introductions to wcdma fdd mode physical layer
TRANSCRIPT
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
Introductions to WCDMA FDD Mode Physical Layer
2
Table of Contents
Traditional Sequential ASIC Design FlowWCDMA Network ArchitecturePhysical Layer General DescriptionMultiplexing and Channel Coding (MCC)WCDMA Uplink Physical LayerWCDMA Downlink Physical LayerCompressed ModeSite Selection Transmit Diversity
3
References
3GPP Technical Specification (Release 1999, 25 Series)WCDMA for UMTS – Radio Access For Third Generation Mobile Communications-- by Harri Holma and Antti Toskala, Artech House, 2001Wireless Communications - Principles & Practice-- by Theodore S. Rappaport, Prentice Hall, 2nd Edition, Dec. 31, 2001WCDMA Requirements and Practical Design-- by Rudolf Tanner and Jason Woodard, John Wiley & Sons, Ltd, March 2005.
4
Communications Hardware Design Flow
Floating Point Simulation
Fixed Point Simulation
System Specifications
RTL Coding
Function Verification
1. Perfect Receiver2. Synchronization3. Channel Estimation4. Channel Decoding5. De-Interleaving6. Performance should meet
system requirements.
1. Hardware cost limits precision of received signal.
2. Hardware architecture should be considered.
3. Performance is worse than floating point simulation.
1. RTL:Register Transfer Level2. Verilog/VHDL
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
WCDMA Network Architecture
6
Network Elements in a WCDMA PLMNUu Iu
USIM
ME
Cu
UE
Node B
Node B
Node B
Node B
RNC
RNC
Iub Iur
UTRAN
MSC/VLR GMSC
SGSN GGSN
HLR
Core Network
PLMN, PSTNISDN, … etc.
Internet
ExternalNetworks
•PLMN: Public Land Mobile Network. One PLMN is operated by a single operator.
7
User Equipment (UE)The UE consists of two parts:
The Mobile Equipment (ME) is the radio terminal used for radio communication over the Uu interface.The UMTS Subscriber Identity Module (USIM) is a smartcard that holds the subscriber identity, performs authentication algorithms, and stores authentication and encryption keys and some subscription information that is needed at the terminal.
UTRAN consists of two distinct elements:The Node B converts the data flow between the Iub and Uuinterfaces. It also participates in radio resource management.The Radio Network Controller (RNC) owns and controls the radio resources in its domain (the Node Bs connected to it). RNC is the service access point for all services UTRAN provides the core network (CN).
8
WCDMA System ArchitectureUMTS system utilizes the same well-known architecture that has been used by all main 2nd generation systems.The network elements are grouped into:
The Radio Access Network (RAN, UMTS Terrestrial RAN = UTRAN) that handles all radio-related functionality.The Core Network (CN) which is responsible for switching and routing calls and data connections to external networks.
Both User Equipment (UE) and UTRAN consist of completely new protocols, which is based on the new WCDMA radio technology.The definition of CN is adopted from GSM.
9
HLR (Home Location Register) is a database located in the user’s home system that stores the master copy of the user’s service profile.
The service profile consists of, for example, information on allowed services, forbidden roaming areas, and Supplementary Service information such as status of call forwarding and the call forwarding number.It is created when a new user subscribes to the system.HLR stores the UE location on the level of MSC/VLR and/or SGSN.
Main Elements of the GSM Core Network
10
MSC/VLR (Mobile Services Switching Center / Visitor Location Register) is the switch (MSC) and database (VLR) that serves the UE in its current location for circuit switched services.
The MSC function is used to switch the CS transactions.The VLR function holds a copy of the visiting user’s service profile, as well as more precise information on the UE’slocation within the serving system.
Main Elements of the GSM Core Network
11
GMSC (Gateway MSC) is the switch at the point where UMTS PLMN is connected to external CS networks.
All incoming and outgoing circuit switched connections go through GMSC.
SGSN (Serving GPRS (General Packet Radio Service) Support Node) functionality is similar to that of MSC/VLR, but is typically used for Packet Switched (PS) services.GGSN (Gateway GPRS Support Node) functionality is close to that of GMSC but is in relation to PS services.
Main Elements of the GSM Core Network
12
InterfacesCu Interface: this is the electrical interface between the USIM smartcard and the ME. The interface follows a standard format for smartcards.Uu Interface: this is the WCDMA radio interface, which is the subject of the main part of WCDMA technology. This is also the most important open interface in UMTS.Iu Interface: this connects UTRAN to the CN.Iur Interface: the open Iur interface allows soft handover between RNCs from different manufacturers.Iub Interface: the Iub connects a Node B and an RNC. UMTS is the first commercial mobile telephony system where the Controller-Base Station interface is standardized as a fully open interface.
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
WCDMA Physical Layer General Description (3G TS 25.201)
14
Establishes the characteristics of the layer-1 transport channels and physical channels in the FDD mode, and specifies:
Transport channelsPhysical channels and their structureRelative timing between different physical
channels in the same link, and relative timing between uplink and downlink;
Mapping of transport channels onto the physical channels.
Physical channels and mapping of transport channels onto physical channels (FDD)
TS 25.211
Describes the contents of the layer 1 documents (TS 25.200 series); where to find information; a general description of layer 1.
Physical Layer –general description
TS 25.201
3GPP RAN Specifications
15
Establishes the characteristics of the spreading and modulation in the FDD mode, and specifies:
Spreading;Generation of channelization and scrambling codes;Generation of random access preamble codes;Generation of synchronization codes;Modulation;
Spreading and Modulation (FDD)
TS 25.213
Describes multiplexing, channel coding, and interleaving in the FDD mode and specifies:
Coding and multiplexing of transport channels;Channel coding alternatives;Coding for layer 1 control information;Different interleavers;Rate matching;Physical channel segmentation and mapping;
Multiplexing and Channel Coding (FDD)
TS 25.212
3GPP RAN Specifications
16
Establishes the characteristics of the physical layer measurements in the FDD mode, and specifies:
The measurements performance by layer 1;Reporting of measurements to higher layers and
network;Handover measurements and idle-mode
measurements.
Physical Layer Measurements (FDD)
TS 25.215
Establishes the characteristics of the physical layer procedures in the FDD mode, and specifies:
Cell search procedures;Power control procedures;Random access procedure.
Physical Layer Procedures (FDD)
TS 25.214
3GPP RAN Specifications
17
General Protocol ArchitectureRadio interface means the Uu point between User Equipment (UE) and network.The radio interface is composed of Layers 1, 2 and 3.
Radio Resource Control (RRC)
Medium Access Control
Transport channels
Physical layer
Con
trol /
Mea
sure
men
ts
Layer 3
Logical channelsLayer 2
Layer 1
18
General Protocol Architecture
The circles between different layer/sub-layers indicate Service Access Points (SAPs).The physical layer offers different Transport channels to MAC.
A transport channel is characterized by how the information is transferred over the radio interface.
MAC offers different Logical channels to the Radio Link Control (RLC) sub-layer of Layer 2.
A logical channel is characterized by the type of information transferred.
19
General Protocol ArchitecturePhysical channels are defined in the physical layer.There are two duplex modes: Frequency Division Duplex (FDD) and Time Division Duplex (TDD).In the FDD mode a physical channel is characterized by the code, frequency and in the uplink the relative phase (I/Q).In the TDD mode the physical channels is also characterized by the timeslot.The physical layer is controlled by RRC.
20
Service Provided to Higher LayerThe 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.
The physical layer is expected to perform the following functions in order to provide the data transport service:
1. Macrodiversity distribution/combining and soft handover execution.
2. Error detection on transport channels and indication to higher layers.
3. FEC encoding/decoding of transport channels.4. Multiplexing of transport channels and demultiplexing of
coded composite transport channels (CCTrCHs).
21
Service Provided to Higher Layer5. Rate matching of coded transport channels to physical
channels.6. Mapping of coded composite transport channels on physical
channels.7. Power weighting and combining of physical channels.8. Modulation and spreading/demodulation and despreading of
physical channels.9. Frequency and time (chip, bit, slot, frame) synchronisation.10. Radio characteristics measurements including FER, SIR,
Interference Power, etc., and indication to higher layers.11. Inner - loop power control.12. RF processing.
22
Multiple AccessUTRA has two modes, FDD (Frequency Division Duplex) & TDD (Time Division Duplex), for operating with paired and unpaired bands respectively.FDD: A pair of frequency bands which have specified separation shall be assigned for the system.TDD: A duplex method whereby uplink and downlink transmissions are carried over same radio frequency by using synchronised time intervals.
In the TDD, time slots in a physical channel are divided into transmission and reception part.
23
Physical Layer MeasurementsRadio characteristics including FER, SIR, Interference power, etc., are measured and reported to higher layers and network. Such measurements are:
1. Handover measurements for handover within UTRA. Specific features being determined in addition to the relative strength of the cell, for the FDD mode the timing relation between cells for support of asynchronous soft handover.
2. The measurement procedures for preparation for handover to GSM900/GSM1800.
3. The measurement procedures for UE before random access process.
24
Transport ChannelsTransport channels are services offered by Layer 1 to the higher layers.A transport channel is defined by how and with what characteristics data is transferred over the air interface.
Two groups of transport channels:Dedicated Transport Channels
Common Transport Channels
25
Transport ChannelsDedicated Transport Channels
DCH – Dedicated Channel (only one type)
Common Transport Channels – divided between all or a group of users in a cell (no soft handover, but some of them can have fast power control)
BCH: Broadcast Channel
FACH: Forward Access Channel
PCH: Paging Channel
RACH: Random Access Channel
CPCH: Common Packet Channel
DSCH: DL Shared Channel
26
Dedicated Transport ChannelsThere exists only one type of dedicated transport channel, the Dedicated Channel (DCH)The Dedicated Channel (DCH) is a downlink or uplink transport channel.The DCH is transmitted over the entire cell or over only a part of the cell using e.g. beam-forming antennas.DCH carries both the service data, such as speech frames, and higher layer control information, such as handover commands or measurement reports from the terminal.
27
Dedicated Transport Channels
The content of the information carried on the DCH is not visible to the physical layer, thus higher layer control information and user data are treated in the same way.The physical layer parameters set by UTRAN may vary between control and data.Possibility of fast rate change (every 10 ms)Support of fast power control.Support of soft handover.
28
Common Transport ChannelBroadcast Channel (BCH) -- mandatory
BCH is a downlink transport channel that is used to broadcast system and cell specific information.BCH is always transmitted over the entire cell.The most typical data needed in every network is the available random access codes and access slots in the cell, or the types of transmit diversity.BCH is transmitted with relatively high power.Single transport format – a low and fixed data rate for the UTRA broadcast channel to support low-end terminals.
29
Common Transport Channel
Paging Channel (PCH) -- mandatoryPCH is a downlink transport channel.PCH is always transmitted over the entire cell.PCH carries data relevant to the paging procedure, that is, when the network wants to initiate communication with the terminal.The identical paging message can be transmitted in a single cell or in up to a few hundreds of cells, depending on the system configuration.
30
Common Transport ChannelRandom Access Channel (RACH) -- mandatory
RACH is an uplink transport channel.RACH is intended to be used to carry control information from the terminal, such as requests to set up a connection.RACH can also be used to send small amounts of packet data from the terminal to the network.The RACH is always received from the entire cell.The RACH is characterized by a collision risk.RACH is transmitted using open loop power control.
31
Common Transport ChannelForward Access Channel (FACH) -- mandatory
FACH is a downlink transport channel.FACH is transmitted over the entire cell or over only a part of the cell using e.g. beam-forming antennas.FACH can carry control information; for example, after a random access message has been received by the base station.FACH can also transmit packet data.FACH does not use fast power control.FACH can be transmitted using slow power control.There can be more than one FACH in a cell.The messages transmitted need to include in-band identification information.
32
Common Transport Channel
Common Packet Channel (CPCH) -- optionalCPCH is an uplink transport channel.CPCH is an extension to the RACH channel that is intended to carry packet-based user data.CPCH is associated with a dedicated channel on the downlink which provides power control and CPCH Control Commands (e.g. Emergency Stop) for the uplink CPCH.The CPCH is characterised by initial collision risk and by being transmitted using inner loop power control.CPCH may last several frames.
33
Common Transport Channel
Downlink Shared Channel (DSCH) -- optionalDSCH is a downlink transport channel shared by several UEsto carry dedicated user data and/or control information.The DSCH is always associated with one or several downlink DCH.The DSCH is transmitted over the entire cell or over only a part of the cell using e.g. beam-forming antennas.DSCH supports fast power control as well as variable bit rate on a frame-by-frame basis.
34
Transport Channel
YesYesYesYesYesNoSuited for bursty data?
Medium or large data amounts.
Medium or large data amounts.
Small or medium data
amounts.
Small data amounts.
Small data amounts.
Medium or large data amount.
Suited for:
NoNoNoNoNoYesSoft Handover
YesYesYesNoNoYesFast PowerControl
Shared between
users.
Shared between
users.
Fixed codes per cell.
Fixed codes per cell.
Fixed codes per cell.
According to maximum bit
rate.
CodeUsage
Uplink, only in TDD.
DownlinkUplinkUplinkDownlinkBothUplink/Downlink
USCHDSCHCPCHRACHFACHDCH
Shared ChannelsCommon ChannelDedicatedChannel
35
Transport Channels
DCH
RACH
CPCH
BCH
FACH
PCH
Physical Channels
Dedicated Physical Data Channel (DPDCH)
Dedicated Physical Control Channel (DPCCH)
Physical Random Access Channel (PRACH)
Physical Common Packet Channel (PCPCH)
Primary Common Control Physical Channel (P-CCPCH)
Secondary Common Control Physical Channel (S-CCPCH)
DSCH Physical Downlink Shared Channel (PDSCH)Common Pilot Channel (CPICH)Synchronization Channel (SCH)
Acquisition Indicator Channel (AICH)
Access Preamble Acquisition Indicator Channel (AP-AICH)
Paging Indicator Channel (PICH)
CPCH Status Indicator Channel (CSICH)
Collision-Detection/Channel-Assignment Indicator Channel (CD/CA-ICH)⎪⎪⎪⎪
⎩
⎪⎪⎪⎪
⎨
⎧
Unmapped
Mapping of Transport Channels onto Physical Channels
36
TFI Transport Block
Transport Block
Transport Ch 1
TFI Transport Block
Transport Block
Transport Ch 2
TFCI Coding & Multiplexing
Physical ControlChannel
Physical DataChannel
TFI Transport Block &Error Indication
Transport Block &Error Indication
Transport Ch 1
TFI Transport Block &Error Indication
Transport Block &Error Indication
Transport Ch 2
TFCI Decoding &Demultiplexing
Physical ControlChannel
Physical DataChannel
Physical Layer
Higher Layer
Interface Between Higher Layers and the Physical Layer
37
Transport Format Indicator (TFI)
The TFI is a label for a specific transport format within a transport format set.It is used in the inter-layer communication between MAC and L1 each time a transport block set is exchanged between the two layers on a transport channel.When the DSCH is associated with a DCH, the TFI of the DSCH also indicates the physical channel (i.e. the channelisation code) of the DSCH that has to be listened to by the UE.
38
This is a representation of the current Transport Format Combination.The TFCI is used in order to inform the receiving side of the currently valid Transport Format Combination, and hence how to decode, de-multiplex and deliver the received data on the appropriate Transport Channels.There is a one-to-one correspondence between a certain value of the TFCI and a certain Transport Format Combination.MAC indicates the TFI to Layer 1 at each delivery of Transport Block Sets on each Transport Channel. Layer 1 then builds the TFCI from the TFIs of all parallel transport channels of the UE, processes the Transport Blocks appropriately and appends the TFCI to the physical control signalling.Through the detection of the TFCI the receiving side is able to identify the Transport Format Combination.
Transport Format Combination Indicator (TFCI)
39
In UTRA, the data generated at higher layers is carried over the air with transport channels, which are mapped in the physical layer to different physical channels.The physical layer is required to support variable bit rate transport channels to offer bandwidth-on-demand services, and to be able to multiplex several services to one connection.The transport channels may have a different number of blocks.Each transport channel is accompanied by the Transport Format Indicator (TFI).
Mapping of Transport Channel to Physical Channel
40
The physical layer combines the TFI information from different transport channels to the Transport Format Combination Indicator (TFCI).TFCI is transmitted in the physical control channel.At any moment, not all the transport channels are necessarily active.One physical control channel and one or more physical data channels form a single Coded Composite Transport Channel (CCTrCh).
Mapping of Transport Channel to Physical Channel
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
Multiplexing and Channel Coding( 3G TS 25.212 )
42
Table of Contents
Overview of MCCTransport channel related terminologiesUL-MCCDL-MCCSome examples
43
Overview of MCCMCC – multiplexing and channel coding
Encoding data stream from MAC and higher layers to offer transport services over the radio transmission linkMap transport block data into physical channel data
Operations performed in MCCCRC attachmentChannel codingInterleavingRadio frame equalization/segmentationRate matchingTransport channel multiplexingMapping to physical channels
44
Overview of MCC
Multiplexing and channel coding (MCC) isa key procedure in 3GPP PHY to support QoSrequirements from upper layersMCC interfaces with the 3GPP MAC layer by transport channels (TrCHs)Different QoS requirements may assign to different transport channelsTransport channels are processed and multiplexed into one or more physical channels (PhCHs) by MCC
45
UL Multiplexing and Channel Coding
46
DL Multiplexing and Channel Coding
47
Transport blockTransport block setTransport block sizeTransport block set sizeTransmission time interval (TTI)Transport formatTransport format setTransport format combinationTransport format combination set
Transport Channel Related Terminologies
48
Transport blockA basic unit exchanged between L1 and MAC
Transport block setA set of transport block exchanged between L1 and MAC at the same time instance in the same transport channel
Transport block sizeSize of transport block
Transport block set sizeSize of transport block set
Transport block TrCH1Transport block
Transport block
Transport block
Transport block
Transport block
Transport Channel Related Terminologies
49
Transport formatFormat of definition for the delivery of transport block set during a TTI (transmission time interval)Format contains
Dynamic partTransport block sizeTransport block set size
Static partTransmission time intervalError protection
Channel coding type (1/2,1/3convolutional, turbo,no cc)Rate matching parameter
CRC size (8bit, 12bit, 16bit, 24bit, no CRC)Ex:{320bits, 640bits}, { 10ms, ½ convolutional code, rate matching parameter = 1, 8bits CRC }
Transport Channel Related Terminologies
50
Transport format setThe set of transport formats associated to a transport channelTransport block set size and transport block size can be different in a transport format setAll other parameters are fixed in a transport format set
Ex:{ 40bits, 40bits } , { 80bits, 80bits }, { 160bits, 160bits }{ 10ms, ½ convolutional code, rate matching parameter = 1, 8bits CRC }
Transport Channel Related Terminologies
51
Transport format combinationL1 multiplexes several transport channels into one physical channelTransport format is a combination of currently valid transport formats of different transport channel
Examples:DCH1: {20bits, 20bits}, {10ms, ½ convolutional code, rm=2}DCH2: {320bits, 1280bits}, {10ms, turbo code, rm = 3}DCH3: {320bits, 320bits}, {40ms, ½ convolutional code, rm= 1}
Transport Channel Related Terminologies
52
Transport format combination setA set of transport format combination
Ex:Combination 1
DCH1{20bits, 20bits}, DCH2{320bits, 1280bits} DCH3{320bits,320bits}Combination 2
DCH1{40bits, 40bits}, DCH2{320bits, 1280bits} DCH3{320bits,320bits}Combination 3
DCH1{160bits, 160bits}, DCH2{320bits, 320bits} DCH3{320bits,320bits}Static part
DCH1: {10ms, ½ convolutional code, rm=2}DCH2: {10ms, turbo code, rm = 3}DCH3: {40ms, ½ convolutional code, rm = 1}
Transport Channel Related Terminologies
53
CRC = 16bitsCC = 1/3
TTI = 40ms
CRC = 12 bitsCC = 1/3
TTI = 20ms
No CRCCC = 1/3
TTI = 20ms
No CRCCC = 1/2
TTI = 20ms
AMR TFCS example
NTRCHa=81 NTRCHb=103 NTRCHc=60
NTRCHa=39
NTRCHa=0
NTRCHb=0
NTRCHb=0
NTRCHc=0
NTRCHc=0
NTRCHd=148
NTRCHd=148
NTRCHd=148
Transport format set aTransport format set b
Transport format set cTransport format set d
Transport formatcombination 1Transport formatcombination 2Transport formatcombination 3
Transport Channel Related Terminologies
54
TFCS is defined every radio link setupEach TF can change every TTI indicated by higher layerReceiver will be noted via “TFCI” bits in DPCCH
Pilot Npilot bits
TPC NTPC bits
DataNdata bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10 bits
1 radio frame: Tf = 10 ms
DPDCH
DPCCHFBI
NFBI bitsTFCI
NTFCI bits
Tslot = 2560 chips, Ndata = 10*2k bits (k=0..6)
Transport Channel Related Terminologies
55
UL-MCCCRC attachmentTrBk concatenation / code block segmentationChannel codingRadio frame equalization1st interleavingRadio frame segmentationRate matchingTrCH multiplexingPhysical channel segmentation2nd interleavingPhysical channel mapping
56
UL-MCCCRC-attachment
For error detectiongCRC24(D) = D24 + D23 + D6 + D5 + D + 1gCRC16(D) = D16 + D12 + D5 + 1gCRC12(D) = D12 + D11 + D3 + D2 + D + 1gCRC8(D) = D8 + D7 + D4 + D3 + D + 1
TrBk
TrBk
57
UL-MCC
TrBk concatenation
Code block segmentationInput block size of channel encoder is limitedconvolutional coding : 504 bit maxturbo coding : 5114 bit maxThe whole input block is segmented into the same smaller size. Filler bits are added to the last block
TrBkTrBk CRC
CRC TrBk CRC TrBk CRC
1498 bits 500 bits 500 bits 498 bits
2 filler bits
58
UL-MCC
Channel codingFor error correction
Turbo-codeHigher error correction capability, long decoding latencyRate = 1/3
Convolutional codeLower error correction capability, short decoding latencyRate = 1/2 or 1/3
59
UL-MCC
Usage of coding scheme and coding rate
No coding1/3Turbo coding
1/3, 1/2CPCH, DCH, DSCH, FACH
RACHPCH
1/2Convolutional codingBCH
Coding rateCoding schemeType of TrCH
60
Convolutional Coding in WCDMA
Output 0G0 = 557 (octal)
InputD D D D D D D D
Output 1G1 = 663 (octal)
Output 2G2 = 711 (octal)
Output 0G0 = 561 (octal)
InputD D D D D D D D
Output 1G1 = 753 (octal)
(a) Rate 1/2 convolutional coder
(b) Rate 1/3 convolutional coder
61
Turbo Coder in WCDMA
xk
xk
zk
Turbo codeinternal interleaver
x’k
z’k
D
DDD
DD
Input
OutputInput
Output
x’k
1st constituent encoder
2nd constituent encoder
62
UL-MCC
Concatenation of encoded blocksRadio frame size equalization
301 301Code block
After CC, rate 1/2 602 16 602 16
Concatenation Of encoded blocks 1236
Assume TTI=8, 1236/8 = 154.5,So we add 4 to let it can be divided by 8
1236 4Radio frame sizeequalization
63
UL-MCC
1st interleaving is an inter-frame interleaving schemeInterleaving period is one TTI
10, 20, 40, 80 ms => 1, 2, 4, 8 columns in the interleaving matrix
1st interleaving including three stepswrite input bits into the matrix row by rowperform inter-column permutation based on pre-defined patterns (according to the TTI)read output bits from the matrix column by column
64
UL-MCC
Input bits
STEP 1Write input bitsrow by row
0 2 1 3
STEP 2Inter-columnpermutation
STEP 3Read output bitscolumn by column
1st interleaving:
65
Rate MatchingRate matching performs after radio frame segmentation (per 10ms data)
Nij: number of bits in a radio frame before RM on TrCH iNdata,j: total number of bits that are available for the CCTrCHRMi: rate matching attribute for transport channel iΔNi,j:number of bits that should be repeated/punctured in each radio frame on TrCH i
⎥⎥⎥⎥⎥
⎦
⎥
⎢⎢⎢⎢⎢
⎣
⎢
×
⎟⎟⎠
⎞⎜⎜⎝
⎛×⎟
⎠
⎞⎜⎝
⎛×
=
∑
∑
=
=
I
mjmm
jdata
i
mjmm
ji
NRM
NNRMZ
1,
,1
,
,
INZZN jijijiji , ... 1,i allfor ,,1,, =−−=Δ −
66
Rate Matching
ExampleAssume 3 TrCH
N0 = 30, RM = 10N1 = 100, RM = 12N2 = 20, RM = 13
If Ndata = 180Z1 = floor(300*180/1760) = 30 : Δ= 0Z2 = floor((300+1200)*180/1760) = 153 : ΔN1 = 23Z3 = floor((300+1200+260)*180/1760) = 180 : ΔN2 = 7
If Ndata = 130Z1 = floor(300*130/1760) = 22 : ΔN0 = -8Z2 = floor((300+1200)*130/1760) = 110 : ΔN1 = -12Z3 = floor((300+1200+260)*130/1760) = 130 : ΔN2 = -10
67
Rate MatchingHow could we decide which bits should be punctured/repeated?Determine of eini, eplus, eminus
e = eini
m = 1do while m < Xi (input bit length before RM)
e = e – eminus -- update errorif e <= 0 then -- check if bit m be punctured/ repeated
Repeat or puncture xm
e = e + eplus -- update errorend if
m = m + 1 -- next bit
end do
68
Rate Matching
Example: eini=3, eminus=2, eplus=5 (Puncturing case)
Variable e: 3 1 -1 4 2 0 5 3 1 -1 4 2 0 5 3Input bits: 0 1 0 0 1 0 0 1 1 0Output bits: 0 X 0 X 1 0 X 1 X 0
0100100110 001010RM
+5 +5 +5 +5
69
UL-MCCTrCH multiplexing
Serially multiplex different transport channels into a coded composite transport channel (CCTrCH)
Physical Channel SegmentationIf more than one physical channel (spreading code) is used, physical channel segmentation is used.
2nd interleavingIntra-frame interleavingSimilar with 1st interleaving, but with C2 = 30
Physical channel mappingMap CCTrCH to one or multiple physical channels
70
UL-MCC
TrCH1
TrCH2 TrCH3
TrCH1
TrCH1TTI=2 TTI=2
TrCH2 TrCH2
TTI=4
TrCH3 TrCH3 TrCH3 TrCH3Radio framesegmentation
Rate matching TrCH1 TrCH2 TrCH3TrCH1 TrCH2 TrCH3 TrCH3 TrCH3
TrCH multiplexing TrCH1 TrCH2 TrCH3
CCTrCH2nd interleaving
Physical channel mapping
PhCH
PhCH
c1
c2
71
DL-MCC1. CRC attachment2. TrBk concatenation / code block segmentation3. Channel coding4. Rate matching5. 1st insertion of DTX indication6. 1st interleaving7. Radio frame segmentation8. TrCH multiplexing9. 2nd insertion of DTX indication10. Physical channel segmentation11. 2nd interleaving12. Physical channel mapping
72
Rate Matching
Since DL rate matching is performed before TrCHmultiplexing, the RM does not know TF of other transport channel
TrCH1 TrCH2 TrCH3
TrCH1 TrCH2 TrCH3
TrCH1
PhCH size PhCH size
?
?
?
RM in UL case RM in DL case
73
Rate Matching
2 solutions in DL-RMFixed position
Use the maximum Ni in TFS i for all i as the data size before RMCalculate for ΔNi as in UL case
Flexible positionFind maximum RMi*Ni,j for all combination jCalculate for ΔNi
74
Rate MatchingTFCS example
Combination 1: DCH1{20bits, 20bits}, DCH2{320bits, 1280bits} DCH3{320bits,320bits}Combination 2: DCH1{40bits, 40bits}, DCH2{320bits, 1280bits} DCH3{320bits,320bits}Combination 3: DCH1{160bits, 160bits}, DCH2{320bits, 320bits} DCH3{320bits,320bits}Assume RM1 = RM2 = RM3 = 100 (same importance)
Fixed positionChoose N1=160, N2=1280, N3=320 to calculate for ΔNi
Flexible positionChoose N1=40, N2=1280, N3=320 to calculate for ΔNi (combination 2)
75
Rate Matching
Normal modeFor frames not overlapping with transmission gap
Compressed modeFrames overlapping with transmission gap
Frame structure of type A
Frame structure of type B
Slot # (Nfirst - 1)
TPC
Data1TFCI Data2 PL
Slot # (Nlast + 1)
PL Data1TPC
TFCI Data2 PL
transmission gap
Slot # (Nfirst - 1)
TPC
Data1TFCI Data2 PL
Slot # (Nlast + 1)
PL Data1TPC
TFCI Data2 PL
transmission gap
TPC
76
Rate MatchingCompressed mode by puncturing
Use rate matching algorithm to generate available space for transmission gapWe insert p-bits corresponding to the transmission gap length and will be removed laterUsing slot format A
Compressed mode by reducing the spreading factor by 2Using slot format B (reduce spreading factor by 2) to increase available transmission bits
Compressed mode by higher layer schedulingHigher layer schedule the transmission dataUsing slot format A
77
DTX Insertion
Since the rate matching output is to match the maximum bit number of each TrCH, DTX (discontinuous transmission bits) should be inserted to match the real bit number after TrCH multiplexing
TrCH1 TrCH2 TrCH3
TrCH1 TrCH2 TrCH3
Before RM
After RM
TrCH1 TrCH2 TrCH3TrCH MUX
PhCH size
DTX
78
Physical Channel Mapping
One radio frame, Tf = 10 ms
TPC NTPC bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2k bits (k=0..7)
Data2Ndata2 bits
DPDCHTFCI
NTFCI bitsPilot
Npilot bitsData1
Ndata1 bits
DPDCH DPCCH DPCCH
79
Detail Issues in MCC
Why RM is done after 1st interleaving and radio frame segmentation in UL ?
Although transport format for the individual TrCH changes only once per TTI, combination of TrCHs may be different in each frameRate matching shall be done on a frame-by-frame basis to dynamically assign PhCH resourcesTherefore, radio frame segmentation is performed before rate matching
80
Detail Issues in MCCBut, why RM is done before 1st interleaving and radio frame segmentation in DL ?
PhCH resources are pre-assigned by the upper layers in DLRate matching must be done before 1st interleaving since DTX insertion of fixed position shall be performed after rate matching and before 1st interleavingRate matching parameters are still calculated on a radio frame basis
81
Some ExamplesUL DCH example
UL 12.2 kbps dataUL 64/128/144 kbps packet dataUL 384 kbps packet data
TrCH multiplexing12.2 kbps data + 3.4 kbps data64 kbps data + 3.4 kbps data
DL DCH exampleDL 12.2 kbps dataDL 64/128/144 kbps packet data
TrCH multiplexing12.2 kbps data + 3.4 kbps data
82
UL 12.2 kbps dataT r C h # aT r a n s p o r t b lo c k
C R C a t t a c h m e n t *
C R C
T a i l b i t a t t a c h m e n t *
C o n v o lu t i o n a lc o d i n g R = 1 /3 , 1 /2
R a t e m a t c h i n g
N T r C H a
N T r C H a
3 * ( N T r C H a + 2 0 )
T a i l8N T r C H a + 1 2
1 s t i n t e r l e a v i n g
1 2
R a d i o f r a m es e g m e n t a t i o n
# 1 a
T o T r C h M u l t ip le x in g
T r C h # bN T r C H b
N T r C H b
3 * ( N T r C H b + 8 * N T r C H b / 1 0 3 )
T a i l8 * N T r C H b / 1 0 3N T r C H b
T r C h # cN T r C H c
N T r C H c
2 * ( N T r C H c + 8 * N T r C H c / 6 0 )
T a i l8 * N T r C H c / 6 0N T r C H c
# 1 c # 2 c
R a d i o f r a m ee q u a l i z a t i o n
3 * ( N T r C H a + 2 0 ) 3 * ( N T r C H b + 8 * N T r C H b / 1 0 3 ) 2 * ( N T r C H c + 8 * N T r C H c / 6 0 )1 1
# 2 b # 1 b # 2 b
3 * ( N T r C H a + 2 0 ) + 1 *⎡ N T r C H a / 8 1 ⎤
3 * (N T r C H b + 8 * N T r C H b / 1 0 3 ) + 1 * N T r C
2 * ( N T r C H c + 8 * N T r C H c / 6 0 )
# 1 a
N R F a N R F a N R F b N R F b N R F c N R F c
# 2 b # 1 b # 2 b # 1 c # 2 cN R F a + N R M _ 1 a N R F a + N R M _ 2 b N R F b + N R M _ 1 b N R F b + N R M _ 2 b N R F c + N R M
_ 1 c
N R F c + N R M _
2 c
N R F a = [ 3 * ( N T r C H a + 2 0 )+ 1 * ⎡ N T r C H a /8 1 ⎤ ] /2N R F b = [ 3 * ( N T r C H b + 8 * N T r C H b / 1 0 3 ) + 1 * N T r C H b / 1 0 3 ] /2N R F c = N T r C H c + 8 * N T r C H c / 6 0
* C R C a n d t a i l b i t s f o r T r C H # a i s a t t a c h e d e v e n i f N T r C h a = 0 b i t s s i n c e C R C p a r i t y b i t a t t a c h m e n t f o r 0 b i t t r a n s p o r tb l o c k i s a p p l i e d .
83
UL 64/128/144 kbps dataT r a n s p o r t b lo c k
C R C a t t a c h m e n t
C R C
T u r b o c o d in g R = 1 /3
R a te m a tc h i n g
3 3 6
3 3 6 1 6
3 5 2 * B
1 0 5 6 * B + 1 2 * ⎡ B /9 ⎤
1 s t i n t e r l e a v i n g
1 0 5 6 * BT a i l b i t a t t a c h m e n t
T a i l1 2 * ⎡ B /9 ⎤1 0 5 6 * B
# 1
T o T r C h M u l t ip l e x in g
T r B k c o n c a t e n a t i o n B T r B k s( B = 0 , 1 , 2 , 4 , 8 , 9 )
# 2
R a d i o f r a m es e g m e n ta t i o n
( 1 0 5 6 * B + 1 2 * ⎡ B /9 ⎤ ) /2 ( 1 0 5 6 * B + 1 2 * ⎡ B /9 ⎤ ) /2
# 1 # 2( 1 0 5 6 * B + 1 2 * ⎡ B /9 ⎤ ) /2 + N R M 1 ( 1 0 5 6 * B + 1 2 * ⎡ B /9 ⎤ ) /2 + N R M 2
84
UL 384 kbps data T r a n s p o r t b l o c k
C R C a t t a c h m e n t
C R C
T u r b o c o d i n g R = 1 / 3
3 3 6
3 3 6 1 6
3 5 2 * B
1 0 5 6 * B + 2 4 * ⎡ B / 2 4 ⎤
1 s t i n t e r l e a v i n g
T a i l b i t a t t a c h m e n t
T o T r C h M u l t i p l e x i n g
T r B k c o n c a t e n a t i o n B T r B k s( B = 0 , 1 , 2 , 4 , 8 , 1 2 , 2 4 )
T a i l
5 2 8 * B
1 7 6 * B 1 7 6 * B
5 2 8 * B 1 2 * ⎡ B / 2 4 ⎤ 5 2 8 * B 1 2 * ⎡ B / 2 4 ⎤
C o d e b l o c k s e g m e n t a t i o n
R a t e m a t c h i n g
# 1 # 2
R a d i o f r a m e s e g m e n t a t i o n
( 1 0 5 6 * B + 2 4 * ⎡ B / 2 4 ⎤ ) / 2 ( 1 0 5 6 * B + 2 4 * ⎡ B / 2 4 ⎤ ) / 2
# 1 # 2( 1 0 5 6 * B + 2 4 * ⎡ B / 2 4 ⎤ ) / 2 + N R M 1 ( 1 0 5 6 * B + 2 4 * ⎡ B / 2 4 ⎤ ) / 2 + N R M 2
T a i l
5 2 8 * B
85
12.2 kbps + 3.4 kbps data
12.2 kbps data 3.4 kbps data
TrCHmultiplexing
60 ksps DPDCH
2nd interleaving
Physical channelmapping
#1#1a #1c
CFN=4N CFN=4N+1
#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
600 600 600 600
12.2 kbps data
CFN=4N+2 CFN=4N+3
86
64 kbps + 3.4 kbps data
#1#1 #2 #3 #4
64 kbps data 3.4 kbps data
#2 #3 #4
240 ksps DPDCH
#1 #1 #2 #2 #3 #3 #4 #4
2nd interleaving
Physical channelmapping
CFN=4N CFN=4N+1 CFN=4N+2 CFN=4N+3
TrCHmultiplexing
87
DL 12.2 kbps dataT r C h # aT r a n s p o r t b l o c k
C R C a t t a c h m e n t *
C R C
T a i l b i t a t t a c h m e n t *
C o n v o l u t i o n a lc o d i n g R = 1 / 3 , 1 / 2
R a t e m a t c h i n g
N T r C H a
N T r C H a
3 * ( N T r C H a + 2 0 )
T a i l8N T r C H a + 1 2
3 * ( N T r C H a + 2 0 ) + N R M a
1 s t i n t e r l e a v i n g
1 2
R a d i o f r a m es e g m e n t a t i o n
# 1 a
T o T r C h M u l t i p l e x i n g
N R F a = [ 3 * ( N T r C H a + 2 0 ) + N R M a + N D I a ] / 2
N R F b = [ 3 * ( N T r C H b + 8 * N T r C H b / 1 0 3 ) + N R M b + N D I b ] / 2
N R F c = [ 2 * ( N T r C H c + 8 * N T r C H c / 6 0 ) + N R M c + N D I c ] / 2
# 2 a
T r C h # bN T r C H b
N T r C H b
3 * ( N T r C H b + 8 * N T r C H b / 1 0 3 )
T a i l8 * N T r C H b / 1 0 3N T r C H b
3 * ( N T r C H b + 8 *N T r C H b / 1 0 3 ) + N R M b
# 1 b
T r C h # cN T r C H c
N T r C H c
2 * ( N T r C H c + 8 * N T r C H c / 6 0 )
T a i l8 * N T r C H c / 6 0N T r C H c
2 * ( N T r C H c + 8 *N T r C H c / 6 0 ) + N R M c
# 1 c # 2 c# 2 bN R F a N R F a N R F b N R F b N R F c N R F c
I n s e r t i o n o f D T Xi n d i c a t i o n
3 * ( N T r C H a + 2 0 ) + N R M a + N D I 1 3 * ( N T r C H b + 8 *N T r C H b / 1 0 3 ) + N R M b + N D I b
2 * ( N T r C H c + 8 *N T r C H c / 6 0 ) + N R M c + N D I c
3 * ( N T r C H a + 2 0 ) + N R M a + N D I 1 3 * ( N T r C H b + 8 *N T r C H b / 1 0 3 ) + N R M b + N D I b
2 * ( N T r C H c + 8 *N T r C H c / 6 0 ) + N R M c + N D I c
* C R C a n d t a i l b i t s f o r T r C H # a i s a t t a c h e d e v e n i f N T r C h a = 0 b i t s s i n c e C R C p a r i t y b i t a t t a c h m e n t f o r 0 b i t t r a n s p o r tb l o c k i s a p p l i e d .
88
DL 64/128/144 kbps dataT r a n s p o r t b l o c k
C R C a t t a c h m e n t
C R C
T u r b o c o d i n g R = 1 / 3
R a t e m a t c h i n g
3 3 6
3 3 6 1 6
3 5 2 * B
T r B kc o n c a t e n a t i o n
1 0 5 6 * B + 1 2 * ⎡ B / 9 ⎤ + N R M
1 s t i n t e r l e a v i n g
1 0 5 6 * B + 1 2 * ⎡ B / 9 ⎤ + N R M
1 0 5 6 * BT a i l b i t a t t a c h m e n t
T a i l1 2 * ⎡ B / 9 ⎤1 0 5 6 * B
T o T r C h M u l t i p l e x i n g
B T r B k s( B = 0 , 1 , 2 , 4 , 8 , 9 )
# 1( 1 0 5 6 * B + 1 2 * ⎡ B / 9 ⎤ + N R M ) / 2
R a d i o f r a m es e g m e n t a t i o n
# 2( 1 0 5 6 * B + 1 2 * ⎡ B / 9 ⎤ + N R M ) / 2
89
12.2 kbps + 3.4 kbps data
12.2 kbps data 3.4 kbps data
TrCHmultiplexing
30 ksps DPCH
2nd interleaving
Physical channelmapping
#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
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
WCDMA Uplink Physical Layer
91
Table of Contents
Overview
Uplink Physical LayerDedicated Uplink Physical Channels
Uplink Dedicated Physical Data Channel (UL DPDCH)Uplink Dedicated Physical Control Channel (UL DPCCH)
Common Uplink Physical ChannelsPhysical Random Access Channel (PRACH)Physical Common Packet Channel (PCPCH)
Uplink Physical Layer Modulation
92
OverviewConfiguration
Radio frameA radio frame is a processing unit which consists of 15 slots.The length of a radio frame corresponds to 38400 chips.
Time slotA time slot is a unit which consists of fields containing bits.The length of a slot corresponds to 2560 chips.
Spreading Modulation: QPSK.Data Modulation: BPSK.Spreading
Two-level spreading processes
93
OverviewSpreading (cont.)
Channelization operationOVSF codes.Transform every data symbol into a number of chips.Increase the bandwidth of the signal.The number of chips per data symbol is called the Spreading Factor.Data symbols on I- and Q-branches are independently multiplied with an OVSF code.
Scrambling operationLong or short Gold codes.Applied to the spread signals.Randomize the codes
Spread signal is further multiplied by complex-valued scrambling
94
Uplink Physical Channels
Dedicated Uplink Physical ChannelsUplink Dedicated Physical Data Channel (UL DPDCH)Uplink Dedicated Physical Control Channel (UL DPCCH)
Common Uplink Physical ChannelsPhysical Random Access Channel (PRACH)Physical Common Packet Channel (PCPCH)
95
Dedicated Uplink Physical Channels
UL Dedicated Physical Data Channel (UL DPDCH)Carry the DCH transport channel (generated at Layer 2 and above).There may be zero, one, or several uplink DPDCHs on each radio link.
UL Dedicated Physical Control Channel (UL DPCCH)Carry control information generated at Layer 1One and only one UL DPCCH on each radio link.
96
Frame Structure for UL DPDCH/DPCCH
PilotNpilot bits
TPCNTPC bits
DataNdata bits
Tslot = 2560 chips, 10 bits
1 radio frame: Tf = 10 ms = 38400 chips
DPDCH
DPCCHFBI
NFBI bitsTFCI
NTFCI bits
Tslot = 2560 chips,
Slot #0 Slot #1 Slot #i Slot #14
Ndata= 10*2k bits (k=0,1,…,6)
One Power Control Period
97
UL DPDCHThe parameter k determines the number of bits per uplink DPDCH slot.It is related to the spreading factor SF of the DPDCH as SF = 256/2k.The DPDCH spreading factor ranges from 256 down to 4.
640640960049609606
320320480084804805
1601602400162402404
80801200321201203
40406006460602
202030012830301
101015025615150
NdataBits/ Slot
Bits/ Frame
SFChannel Symbol Rate
(ksps)
Channel Bit Rate (kbps)
Slot Format #i
98
UL DPCCH - Layer 1 Control Information
The spreading factor of the uplink DPCCH is always equal to 256, i.e. there are 10 bits per uplink DPCCH slot.
8-924131015025615155B
10-1423141015025615155A
1522151015025615155
8-1520261015025615154
8-1510271015025615153
8-914231015025615152B
10-1413241015025615152A
1512251015025615152
8-1500281015025615151
8-904241015025615150B
10-1403251015025615150A
1502261015025615150
Transmitted slots per
radio frame
NFBINTFCINTPCNpilotBits/Slot
Bits/Frame
SFChannel Symbol Rate
(ksps)
Channel Bit Rate (kbps)
Slot Format #i
99
UL DPCCH - Layer 1 Control Information
Pilot Bits.Support channel estimation for coherent detection.Frame Synchronization Word (FSW) can be sued to confirm frame synchronizaton.
Transmit Power Control (TPC) command.Inner loop power control commands.
Feedback Information (FBI).Support of close loop transmit diversity.Site Selection Diversity Transmission (SSDT)
Transport-Format Combination Indicator (TFCI) – optionalTFCI informs the receiver about the instantaneous transport format combination of the transport channels.
100
Pilot Bit Patterns with Npilot=3,4,5,6
001010000111011
110001001101011
111111111111111
101001101110000
100011110101100
111111111111111
001010000111011
110001001101011
111111111111111
101001101110000
100011110101100
111111111111111
101001101110000
100011110101100
111111111111111
111111111111111
101001101110000
100011110101100
Slot #0123456789
1011121314
543210432103210210Bit #Npilot = 6Npilot = 5Npilot = 4Npilot = 3
Shadowed column is defined as FSW (Frame Synchronization Word).
101
Pilot Bit Patterns with Npilot=7,8
Shadowed column is defined as FSW (Frame Synchronization Word).
001010000111011
111111111111111
110001001101011
111111111111111
101001101110000
111111111111111
100011110101100
111111111111111
111111111111111
001010000111011
110001001101011
111111111111111
101001101110000
100011110101100
111111111111111
Slot #01234567891011121314
765432106543210Bit #Npilot = 8Npilot = 7
102
FBI BitsThe FBI bits are used to support techniques requiring feedback from the UE to the UTRAN Access Point, including closed loop mode transmit diversity and site selection diversity transmission (SSDT).
The S field is used for SSDT signalling, while the D field is used for closed loop mode transmit diversity signalling.The S field consists of 0, 1, or 2 bits. The D field consists of 0 or 1 bit. Simultaneous use of SSDT power control and closed loop mode transmit diversity requires that the S field consists of 1 bit.
S field D field
NFBI
103
TFCI BitsThere are two types of uplink dedicated physical channels:
those that include TFCI (e.g. for several simultaneous services)those that do not include TFCI (e.g. for fixed-rate services).
It is the UTRAN that determines if a TFCI should be transmitted and it is mandatory for all UEs to support the use of TFCI in the uplink.In compressed mode, DPCCH slot formats with TFCI fields are changed.There are two possible compressed slot formats for each normal slot format.
104
TPC Bit Patterns
10
1100
10
NTPC = 2NTPC = 1
Transmitter power control
command
TPC Bit Pattern
105
IΣ
j
c d , 1 β d
S lo n g , n o r S s h o r t , n
I+ jQ
D P D C H 1
Q
c d , 3 β d
D P D C H 3
c d , 5 β d
D P D C H 5
c d , 2 β d
D P D C H 2
c d , 4 β d
D P D C H 4
c d , 6 β d
D P D C H 6
c c β c
D P C C H
Σ
Spreading of UL DPCH
106
Spreading of UL DPCHThe binary DPCCH and DPDCHs to be spread are represented by real-valued sequences, i.e. the binary value "0" is mapped to the real value +1, while the binary value "1" is mapped to the real value –1.The DPCCH is spread to the chip rate by the channelization code cc, while the n:th DPDCH called DPDCHn is spread to the chip rate by the channelizationcode cd,n.One DPCCH and up to six parallel DPDCHs can be transmitted simultaneously, i.e. 1 ≤ n ≤ 6.
107
Channelization Codes
Each CDMA channel is distinguished via a unique spreading code.These spreading codes should have low cross-correlation values.In 3GPP W-CDMA, Orthogonal Variable Spreading Factor (OVSF) codes are used.Preserve the orthogonality between a user’s different physical channels.Scrambling is used on top of spreading.
108
Code-tree for Generation of Orthogonal Variable Spreading Factor (OVSF) Codes
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)
The channelization codes are uniquely described as Cch,SF,k, where SF isthe spreading factor of the code and k is the code number, 0 ≤ k ≤ SF-1.
109
Channelization Codes
As the chip rate is already achieved in the spreading by the channelization codes, the symbol rate is not affected by the scrambling.Another physical channel may use a certain code in the tree if no other physical channel to be transmitted using the same code three is using a code that is on an underlying branch, i.e. using a higher spreading factor code generated from the intended spreading code to be used.Neither can a smaller spreading factor code on the path to the root of the tree be used.
110
Channelization Codes
The downlink orthogonal codes within each base station are managed by the radio network controller (RNC) in the network.The definition for the same code tree means that for transmission from a single source, from either a terminal or a base station.One code tree is used with one scrambling code on top of the tree.Different terminals and different base stations may operate their code trees independently of each other.
111
Generation of Channelization Codes1Cch,1,0 =
⎥⎦
⎤⎢⎣
⎡−
=⎥⎦
⎤⎢⎣
⎡−
=⎥⎦
⎤⎢⎣
⎡
1111
0,1,
0,1,
0,1,
0,1,
1,2,
0,2,
ch
ch
ch
ch
ch
ch
CC
CC
CC
( )
( )
( )
( )
( ) ( )
( ) ( ) ⎥⎥⎥⎥⎥⎥⎥⎥⎥
⎦
⎤
⎢⎢⎢⎢⎢⎢⎢⎢⎢
⎣
⎡
−
−
−
=
⎥⎥⎥⎥⎥⎥⎥⎥⎥
⎦
⎤
⎢⎢⎢⎢⎢⎢⎢⎢⎢
⎣
⎡
−−
−−
−++
−++
+
+
+
+
12,2,12,2,
12,2,12,2,
1,2,1,2,
1,2,1,2,
0,2,0,2,
0,2,0,2,
112,12,
212,12,
3,12,
2,12,
1,12,
0,12,
:::
nnchnnch
nnchnnch
nchnch
nchnch
nchnch
nchnch
nnch
nnch
nch
nch
nch
nch
CCCC
CCCCCC
CC
CC
CCCC
112
OVSF Code Allocation for UL DPCH
DPCCH is always spread by cc= Cch,256,0
When there is only one DPDCHDPDCH1 is spread by cd,1= Cch,SF,k (k= SF / 4)
When there are more than one DPDCHAll DPDCHs have SF=4
DPDCHn is spread by the the code cd,n = Cch,4,k
k = 1 if n ∈ {1, 2}, k = 3 if n ∈ {3, 4} and k = 2 if n ∈ {5, 6}
113
Gain of UL DPCHAfter channelization, the real-valued spread signals are weighted by gain factors, βc for DPCCH and βd for all DPDCHs.At every instant in time, at least one of the values βc and βd has the amplitude 1.0. The β-values are quantized into 4 bit words.After the weighting, the stream of real-valued chips on the I- and Q-branches are then summed and treated as a complex-valued stream of chips.This complex-valued signal is then scrambled by the complex-valued scrambling code Sdpch,n.
114
Signaling values for βc and βd
Quantized amplitude ratios βc and βd
15 1.0 14 0.9333 13 0.8666 12 0.8000 11 0.7333 10 0.6667 9 0.6000 8 0.5333 7 0.4667 6 0.4000 5 0.3333 4 0.2667 3 0.2000 2 0.1333 1 0.0667 0 Switch off
Gain of UL DPCH
115
Long scrambling code allocationThe n-th UL long scrambling code
Sdpch,n(i) = Clong,n(i), i = 0, 1, …, 38399
Short scrambling code allocationThe n-th UL short scrambling code
Sdpch,n(i) = Cshort,n(i), i = 0, 1, …, 38399
⎭⎬⎫
⎩⎨⎧
⎥⎦⎥
⎢⎣⎢−+= )2
2()1(1)()( ,2,,1,,icjiciC nlong
inlongnlong
⎭⎬⎫
⎩⎨⎧
⎟⎠⎞
⎜⎝⎛
⎥⎦⎥
⎢⎣⎢−+=
2256mod2)1(1)256mod()( ,2,,1,,
icjiciC nshorti
nshortnshort
Scrambling Codes of UL DPCH
116
Configuration of Uplink Scrambling Sequence Generator
clong,1,n
clong,2,n
MSB LSBx
y
117
Uplink Long Scrambling Codes
Two elementary codes: clong,1,n and clong,2,n.
clong,1,n and clong,2,n are constructed from position wise modulo 2 sum of 38400 chip segments of two binary m-sequences, x and y.
x and y are originated from two generator polynomials of degree 25.x sequence: generator polynomial: X25+X3+1y sequence: generator polynomial: y25+y3+y2+y+1
The sequence clong,2,n is a 16777232 chip shifted version of the sequence clong,1,n.clong,1,n and clong,2,n are Gold codes.
118
Uplink Long Scrambling Codes
For code number, nn=[n23 … n0 ], with n0 being the LSB
Let xn(i) and y(i) denote the i -th chip of the sequence xn and y .
Initial conditionsxn(0)=n0, xn(1)=n1, … , xn(22)=n22, xn(23)=n23, xn(24)=1
y(0)=y(1)= … =y(23)= y(24)=1
119
Uplink Long Scrambling Codes
Recursive formulation, i=0,…, 225-27xn(i+25) =xn(i+3) + xn(i) modulo 2
y(i+25) = y(i+3)+y(i+2) +y(i+1)+y(i) modulo 2
Gold sequence zn
zn(i ) = xn(i ) + y (i ) modulo 2, i = 0, 1, 2, …, 225-2
.22,,1,01)(10)(1
)( 25 −=⎩⎨⎧
=−=+
= …iforizifizif
iZn
nn
120
Uplink Long Scrambling Codes
clong,1,n(i ) = Zn(i ), i = 0, 1, 2, …, 225-2
clong,2,n is a 16777232 chip shifted version of the sequence clong,1,n
clong,2,n(i ) = Zn((i + 16777232) modulo (225 – 1)), i = 0, 1, 2, …, 225-2
⎭⎬⎫
⎩⎨⎧
⎥⎦⎥
⎢⎣⎢−+= )2
2()1(1)()( ,2,,1,,icjiciC nlong
inlongnlong
121
Uplink Short Scrambling Sequence Generator for 255 Chip Sequence
07 4
+ mod n addition
d(i)12356
2
mod 2
07 4b(i)
12356
2
mod 2
+mod 4multiplication
zn(i)
07 4 12356
+mod 4
Mapper
cshort,1,n(i)
a(i)
+ + +
+ ++
+ ++
3 3
3
2
cshort,2,n(i)
122
Uplink Short Scrambling Codes
Two elementary codes: cshort,1,n and cshort,2,n256 chips
GenerationFrom the family of periodically extended S(2) codesThe n:th quaternary S(2) sequence zn(i ), 0 ≤ n ≤ 16777215, is obtained by modulo 4 addition of three sequences
One quaternary sequence a (i )Two binary sequences b (i ) and d (i )
123
Uplink Short Scrambling Codeszn(i ) = a(i ) + 2b(i ) + 2d (i ) modulo 4 (i = 0.. 254)Given a code number n =[n23n22…n0] quaternary sequence a (i ): g0(x)= x8+x5+3x3+x2+2x+1
Initial conditionsa (0) = 2n0 + 1 modulo 4
a (i) = 2ni modulo 4, i = 1, 2, …, 7,
Recursive formulationa (i) = 3a (i-3) + a (i-5) + 3a (i-6) + 2a (i-7) + 3a (i-8) modulo 4, i = 8, 9, …, 254
124
Uplink Short Scrambling Codes
Binary sequence b(i): g1(x)= x8+x7+x5+x+1
Initial conditionsB (i ) = n8+i modulo 2, i = 0, 1, …, 7,
Recursive formulationb (i) = b (i-1) + b (i-3) + b (i-7) + b (i-8) modulo 2, i = 8, 9, …, 254
125
Uplink Short Scrambling Codes
Binary sequence d (i ): g2(x)= x8+x7+x5+x4+1
Initial conditionsd (i ) = n16+i modulo 2, i = 0, 1, …, 7
Recursive formulationd (i ) = d (i-1) + d (i-3) + d (i-4) + d (i-8) modulo 2, i = 8, 9, …, 254
zn(i) = a (i) + 2b (i) + 2d (i) modulo 4 (i = 0.. 254)
126
Uplink Short Scrambling Codes
zn(i) is extended to length 256 chipszn(255) = zn(0)
Mapping
Cshort, n is
zn(i) cshort,1,n(i) cshort,2,n(i)0 +1 +11 -1 +12 -1 -13 +1 -1
⎭⎬⎫
⎩⎨⎧
⎟⎠⎞
⎜⎝⎛
⎥⎦⎥
⎢⎣⎢−+=
2256mod2)1(1)256mod()( ,2,,1,,
icjiciC nshorti
nshortnshort
127
PRACH is used to carry the RACH.The random access transmission is based on a Slotted ALOHA approach with fast acquisition indication.The UE can start the random-access transmission at the beginning of a number of well-defined time intervals, denoted access slots.There are 15 access slots per two frames and they are spaced 5120 chips apart.Information on what access slots are available for random-access transmission is given by higher layers.
Physical Random Access Channel (PRACH)
128
#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
PRACH Access Slot Numbers and Their Spacing
129
Message partPreamble
4096 chips10 ms (one radio frame)
Preamble Preamble
Message partPreamble
4096 chips 20 ms (two radio frames)
Preamble Preamble
The random-access transmission consists of one or several preambles of length 4096 chips and amessage of length 10 ms or 20 ms.
Structure of the Random-Access Transmission
130
RACH Preamble Code ConstructionEach preamble is of length 4096 chips and consists of 256 repetitions of a signature of length 16 chips. There are a maximum of 16 available signatures. The random access preamble code Cpre,n, is a complex valued sequence.It is built from a preamble scrambling code Sr-pre,nand a preamble signature Csig,s as follows:
where k=0 corresponds to the chip transmitted first in time.
4095,,2,1,0 ,)()()()
24(
,,,, …=××=+
− kekCkSkCkj
ssignprersnpre
ππ
131
PRACH Preamble Scrambling Code
The scrambling code for the PRACH preamble part is constructed from the long scrambling sequences.There are 8192 PRACH preamble scrambling codes in total.The n:th preamble scrambling code, n = 0, 1, …, 8191, is defined as:
Sr-pre,n(i ) = clong,1,n(i ), i = 0, 1, …, 4095;
132
PRACH Preamble Scrambling Code
The 8192 PRACH preamble scrambling codes are divided into 512 groups with 16 codes in each group.There is a one-to-one correspondence between the group of PRACH preamble scrambling codes in a cell and the primary scrambling code used in the downlink of the cell.The k:th PRACH preamble scrambling code within the cell with downlink primary scrambling code m, k = 0, 1, 2, …, 15 and m = 0, 1, 2, …, 511, is Sr-pre,n(i) as defined above with n = 16×m + k.
133
The preamble signature corresponding to a signature s consists of 256 repetitions of a length 16 signature Ps(n), n=0…15. This is defined as follows:
Csig,s(i) = Ps(i modulo 16), i = 0, 1, …, 4095.
The signature Ps(n) is from the set of 16 Hadamard codes of length 16.
PRACH Preamble Signatures
134
PRACH Preamble Signatures
1-1-11-111-1-111-11-1-11P15(n)
-1-11111-1-111-1-1-1-111P14(n)
-11-111-11-11-11-1-11-11P13(n)
1111-1-1-1-1-1-1-1-11111P12(n)
-111-1-111-11-1-111-1-11P11(n)
11-1-111-1-1-1-111-1-111P10(n)
1-11-11-11-1-11-11-11-11P9(n)
-1-1-1-1-1-1-1-111111111P8(n)
-111-11-1-11-111-11-1-11P7(n)
11-1-1 -1-11111-1 -1-1-111P6(n)
1-11-1-11-111-11-1-11-11P5(n)
-1-1-1-11111-1-1-1-11111P4(n)
1-1-111-1-111-1-111-1-11P3(n)
-1-111-1-111-1-111-1-111P2(n)
-11-11-11-11-11-11-11-11P1(n)
1111111111111111P0(n)
1514131211109876543210
Value of nPreambleSignature
135
PilotNpilotbits
DataNdatabits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2k bits (k=0,1,2,3.)
Message part radio frame TRACH = 10 ms
Data
Control TFCINTFCIbits
Tslot = 2560 chips, 10 bits
Structure of the Random-Access Message Part Radio Frame
136
PRACH Message PartData part
10*2k bits, where k=0,1,2,3.Corresponds to a SF of 256, 128, 64, and 32.
Control partSF=256.
8 known pilot bits to support channel estimation for coherent detection.
2 TFCI bits corresponds to a certain transport format of the current Random-access message.
The message part length can be determined from the sued signature and/or access slot, as configured by higher layers.
137
PRACH Message Part
Slot Format#i
Channel BitRate (kbps)
ChannelSymbol Rate
(ksps)
SF Bits/Frame
Bits/Slot
Ndata
0 15 15 256 150 10 101 30 30 128 300 20 202 60 60 64 600 40 403 120 120 32 1200 80 80
Slot Format#i
Channel BitRate (kbps)
ChannelSymbol Rate
(ksps)
SF Bits/Frame
Bits/Slot
Npilot NTFCI
0 15 15 256 150 10 8 2
Random-access message data fields
Random-access message control fields
138
001010000111011
111111111111111
110001001101011
111111111111111
101001101110000
111111111111111
100011110101100
111111111111111
Slot #01234567891011121314
76543210Bit #
Npilot = 8
PRACH Message Part Pilot Bit Pattern
139
jβccc
cd βd
Sr-msg,n
I+jQ
PRACH messagecontrol part
PRACH messagedata part
Q
I
Spreading of PRACH Message Part
Message part OVSF Code AllocationGiven the preamble signature s, 0 ≤ s ≤ 15Control part : cc = Cch,256,m with m = 16s + 15Data part: cd = Cch,SF,m with m = SF x s/16 and SF=32 to 256
140
PRACH Message Part Scrambling CodeThe scrambling code used for the PRACH message part is 10 ms long, and there are 8192 different PRACH scrambling codes defined.The n:th PRACH message part scrambling code, denoted Sr-
msg,n, where n = 0, 1, …, 8191, is based on the long scrambling sequence and is defined as:
Sr-msg,n(i) = Clong,n(i + 4096), i = 0, 1, …, 38399The message part scrambling code has a one-to-one correspondence to the scrambling code used for the preamble part.For one PRACH, the same code number is used for both scrambling codes.
141
PCPCH is used to carry the CPCH.The CPCH transmission is based on DSMA-CD (Digital Sense Multiple Access – Collision Detection) approach with fast acquisition indication.The UE can start transmission at the beginning of a number of well-defined time-intervals.
Physical Common Packet Channel (PCPCH)
142
The PCPCH access transmission consists of:one or several Access Preambles [A-P] of length 4096 chips.one Collision Detection Preamble (CD-P) of length 4096 chipsa DPCCH Power Control Preamble (PC-P) which is either 0 slots or 8 slots in lengtha message of variable length Nx10 ms.
4096 chips
P0P1
Pj Pj
Collision DetectionPreamble
Access Preamble Control Part
Data part
0 or 8 slots N*10 msec
Message Part
Structure of the CPCH Access Transmission
143
CPCH Access Preamble Part
PCPCH access preamble codes Cc-acc,n,s, are complex valued sequences.
The RACH preamble signature sequences are used.The scrambling codes could be either
A different code segment of the Gold code used to form the scrambling code of the RACH preambles orThe same scrambling code in case the signature set is shared.
4095,,2,1,0 ,)()()()
24(
,,,, …=××=+
−− kekCkSkCkj
ssignacccsnaccc
ππ
144
There are 40960 PCPCH access preamble scrambling codes in total.
The n:th PCPCH access preamble scrambling code is defined as:Sc-acc,n (i) = clong,1,n(i), i = 0, 1, …, 4095;
The codes are divided into 512 groups with 80 codes in each group.There is a one-to-one correspondence between the group of PCPCH access preamble scrambling codes in a cell and the primary scrambling code used in the downlink of the cell.
The k:th PCPCH scrambling code within the cell with downlink primary scrambling code m, for k = 0,..., 79 and m = 0, 1, 2, …, 511, is Sc-acc,n as defined above with n=16×m+k for k=0,...,15 and n = 64×m + (k-16)+8192 for k=16,..., 79.
PCPCH Access Preamble Scrambling Code
145
The PCPCH CD preamble codes Cc-cd,n,s are complex valued sequences.
The RACH preamble signature sequences are used.The scrambling code is chosen to be a different code segment of the Gold code used to form the scrambling code for the RACH and CPCH preambles.
4095,,2,1,0 ,)()()()
24(
,,,, …=××=+
−− kekCkSkCkj
ssigncdcsncdc
ππ
CPCH Collision Detection (CD) Preamble Part
146
PCPCH CD Preamble Scrambling CodeThere are 40960 PCPCH-CD preamble scrambling codes in total.
The n:th PCPCH CD access preamble scrambling code, where n = 0 ,..., 40959, is defined as:Sc-cd,n(i) = clong,1,n(i), i = 0, 1, …, 4095;
The 40960 PCPCH scrambling codes are divided into 512 groups with 80 codes in each group.There is a one-to-one correspondence between the group of PCPCH CD preamble scrambling codes in a cell and the primary scrambling code used in the downlink of the cell.
The k:th PCPCH scrambling code within the cell with downlink primary scrambling code m, k = 0,1, …, 79 and m = 0, 1, 2, …, 511, is Sc-cd, n as defined above with n=16×m+k for k = 0,...,15 and n = 64×m + (k-16)+8192 for k=16,...,79.
147
CPCH Power Control Preamble Part
The power control preamble segment is called the CPCH Power Control Preamble (PC-P) part.The slot format for CPCH PC-P part shall be the same as for the CPCH message part.
The scrambling code for the PCPCH power control preamble is the same as for the PCPCH message part.The channelization code the PCPCH power control preamble is the same as the control part of message part.
1225101502561515102261015025615150
NFBINTFCINTPCNpilotBits /Slot
Bits /Slot
SFChannelSymbol Rate
(ksps)
Channel BitRate (kbps)
SlotFormat #i
148
Frame Structure for PCPCH
PilotNpilot bits
TPCNTPC bits
DataNdata bits
Tslot = 2560 chips, 10 bits
1 radio frame: Tf = 10 ms = 38400 chips
Data
ControlFBI
NFBI bitsTFCI
NTFCI bits
Tslot = 2560 chips,
Slot #0 Slot #1 Slot #i Slot #14
Ndata= 10*2k bits (k=0,1,…,6)
149
PCPCH Message PartUp to N_MAX_frames 10ms frames.
N_Max_frames is a higher layer parameter.
Each 10 ms frame is split into 15 slots, each of length 2560 chips.
Each slot consists of two parts:Data part carries higher layer information.
Data part consists of 10*2k bits, where k = 0, 1, 2, 3, 4, 5, 6.
SF= 256, 128, 64, 32, 16, 8, 4.
Control part carries Layer 1 control information with SF = 256. Slot format is the same as CPCH PC-P part.
150
PCPCH Message Part Spreading
jβccc
cd βd
Sc-msg,n
I+jQ
PCPCH messagecontrol part
PCPCH messagedata part
Q
I
151
Control part is always spread by cc = Cch,256,0
Data part is spread by cd = Cch,SF,k with SF = 4 to 256 and k = SF/4.A UE is allowed to increase SF during the message transmission on a frame by frame basis.
PCPCH Message Part OVSF Code Allocation
152
The set of scrambling codes are10 ms long
Cell-specific
one-to-one correspondence to the signature sequences and the access sub-channel used by the access preamble part.
Both long or short scrambling codes can be used.
There are 64 uplink scrambling codes defined per cell and 32768 different PCPCH scrambling codes defined in the system.
PCPCH Message Part Scrambling Code Allocation
153
The n:th PCPCH message part scrambling code, denoted Sc-msg,n, where n =8192,8193, …,40959 is based on the scrambling sequence and is defined as:
Long scrambling codes : Sr-msg,n(i) = Clong,n(i ), i = 0, 1, …, 38399
Short scrambling codes : Sr-msg,n(i) = Cshort,n(i), i = 0, 1, …, 38399
The 32768 PCPCH scrambling codes are divided into 512 groups with 64 codes in each group.
There is a one-to-one correspondence between the group of PCPCH preamble scrambling codes in a cell and the primary scrambling code used in the downlink of the cell.
PCPCH Message Part Scrambling Code Allocation
154
Uplink Modulation
The modulation chip rate is 3.84 Mcps.The complex-valued chip sequence generated by the spreading process is QPSK modulated.
S
Im{S}
Re{S}
cos(ωt)
Complex-valuedchip sequencefrom spreadingoperations
-sin(ωt)
Splitreal &imag.parts
Pulse-shaping
Pulse-shaping
155
Uplink Modulation
The uplink modulation should be designed:The audible interference from the terminal transmission is minimized.The terminal amplifier efficiency is maximized.
Audible interference:Discontinuous uplink transmission can cause audible interference to audio equipment that is very close to the terminal.Solution: WCDMA uplink doesn’t adopt time multiplexing.
Physical Layer Control Information (DPDCH)
User Data (DPDCH) User Data (DPDCH)DTX Period
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
WCDMA Downlink Physical Layer
157
Table of ContentsIntroductionDownlink Transmit Diversity
Open loop transmit diversitySpace Time Block Coding Based Transmit Antenna Diversity (STTD)Time Switched Transmit Diversity for Synchronization Channel (TSTD)
Closed loop transmit diversityDedicated Downlink Physical Channels
Downlink Dedicated Physical Channel (DL DPCH)Common Downlink Physical Channels1. Common Pilot Channel (CPICH)2. Primary Common Control Physical Channel (P-CCPCH)3. Secondary Common Control Physical Channel (S-CCPCH)
158
Table of Contents
Common Downlink Physical Channels (continue)4. Synchronization Channel (SCH)5. Physical Downlink Shared Channel (PDSCH)6. Acquisition Indicator Channel (AICH)7. CPCH Access Preamble Acquisition Indicator Channel (AP-AICH)8. CPCH Collision Detection/Channel Assignment Indicator Channel
(CD/CA-ICH)9. Page indicator channel (PICH)10. CPCH Status Indicator Channel (CSICH)
SpreadingModulationTiming Relationship
159
Introduction
Downlink DPCHAICH, CPICHCCPCH, PICH
IdleMS
On-lineMS
Power-onMS
SCH
160
Downlink Transmit Diversity
Open loop transmit diversity: STTD and TSTDClosed loop transmit diversity BS
ˇˇ-DL-DPCCH for CPCH
-ˇ-CD/CA-ICH
-ˇ-AP-AICH
–ˇ–CSICH
–ˇ–AICH
ˇˇ–PDSCH
–ˇ–PICH
ˇˇ–DPCH
–ˇ–S-CCPCH
––ˇSCH
–ˇ–P-CCPCH
ModeSTTDTSTD
Closed loopOpen loop modePhysical channel type
161
The STTD encoding is optional in UTRAN. STTD support is mandatory at the UE.STTD encoding is applied on blocks of 4 consecutive channel bits.
b 0 b 1 b 2 b 3
b 0 b 1 b 2 b 3
-b 2 b 3 b 0 -b 1
A ntenna 1
A ntenna 2C hanne l b its
S T T D enco d ed channe l b itsfo r an tenna 1 and an tenna 2 .
Space Time Block Coding Based Transmit Antenna Diversity (STTD)
162
Prim arySCH
SecondarySCH
256 ch ips
2560 chips
O ne 10 m s SCH radio fram e
acsi,0
acp
acsi,1
acp
acsi,14
acp
S lot #0 Slo t #1 Slot #14
TSTD can be applied to TSTD.TSTD for the SCH is optional in UTRAN, while TSTD support is mandatory in the UE.
Antenna 1
Antenna 2
acsi,0
acp
acsi,1
acp
acsi,14
acp
Slot #0 Slot #1 Slot #14
acsi,2
acp
Slot #2
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
(Tx OFF)
Time Switched Transmit Diversity for SCH (TSTD)
163
Spread/scramblew1
w2
DPCHDPCCH
DPDCH
∑
CPICH1
∑
CPICH2
Ant1
Ant2
Weight Generation
w1 w2
Determine FBI messagefrom Uplink DPCCH
Closed Loop Mode Transmit Diversity
164
The spread complex valued signal is fed to both TX antenna branches, and weighted with antenna specific weight factors w1 and w2 , where wi = ai + jbi .The weight factors (phase adjustments in closed loop mode 1 and phase/amplitude adjustments in closed loop mode 2) are determined by the UE, and signalled to the UTRAN access point (=cell transceiver) using the D sub-field of the FBI field of uplink DPCCH.For the closed loop mode 1 different (orthogonal) dedicated pilot symbols in the DPCCH are sent on the 2 different antennas. For closed loop mode 2 the same dedicated pilot symbols in the DPCCH are sent on both antennas.
Closed Loop Mode Transmit Diversity
165
Summary of number of feedback information bits per slot, NFBD, feedback command length in slots, NW, feedback command rate, feedback bit rate, number of phase bits, Nph, per signalling word, number of amplitude bits, Npo, per signalling word and amount of constellation rotation at UE for the two closed loop modes.
N/A311500 bps1500 Hz412
π/2101500 bps1500 Hz111
Constellation rotation
NphNpoFeedback bit rate
Update rate
NWNFBDClosed loop mode
Number of Feedback Information in Closed Loop Transmit Diversity
166
The UE uses the CPICH to separately estimate the channels seen from each antenna.Once every slot, the UE computes the phase adjustment, φ, and for mode 2 the amplitude adjustment that should be applied at the UTRAN access point to maximise the UE received power.The UE feeds back to the UTRAN access point the information on which phase/power settings to use.Feedback Signalling Message (FSM) bits are transmitted in the portion of FBI field of uplink DPCCH slot(s) assigned to closed loop mode transmit diversity, the FBI D field. Each message is of length NW = Npo+Nph bits.
Determination of Feedback Information in Closed Loop Mode Transmit Diversity
167
Closed Loop Mode 1The UE uses the CPICH transmitted both from antenna 1 and antenna 2 to calculate the phase adjustment to be applied at UTRAN access point to maximise the UE received power.In each slot, UE calculates the optimum phase adjustment, φ, for antenna 2, which is then quantized into having two possible values as follows:
where
If = 0, a command '0' is sent to UTRAN using the FSMphfield. If = π, command '1' is sent to UTRAN using the FSMphfield.
⎩⎨⎧ ≤−<
=otherwise,0
2/3)(2/ if, πφφππφ
irQ
⎩⎨⎧
==
=13,11,9,7,5,3,1,2/
14,12,10,8,6,4,2,0,0)(
ii
ir πφ
QφQφ
168
Closed Loop Mode 2In closed loop mode 2 there are 16 possible combinations of phase and power adjustment.
0.20.81
0.80.20
Power_ant2Power_ant1FSMpo
3π/4100π/2101π/41110110
-π/4010-π/2011-3π/4001
π000Phase difference between antennas (radians)FSMph
FSMpo subfield ofsignalling message
FSMph subfield ofsignalling message
169
There is only one type of downlink dedicated physical channel, the Downlink Dedicated Physical Channel (DL DPCH). Within one downlink DPCH, dedicated data generated at Layer 2 and above, i.e. the dedicated transport channel (DCH), is transmitted in time-multiplex with control information generated at Layer 1 (known pilot bits, TPC commands, and an optional TFCI).
Downlink Dedicated Physical Channels(DPCH)
170
Frame Structure of DL DPCH
One radio frame, Tf = 10 ms
TPC NTPC bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2k bits (k=0..7)
Data2Ndata2 bits
DPDCHTFCI
NTFCI bitsPilot
Npilot bitsData1
Ndata1 bits
DPDCH DPCCH DPCCH
171
DL DPCHParameters
Each frame= 15 slots = 10 msEach slot= 2560 chips
Each slot= one power-control period.
SF = 512/2k (e.g., SF=512, 256, ...,4)Two basic types
With TFCI (for several simultaneous services)Without TFCI (fixed-rate services)
It is the UTRAN that determines if a TFCI should be transmitted and it is mandatory for all UEs to support the use of TFCI in the downlink.
172
DL DPCH Compressed Mode
In compressed frames, a different slot format is used compared to normal mode.There are two possible compressed slot formats that are labelled A and B.
Slot format B shall be used in frames compressed by spreading factor reduction.Slot format A shall be used in frames compressed by puncturing or higher layer scheduling.
Reference: 3GPP TS 25-212 V3.8.0 4.4 Compressed Mode
173
DL DPCH Fields (table is not completed)
8-14442822025615305A
154221022025615305
8-148042444012830604B
8-144021222025615304A
154021222025615304
8-144442444012830603B
8-142421022025615303A
152221222025615303
8-144042844012830602B
8-142021422025615302A
152021422025615302
8-14844402025615301B
1542220105127.5151
8-14804802025615300B
8-1440240105127.5150A
1540240105127.5150
NPilotNTFCINTPCNData2NData1
Transmittedslots per
radio frame NTr
DPCCHBits/Slot
DPDCHBits/Slot
Bits /Slot
SFChannelSymbol
Rate (ksps)
ChanneBit Rate(kbps)
SlotFormat #i
174
DL DPCH Pilot Bit Patterns
100000101101110011111010010001
111111111111111111111111111111
111110011101101000001100010010
111111111111111111111111111111
101001000110000010110111001111
111111111111111111111111111111
110001001011111001110110100000
111111111111111111111111111111
101001000110000010110111001111
111111111111111111111111111111
110001001011111001110110100000
111111111111111111111111111111
110001001011111001110110100000
111111111111111111111111111111
110001001011111001110110100000
Slot #01234567891011121314
765432103210100Symbol#
Npilot = 16(*3)
Npilot = 8(*2)
Npilot = 4(*1)
Npilot=2
175
DL DPCH TPC & TFCI
TPC
TFCITFCI value in each radio frame corresponds to a certain combination of bit rates of the DCHscurrently in use.
10
1111111100000000
11110000
1100
NTPC = 8NTPC = 4NTPC = 2
Transmitter Power Control Command
TPC Bit Pattern
176
DL DPCH Multi-Code Transmission
TransmissionPower Physical Channel 1
TransmissionPower Physical Channel 2
TransmissionPower Physical Channel L
DPDCH
One Slot (2560 chips)
TFCI PilotTPC
• •
•
DPDCH Condition:
Total bit rate to be transmitted exceeds the maximum bit rate
Layer 1 control information is transmitted only on the first DL DPCH.
Multicodetransmission is mapped onto several parallel downlink DPCHs using the same spreading factor.
177
Common Pilot Channel (CPICH)Frame Structure:
Pre-defined symbol sequence
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips , 20 bits = 10 symbols
1 radio frame: Tf = 10 ms
178
Common Pilot Channel
The CPICH is a fixed rate (30 kbps, SF=256) downlink physical channel that carries a pre-defined bit/symbol sequence.In case transmit diversity (open or closed loop) is used on any downlink channel in the cell, the CPICH shall be transmitted from both antennas using the same channelization and scrambling code.There are two types of Common pilot channels:
The Primary CPICH.The Secondary CPICH.
179
Transmit Diversity of CPICH
Modulation pattern for Common Pilot Channel (with A = 1+j)
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
In case of no transmit diversity, thesymbol sequence of Antenna 1 is used.
180
The Primary CPICHThe Primary Common Pilot Channel (P-CPICH) has the following characteristics:
The same channelization code is always used for the P-CPICH;The P-CPICH is scrambled by the primary scrambling code;There is one and only one P-CPICH per cell;The P-CPICH is broadcast over the entire cell.
The Primary CPICH is a phase reference for the following downlink channels: SCH, Primary CCPCH, AICH, PICH AP-AICH, CD/CA-ICH, CSICH, DL-DPCCH for CPCH and the S-CCPCH.By default, the Primary CPICH is also a phase reference for downlink DPCH and any associated PDSCH.The Primary CPICH is always a phase reference for a downlink physical channel using closed loop TX diversity.
181
A Secondary Common Pilot Channel (S-CPICH) has the following characteristics:
An arbitrary channelization code of SF=256 is used for the S-CPICH;A S-CPICH is scrambled by either the primary or a secondary scrambling code;There may be zero, one, or several S-CPICHs per cell;A S-CPICH may be transmitted over the entire cell or only over a part of the cell;
A Secondary CPICH may be a phase reference for a downlink DPCH.The Secondary CPICH can be a phase reference for a downlink physical channel using open loop TX diversity, instead of the Primary CPICH being a phase reference.
Secondary Common Pilot Channel(S-CPICH)
182
Downlink Phase Reference
––ˇDL-DPCCH for CPCH
––ˇCSICH
––ˇAICH
ˇˇˇPDSCH*
––ˇPICH
ˇˇˇDPCH
––ˇS-CCPCH
––ˇSCH
––ˇP-CCPCH
Dedicated PilotSecondary-CPICHPrimary-CPICHPhysical Channel Type
Note *: the same phase reference as with the associated DPCH shall be used.
183
Fixed rate: 30 kbps, SF=256.Used to carry the BCH transport channel.No TPC commands, no TFCI and no pilot bits.Frame structure:
Data Ndata1=18 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)
184
S-CCPCH is used to carry the FACH and PCH. Two types of S-CCPCHs: those that include TFCI and those that do not include TFCI.It is the UTRAN that determines if a TFCI should be transmitted, hence making it mandatory for all UEs to support the use of TFCI.
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 20*2k bits (k=0..6)
Pilot Npilot bits
Data Ndata1 bits
1 radio frame: Tf = 10 ms
TFCI NTFCI bits
Secondary Common Control Physical Channel (S-CCPCH)
185
Secondary CCPCH Fields
816125612801920049601920 17
80127212801920049601920 16
8166166409600848096015
806326409600848096014
816296320480016240480 13
80312320480016240480 12
88144160240032120240 11
80152160240032120240 10
88648012006460120 9
80728012006460120 8
2830406001283060 7
2038406001283060 6
0832406001283060 5
0040406001283060 4
2810203002561530 3
2018203002561530 2
0812203002561530 1
0020203002561530 0
NTFCINpilotNdata1Bits/ Slot
Bits/ Frame
SFChannel SymbolRate (ksps)
Channel Bit Rate (kbps)
Slot Format #i
186
S-CCPCH Pilot Symbol Patterns
100000101101110011111010010001
111111111111111111111111111111
111110011101101000001100010010
111111111111111111111111111111
101001000110000010110111001111
111111111111111111111111111111
110001001011111001110110100000
111111111111111111111111111111
101001000110000010110111001111
111111111111111111111111111111
110001001011111001110110100000
111111111111111111111111111111
Slot #01234567891011121314
765432103210Symbol #
Npilot = 16Npilot = 8
187
Characteristics of S-CCPCHThe FACH and PCH can be mapped to the same or to separate Secondary CCPCHs.If FACH and PCH are mapped to the same S-CCPCH, they can be mapped to the same frame.The main difference between a CCPCH and a downlink dedicated physical channel is that a CCPCH is not inner-loop power controlled.The main difference between the P-CCPCH and S-CCPCH is that the transport channel mapped to the P-CCPCH can only have a fixed predefined transport format combination, while the S-CCPCH support multiple transport format combinations using TFCI.
188
Synchronization Channel (SCH)The SCH is a downlink signal used for cell search.The SCH consists of: the Primary and Secondary SCH.The 10 ms radio frames of the Primary and Secondary SCH are divided into 15 slots, each of length 2560 chips.
PrimarySCH
SecondarySCH
256 chips
2560 chips
One 10 ms SCH radio frame
acsi,0
acp
acsi,1
acp
acsi,14
acp
Slot #0 Slot #1 Slot #14
189
Synchronization Channel (SCH)
The Primary SCH consists of a modulated code of length 256 chips, the Primary Synchronisation Code (PSC), transmitted once every slot.The PSC is the same for every cell in the system.The primary and secondary synchronization codes are modulated by the symbol a, which indicates the presence/ absence of STTD encoding on the P-CCPCH:
a = -1P-CCPCH not STTD encodeda = +1P-CCPCH STTD encoded
190
Synchronization Channel (SCH)
The Secondary SCH consists of repeatedly transmitting a length 15 sequence of modulated codes of length 256 chips, the Secondary Synchronisation Codes (SSC), transmitted in parallel with the Primary SCH.The SSC is denoted cs
i,k, where i = 0, 1, …, 63 is the number of the scrambling code group, and k = 0, 1, …, 14 is the slot number.Each SSC is chosen from a set of 16 different codes of length 256.This sequence on the Secondary SCH indicates which of the code groups the cell's downlink scrambling code belongs to.
191
The PDSCH is used to carry the Downlink Shared Channel (DSCH).A PDSCH corresponds to a channelisation code below or at a PDSCH root channelisation code.A PDSCH is allocated on a radio frame basis to a UE.Within one radio frame, UTRAN may allocate different PDSCHs under the same PDSCH root channelisation code to different UEs based on code multiplexing.Within the same radio frame, multiple parallel PDSCHs, with the same spreading factor, may be allocated to a single UE.All the PDSCHs are operated with radio frame synchronisation.
Physical Downlink Shared Channel (PDSCH)
192
PDSCHs allocated to the same UE on different radio frames may have different spreading factors.Frame structure of PDSCH:
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 20*2k bits (k=0..6)
Data Ndata1 bits
1 radio frame: Tf = 10 ms
Physical Downlink Shared Channel (PDSCH)
193
For each radio frame, each PDSCH is associated with one downlink DPCH. The PDSCH and associated DPCH do not necessarily have the same spreading factors and are not necessarily frame aligned.All relevant Layer 1 control information is transmitted on the DPCCH part of the associated DPCH, i.e. the PDSCH does not carry Layer 1 information. To indicate for UE that there is data to decode on the DSCH, the TFCI field of the associated DPCH shall be used.The TFCI informs the UE of the instantaneous transport format parameters related to the PDSCH as well as the channelisation code of the PDSCH.
Physical Downlink Shared Channel (PDSCH)
194
The Acquisition Indicator channel (AICH) is a fixed rate (SF=256) physical channel used to carry Acquisition Indicators (AI).Acquisition Indicator AIs corresponds to signature s on the PRACH.Frame structure:
1024 chips
Transmission Off
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
a1 a2a0 a31a30
AI part = 4096 chips, 32 real-valued symbols
20 ms
Acquisition Indicator Channel (AICH)
195
The AICH consists of a repeated sequence of 15 consecutive access slots (AS), each of length 5120 chips. Each access slot consists of two parts, an Acquisition-Indicator (AI) part consisting of 32 real-valued symbols a0, …, a31 and a part of duration 1024 chips with no transmission that is not formally part of the AICH.The part of the slot with no transmission is reserved for possible use by CSICH or possible future use by other physical channels.
Acquisition Indicator Channel (AICH)
196
The spreading factor (SF) used for channelisation of the AICH is 256.The phase reference for the AICH is the Primary CPICH.The real-valued symbols a0, a1, …, a31 are given by
AIs (1, 0, -1) ~( ACK, No ACK, NACK)Each slot can ack 16 signatures.
∑=
=15
0js,sj bAIa
s
Acquisition Indicator Channel (AICH)
197
AICH signature patterns bs,0, …, bs,31:
Acquisition Indicator Channel (AICH)
198
The AP-AICH is a fixed rate (SF=256) physical channel used to carry AP acquisition indicators (API) of CPCH.AP acquisition indicator APIs corresponds to AP signature s transmitted by UE.Frame structure:
1024 chips
Transmission Off
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
a1 a2a0 a31a30
API part = 4096 chips, 32 real-valued symbols
20 ms
CPCH Access Preamble Acquisition Indicator Channel (AP-AICH)
199
AP-AICH and AICH may use the same or different channelisation codes. The phase reference for the AP-AICH is the Primary CPICH.The AP-AICH has a part of duration 4096 chips where the AP acquisition indicator (API) is transmitted, followed by a part of duration 1024chips with no transmission that is not formally part of the AP-AICH.The spreading factor (SF) used for channelisation of the AP-AICH is 256.APIs (1, 0, -1) ~( ACK, No ACK, NACK)
CPCH Access Preamble Acquisition Indicator Channel (AP-AICH)
200
The CD/CA-ICH is a fixed rate (SF=256) physical channel used to carry CD Indicator (CDI) only if the CA is not active, or CD Indicator/CA Indicator (CDI/CAI) at the same time if the CA is active.CD/CA-ICH frame structure:
1024 chips
Transmission Off
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
a1 a2a0 a31a30
CDI/CAI part = 4096 chips, 32 real-valued symbols
20 ms
CPCH Collision Detection/Channel Assignment Indicator Channel (CD/CA-ICH)
201
CD/CA-ICH and AP-AICH may use the same or different channelisation codes.The CD/CA-ICH has a part of duration of 4096chips where the CDI/CAI is transmitted, followed by a part of duration 1024chips with no transmission that is not formally part of the CD/CA-ICH.The spreading factor (SF) used for channelisation of the CD/CA-ICH is 256.
CPCH Collision Detection/Channel Assignment Indicator Channel (CD/CA-ICH)
202
Paging Indicator Channel (PICH)The PCH is to provide terminals with efficient sleep mode operation.For detection of the PICH, the terminal needs to obtain the phase reference from the CPICH, and as with the AICH, the PICH needs to be heard by all terminals in the cell and thus needs to be sent at high power level without power control.The PICH is a fixed rate (SF=256) physical channel used to carry the paging indicators.The PICH is always associated with an S-CCPCH to which a PCH transport channel is mapped.
203
Paging Indicator Channel (PICH)
One PICH radio frame of length 10 ms consists of 300 bits (b0, b1, …, b299).288 bits (b0, b1, …, b287) are used to carry paging indicators.The remaining 12 bits are not formally part of the PICH and shall not be transmitted.The part of the frame with no transmission is reserved for possible future use.
b1b0
288 bits for paging indication12 bits (transmission
off)
One radio frame (10 ms)
b287 b288 b299
204
Paging Indicator Channel (PICH)
In each PICH frame, Np paging indicators {P0, …, PNp-1} are transmitted, where Np=18, 36, 72, or 144.The PI calculated by higher layers for use for a certain UE, is associated to the paging indicator Pq, where q is computed as a function of:
The PI computed by higher layers;The SFN of the P-CCPCH radio frame during which the start of the PICH radio frame occurs;The number of paging indicators per frame (Np).
⎣ ⎦ ⎣ ⎦ ⎣ ⎦( )( )( ) NpNpSFNSFNSFNSFNPIq mod144
144mod512/64/8/18 ⎟⎟⎠
⎞⎜⎜⎝
⎛⎥⎦⎥
⎢⎣⎢ ×+++×+=
205
Paging Indicator Channel (PICH)The PI calculated by higher layers is associated with the value of the paging indicator Pq.If a paging indicator in a certain frame is set to "1“, it is an indication that UEs associated with this paging indicator and PI should read the corresponding frame of the associated S-CCPCH.The PI bitmap in the PCH data frames over Iub contains indication values for all higher layer PI values possible. Each bit in the bitmap indicates if the paging indicator associated with that particular PI shall be set to 0 or 1. Hence, the calculation in the formula above is to be performed in Node B to make the association between PI and Pq.
206
Paging Indicator Channel (PICH)Mapping of paging indicators Pq to PICH bits
{b2q, b2q+1} = {+1,+1}
{b2q, b2q+1} ={-1,-1}
Np=144
{b4q, …, b4q+3} ={+1, +1,…,+1}
{b4q, …, b4q+3} = {-1, -1,…,-1}
Np=72
{b8q, …, b8q+7} = {+1,+1,…,+1}
{b8q, …, b8q+7} = {-1,-1,…,-1}
Np=36
{b16q, …, b16q+15} = {+1,+1,…,+1}
{b16q, …, b16q+15} = {-1,-1,…,-1}
Np=18
Pq = 0Pq = 1Number of paging indicators per frame
(Np)
207
CPCH Status Indicator Channel (CSICH)
The CSICH is a fixed rate (SF=256) physical channel used to carry CPCH status information.The CSICH bits indicate the availability of each physical CPCH channel and are used to tell the terminal to initiate access only on a free channel but, on the other hand, to accept a channel assignment command to an unused channel.A CSICH is always associated with a physical channel used for transmission of CPCH AP-AICH and uses the same channelization and scrambling codes.
208
CPCH Status Indicator Channel (CSICH)
The CSICH frame consists of 15 consecutive access slots (AS) each of length 40 bits.Each access slot consists of two parts, a part of duration 4096 chips with no transmission, and a Status Indicator (SI) part consisting of 8 bits b8i,….b8i+7, where i is the access slot number. The part of the slot with no transmission is reserved for use byAICH, AP-AICH or CD/CA-ICH.
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
b8i b8i+1
4096 chips
Transmission off
SI part
20 ms
b8i+7b8i+6
209
CPCH Status Indicator Channel (CSICH)
The modulation used by the CSICH is the same as for the PICH.The phase reference for the CSICH is the Primary CPICH.N Status Indicators {SI0, …, SIN-1} shall be transmitted in each CSICH frame.The Status Indicators shall be transmitted in all the access slots of the CSICH frame, even if some signatures and/or access slots are shared between CPCH and RACH.
210
CPCH Status Indicator Channel (CSICH)Mapping of Status Indicators (SI) to CSICH bits:
{b2n, b2n+1} = {+1,+1}{b2n, b2n+1} = {-1,-1}N=60
{b4n, …, b4n+3} ={+1, +1, +1, +1}
{b4n, …, b4n+3} ={-1, -1, -1, -1}
N=30
{b8n, …, b8n+7} ={+1,+1,…,+1}
{b8n, …, b8n+7} = {-1,-1,…,-1}
N=15
{b24n, …, b24n+23} ={+1,+1,…,+1}
{b24n, …, b24n+23} = {-1,-1,…,-1}
N=5
{b40n, …, b40n+39} ={+1,+1,…,+1}
{b40n, …, b40n+39} ={-1,-1,…,-1}
N=3
{b0, …, b119} ={+1,+1,…,+1}
{b0, …, b119} = {-1,-1,…,-1}
N=1
SIn = 0SIn = 1Number of SI per frame (N)
211
k:th S-CCPCH
AICH access slots
Secondary SCH
Primary SCH
τS-CCPCH,k
10 ms
τPICH
#0 #1 #2 #3 #14 #13 #12 #11 #10 #9 #8 #7 #6 #5 #4
Radio frame with (SFN modulo 2) = 0 Radio frame with (SFN modulo 2) = 1
τDPCH,n
P-CCPCH
Any CPICH
PICH for k:th S-CCPCH
Any PDSCH
n:th DPCH
10 ms
Timing Relationship between Physical Channels
212
The P-CCPCH, on which the cell SFN is transmitted, is used as timing reference for all the physical channels, directly for downlink and indirectly for uplink.Transmission timing for uplink physical channels is given by the received timing of downlink physical channels.SCH (primary and secondary), CPICH (primary and secondary), P-CCPCH, and PDSCH have identical frame timings.
Timing Relationship between Physical Channels
213
The S-CCPCH timing may be different for different S-CCPCHs, but the offset from the P-CCPCH frame timing is a multiple of 256 chips, i.e. τS-CCPCH,k = Tk × 256 chip, Tk ∈ {0, 1, …, 149}.The PICH timing is τPICH = 7680 chips prior to its corresponding S-CCPCH frame timing, i.e. the timing of the S-CCPCH carrying the PCH transport channel with the corresponding paging information.AICH access slots #0 starts the same time as P-CCPCH frames with (SFN modulo 2) = 0.The DPCH timing may be different for different DPCHs, but the offset from the P-CCPCH frame timing is a multiple of 256 chips, i.e. τDPCH,n = Tn × 256 chip, Tn ∈ {0, 1, …, 149}.
Timing Relationship between Physical Channels
214
PICH/S-CCPCH Timing Relation
The S-CCPCH frame that carries the paging information is related to the paging indicators in the PICH frame.A paging indicator set in a PICH frame means that the paging message is transmitted on the PCH in the S-CCPCH frame starting τPICH chips after the transmitted PICH frame.
τPICH
Associated S-CCPCH frame
PICH frame containing paging indicator
215
PRACH/AICH Timing RelationThe downlink AICH is divided into downlink access slots, each access slot is of length 5120 chips.The uplink PRACH is divided into uplink access slots, each access slot is of length 5120 chips.Uplink access slot number n is transmitted from the UE τp-a chips prior to the reception of downlink access slot number n, n = 0, 1, …, 14.
One access slot
τp-a
τp-mτp-p
Pre-amble
Pre-amble Message part
Acq.Ind.AICH access
slots RX at UE
PRACH accessslots TX at UE
216
PRACH/AICH Timing Relation
Transmission of downlink acquisition indicators may only start at the beginning of a downlink access slot.Similarly, transmission of uplink RACH preambles and RACH message parts may only start at the beginning of an uplink access slot.The preamble-to-preamble distance τp-p shall be larger than or equal to the minimum preamble-to-preamble distanceτp-p,min, i.e. τp-p ≥ τp-p,min.
217
PRACH/AICH Timing RelationIn addition to τp-p,min, the preamble-to-AI distance τp-aand preamble-to-message distance τp-m are defined as follows:
When AICH_Transmission_Timing is set to 0, thenτp-p,min = 15360 chips (3 access slots)τp-a = 7680 chipsτp-m = 15360 chips (3 access slots)
When AICH_Transmission_Timing is set to 1, thenτp-p,min = 20480 chips (4 access slots)τp-a = 12800 chipsτp-m = 20480 chips (4 access slots)
The parameter AICH_Transmission_Timing is signalled by higher layers.
218
DPCH/PDSCH Timing RelationThe start of a DPCH frame is denoted TDPCH and the start of the associated PDSCH frame is denoted TPDSCH.Any DPCH frame is associated to one PDSCH frame through the relation 46080 chips ≤ TPDSCH - TDPCH < 84480 chips, i.e., the associated PDSCH frame starts between three slots after the end of the DPCH frame and 18 slots after the end of the DPCH frame.
TDPCH
Associated PDSCH frame
DPCH frame
TPDSCH
219
DPCCH/DPDCH Timing RelationsUplink
In uplink the DPCCH and all the DPDCHs transmitted from one UE have the same frame timing.
DownlinkIn downlink, the DPCCH and all the DPDCHs carrying CCTrCHs of dedicated type to one UE have the same frame timing.Note: support of multiple CCTrChs of dedicated type is not part of the current release.
Uplink/downlink timing at UEAt the UE, the uplink DPCCH/DPDCH frame transmission takes placeapproximately T0 chips after the reception of the first detected path (in time) of the corresponding downlink DPCCH/DPDCH frame.T0 is a constant defined to be 1024 chips.
220
Spreading without SCHThe non-spread physical channel consists of a sequence of real-valued symbols.For all channels except AICH, the symbols can take the three values +1, -1, and 0, where 0 indicates DTX.For AICH, the symbol values depend on the exact combination of acquisition indicators to be transmitted.
I
Any downlinkphysical channelexcept SCH
S→P
Cch,SF,m
j
Sdl,n
Q
I+jQ S
221
Spreading with SCH
Different downlinkPhysical channels
Σ
G1
G2
GP
GS
S-SCH
P-SCH Σ
222
Downlink Scrambling Codes
8192 codes are chosen from a total of 218-1 scrambling codes, numbered 0,…,262142
These chosen scrambling codes are divided into 512 sets, each set has
One primary scrambling codeCode number, n=16*i (i=0…511)
15 secondary scrambling codes Code number, n=16*i+k (k=1…15)
223
Downlink Scrambling Codes512 primary scrambling codes
Further divided into 64 scrambling code groups
Each group consisting of 8 primary scrambling codes
The j:th scrambling code group consists of primary scrambling codes 16*8*j+16*k (j=0..63 & k=0..7)
Each cell is allocated one and only one primary scrambling code.The primary CCPCH, primary CPICH, PICH, AICH, AP-AICH, CD/CA-ICH, CSICH and S-CCPCH carrying PCH are always transmitted using the primary scrambling code.The other downlink physical channels can be transmitted with either the primary scrambling code or a secondary scrambling code from the set associated with the primary scrambling code of the cell.
224
Configuration of Downlink Scrambling Code Generator
I
Q
1
1 0
02
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
17
17
16
16
15
15
14
14
13
13
12
12
11
11
10
10
225
Downlink Scrambling CodesConstructed by combining two real sequencesEach is constructed as the position wise modulo 2 sum of two binary m-sequences, x and y
Generator polynomials is of degree 18
38400 chip segments (10 ms radio frame)
Gold sequences
x sequence: generator polynomial 1+X7+X18
Initial: x (0)=1, x(1)= x(2)=...= x (16)= x (17)=0
x(i+18) =x(i+7) + x(i) modulo 2, i=0,…,218-20,
y sequence: generator polynomial 1+y 5+y 7+ y 10+y 18
Initial: y(0)=y(1)= … =y(16)= y(17)=1
y(i+18) = y(i+10)+y(i+7)+y(i+5)+y(i) modulo 2, i=0,…, 218-20
226
Downlink Scrambling Codes
The nth Gold code sequence zn iszn(i) = x((i+n) modulo (218 - 1)) + y(i) modulo 2, i=0,…, 218-2
Mapping
The n:th complex scrambling code sequence Sdl,n is defined as:
.22,,1,01)(10)(1
)( 18 −=⎩⎨⎧
=−=+
= …iforizifizif
iZn
nn
Sdl,n(i) = Zn(i) + j Zn((i+131072) modulo (218-1)), i=0,1,…,38399.
227
Downlink Modulation
In the downlink, the complex-valued chip sequence generated by the spreading process is QPSK modulated:
T
Im{T}
Re{T}
cos(ωt)
Complex-valuedchip sequencefrom summingoperations
-sin(ωt)
Splitreal &imag.parts
Pulse-shaping
Pulse-shaping
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
Compressed Mode
229
Compressed ModeOften referred to as the slotted mode.Inter-frequency handovers are needed for utilization of hierarchical cell structures and for handovers to 2nd generation systems.To complete inter-frequency handovers, measurements on other frequencies while still having the connection running on the current frequency are needed:
Dual Receiver;Compressed Mode;
Lowering the data rate from higher layers.Variable spreading factor.Code rate increase.Puncturing at the physical layer.Multi-code.Higher order modulation. 3GPP TS 25.212 V.3.8.0 4.4
230
Compressed Mode
The specified Transmission Gap Length (TGL) are 3, 4, 7, 10, and 14 slots.
One frame(10 ms) Transmission gap available for
inter-frequency measurements
231
Compressed ModeIn compressed frames, TGL slots from Nfirst to Nlastare not used for transmission of data.The instantaneous transmit power is increased in the compressed frame in order to keep the quality (BER, FER, etc.) unaffected by the reduced processing gain.The amount of power increase depends on the transmission time reduction method.What frames are compressed, are decided by the network.When in compressed mode, compressed frames can occur periodically, or requested on demand.
232
Slot # (Nlast + 1)
Data
Pilot TFCI FBI TPC
Slot # (Nfirst – 1)
Data
Pilot TFCI FBI TPC
transmission gap
Compressed Mode Frame Structure in the Uplink
233
There are two different types of DL frame structures:Type A maximizes the transmission gap length.Type B is optimized for power control.
Type A: the pilot field of the last slot in the transmission gap is transmitted.Type B: the TPC field of the first slot in the transmission gap and the pilot field of the last slot in the transmission gap is transmitted.
Slot # (Nfirst - 1)
TPC
Data1TFCI Data2 PL
Slot # (Nlast + 1)
PL Data1TPC
TFCI Data2 PL
transmission gap
Slot # (Nfirst - 1)
TPC
Data1TFCI Data2 PL
Slot # (Nlast + 1)
PL Data1TPC
TFCI Data2 PL
transmission gap
TPC
A:
B:
Compressed Mode Frame Structure Types in the Downlink
234
When in compressed mode, the information normally transmitted during a 10 ms frame is compressed in time.The mechanisms provided for achieving this are:
puncturing,reduction of the spreading factor by a factor of two,higher layer scheduling.
In the downlink, all methods are supported while compressed mode by puncturing is not used in the uplink. The maximum idle length is defined to be 7 slots per one 10 ms frame.
Compressed Mode Transmission Time Reduction Method
235
Transmission gaps can be placed at different positions for interfrequency power measurement, acquisition of control channel of other system/carrier, and handover operation.There are two methods:
Single frame methodDouble frame method
# 1 4# N firs t-1(1 ) S in g le - fra m e m e th o d
(2 ) D o u b le - fra m e m e th o d
F irs t ra d io fra m e S e c o n d ra d io fra m e
R a d io fra m eT ra n s m is s io n g a p
T ra n s m is s io n g a p
# 0
# 1 4
# N la s t+ 1
# N firs t-1 # N la s t+ 1# 0
Compressed Mode Transmission Gap Position
236
Compressed Mode TGL
R a d io f r a m e
F ir s t r a d io f r a m e S e c o n d r a d io f r a m eT r a n s m is s io n g a p
( 2 ) D o u b le - f r a m e m e t h o d
( 1 ) S in g le - f r a m e m e t h o d
::
::
R a d io f r a m e
T r a n s m is s io n g a p
T r a n s m is s io n g a p
T r a n s m is s io n g a p
T r a n s m is s io n g a p
T r a n s m is s io n g a p
TGL=3,4, and 7.
TGL=3,4,7,10,14.
When the transmission gap spans two consecutive radio frames, Nfirst andTGL must be chosen so that at least 8 slots in each radio frame are transmitted.
237
Idle Lengths for UL
(D) =(7,7)9.3314
(D)=(3,7), (4,6), (5,5), (6,4) or (7,3)
6.6710
(S)(D)=(1,6), (2,5), (3,4), (4,3),
(5,2) or (6,1)
4.677
(S)(D) = (1,4), (2,3), (3, 2) or
(4,1)
3.335
(S)(D) =(1,3), (2,2) or (3,1)
2.674
(S)(D) =(1,2) or (2,1)
Spreading factor division by 2 or
Higher layer scheduling
2.00256 – 43
Idle frameCombining
Transmission timeReduction method
Idle length [ms]
Spreading Factor
TGL
(S): Single-frame method. (D): Double-frame method.(x,y) indicates x: the number of idle slots in the first frame,
y: the number of idle slots in the second frame.
238
Idle Lengths for DL
8.93 – 9.19B
(D) =(7,7)9.07 – 9.33A14
6.27 – 6.53B
(D)=(3,7), (4,6), (5,5), (6,4) or (7,3)
6.40 – 6.66A10
4.27 – 4.53B
(S)(D)=(1,6), (2,5), (3,4), (4,3),
(5,2) or (6,1)
4.40 – 4.66A7
2.93 – 3.19B
(S)(D) = (1,4), (2,3), (3, 2) or
(4,1)
3.07 – 3.33A5
2.27 – 2.53B
(S)(D) =(1,3), (2,2) or (3,1)
2.40 – 2.66A4
1.60 – 1.86B
(S)(D) =(1,2) or (2,1)
Puncturing, Spreading factor division by 2 or
Higher layer scheduling
1.73 – 1.99512 – 4A3
Idle frameCombining
Transmission timeReduction method
Idle length [ms]
Spreading Factor
DL FrameType
TGL
239
Idle Lengths for Combined UL/DL
(D) =(7,7)8.80 – 9.0614
(D)=(3,7), (4,6), (5,5), (6,4) or (7,3)
6.13 – 6.3910
(S)(D)=(1,6), (2,5), (3,4),
(4,3), (5,2) or (6,1)
4.13 – 4.397
(S)(D) = (1,4), (2,3), (3, 2)
or (4,1)
2.80 – 3.065
(S)(D) =(1,3), (2,2) or (3,1)
2.13 – 2.394
(S)(D) =(1,2) or (2,1)
DL:Puncturing,
Spreading factor division by 2 or
Higher layer scheduling
UL:Spreading factor division by 2 or
Higher layer scheduling
1.47 – 1.73DL:512 – 4
UL:256 – 4
A or B3
Idle frameCombining
Transmission time
Reduction method
Idle length [ms]
Spreading Factor
DL FrameType
TGL
Wireless Information Transmission System Lab.
National Sun Yat-sen UniversityInstitute of Communications Engineering
Site Selection Diversity Transmission
241
Site selection diversity transmit power control (SSDT) is a macro diversity method in soft handover mode.This method is optional in UTRAN.The UE selects one of the cells from its active set to be `primary', all other cells are `non primary'.
The main objective is to transmit on the downlink from the primary cell, thus reducing the interference caused by multiple transmissions in a soft handover mode.A second objective is to achieve fast site selection without network intervention, thus maintaining the advantage of the soft handover.
Site Selection Diversity Transmission
242
In order to select a primary cell, each cell is assigned a temporary identification (ID) and UE periodically informs a primary cell ID to the connecting cells.The non-primary cells selected by UE switch off the transmission power.The primary cell ID is delivered by UE to the active cells via uplink FBI field.SSDT activation, SSDT termination and ID assignment are all carried out by higher layer signalling.
Site Selection Diversity Transmission
243
Definition of Temporary Cell IDEach cell is given a temporary ID during SSDT and the ID is utilised as site selection signal.The ID is given a binary bit sequence.There are three different lengths of coded ID available denoted as "long", "medium" and "short".The network decides which length of coded ID is used.The ID code(s) are transmitted aligned to the radio frame structure (i.e. ID codes shall be terminated within a frame).If FBI space for sending the last ID code within a frame cannot be obtained, the first bit(s) from that ID code are punctured.
244
Settings of ID codes for 1 bit FBI
10101(0)1101001110100101101001h11100(0)0111100011110000111100g01110(0)1011010101101001011010f00111(0)0001111000111100001111e10010(0)1100110110011001100110d11011(0)0110011011001100110011c01001(0)1010101101010101010101b00000(0)0000000000000000000000a
"short""medium""long"ID label
ID code
245
Settings of ID codes for 2 bit FBI
110001
(0)110(1)001
(0)1100110(1)0011001
h
110110
(0)110(0)110
(0)1100110(0)1100110
g
011100
(0)011(1)100
(0)0110011(1)1001100
f
011011
(0)011(0)011
(0)0110011(0)0110011
e
101010
(0)101(1)010
(0)1010101(1)0101010
d
101101
(0)101(0)101
(0)1010101(0)1010101
c
000111
(0)000(1)111
(0)0000000(1)1111111
b
000000
(0)000(0)000
(0)0000000(0)0000000
a"short""medium""long"ID label
ID code (Column and Row denote slot position and FBI-bit position.)
246
TPC Procedure in the UE
The UE shall generate TPC commands to control the network transmit power and send them in the TPC field of the uplink DPCCH based on the downlink signals from the primary cell only.The UE selects a primary cell periodically by measuring the RSCP (Received Signal Code Power) of P-CPICHs transmitted by the active cells.The cell with the highest P-CPICH RSCP is detected as a primary cell.
247
Period of Primary Cell Update
At the UE, the primary ID code to be sent to the cells is segmented into a number of portions.These portions are distributed in the uplink FBI S-field.The cell in SSDT collects the distributed portions of the primary ID code and then detects the transmitted ID.
5 updates per frame 3 updates per frame "short"4 updates per frame 2 updates per frame "medium"2 updates per frame 1 update per frame "long"
21code lengthThe number of FBI bits per slot assigned for SSDT
248
Downlink Receiver Architecture
RF
ADC
SRRC
Slot Sync.
Frame Sync./Code Group Identification
Scrambling Code Identification
Multi-path Searcher Rake Finger Management
Frame Boundary / Scrambling Code
ChannelEstimation
CodeTracking
De-Spreading
De-Scrambling MRC Channel
Decoding
Cell Search
Rake Receiver
249
Uplink Receiver Architecture
RF
ADC
SRRC
PRACH Preamble Detection
Multi-path Searcher Rake Finger Management
ChannelEstimation
CodeTracking
De-Spreading
De-Scrambling MRC Channel
Decoding
Rake ReceiverFrame Boundary
250
Uplink Transmitter Functional Block
DI
DQ
Antipodal Conv.
“0”>+1, “1”>-1
Antipodal Conv.
“0”>+1, “1”>-1
∑
Pulse Shaping
Filter
Pulse Shaping
Filter
∑
Root Nyquist,r=0.22
Root Nyquist,r=0.22
Channel Model
TS′TS+
+
+
+
IC
IC
QC
Gain Controlch1C
256,1C
DPDCH
DPCCH
tAcos cω
tAsin cω
-Complex Gaussian
-MultipathRayleigh
-UMTS Channel
∑
+
−
251
Downlink Transmitter Functional Block
DI
DQ
jAntipodal Conv.
“0”>+1, “1”>-1 ∑
Pulse Shaping
Filter
Pulse Shaping
Filter
∑
Root Nyquist,r=0.22
Root Nyquist,r=0.22
Channel Model
-Complex Gaussian
-MultipathRayleigh
-UMTS Channel
TS′TS+
+
+
+
Other User Signals
IC
IC
QC
ch1C
ch1C
DPDCH1/DPCCH
Antipodal Conv.
“0”>+1, “1”>-1
Gain Control
∑+
−