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www.huawei.com
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
WCDMA RAN Principle
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page1
Objectives
Upon completion of this course, you will be able to:
Describe the development of 3G
Outline the advantage of CDMA principle
Characterize code sequence
Outline the fundamentals of RAN
Describe feature of wireless propagation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page2
Contents
1. 3G Overview
2. CDMA Principle
3. WCDMA Network Architecture and protocol structure
4. WCDMA Wireless Fundamental
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page3
Different Service, Different Technology
AMPS
TACS
NMT
Others
1G 1980s
Analog
GSM
CDMA IS-95
TDMA IS-136
PDC
2G 1990s Digital
Technologies
drive
3G IMT-2000
UMTS WCDMA
cdma 2000
Demands
drive
TD-SCDMA
3G provides compositive services for both operators and subscribers
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page5
3G Evolution
Proposal of 3G
IMT-2000: the general name of third generation mobile
communication system
The third generation mobile communication was first
proposed in 1985,and was renamed as IMT-2000 in the
year of 1996
Commercialization: around the year of 2000
Work band : around 2000MHz
The highest service rate :up to 2000Kbps
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page7
Bands WCDMA Used
Main bands
1920 ~ 1980MHz / 2110 ~ 2170MHz
Supplementary bands: different country maybe different
1850 ~ 1910 MHz / 1930 MHz ~ 1990 MHz (USA)
1710 ~ 1785MHz / 1805 ~ 1880MHz (Japan)
890 ~ 915MHz / 935 ~ 960MHz (Australia)
. . .
Frequency channel number=central frequency×5, for main band:
UL frequency channel number :9612~9888
DL frequency channel number : 10562~10838
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page8
3G Application Service
Time Delay
Error Ratio
background
conversational
streaming
interactive
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page9
The Core technology of 3G: CDMA
CDMA
WCDMA
CN: based on MAP and GPRS
RTT: WCDMA
TD-SCDMA CN: based on MAP and GPRS
RTT: TD-SCDMA
cdma2000 CN: based on ANSI 41 and
MIP RTT: cdma2000
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page10
Contents
1. 3G Overview
2. CDMA Principle
3. WCDMA Network Architecture and protocol structure
4. WCDMA Wireless Fundamental
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page11
Multiple Access and Duplex Technology Multiple Access Technology
Frequency division multiple access (FDMA)
Time division multiple access (TDMA)
Code division multiple access (CDMA)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page12
Multiple Access Technology
Power
FDMA
Power
TDMA
Power
CDMA
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page13
Multiple Access and Duplex Technology Duplex Technology
Frequency division duplex (FDD)
Time division duplex (TDD)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page14
Duplex Technology
Time
Frequency
Power
TDD
USER 2
USER 1
DL
UL
DL
DL
UL
FDD
Time
Frequency
Power
UL DL
USER 2
USER 1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page15
Contents
1. 3G Overview
2. CDMA Principle
3. WCDMA Network Architecture and protocol structure
4. WCDMA Wireless Fundamental
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page16
WCDMA Network Architecture
RNS
RNC
RNS
RNC
Core Network
Node B Node B Node B Node B
Iu-CS Iu-PS
Iur
Iub Iub Iub Iub
CN
UTRAN
UE Uu
CS PS
Iu-CS Iu-PS
CS PS
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page17
WCDMA Network Version Evolution
3GPP Rel99 3GPP Rel4
3GPP Rel5
2000 2001 2002
GSM/GPRS CN
WCDMA RTT
IMS
HSDPA 3GPP Rel6
MBMS
HSUPA
2005
CS domain change to NGN
WCDMA RTT
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page18
WCDMA Network Version Evolution
Features of R6
MBMS is introduced
HSUPA is introduced to achieve the service rate up to 5.76Mbps
Features of R7
HSPA+ is introduced, which adopts higher order modulation and MIMO
Max DL rate: 28Mbps, Max UL rate:11Mbps
Features of R8
HSPA+ PhaseII is introduced, which adopts 64QAM+MIMO or 64QAM+DC
in downlink (Defined by 3GPP 25.XXX)
LTE is introduced which adopts OFDMA instead of CDMA (Defined by 3GPP
36.XXX)
Max DL rate: 100Mbps, Max UL rate: 50Mbps (with 20MHz bandwidth)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page19
Uu Interface protocol structure
L3
co
ntr
ol
co
ntr
ol
co
ntr
ol
co
ntr
ol
C-plane signaling U-plane information
PHY
L2/MAC
L1
RLC
DC Nt GC
L2/RLC
MAC
RLC RLC
RLC
Duplication avoidance
UuS boundary
L2/BMC
control
PDCP PDCP L2/PDCP
DC Nt GC
RRC
RLC RLC
RLC RLC
BMC
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page20
General Protocol Mode for UTRAN Terrestrial Interface The structure is based on the principle that the layers and
planes are logically independent of each other.
Application
Protocol
Data
Stream(s)
ALCAP(s)
Transport
Network
Layer
Physical Layer
Signaling
Bearer(s)
Control Plane User Plane
Transport Network
User Plane
Transport Network
Control Plane
Radio
Network
Layer
Signaling
Bearer(s)
Data
Bearer(s)
Transport Network
User Plane
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page22
Iu-CS Interface
ALCAP
Control Plane
Transport Network
Control Plane
User plane Radio
Network
Layer
Transport Network
User Plane
Transport
Network
Layer
A B
RANAP
AAL2 PATH
ATM
Physical Layer
SAAL NNI
SCCP
MTP3-B
Iu UP
SAAL NNI
MTP3-B
Transport Network
User Plane
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page23
Iu-PS Interface
Control Plane User plane Radio
Network
Layer
Transport Network
User Plane Transport
Network
Layer
Transport Network
User Plane
C
RANAP
ATM
SAAL NNI
SCCP
MTP3-B
Iu UP
AAL Type 5
IP
UDP
GTP-U
Physical Layer
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page24
Iub Interface
ALCAP
Control Plane
Transport Network
Control Plane
User plane Radio
Network
Layer
Transport Network
User Plane
Transport
Network
Layer
Transport Network
User Plane
NBAP
AAL2 PATH
ATM
Physical Layer
SAAL UNI
Iub FP
SAAL UNI
NCP CCP
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page25
Iur Interface
ALCAP
Control Plane
Transport Network
Control Plane
User plane Radio
Network
Layer
Transport
Network
Layer
A B
RNSAP
AAL2 PATH
ATM
Physical Layer
SAAL NNI
SCCP
MTP3-B
Iur Data
Stream
SAAL NNI
MTP3-B
Transport Network
User Plane Transport Network
User Plane
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page26
Contents
1. 3G Overview
2. CDMA Principle
3. WCDMA Network Architecture and protocol structure
4. WCDMA Wireless Fundamental
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page27
Processing Procedure of WCDMA System
Source
Coding Channel Coding & Interleaving
Spreading Modulation
Source
Decoding Channel Decoding
& Deinterleaving Despreading Demodulation
Transmission
Reception
chip modulated
signal bit symbol
Service
Signal
Radio
Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page28
WCDMA Source Coding
AMR (Adaptive Multi-Rate)
Speech
A integrated speech codec with 8
source rates
The AMR bit rates can be controlled
by the RAN depending on the
system load and quality of the
speech connections
Video Phone Service
H.324 is used for VP Service in CS
domain
Includes: video codec, speech codec,
data protocols, multiplexing and etc.
CODEC Bit Rate (kbps)
AMR_12.20 12.2 (GSM EFR)
AMR_10.20 10.2
AMR_7.95 7.95
AMR_7.40 7.4 (TDMA EFR)
AMR_6.70 6.7 (PDC EFR)
AMR_5.90 5.9
AMR_5.15 5.15
AMR_4.75 4.75
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page29
Processing Procedure of WCDMA System
Transmitter
Source
Coding Channel Coding & Interleaving
Spreading Modulation
Source
Decoding Channel Decoding
& Deinterleaving Despreading Demodulation
Transmission
Reception
chip modulated
signal bit symbol
Service
Signal
Radio
Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page30
WCDMA Block Coding - CRC
Block coding is used to detect if there are any
uncorrected errors left after error correction.
The cyclic redundancy check (CRC) is a common method
of block coding.
Adding the CRC bits is done before the channel encoding
and they are checked after the channel decoding.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page31
WCDMA Channel Coding
Effect
Enhance the correlation among symbols so as to recover the signal when
interference occurs
Provides better error correction at receiver, but brings increment of the
delay
Types
No Coding
Convolutional Coding (1/2, 1/3)
Turbo Coding (1/3)
Code Block
of N Bits
No Coding
1/2 Convolutional
Coding
1/3 Convolutional
Coding
1/3 Turbo Coding
Uncoded N bits
Coded 2N+16 bits
Coded 3N+24 bits
Coded 3N+12 bits
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page32
WCDMA Interleaving
Effect
Interleaving is used to reduce the probability of consecutive bits
error
Longer interleaving periods have better data protection with more
delay
1110
1.........
............
...000
0100
0 0 1 0 0 0 0 . . . 1 0 1 1 1
1110
1.........
............
...000
01000 0 … 0 1 0 … 1 0 0 … 1 0 … 1 1
Inter-column permutation
Output bits
Input bits
Interleaving periods:
20, 40, or 80 ms
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page33
Processing Procedure of WCDMA System
Source
Coding Channel Coding & Interleaving
Spreading Modulation
Source
Decoding Channel Decoding
& Deinterleaving Despreading Demodulation
Transmission
Reception
chip modulated
signal bit symbol
Service
Signal
Radio
Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page34
Correlation
Correlation measures similarity between any two arbitrary
signals.
Identical and Orthogonal signals:
Correlation = 0
Orthogonal signals
-1 1 -1 1
-1 1 -1 1
1 1 1 1
+1
-1
+1
-1
+1
-1
+1
-1
Correlation = 1
Identical signals
-1 1 -1 1
1 1 1 1
-1 1 -1 1
C1
C2 +1
+1
C1
C2
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page35
Orthogonal Code Usage - Coding
UE1: +1 -1
UE2: -1 +1
C1 : -1 +1 -1 +1 -1 +1 -1 +1
C2 : +1 +1 +1 +1 +1 +1 +1 +1
UE1×c1: -1 +1 -1 +1 +1 -1 +1 -1
UE2×c2: -1 -1 -1 -1 +1 +1 +1 +1
UE1×c1+ UE2×c2: -2 0 -2 0 +2 0 +2 0
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page36
Orthogonal Code Usage - Decoding
UE1×C1+ UE2×C2: -2 0 -2 0 +2 0 +2 0
UE1 Dispreading by c1: -1 +1 -1 +1 -1 +1 -1 +1
Dispreading result: +2 0 +2 0 -2 0 -2 0
Integral judgment: +4 (means+1) -4 (means-1)
UE2 Dispreading by c2: +1 +1 +1 +1 +1 +1 +1 +1
Dispreading result: -2 0 -2 0 +2 0 +2 0
Integral judgment: -4 (means-1) +4 (means+1)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page37
Spectrum Analysis of Spreading & Dispreading
Spreading code
Spreading code
Signal
Combination
Narrowband signal
f
P(f)
Broadband signal
P(f)
f
Noise & Other Signal
P(f)
f
Noise+Broadband signal
P(f)
f
Recovered signal
P(f)
f
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page38
Spectrum Analysis of Spreading & Dispreading
Max allowed interference
Eb/No
Requirement
Power
Max interference caused by
UE and others
Processing Gain
Ebit
Interference from
other UE Echip
Eb / No = Ec / No ×PG
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page39
Process Gain
Process Gain
Process gain differs for each service.
If the service bit rate is greater, the process gain is smaller,
UE needs more power for this service, then the coverage of
this service will be smaller, vice versa.
)rate bit
rate chiplog(10Gain ocessPr
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page40
Spreading Technology
Spreading consists of 2 steps:
Channelization operation, which transforms data symbols into
chips
Scrambling operation is applied to the spreading signal
scrambling channelization
Data
symbol
Chips after
spreading
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page41
WCDMA Channelization Code
OVSF Code (Orthogonal Variable Spreading Factor) is used as
channelization code
SF = 8 SF = 1 SF = 2 SF = 4
C ch,1,0 = (1)
C ch,2,0 = (1,1)
C ch,2,1 = (1, -1)
C ch,4,0 = (1,1,1,1)
C ch,4,1 = (1,1,-1,-1)
C ch,4,2 = (1,-1,1,-1)
C ch,4,3 = (1,-1,-1,1)
C ch,8,0 = (1,1,1,1,1,1,1,1)
C ch,8,1 = (1,1,1,1,-1,-1,-1,-1)
C ch,8,2 = (1,1,-1,-1,1,1,-1,-1)
C ch,8,3 = (1,1,-1,-1,-1,-1,1,1)
C ch,8,4 = (1,-1,1,-1,1,-1,1,-1)
C ch,8,5 = (1,-1,1,-1,-1,1,-1,1)
C ch,8,6 = (1,-1,-1,1,1,-1,-1,1)
C ch,8,7 = (1,-1,-1,1,-1,1,1,-1)
……
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page42
WCDMA Channelization Code
SF = chip rate / symbol rate
High data rates → low SF code
Low data rates → high SF code
Radio bearer SF Radio bearer SF
Speech 12.2 UL 64 Speech 12.2 DL 128
Data 64 kbps UL 16 Data 64 kbps DL 32
Data 128 kbps UL 8 Data 128 kbps DL 16
Data 144 kbps UL 8 Data 144 kbps DL 16
Data 384 kbps UL 4 Data 384 kbps DL 8
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page43
Purpose of Channelization Code
Channelization code is used to distinguish different
physical channels of one transmitter
For downlink, channelization code ( OVSF code ) is used to
separate different physical channels of one cell
For uplink, channelization code ( OVSF code ) is used to
separate different physical channels of one UE
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page44
Purpose of Scrambling Code
Scrambling code is used to distinguish different
transmitters
For downlink, scrambling code is used to separate different
cells in one carrier
For uplink, scrambling code is used to separate different
UEs in one carrier
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page45
Scrambling Code
Scrambling code: GOLD sequence.
There are 224 long uplink scrambling codes which are used for
scrambling of the uplink signals. Uplink scrambling codes are
assigned by RNC.
For downlink, 512 primary scrambling codes are used.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page46
Primary Scrambling Code Group
Primary
scrambling
codes for
downlink
physical
channels
Group 0
…
Primary scrambling code 0
……
Primary scrambling code
8*63
……
Primary scrambling code
8*63 +7 512 primary
scrambling
codes
……
……
Group 1
Group 63
Primary scrambling code 1
Primary scrambling code 7
64 primary
scrambling code
groups
Each group consists of 8
primary scrambling codes
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page47
Code Multiplexing
Downlink Transmission on a Cell Level
Scrambling code
Channelization code 1
Channelization code 2
Channelization code 3
User 1 signal
User 2 signal
User 3 signal
NodeB
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page48
Code Multiplexing
Uplink Transmission on a Cell Level
NodeB
Scrambling code 3
User 3 signal
Channelization code
Scrambling code 2
User 2 signal
Channelization code
Scrambling code 1
User 1 signal
Channelization code
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page49
Processing Procedure of WCDMA System
Source
Coding Channel Coding & Interleaving
Spreading Modulation
Source
Decoding Channel Decoding
& Deinterleaving Despreading Demodulation
Transmission
Reception
chip modulated
signal bit symbol
Service
Signal
Radio
Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page50
Modulation Overview
1 0 0 1
time
Basic steady radio
wave:
carrier = A.cos(2pFt+f)
Amplitude Shift
Keying:
A.cos(2pFt+f)
Frequency Shift
Keying:
A.cos(2pFt+f)
Phase Shift Keying:
A.cos(2pFt+f)
Data to be transmitted:
Digital Input
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page51
Modulation Overview
Digital Modulation - BPSK
1
t
1 1 0
1
t -1
NRZ coding
fo
BPSK
Modulated
BPSK signal
Carrier
Information signal
f=0 f=p f=0
1 10 2 3 4 9 8 7 5 6
1 10 2 3 4 9 8 7 5 6
Digital Input
High Frequency
Carrier
BPSK Waveform
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page52
Modulation Overview
Digital Modulation - QPSK
-1 -1
1 10 2 3 4 9 8 7 5 6
1 10 2 3 4 9 8 7 5 6
NRZ Input
I di-Bit Stream
Q di-Bit Stream
I
Component
Q
Component
QPSK Waveform
1
1
-1
1
-1
1
1
-1
-1
-1
1 1 -1 1 -1 1 1 -1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page53
Modulation Overview
NRZ coding
90o
NRZ coding
QPSK
Q(t)
I(t)
fo
±A
±A ±Acos(ot)
±Acos(ot + p/2)
f
1 1 p/4
1 -1 7p/4
-1 1 3p/4
-1 -1 5p/4
)cos(2: f tAQPSK o
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page54
Demodulation
QPSK Constellation Diagram
1 10 2 3 4 9 8 7 5 6
QPSK Waveform
1,1
-1,-1
-1,1
1,-1
1 -1 1 -1 1 -1 -1 1 -1 1
-1,1
NRZ Output
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page55
WCDMA Modulation
Different modulation methods corresponding to different
transmitting abilities in air interface
HSDPA: QPSK or 16QAM R99/R4: QPSK
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page56
Processing Procedure of WCDMA System
Source
Coding Channel Coding
Spreading Modulation
Source
Decoding
Channel
Decoding Despreading Demodulation
Transmission
Reception
chip modulated
signal bit symbol
Service
Signal
Radio
Channel
Service
Signal
Transmitter
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page57
Wireless Propagation
Received
Signal
Transmitted
Signal
Transmission Loss:
Path Loss + Multi-path Fading
Time
Amplitude
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Propagation of Radio Signal Signal at Transmitter
Signal at Receiver
-40
-35
-30
-25
-20
-15
-10
-5
dB
0
0
dB
m
-20
-15
-10
-5
5
10
15
2
0
Fading
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page59
Fading Categories
Fading Categories
Slow Fading
Fast Fading
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page60
Diversity Technique
Diversity technique is used to obtain uncorrelated signals
for combining
Reduce the effects of fading
Fast fading caused by multi-path
Slow fading caused by shadowing
Improve the reliability of communication
Increase the coverage and capacity
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page61
Diversity
Time diversity
Channel coding, Block interleaving
Frequency diversity
The user signal is distributed on the whole bandwidth
frequency spectrum
Space diversity
Polarization diversity
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page62
Principle of RAKE Receiver
Receive set
Correlator 1
Correlator 2
Correlator 3
Searcher correlator Calculate the
time delay and
signal strength
Combiner The combined
signal
t t
s(t) s(t)
RAKE receiver help to overcome on the multi-path fading and enhance the receive
performance of the system
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page63
Summary
In this course, we have discussed basic concepts of WCDMA:
Spreading / Despreading principle
UTRAN Voice Coding
UTRAN Channel Coding
UTRAN Spreading Code
UTRAN Scrambling Code
UTRAN Modulation
UTRAN Transmission/Receiving