www.huawei.com Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. WCDMA RAN Overview
www.huawei.com
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
WCDMA RAN Overview
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page3
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. Page4
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. Page5
Different Service, Different Technology
AMPS
TACS
NMT
Others
1G 1980sAnalog
GSMGSM
CDMA CDMA IS-95IS-95
TDMATDMAIS-136IS-136
PDCPDC
2G 1990sDigital
Technologies drive
3G IMT-2000
UMTSUMTSWCDMAWCDMA
cdmacdma20002000
Demands drive
TD-SCDMA
TD-SCDMA
3G provides compositive services for both operators and subscribers
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page7
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. Page8
3G Spectrum Allocation
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page9
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. Page10
3G Application Service
Time Delay
Error Ratio
background
conversational
streaming
interactive
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page11
The Core technology of 3G: CDMA
CDMA
WCDMAWCDMACN: based on MAP and GPRS
RTT: WCDMA
TD-SCDMACN: based on MAP and GPRS
RTT: TD-SCDMA
cdma2000CN: based on ANSI 41 and
MIPRTT: cdma2000
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page12
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. Page13
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. Page14
Multiple Access Technology
Frequency
Time
Power
FDMA
FrequencyTime
Power
TDMA
Power
Time
CDMA
Frequency
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page15
Multiple Access and Duplex Technology Duplex Technology
Frequency division duplex (FDD)
Time division duplex (TDD)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page16
Duplex Technology
Time
Frequency
Power
TDD
USER 2
USER 1
DL
ULDL
DL
UL
FDD
Time
Frequency
Power
UL DL
USER 2
USER 1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page17
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. Page18
WCDMA Network 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
Iu-CSIu-PS
CSPS
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page19
WCDMA Network Version Evolution
3GPP Rel993GPP 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. Page20
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. Page21
Uu Interface protocol structure
L3
contr
ol
contr
ol
contr
ol
contr
ol
C-plane signaling U-plane information
PHY
L2/MAC
L1
RLC
DCNtGC
L2/RLC
MAC
RLCRLCRLC
Duplication avoidance
UuS boundary
L2/BMC
control
PDCPPDCP L2/PDCP
DCNtGC
RRC
RLCRLCRLC
RLC
BMC
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page22
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. Page23
Processing Procedure of WCDMA System
SourceCoding
Channel Coding& Interleaving Spreading Modulation
SourceDecodin
g
Channel Decoding& Deinterleaving
Despreading
Demodulation
Transmission
Reception
chipmodulated
signalbit symbol
Service
Signal
Radio Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page24
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_12.2
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page25
Processing Procedure of WCDMA System
Transmitter
SourceCoding
Channel Coding& Interleaving Spreading Modulation
SourceDecodin
g
Channel Decoding& Deinterleaving
Despreading
Demodulation
Transmission
Reception
chipmodulated
signalbit symbol
Service
Signal
Radio Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page26
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. Page27
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. Page28
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 permutatio
n
Output bits
Input bits
Interleaving periods: 20, 40, or 80 ms
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page29
Processing Procedure of WCDMA System
SourceCoding
Channel Coding& Interleaving Spreading Modulation
SourceDecodin
g
Channel Decoding& Deinterleaving
Despreading
Demodulation
Transmission
Reception
chipmodulated
signalbit symbol
Service
Signal
Radio Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page30
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page31
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page32
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)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page33
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. Page34
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. Page35
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. Page36
Spreading Technology
Spreading consists of 2 steps:
Channelization operation, which transforms data symbols
into chips
Scrambling operation is applied to the spreading signal
scramblingchannelization
Data symbol
Chips after spreading
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page37
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)
……
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page38
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. Page39
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. Page40
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. Page41
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. Page42
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 7
64 primary scrambling code groups
Each group consists of 8 primary scrambling
codes
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page43
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page44
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. Page45
Processing Procedure of WCDMA System
SourceCoding
Channel Coding& Interleaving Spreading Modulation
SourceDecodin
g
Channel Decoding& Deinterleaving
Despreading
Demodulation
Transmission
Reception
chipmodulated
signalbit symbol
Service
Signal
Radio Channel
Service
Signal
Receiver
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page46
Modulation Overview
1 00 1
time
Basic steady radio wave:
carrier = A.cos(2Ft+)
Amplitude Shift Keying:
A.cos(2Ft+)
Frequency Shift Keying:
A.cos(2Ft+)
Phase Shift Keying:
A.cos(2Ft+)
Data to be transmitted:Digital Input
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page47
Modulation Overview
Digital Modulation - BPSK
1
t
1 10
1
t-1
NRZ coding
fo
BPSK
Modulated
BPSK signal
Carrier
Information signal
=0 = =0
1 102 3 4 9875 6
1 102 3 4 9875 6
Digital Input
High FrequencyCarrier
BPSK Waveform
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page48
Modulation Overview
Digital Modulation - QPSK
-1 -1
1 102 3 4 9875 6
1 102 3 4 9875 6
NRZ Input
I di-Bit Stream
Q di-Bit Stream
IComponent
QComponent
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. Page49
Demodulation
QPSK Constellation Diagram
1 102 3 4 9875 6
QPSK Waveform
1,1
-1,-1
-1,1
1,-1
1 -11 -1 1 -1-11-1 1
-1,1
NRZ Output
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page50
WCDMA Modulation
Different modulation methods corresponding to
different transmitting abilities in air interface
HSDPA: QPSK or 16QAMR99/R4: QPSK
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page51
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page52
Wireless Propagation
ReceivedSignal
TransmittedSignal
Transmission Loss:Path Loss + Multi-path Fading
Time
Amplitude
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page53
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page54
Fading Categories
Fading Categories
Slow Fading
Fast Fading
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page55
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. Page56
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. Page57
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page58
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
Thank youwww.huawei.com