1.wcdma ran fudamental
DESCRIPTION
WCDMATRANSCRIPT
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Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
WCDMA RAN Fundamental
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Objectives
Upon completion of this course, you will be able to:
Know the development of 3G
Outline the advantage of CDMA
Characterize code sequence
Outline the fundamentals of RAN
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Contents
1. CDMA Principle
2. 3G Overview
3. WCDMA Fundamental
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Contents
1. CDMA Principle
2. 3G Overview
3. WCDMA Fundamental
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Multiple Access and Duplex Technology Multiple Access Technology
Frequency division multiple access (FDMA)
Time division multiple access (TDMA)
Code division multiple access (CDMA)
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Multiple Access Technology
frequency
time
power
FDMA
frequencytime
power
TDMA
power
time
CDMA
frequency
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Multiple Access and Duplex Technology Duplex Technology
Frequency division duplex (FDD)
Time division duplex (TDD)
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Duplex Technology
Time
Frequency
Power
TDD
USER 2
USER 1
DL
ULDL
DL
UL
FDD
Time
Frequency
Power
UL DL
USER 2
USER 1
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Contents
1. CDMA Principle
2. 3G Overview
3. WCDMA Fundamental
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0G : MTS Mobile telephone system
Page10
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1G : AMPS Advance Mobile Phone Service
Page11
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First generations different standard
Page12
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2G :GSM Global system for Mobile communication
Page13
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2G System Evolution
Page14
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2G System Evolution
Page15
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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
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3G Spectrum Allocation
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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
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3G Application Service
Time Delay
BER
background
conversational
streaming
interactive
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WCDMA System Architecture
RNS
RNC
RNS
RNC
Core Network
Node B Node B Node B Node B
Iu-CS Iu-PS
Iur
Iub IubIub Iub
CN
UTRAN
UEUu
CS PS
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WCDMA Protocol Version Evolution
3GPP Rel993GPP Rel4
3GPP Rel5
2000 2001 2002
GSM/GPRS CN
IMS
HSDPA 3GPP Rel6
MBMS
HSUPA
2005
CS domain change to NGN
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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
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)
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Contents
1. CDMA Principle
2. 3G Overview
3. WCDMA Fundamental
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Processing Procedure of WCDMA System
SourceCoding
Channel
CodingSpreading Modulation
SourceDecodin
g
ChannelDecodin
g
Despreading
Demodulation
Transmission
Reception
chipmodulated
signalbit symbol
Service
Signal
Radio Channel
Service
Signal
Transmitter
Receiver
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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.
CODEC Bit Rate
(kbps)
AMR_12.2
0
12.2 (GSM
EFR)
AMR_10.2
0
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
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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
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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
00100 0 … 0 1 0 … 1 0 0 … 1 0 … 1 1
Inter-column permutation
Output bits
Input bits
Interleaving periods: 10, 20, 40, or 80 ms
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Correlation
Correlation measures similarity between any two arbitrary signals.
Identical and Orthogonal signals:
Correlation = 0Orthogonal signals
-1 1 -1 1
-1 1 -1 1
1 1 1 1
+1
-1
+1
-1
+1
-1
+1
-1
Correlation = 1Identical signals
-1 1 -1 1
1 1 1 1
-1 1 -1 1
C1
C2
+1
+1
C1
C2
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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
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
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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)
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)
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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
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Spreading Technology
Spreading consists of 2 steps
Channelization operation, which transforms data symbols into chips
Scrambling operation is applied to the spreading signal
Data bit
OVSF code
Scrambling code
Chips after spreading
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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
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Purpose of Scrambling Code
Scrambling code is used to distinguish different
transmitters
For downlink, Scrambling code is used to separate
different cells
For uplink, scrambling code is used to separate
different UE
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Code Multiplexing
Downlink Transmission on a Cell Level
Scrambling codeScrambling code
Channelization code 1Channelization code 1
Channelization code 2Channelization code 2
Channelization code 3Channelization code 3
User 1 signal
User 2 signal
User 3 signal
NodeB
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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
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WCDMA Channelization Code
OVSF Code (Orthogonal Variable Spreading Factor) is
used as channelization code
SF = 8SF = 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)
Cch,8,0 = (1,1,1,1,1,1,1,1)
Cch,8,1 = (1,1,1,1,-1,-1,-1,-1)
Cch,8,2 = (1,1,-1,-1,1,1,-1,-1)
Cch,8,3 = (1,1,-1,-1,-1,-1,1,1)
Cch,8,4 = (1,-1,1,-1,1,-1,1,-1)
Cch,8,5 = (1,-1,1,-1,-1,1,-1,1)
Cch,8,6 = (1,-1,-1,1,1,-1,-1,1)
Cch,8,7 = (1,-1,-1,1,-1,1,1,-1)
……
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WCDMA Channelization Code
SF = chip rate / bit rate
High data rates → low SF code
Low data rates → high SF code
Radio bearer SF Radio bearer SF
Speech 4.75 UL 12
8
Speech 4.75 DL 256
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
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Scrambling Code
Scrambling code: GOLD sequence.
There are 224 long uplink scrambling codes which are
used for scrambling of the uplink CHs. Uplink scrambling
codes are assigned by higher layers.
For downlink physical channels, 8192 scrambling codes
are used.
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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 +7512 primary scrambling
codes
……
……
Group 1
Group 63
Primary scrambling
code 1
Primary scrambling
code 8
64 primary scrambling code groups
Each group consists of 8 primary scrambling
codes
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Modulation Overview
NRZ coding
90o
NRZ coding
QPSK
Q(t)
I(t)
fo
±A
±A ±Acos(ot)
±Acos(ot + /2)
1 1 /4
1 -1 7/4
-1 1 3/4
-1 -1 5/4
)cos(2: oAQPSK
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WCDMA Modulation
Different modulation methods corresponding to
different transmitting abilities in air interface
HSDPA: adopt 16QAMR99/R4: adopt QPSK
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Wireless Propagation
ReceivedSignal
TransmittedSignal
Transmission Loss:Path Loss + Multi-path Fading
Time
Amplitude
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Propagation of Radio SignalSignal 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
20
Fading
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Fading Categories
Fading Categories
Slow Fading
Fast Fading
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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
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Diversity
Time diversity
Channel coding, Block interleaving
Frequency diversity
The user signal is distributed on the whole bandwidth frequency
spectrum
Space diversity
Receive space diversity
Transmit space diversity
Polarization diversity
Vertical polarization
Horizontal polarization
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Principle of RAKE Receiver
Receive set
Correlator 1
Correlator 2
Correlator 3
Searcher correlator
Calculate the time delay and signal strength
CombinerThe
combined signal
tt
s(t) s(t)
RAKE receiver help to overcome on the multi-path fading and enhance the receive performance of the system
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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
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