wcdma fdd mode transmitter
TRANSCRIPT
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Table of Contents Traditional Sequential ASIC Design Flow Introduction to WCDMA Transmitter Specifications
WCDMA Network Architecture Physical Layer General Description Multiplexing and Channel Coding (MCC) WCDMA Uplink Physical Layer WCDMA Downlink Physical Layer
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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, 2001
Wireless Communications - Principles & Practice -- by Theodore S. Rappaport, Prentice Hall, 2nd Edition, Dec. 31, 2001
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System Models Architecture Design
USIM
ME
Cu
UE
External Networks
•PLMN: Public Land Mobile Network. One PLMN is operated by a single operator.
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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 Uu interfaces. 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).
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WCDMA System Architecture
UMTS 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.
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Main Elements of the GSM Core Network
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.
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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’s location within the serving system.
Main Elements of the GSM Core Network
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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
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Interfaces Cu 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.
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Information Bits
)(ˆ tsi
Multiple Access
Source Bits Channel Bits
Multiple Access
Establishes the characteristics of the layer-1 transport channels and physical channels in the FDD mode, and specifies:
Transport channels Physical channels and their structure Relative 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
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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
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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.
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)
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General Protocol Architecture Radio 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)
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.
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Transport Channels
Transport 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
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
Dedicated Transport Channels
There 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. Possibility of fast rate change (every 10 ms) Support of fast power control and soft handover.
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Common Transport Channel Broadcast 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.
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Common Transport Channel Paging Channel (PCH) -- mandatory
PCH 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.
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Common Transport Channel Random 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.
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Common Transport Channel Forward 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.
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Common Transport Channel Common Packet Channel (CPCH) -- optional
CPCH 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.
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Common Transport Channel Downlink Shared Channel (DSCH) -- optional
DSCH is a downlink transport channel shared by several UEs to 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.
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Transport Channels
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)
Paging Indicator Channel (PICH)
Collision-Detection/Channel-Assignment Indicator Channel
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CRC-Attachment CRC-attachment
For error detection gCRC24(D) = D24 + D23 + D6 + D5 + D + 1 gCRC16(D) = D16 + D12 + D5 + 1 gCRC12(D) = D12 + D11 + D3 + D2 + D + 1 gCRC8(D) = D8 + D7 + D4 + D3 + D + 1
TrBk
TrBk
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No coding 1/3Turbo coding
RACH PCH
1/2Convolutional codingBCH
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Overview Configuration
Radio frame A radio frame is a processing unit which consists of 15 slots. The length of a radio frame corresponds to 38400 chips.
Time slot A 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
Overview Spreading (cont.)
Channelization operation OVSF 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 operation Long or short Gold codes. Applied to the spread signals. Randomize the codes
Spread signal is further multiplied by complex-valued scrambling
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Dedicated Uplink Physical Channels Uplink Dedicated Physical Data Channel (UL DPDCH) Uplink Dedicated Physical Control Channel (UL DPCCH)
Common Uplink Physical Channels Physical Random Access Channel (PRACH) Physical Common Packet Channel (PCPCH)
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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 1 One and only one UL DPCCH on each radio link.
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Pilot Npilot bits
TPC NTPC bits
Data Ndata bits
1 radio frame: Tf = 10 ms = 38400 chips
DPDCH
Ndata= 10*2k bits (k=0,1,…,6)
One Power Control Period
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UL DPDCH The 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
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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
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) – optional
TFCI informs the receiver about the instantaneous transport format combination of the transport channels.
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Pilot Bit Patterns with Npilot=3,4,5,6
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
Slot #0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
543210432103210210Bit # Npilot = 6Npilot = 5Npilot = 4Npilot = 3
Shadowed column is defined as FSW (Frame Synchronization Word).
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Shadowed column is defined as FSW (Frame Synchronization Word).
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Slot #0 1 2 3 4 5 6 7 8 9
10 11 12 13 14
765432106543210Bit # Npilot = 8Npilot = 7
c d ,1 β d
S lo n g ,n o r S s h o r t ,n
I+ jQ
Q
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
Σ
Spreading of UL DPCH
One and only one UL DPCCH. Up to six parallel DPDCHs.
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Spreading of UL DPCH The 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 channelization code cd,n. One DPCCH and up to six parallel DPDCHs can be transmitted simultaneously, i.e. 1 ≤ n ≤ 6.
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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.
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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 is the spreading factor of the code and k is the code number, 0 ≤ k ≤ SF-1.
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−
=
−
=
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OVSF Code Allocation for UL DPCH DPCCH is always spread by cc= Cch,256,0
When there is only one DPDCH DPDCH1 is spread by cd,1= Cch,SF,k (k= SF / 4)
When there are more than one DPDCH All 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}
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Gain of UL DPCH After 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 valuesβc andβd 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.
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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
clong,1,n
clong,2,n
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+1 y 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.
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Uplink Long Scrambling Codes
For code number, n n=[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 conditions xn(0)=n0, xn(1)=n1, … , xn(22)=n22, xn(23)=n23, xn(24)=1
y(0)=y(1)= … =y(23)= y(24)=1
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Uplink Long Scrambling Codes
Recursive formulation, i=0,…, 225-27 xn(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,,1,0 1)(1 0)(1
clong,1,n(i ) = Zn(i ), i = 0, 1, 2, …, 225-2
07 4
Uplink Short Scrambling Codes Two elementary codes: cshort,1,n and cshort,2,n
256 chips
Generation From the family of periodically extended S(2) codes The 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 )
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Uplink Short Scrambling Codes zn(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 conditions a (0) = 2n0 + 1 modulo 4
a (i) = 2ni modulo 4, i = 1, 2, …, 7,
Recursive formulation a (i) = 3a (i-3) + a (i-5) + 3a (i-6) + 2a (i-7) + 3a (i-8) modulo 4, i = 8, 9, …, 254
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Uplink Short Scrambling Codes Binary sequence b(i): g1(x)= x8+x7+x5+x+1
Initial conditions B (i ) = n8+i modulo 2, i = 0, 1, …, 7,
Recursive formulation b (i) = b (i-1) + b (i-3) + b (i-7) + b (i-8) modulo 2, i = 8, 9, …, 254
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Uplink Short Scrambling Codes Binary sequence d (i ): g2(x)= x8+x7+x5+x4+1
Initial conditions d (i ) = n16+i modulo 2, i = 0, 1, …, 7
Recursive formulation d (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)
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Uplink Short Scrambling Codes zn(i) is extended to length 256 chips
zn(255) = zn(0)
Cshort, n is
−+=
nshortnshort
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Uplink Modulation The modulation chip rate is 3.84 Mcps. The complex-valued chip sequence generated by the spreading process is QPSK modulated.
S
-sin(ωt)
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Downlink Dedicated Physical Channel (DL DPCH)
Common Downlink Physical Channels Common Pilot Channel (CPICH)
Timing Relationship Spreading Modulation
Idle MS
On-line MS
Power-on MS
SCH
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Downlink Transmit Diversity Open loop transmit diversity: STTD and TSTD Closed loop transmit diversity BS
-DL-DPCCH for CPCH
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Space Time Block Coding Based Transmit Antenna Diversity (STTD)
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 2 C hannel b its
ST T D encoded channel b its fo r antenna 1 and antenna 2 .
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Time Switched Transmit Diversity for SCH (TSTD)
TSTD can be applied to TSTD. TSTD for the SCH is optional in UTRAN, while TSTD support is mandatory in the UE. Prim ary SCH
Secondary SCH
256 chips
2560 chips
acs i,0
Antenna 1
Antenna 2
acs i,0
acs i,2
Spread/scramble w1
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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
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Number of Feedback Information in Closed Loop Transmit Diversity
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
Determination of Feedback Information in Closed Loop Mode Transmit Diversity
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.
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Closed Loop Mode 1
The 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
≤−<
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Closed Loop Mode 2 In closed loop mode 2 there are 16 possible combinations of phase and power adjustment.
0.20.81
0.80.20
Power_ant2Power_ant1FSMpo
FSMpo subfield of signalling message
FSMph subfield of signalling message
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Downlink Dedicated Physical Channels (DPCH)
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).
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One radio frame, Tf = 10 ms
TPC NTPC bits
Data2 Ndata2 bits
Each slot= 2560 chips
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.
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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
DL DPCH Pilot Bit Patterns
10 00 00 10 11 01 11 00 11 11 10 10 01 00 01
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 11 10 01 11 01 10 10 00 00 11 00 01 00 10
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
10 10 01 00 01 10 00 00 10 11 01 11 00 11 11
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
10 10 01 00 01 10 00 00 10 11 01 11 00 11 11
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
Slot #0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
765432103210100Symbol #
DPDCH
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.
Multicode transmission is mapped onto several parallel downlink DPCHs using the same spreading factor.
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Pre-defined symbol sequence
Tslot = 2560 chips , 20 bits = 10 symbols
1 radio frame: Tf = 10 ms
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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.
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Transmit Diversity of CPICH Modulation pattern for Common Pilot Channel (with A = 1+j)
slot #1
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, the symbol sequence of Antenna 1 is used.
89
The Primary CPICH The 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.
90
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.
91
Dedicated PilotSecondary-CPICHPrimary-CPICHPhysical Channel Type
Note *: the same phase reference as with the associated DPCH shall be used.
92
k:th S-CCPCH
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
I
S → P
Spreading and Modulation for SCH and P- CCPCH
Different downlink Physical channels (point S in Figure of previous page.)
Σ
G1
G2
GP
GS
S-SCH
P-SCH
Σ
95
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 code Code number, n=16*i (i=0…511)
15 secondary scrambling codes Code number, n=16*i+k (k=1…15)
96
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.
97
I
Q
1
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
98
Downlink Scrambling Codes Constructed by combining two real sequences Each 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
99
Downlink Scrambling Codes
The nth Gold code sequence zn is zn(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,,1,0 1)(1 0)(1
100
Downlink Modulation In the downlink, the complex-valued chip sequence generated by the spreading process is QPSK modulated:
T
-sin(ωt)
Table of Contents Traditional Sequential ASIC Design Flow Introduction to WCDMA Transmitter Specifications
WCDMA Network Architecture Physical Layer General Description Multiplexing and Channel Coding (MCC) WCDMA Uplink Physical Layer WCDMA Downlink Physical Layer
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, 2001
Wireless Communications - Principles & Practice -- by Theodore S. Rappaport, Prentice Hall, 2nd Edition, Dec. 31, 2001
4
5
System Models Architecture Design
USIM
ME
Cu
UE
External Networks
•PLMN: Public Land Mobile Network. One PLMN is operated by a single operator.
8
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 Uu interfaces. 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).
9
WCDMA System Architecture
UMTS 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.
10
Main Elements of the GSM Core Network
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.
11
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’s location within the serving system.
Main Elements of the GSM Core Network
12
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
13
Interfaces Cu 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.
14
15
Information Bits
)(ˆ tsi
Multiple Access
Source Bits Channel Bits
Multiple Access
Establishes the characteristics of the layer-1 transport channels and physical channels in the FDD mode, and specifies:
Transport channels Physical channels and their structure Relative 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
17
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
18
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.
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)
19
General Protocol Architecture Radio 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)
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.
21
Transport Channels
Transport 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
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
Dedicated Transport Channels
There 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. Possibility of fast rate change (every 10 ms) Support of fast power control and soft handover.
24
Common Transport Channel Broadcast 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.
25
Common Transport Channel Paging Channel (PCH) -- mandatory
PCH 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.
26
Common Transport Channel Random 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.
27
Common Transport Channel Forward 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.
28
Common Transport Channel Common Packet Channel (CPCH) -- optional
CPCH 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.
29
Common Transport Channel Downlink Shared Channel (DSCH) -- optional
DSCH is a downlink transport channel shared by several UEs to 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.
30
Transport Channels
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)
Paging Indicator Channel (PICH)
Collision-Detection/Channel-Assignment Indicator Channel
32
33
34
CRC-Attachment CRC-attachment
For error detection gCRC24(D) = D24 + D23 + D6 + D5 + D + 1 gCRC16(D) = D16 + D12 + D5 + 1 gCRC12(D) = D12 + D11 + D3 + D2 + D + 1 gCRC8(D) = D8 + D7 + D4 + D3 + D + 1
TrBk
TrBk
35
No coding 1/3Turbo coding
RACH PCH
1/2Convolutional codingBCH
36
37
Overview Configuration
Radio frame A radio frame is a processing unit which consists of 15 slots. The length of a radio frame corresponds to 38400 chips.
Time slot A 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
Overview Spreading (cont.)
Channelization operation OVSF 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 operation Long or short Gold codes. Applied to the spread signals. Randomize the codes
Spread signal is further multiplied by complex-valued scrambling
39
Dedicated Uplink Physical Channels Uplink Dedicated Physical Data Channel (UL DPDCH) Uplink Dedicated Physical Control Channel (UL DPCCH)
Common Uplink Physical Channels Physical Random Access Channel (PRACH) Physical Common Packet Channel (PCPCH)
40
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 1 One and only one UL DPCCH on each radio link.
41
Pilot Npilot bits
TPC NTPC bits
Data Ndata bits
1 radio frame: Tf = 10 ms = 38400 chips
DPDCH
Ndata= 10*2k bits (k=0,1,…,6)
One Power Control Period
42
UL DPDCH The 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
43
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
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) – optional
TFCI informs the receiver about the instantaneous transport format combination of the transport channels.
45
Pilot Bit Patterns with Npilot=3,4,5,6
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
Slot #0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
543210432103210210Bit # Npilot = 6Npilot = 5Npilot = 4Npilot = 3
Shadowed column is defined as FSW (Frame Synchronization Word).
46
Shadowed column is defined as FSW (Frame Synchronization Word).
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 1 0 1 0 0 0 0 1 1 1 0 1 1
1 1 0 0 0 1 0 0 1 1 0 1 0 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 0 1 0 0 1 1 0 1 1 1 0 0 0 0
1 0 0 0 1 1 1 1 0 1 0 1 1 0 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Slot #0 1 2 3 4 5 6 7 8 9
10 11 12 13 14
765432106543210Bit # Npilot = 8Npilot = 7
c d ,1 β d
S lo n g ,n o r S s h o r t ,n
I+ jQ
Q
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
Σ
Spreading of UL DPCH
One and only one UL DPCCH. Up to six parallel DPDCHs.
48
Spreading of UL DPCH The 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 channelization code cd,n. One DPCCH and up to six parallel DPDCHs can be transmitted simultaneously, i.e. 1 ≤ n ≤ 6.
49
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.
50
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 is the spreading factor of the code and k is the code number, 0 ≤ k ≤ SF-1.
51
−
=
−
=
52
OVSF Code Allocation for UL DPCH DPCCH is always spread by cc= Cch,256,0
When there is only one DPDCH DPDCH1 is spread by cd,1= Cch,SF,k (k= SF / 4)
When there are more than one DPDCH All 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}
53
Gain of UL DPCH After 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 valuesβc andβd 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.
54
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
clong,1,n
clong,2,n
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+1 y 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.
57
Uplink Long Scrambling Codes
For code number, n n=[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 conditions xn(0)=n0, xn(1)=n1, … , xn(22)=n22, xn(23)=n23, xn(24)=1
y(0)=y(1)= … =y(23)= y(24)=1
58
Uplink Long Scrambling Codes
Recursive formulation, i=0,…, 225-27 xn(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,,1,0 1)(1 0)(1
clong,1,n(i ) = Zn(i ), i = 0, 1, 2, …, 225-2
07 4
Uplink Short Scrambling Codes Two elementary codes: cshort,1,n and cshort,2,n
256 chips
Generation From the family of periodically extended S(2) codes The 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 )
62
Uplink Short Scrambling Codes zn(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 conditions a (0) = 2n0 + 1 modulo 4
a (i) = 2ni modulo 4, i = 1, 2, …, 7,
Recursive formulation a (i) = 3a (i-3) + a (i-5) + 3a (i-6) + 2a (i-7) + 3a (i-8) modulo 4, i = 8, 9, …, 254
63
Uplink Short Scrambling Codes Binary sequence b(i): g1(x)= x8+x7+x5+x+1
Initial conditions B (i ) = n8+i modulo 2, i = 0, 1, …, 7,
Recursive formulation b (i) = b (i-1) + b (i-3) + b (i-7) + b (i-8) modulo 2, i = 8, 9, …, 254
64
Uplink Short Scrambling Codes Binary sequence d (i ): g2(x)= x8+x7+x5+x4+1
Initial conditions d (i ) = n16+i modulo 2, i = 0, 1, …, 7
Recursive formulation d (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)
65
Uplink Short Scrambling Codes zn(i) is extended to length 256 chips
zn(255) = zn(0)
Cshort, n is
−+=
nshortnshort
66
Uplink Modulation The modulation chip rate is 3.84 Mcps. The complex-valued chip sequence generated by the spreading process is QPSK modulated.
S
-sin(ωt)
69
Downlink Dedicated Physical Channel (DL DPCH)
Common Downlink Physical Channels Common Pilot Channel (CPICH)
Timing Relationship Spreading Modulation
Idle MS
On-line MS
Power-on MS
SCH
71
Downlink Transmit Diversity Open loop transmit diversity: STTD and TSTD Closed loop transmit diversity BS
-DL-DPCCH for CPCH
72
Space Time Block Coding Based Transmit Antenna Diversity (STTD)
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 2 C hannel b its
ST T D encoded channel b its fo r antenna 1 and antenna 2 .
73
Time Switched Transmit Diversity for SCH (TSTD)
TSTD can be applied to TSTD. TSTD for the SCH is optional in UTRAN, while TSTD support is mandatory in the UE. Prim ary SCH
Secondary SCH
256 chips
2560 chips
acs i,0
Antenna 1
Antenna 2
acs i,0
acs i,2
Spread/scramble w1
75
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
76
Number of Feedback Information in Closed Loop Transmit Diversity
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
Determination of Feedback Information in Closed Loop Mode Transmit Diversity
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.
78
Closed Loop Mode 1
The 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
≤−<
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Closed Loop Mode 2 In closed loop mode 2 there are 16 possible combinations of phase and power adjustment.
0.20.81
0.80.20
Power_ant2Power_ant1FSMpo
FSMpo subfield of signalling message
FSMph subfield of signalling message
80
Downlink Dedicated Physical Channels (DPCH)
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).
81
One radio frame, Tf = 10 ms
TPC NTPC bits
Data2 Ndata2 bits
Each slot= 2560 chips
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.
83
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
DL DPCH Pilot Bit Patterns
10 00 00 10 11 01 11 00 11 11 10 10 01 00 01
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 11 10 01 11 01 10 10 00 00 11 00 01 00 10
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
10 10 01 00 01 10 00 00 10 11 01 11 00 11 11
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
10 10 01 00 01 10 00 00 10 11 01 11 00 11 11
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
11 00 01 00 10 11 11 10 01 11 01 10 10 00 00
Slot #0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
765432103210100Symbol #
DPDCH
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.
Multicode transmission is mapped onto several parallel downlink DPCHs using the same spreading factor.
86
Pre-defined symbol sequence
Tslot = 2560 chips , 20 bits = 10 symbols
1 radio frame: Tf = 10 ms
87
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.
88
Transmit Diversity of CPICH Modulation pattern for Common Pilot Channel (with A = 1+j)
slot #1
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, the symbol sequence of Antenna 1 is used.
89
The Primary CPICH The 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.
90
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.
91
Dedicated PilotSecondary-CPICHPrimary-CPICHPhysical Channel Type
Note *: the same phase reference as with the associated DPCH shall be used.
92
k:th S-CCPCH
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
I
S → P
Spreading and Modulation for SCH and P- CCPCH
Different downlink Physical channels (point S in Figure of previous page.)
Σ
G1
G2
GP
GS
S-SCH
P-SCH
Σ
95
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 code Code number, n=16*i (i=0…511)
15 secondary scrambling codes Code number, n=16*i+k (k=1…15)
96
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.
97
I
Q
1
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
98
Downlink Scrambling Codes Constructed by combining two real sequences Each 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
99
Downlink Scrambling Codes
The nth Gold code sequence zn is zn(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,,1,0 1)(1 0)(1
100
Downlink Modulation In the downlink, the complex-valued chip sequence generated by the spreading process is QPSK modulated:
T
-sin(ωt)