical Random Access Channel
AICH-Acquisition Indicator ChannelAICH-Acquisition Indicator Channel
Random access channels
HS-DPCCH-High Speed Dedicated Physical Control ChannelHS-DPCCH-High Speed Dedicated Physical Control Channel
HS-SCCH-High Speed Share Control Channel HS-SCCH-High Speed Share Control Channel
HS-PDSCH-High Speed Physical Downlink Share ChannelHS-PDSCH-High Speed Physical Downlink Share Channel
High speed downlink share channels
HUAWEI TECHNOLOGIES CO., LTD. Page 26All rights reserved
Primary Synchronization Channel (P-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, and there are altogether 64 SSC sequences correspond to 64 primary scrambling code groups
Primary SCH
Secondary SCH
Slot #0 Slot #1 Slot #14
acsi,0
pac pac pac
acsi,1 acs
i,14
256 chips
2560 chips
One 10 ms SCH radio frame
HUAWEI TECHNOLOGIES CO., LTD. Page 27All rights reserved
slot number Scrambling Code Group #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14
Group 0 1 1 2 8 9 10 15 8 10 16 2 7 15 7 16
Group 1 1 1 5 16 7 3 14 16 3 10 5 12 14 12 10
Group 2 1 2 1 15 5 5 12 16 6 11 2 16 11 15 12
Group 3 1 2 3 1 8 6 5 2 5 8 4 4 6 3 7
Group 4 1 2 16 6 6 11 15 5 12 1 15 12 16 11 2
…
Group 61 9 10 13 10 11 15 15 9 16 12 14 13 16 14 11
Group 62 9 11 12 15 12 9 13 13 11 14 10 16 15 14 16
Group 63 9 12 10 15 13 14 9 14 15 11 11 13 12 16 10
Secondary Synchronization Channel (S-SCH)
……..
2560 chips
acp
Slot # ?
P-SCHP-SCH acp
Slot #?
16 6S-SCHS-SCH
acp
Slot #?
11 Group 2Group 2Slot 7, 8, 9Slot 7, 8, 9
256 chips
HUAWEI TECHNOLOGIES CO., LTD. Page 28All rights reserved
Common Pilot Channel (CPICH) Common Pilot Channel (CPICH)
Carries pre-defined sequence
Fixed rate 30Ksps , SF=256
Primary CPICH (P-CPICH)
Uses the fixed channel code -- Cch,256,0
Scrambled by the primary scrambling code
Only one CPICH per cell
Broadcast over the entire cell
The P-CPICH is a phase reference for SCH, Primary CCPCH, AICH, PICH. By default, it is also a phase reference for downlink DPCH
Pre-defined symbol sequence
Slot #0 Slot #1 Slot # i Slot #14
Tslot = 2560 chips , 20 bits
1 radio frame: Tr = 10 ms
HUAWEI TECHNOLOGIES CO., LTD. Page 29All rights reserved
Primary Common Control Physical Channel (P-CCPCH) Fixed rate, fixed OVSF code ( 30ksps , Cch,256,1 ) 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
PCCPCH Data
18 bits
Slot #0
1 radio frame: T f = 10 ms
Slot #1 Slot #i
256 chips
Slot #14
T slot = 2560 chips,20 bits
SCH
HUAWEI TECHNOLOGIES CO., LTD. Page 30All rights reserved
Paging Indicator Channel (PICH) PICH is a fixed-rate (SF=256) physical channel used to carry the Paging Indicators (PI). Frame structure of PICH: one frame of length 10ms consists of 300 bits of which 288 bits
are used to carry paging indicators and the remaining 12 bits are not defined
N paging indicators {PI0, …, PIN-1} in each PICH frame, N=18, 36, 72, or 144
If a paging indicator in a certain frame is set to 1, it indicates that UEs associated with this paging indicator should read the corresponding frame of the associated S-CCPCH
One radio frame (10 ms)
b1 b0
288 bits for paging indication 12 bits (undefined)
b287 b288 b299
HUAWEI TECHNOLOGIES CO., LTD. Page 31All rights reserved
Secondary Common Control Physical Channel (S-CCPCH)
Carry FACH and PCH Two kinds of S-CCPCH: with or without TFCI. UTRAN decides if a TFCI should be transmitted, UE must support TFCI Possible rates are the same as that of downlink DPCH
SF =256 - 4
FACH and PCH can be mapped to the
same or separate S-CCPCHs. If
mapped to the same S-CCPCH, they
can be mapped to the same fame
DataN bits
Slot #0 Slot #1 Slot #i Slot #14
1 radio frame: T f = 10 ms
T slot = 2560 chips,
Data
PilotN bitsPilotN bits
TFCITFCI
20*2 k bits (k=0..6)
HUAWEI TECHNOLOGIES CO., LTD. Page 32All rights reserved
Physical Random Access Channel (PRACH) The random-access transmission data consists of two parts:
One or several preambles: each preamble is of length 4096chips and consists of 256 repetitions of a signature whose length is 16 chips, 16 available signatures totally
10 or 20ms message part
Which signature is available and the length of message part are determined by higher layer
Message partPreamble
4096 chips10 ms (one radio frame)
Preamble Preamble
Message partPreamble
4096 chips 20 ms (two radio frames)
Preamble Preamble
HUAWEI TECHNOLOGIES CO., LTD. Page 33All rights reserved
PRACH Access Timeslot Structure
#1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14
5120 chips
radio frame: 10 ms radio frame: 10 ms
Access slot #0 Random Access TransmissionRandom Access Transmission
Access slot #1
Access slot #7
Access slot #14
Random Access Transmission
Random Access TransmissionRandom Access Transmission
Random Access TransmissionRandom Access TransmissionAccess slot #8
HUAWEI TECHNOLOGIES CO., LTD. Page 34All rights reserved
PRACH Message Structure
PilotN bits
Slot # 0 Slot # 1 Slot # i Slot # 14
Message part radio frame TRACH = 10 ms
Tslot = 2560 chips, 10*2
Pilot
TFCI
N bitsTFCI
DataN data bitsData
Control
k bits (k=0..3)
HUAWEI TECHNOLOGIES CO., LTD. Page 35All rights reserved
Acquisition Indicator Channel (AICH) Frame structure of AICH : two frames, 20 ms, consists of a repeated sequence
of 15 consecutive AS, each of length 40 symbols(5120 chips). Each time slot
consists of two parts , an Acquisition-Indicator(AI) and a part of duration
1024chips with no transmission
Acquisition-Indicator AI have 16 kinds of Signature
P-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
HUAWEI TECHNOLOGIES CO., LTD. Page 36All rights reserved
Uplink Dedicated Physical Channel (DPDCH&DPCCH)
Uplink DPDCH and DPCCH are I/Q code division multiplexed (CDM)
within each radio frame
Uplink DPDCH carries data generated at higher layer
Uplink 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 uplink DPDCH is from 4 to 256
The spreading factor of uplink DPDCH and DPCCH can be different in
the same Layer 1 connection
Each DPCCH time slot consists of Pilot, TFCI , FBI , TPC
HUAWEI TECHNOLOGIES CO., LTD. Page 37All rights reserved
Frame Structure of Uplink DPDCH/DPCCH
Pilot Npilot bits
TPC NTPC bits
DataNdata bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2 k bits (k=0..6)
1 radio frame: T = 10 msf
DPDCH
DPCCHFBI
NFBI bitsTFCI
NTFCI bits
HUAWEI TECHNOLOGIES CO., LTD. Page 38All rights reserved
Downlink Dedicated Physical Channel (DPDCH+DPCCH)
DPCH consists of dedicated data and control information
Control information includes : Pilot 、 TPC 、 TFCI (optional)
The spreading factor of DCH can be from 512 to 4,and can be
changed during connection
Downlink DPDCH and DPCCH is time division multiplexing (TDM)
HUAWEI TECHNOLOGIES CO., LTD. Page 39All rights reserved
Frame Structure of Downlink DPCH (DPDCH+DPCCH)
One radio frame, Tf = 10 ms
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2 k bits (k=0..7)
Data2Ndata2 bits
DPDCH
TFCI NTFCI bits
Pilot Npilot bits
Data1Ndata1 bits
DPDCH DPCCH DPCCH
TPC NTPC bits
HUAWEI TECHNOLOGIES CO., LTD. Page 40All rights reserved
High-Speed Physical Downlink Shared Channel (HS-PDSCH)
Bear HSDPA traffic data and layer2 bits mapped from the transport
channel
SF=16, can be configured several channels to increase data service
Slot #0 Slot#1 Slot #2
T slot = 2560 chips, M*10*2k bits (k=4)
DataN Data 1 bits
1 subframe: Tf = 2 ms
HUAWEI TECHNOLOGIES CO., LTD. Page 41All rights reserved
High-Speed Shared Control Channel (HS-SCCH)
Carries physical layer signalling to a single UE ,such as modulation scheme (1
bit) ,channelization code set (7 bit), transport Block size (6bit),HARQ process
number (3bit), redundancy version (3bit), new data indicator (1bit), UE identity
(16bit)
HS-SCCH is a fixed rate (60 ksps, SF=128) downlink physical channel used to
carry downlink signalling related to HS-DSCH transmission
Slot #0 Slot#1 Slot #2
T slot= 2560 chips, 40 bits
DataN Data 1 bits
1 subframe: T f = 2 ms
HUAWEI TECHNOLOGIES CO., LTD. Page 42All rights reserved
High-Speed Dedicated Physical Control Channel (HS-DPCCH )
HS-DPCCH carries information to acknowledge downlink transport blocks and
feedback information to the system for scheduling and link adaptation of
transport block
CQI and ACK/NACK
Physical Channel , Uplink , SF=256, power control
Subframe #0 Subframe # i Subframe #4
HARQ-ACK CQI
One radio frame T f = 10 ms
One HS-DPCCH subframe (2 ms)
2 T slot = 5120 chips T slot = 2560 chips
HUAWEI TECHNOLOGIES CO., LTD. Page 43All rights reserved
Chapter 2 Physical Layer Key Technology Chapter 2 Physical Layer Key Technology
Section 1 Physical Channel Structure and FunctionsSection 1 Physical Channel Structure and Functions
Section 2 Channel MappingSection 2 Channel Mapping
HUAWEI TECHNOLOGIES CO., LTD. Page 44All rights reserved
Mapping Relation Between ChannelsLogical channels Transport channels Physical channels
BCCH BCH P-CCPCH
FACH S-CCPCH
PCCH PCH S-CCPCH
CCCH RACH PRACH
FACH S-CCPCH
CTCH FACH S-CCPCH
DCCH, DTCH DCH DPDCH
HS-DSCH HS-PDSCH
RACH, FACH PRACH, S-CCPCH
HUAWEI TECHNOLOGIES CO., LTD. Page 45All rights reserved
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
HUAWEI TECHNOLOGIES CO., LTD. Page 46All rights reserved
Synchronization Procedure—Cell Search
Frame synchronization and code-group identification
Scrambling-code identification
UE uses SSC to find frame synchronization and identify the 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
Slot synchronizationUE uses PSC to acquire slot synchronization to a cell
HUAWEI TECHNOLOGIES CO., LTD. Page 47All rights reserved
Synchronization Procedure— Channel Timing Relationship
AICH access slo ts
Secondary SCH
Primary SCH
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 DPCH DPCH,n
HUAWEI TECHNOLOGIES CO., LTD. Page 48All rights reserved
Random Access ProcedureSTART
Choose a RACH sub channel fromavailable ones
Get available signatures
Set Preamble Retrans Max
Set Preamble_Initial_Power
Send a preamble
Check the corresponding AI
Increase message part power by p-m based on preamble power
Set physical status to be RACH message transmitted Set physical status to be Nack
on AICH received
Choose a access slot again
Counter> 0 & Preamble power-maximum allowed power<6 dB
Choose a signature and increase preamble transmit power
Set physical status to be Nack on AICH received
Get negative AI
No AI
Report the physical status to MAC
END
Get positive AI
The counter of preamble retransmit Subtract-1, Commanded preamble power
increased by Power Ramp Step
N
Y
Send the corresponding message part
HUAWEI TECHNOLOGIES CO., LTD. Page 49All rights reserved
Random Access Procedure—RACH Physical random access procedure
1. Derive the available uplink access slots, in the next full access slot set, for the set of available RACH sub-channels within the given ASC. Randomly select one access slot among the ones previously determined. If there is no access slot available in the selected set, randomly select one uplink access slot 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
2. Randomly select a signature from the set of available signatures within the given ASC
3. Set the Preamble Retransmission Counter to Preamble_ Retrans_ Max
HUAWEI TECHNOLOGIES CO., LTD. Page 50All rights reserved
Random Access Procedure—RACH
4. Set the parameter Commanded Preamble Power to Preamble_Initial_Power
5. Transmit a preamble using the selected uplink access slot, signature, and preamble transmission power
6. If no positive or negative acquisition indicator (AI +1 nor –1) corresponding to the selected signature is detected in the downlink access slot corresponding to the selected uplink access slot:
− A: Select the next available access slot in the set of available RACH sub-channels within the given ASC
− B: select a signature
− C: Increase the Commanded Preamble Power
− D: Decrease the Preamble Retransmission Counter by one. If the Preamble Retransmission Counter > 0 then repeat from step 6. Otherwise exit the physical random access procedure
HUAWEI TECHNOLOGIES CO., LTD. Page 51All rights reserved
Random Access Procedure—RACH
7. If a negative acquisition indicator corresponding to the selected
signature is detected in the downlink access slot corresponding to
the selected uplink access slot, exit the physical random access
procedure Signature
8. If a positive acquisition indicator corresponding to the selected
signature is detected , Transmit the random access message three
or four uplink access slots after the uplink access slot of the last
transmitted preamble
9. Exit the physical random access procedure
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Transmit diversity Mode
Application of Tx diversity modes on downlink physical channel
Physical channel type Open loop mode Closed loop mode
TSTD STTD Mode 1 Mode 2
P-CCPCH – applied – –
SCH applied – – –
S-CCPCH – applied – –
DPCH – applied applied applied
PICH – applied – –
HS-PDSCH – applied applied –
HS-SCCH – applied – –
AICH – applied – –
HUAWEI TECHNOLOGIES CO., LTD. Page 54All rights reserved
Transmit Diversity-STTD
Space time block coding based transmit antenna diversity(STTD ) 4 consecutive bits b0, b1, b2, b3 using STTD coding
b0 b1 b2 b3
b0 b1 b2 b3
-b2 b3 b0 -b1
Antenna 1
Antenna 2Channel bits
STTD encoded channel bitsfor antenna 1 and antenna 2.
HUAWEI TECHNOLOGIES CO., LTD. Page 55All rights reserved
Transmit Diversity-TSTD
Time switching transmit diversity (TSTD) is used only on SCH channel.
Antenna 1
Antenna 2
ac si,0
acp
acsi,1
acp
acsi,14
acp
Slot #0 Slot #1 Slot #14
acsi,2
acp
Slot #2
(Tx OFF)
(Tx OFF)(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)(Tx OFF)(Tx OFF)
HUAWEI TECHNOLOGIES CO., LTD. Page 56All rights reserved
Summary
This course mainly introduces the basic
concept, key technology and procedures of
WCDMA physical layer
This is very helpful for comprehension of Uu
interface features and further study