of 120
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CDMA Fundamentals
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Agenda
CDMA introduction
CDMA makes use of Diversity
Power control
CDMA Forward Link
CDMA Reverse Link
CDMA call processing CDMA Measurement
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Cellular Access Methods
Power Time
FrequencyFDMA
PowerTime
Frequency
Power
Time
Frequency
TDMA
CDMA
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User #3
Frequency Domain
User #2
User #1
Synch
Paging
Pilot
1.2288 MHzfreq
Code Domain
0 1 2 3 4 5 6 7 8 9 32 40 63
User
1
User
3
User
2
Walsh Code
Pilot Paging Synch
Code Domain Power (cdma2000/IS-95)
The CDMA Concept
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CDMA is Also Full Duplex
US Cellular Channel 384Amplitude
Frequency
AMPS
CDMAFrequency
Amplitude
Reverse Link
Reverse Link
Forward Link
Forward Link
45 MHz
45 MHz
836.52 MHz
836.52 MHz 881.52 MHz
881.52 MHz
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Code Division MultipleAccess
What is CDMA ?
Spread spectrum technique
Multiple users share the same frequency in one cell
Same frequency in all the cells Operates under presence of interference
Takes advantage of multipath
Capacity is soft
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Cellular Frequency Reuse Patterns
3
6
CDMA ReuseFDMA Reuse
11
1
1
1
1
11
1
62
2
1
4
5
7
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The CDMA Concept
Baseband
Data
Encoding &
Interleaving
Walsh Code
Spreading
Walsh Code
Correlator
Baseband
Data
Decode & De-
Interleaving
0 0fcfc
fcfcfcfc
10 Khz BW 1.23 Mhz BW 10 Khz BW1.23 Mhz BW
1.23 Mhz BW1.23 Mhz BWSpurious Signals-113 dBm/1.23 Mhz
CDMA
Transmitter
CDMA
Receiver
9.6 kbps 19.2 kbps 1228.8 kbps 9.6 kbps19.2 kbps1228.8 kbps
Background Noise External Interference Other Cell Interference Other User Noise
Interference Sources
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z Multiple user data can be spread by using combinations ofthis PN code
Direct Sequence Spread Spectrum
Baseband data multiplied by a Pseudo Random Noise (PN)Code, which is a sequence of chips valued -1 & +1 or 0 & 1
PN code is a noise-like code with certain properties (ex:orthogonal)
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Direct Sequence Spread Spectrum
Direct sequence spreadspectrum signal is generated
by multiplying narrowbanduser data with a well-defined
wideband pseudo-random
sequence.
Recovering the narrowbanduser data is achieved by
multiplying the received
signal by an identical,
accurately timed pseudo-random sequence.
Direct Sequence Spread Spectrum
Power SpectralDensity
Freq
Direct sequencespread signal
Narrowband userdata
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Direct Sequence Spread Spectrum
Source InformationBits
I-Q Modulator
CarrierCode Generator BitStream
TransmitDSSS Signal
Block diagram of a Direct Sequence SpreadSpectrum Transmitter
Bits toI-Q
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Direct Sequence Spread Spectrum
Received
DSSSsignal
CodeSynchronization Code Generator
Demodulator
Carrier
Data
Block diagram of a Direct Sequence Spread Spectrum Receiver
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What is Correlation ?
Is a Measure of HowWell a Given Signal
Matches a Desired
Code
The Desired Code isCompared to the
Given Signal at
Various Test times
Received Signal
Time
Correlation = 1
Correlation = 0
Correlation = 0
Correlation = 0
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Auto-Correlation
Is a Comparison of a Signal
Against Itself
Good Pseudo-RandomPatterns Have:
Strong Correlation at Zero Time
Offset
Weak Correlation at Other
Time Offsets
Pseudo-Random Sequence
Auto-Correlation Versus Time Offset
1
0
1
300 5 10 15 20 25
0 10 205 15 25 30
0
Chip Offset
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Analog
Analog
CDMA Paradigm Shift
Multiple Users on One Frequency99 Analog/TDMA Try to Prevent Mu lt ip le UsersAnalog/TDMA Try to Prevent Mu lt ip le Users
InterfaceInterface
Channel is Defined by Code99 Analog Systems Def ined Channels byAnalog Systems Def ined Channels by
FrequencyFrequency
Traditional FDMA/TDMA are capacity-
limited99 Given N t imeslots per frame and KGiven N t imeslots per frame and Kfrequency channels , max imum n umber off requency channels , max imum n umber of
users is KN;users is KN;
99 To increase the number of u sers in theTo increase the num ber of us ers in the
system , frequency reuse is usedsystem , frequency reuse is us ed
Capacity Limit is Soft99 Al low s Degradin g Voice Quali ty toAl low s Degradin g Voice Qual i ty to
Temporari ly Increase CapacityTempo rari ly Inc rease Capacity
99 Reduce Surrounding Cel l Capaci ty toReduce Surrou nd ing Cel l Capaci ty to
Increase a CellIncrease a Cells Capacitys Capacity
CD
MA
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CDMA Capacity Gains
ProcessingProcessingGainGain
AMPS = 1.5 MHz / 30 kHz = 50 Channels
Capacity = 50 Channels / 7 ( 1/7 Frequency Reuse )
AMPS = 7 Calls ( Usin g 1.5 MHz BW )
CDMA = 42 Calls ( Usin g 1.5 MHz BW )
(1,230,000) (1) (1)CDMA = ____________ X _____ X _____ X (0.67)(9,600) (5.01) (.40)
Capacity = _____________ X _____ X ____ X (Fr)(Data Rate) (S/N) (Vaf)
(Chan BW) (1) (1)
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CDMA makes use of Diversity
Spatial Diversity
Making Use of Differences in Position
Frequency Diversity Making Use of Differences in Frequency
Time Diversity
Making Use of Differences in Time
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CDMA Spatial Diversity
Diversity Reception:
Multiple Antennas at Base Station
99Each A ntenna is Affected byEach A ntenna is Affected b yMul t ipathMul t ipathDifferently Due to TheirDifferently Due to TheirDi f ferent L ocat ionDif ferent L ocat ion
99Al low s Select ion o f the Signal Least A ffected byAl low s Select ion of the Signal Least Affected byMul t ipathMul t ipath
FadingFading
If Diversity Antennas are Good, Why Not Use Base Stationsas a Diversity Network?
Soft Handoff
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Spatial Diversity During Soft Handoff
MTSO
Base Station 1
Land Link
Vocoder /
Selector
Base Station 2
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CDMA Time Diversity
Rake Receiver to Find and DemodulateMultipath Signals
Data is Interleaved
Spreads Adjacent Data in time to Improve
Error Correction Efficiency
Convolutional EncodingAdds Error Correction and Detection
Viterbi Decoding
Most Likely Path Decoder forConvolutionaly Encoded Data
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Why Interleaving Works
1 2 3 4
5 6 7 89 10 11 12
13 14 15 16
1 5 9 13
3 7 11 15
4 8 12 16
1 2 3 4
9 10 11 12
13 14 15 16
5 6 7 8
Original Data Frame
Interleaved Data Frame
Errors/Time
TX1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Errors/Time
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
RX
Errors/Time
TX
1 5 9 13 2 6 10 14 3 7 11 15 4 8 12 16
Errors/Time
RX
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
2 6 10 14
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The Rake Receiver
Amplitude
Frequency
Time
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Rake Receiver Design
T0 T1 T4T3T2
W0 W1 W2 W3 W4
Antenna
Output
Delay
Taps
Tap
Weights
+
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Synchronization
All Direct Sequence, SpreadSpectrum Systems Should be
Accurately Synchronized for
Efficient searching
Finding the Desired CodeBecomes Difficult without
Synchronization
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Power Control
Near-end Far-end Problem
- 60dBm
- 30dBm
A
B
At the BS receiver,
SNR for A reception = 30 dB, certified
SNR for B reception = -30 dB, not certified
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z Acceptable SNR is at least 7 dB
z For B, the signal needs 37 dB gain to meet the condition
z What if we increase the processing gain from 21 dB to 37
dB?
Pgain = 10 log ( W / R )
R is fixed at 9600 bps, W can be increased
Is there another way to improve S/N?
In this case, W = 48 MHz not practical
Power Control
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z In this case, B is the Signal and A is the Noise
z Both A and B are transmitting at constant power
z Since A is near, it can be asked to transmit at low power
z
Since B is far, it can increase the powerThis is Power Control !This is Power Control !
z Base Station will change power levels based on
the Path loss.
z Base Station will also command Mobile to
increase or decrease power levels.
Power Control
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Maximum System Capacity is Achieved if:
9All Mobiles are Power Controlled to the Minimum
Power for Acceptable Signal Quality
9As a Result, all Mobiles are Received at About
Equal Power at the Base Station Independent of
Their Location
Two Types of Control
Open Loop Power Control
Closed Loop Power Control
Open & Closed Loop Power Control areAlways Both ActiveAlways Both Active
Reverse Link Power Control
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Open Loop Power Control
Assumes Loss is Similar on Forward and ReversePaths
Receive Power + Transmit Power = -73(-76dB forPCS Band
All Powers in dBm
Example:
For a Received Power of -85 dBm Transm it Power = (Transm it Power = (--73)73)--((--85)85)
Transm it Power = +12Transm it Power = +12dBmdBm
Provides an Estimate of Reverse TX Power for GivenPropagation Conditions
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Directed by Base Station
Updated Every 1.25 msec
Commands Mobile to Change TXPower in +/- 1 dB Step Size
Fine Tunes Open Loop PowerEstimate
Power Control Bits are Puncturedover the Encoded Voice Data
Puncture Period is Two 19.2 kbps
Symbol Periods = 104.2 usec
Closed Loop Power Control
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CDMA Variable Rate Speech Coder
DSP Analyzes 20 Millisecond Blocks of Speech for Activity
Selects Encoding Rate Based on Activity:
a High Activity Full Data Rate Encoding (9600 bps)a Some Activity Half Data Rate Encoding (4800 bps)
a Low Activity Quarter Data Rate Encoding (2400 bps)
a No Activity 1/8 Data Rate Encoding (1200 bps)
How Does This Improve Capacity? Mobile Transmits in Bursts of 1.25 ms
System Capacity Increases by 1/Voice Activity Factor
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Mobile Power Bursting
Each Frame is Dividedinto 16 Power Control
Groups
Each Power ControlGroup Contains 1536
Chips (represents 12
encoded voice bits)
Average Power isLowered 3 dB for Each
Lower Data Rate
CDMA Frame = 20 ms Full Rate
Half Rate
Quarter Rate
Eighth Rate
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The CDMA2000 evolution path is flexible
and future-proof
Voice
Data up to
14.4 kbps
Voice
Data up to
115 kbps
2x increases in voice capacity
Up to 307 kbps* packet data
on a single (1.25 MHz) carrier
First 3G system for any
technology worldwide
Optimized, very high-speed
data (Phase 1)
Up to 2.4 Mbps* packet data
on a single (1.25 MHz) carrier
Integrated voice and data
(Phase 2); up to 4.8 Mbps
*downlink
From CDG
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CDMA Protocol Stacks
IS -95 Rev 0Original System-never actually deployed
ARIB T53Japan CDMA
System Cellular
Protocol
IS -95 Rev ABackwards compatible with IS-95. First Deployed Protocol
TBS- 74Cellular Protocol that adds 14400 Channel Support
J-STD-008Not Backwards Compatible, PCS only Protocol
EIA/TIA-95 Rev BCombines TSB-74 & J-STD-008 for a Universal Protocol
EIA/TIA/IS-2000 Rev 0First release of IS-2000 standard (add QPCH)
EIA/TIA/IS-2000 Rev AAdd BCH,CCCH,CACHnew channel
EIA/TIA/IS-2000 Rev BAdd new functionality and support
EIA/TIA/IS-2000 Rev C(1x EV-DV)Segment channel between Voice and Data
EIA/TIA/IS-856(1x EV-DO)Optimized for packet data.
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The architecture for CDMA2000
IS634
PSDN
MSC
HLR/AUCHLR/AUC
Laptops with
Cell Phones
Cell
Phones
Smartphones
and PDAs
BSCAAAAAA
ServerServer
PSTN
Internet
IWF
IP Router
Core
Elements
Core
Elements
From CDG
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cdma2000 Key Standards
EIA/TIA/IS-2000 rev. 0 Interoperability Standard forcdma2000 Spread Spectrum Systems
Defines channel coding, call processing procedures, protocoland other mobile / base procedures and RF requirements to
ensure interoperability of equipment from multiple vendors
Defines how entire system works together in extreme detail
Revision 0 was first release of standard.
Revision A adds enhanced channels for paging, call set-up and
call control.
Revision B enhanced from the cdma2000 Release A
specifications
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TIA/ EIA-95-B IS-2000 IS-2000-A
F-Pilot F-Pilot F-Pilot
F-Sync F-Sync F-Sync
F-PCH F-PCH F-BCCHF-CCCH
F-QPCH optional F-QPCH optional
F-CACH
F-CPCCH
Forward
Channels
F-Traffic
F-FCH
F-SCH
F-DCCH optional
F-FCH
F-SCH
F-DCCH optional
N/ A R-Pilot R-Pilot
R-ACH R-ACH R-EACHorR-CCCHReverse
ChannelsR-Traffic
R-FCH
R-SCH
R-DCCH optional
R-FCH
R-SCH
R-DCCH optional
cdma2000 Standards Overview - IS-2000
Release 0 versus Revision A
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Benefits of cdma2000
Improved Performance and Capacity:
About 2X Voice Capacity of TIA/EIA-95-B
Handles a Wide Range of Data Rates:99Voice and Low Speed Data wh i le Driv ingVoice and Low Speed Data whi le Driv ing
99Up to 384 kbps Packet or Circui t Data wh i le Movin gUp to 384 kbps Packet or Circui t Data wh i le Moving
99Up to 2 Mbps Data Rates for Fixed Ins tal lat ion sUp to 2 Mbps Data Rates fo r Fixed Ins tal lat ion s
Meets All IMT-2000 Requirements Easy Upgrade for Service Providers Who Currently Operate
TIA/EIA-95 Systems
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cdm
a
2000
Performance Enhancements
Reverse Link Pilot for Each Mobile
True QPSK Modulation
Continuous Reverse Link Waveform Improved Convolutional Encoding for 14.4
kbps Voice Channels
Fast Forward & Reverse Link Power Control
Supports Auxiliary Pilots for Beam Forming
Forward Link Transmit Diversity - OTD,
STS, Multi-Antenna
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Terms and Definitions
Chip
99 Is the period o f a data bit at the final spreadin g rateIs the period o f a data bit at the final spreadin g rate
SR - Spreading Rate99Defines the fin al sp readin g rate in terms o f 1.2288 Mcps(SR1).Defines the fin al spreadin g rate in terms of 1.2288 Mcps (SR1).
So a 3.6864So a 3.6864McpsMcpssystem is cal led a SR3 system.system is cal led a SR3 system.
RC - Radio Configuration
99Defines the physical channel con f igurat ion based upon a baseDef ines the physical channel conf ig urat ion based upon a basechannel data rate.channel data rate.
99RCsRCscontain rates derived from their base rate. For examp le,contain rates derived from their base rate. For examp le,
RC3 is b ased on 9.6 kbps and inclu des 1.5, 2.7, 4.8, 9.6, 19.2,RC3 is based on 9.6 kbps and inclu des 1.5, 2.7, 4.8, 9.6, 19.2,
38.4, 76.8, 153.6, and 307.200 kb ps .38.4, 76.8, 153.6, and 307.200 kb ps.
99RCsRCsare cou pled to speci f ic Spreading Ratesare cou pled to speci f ic Spreading Rates
IS 2000 SR1 ( k 1 RTT)
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IS-2000 SR1 (aka 1xRTT)
Is an Improved TIA/EIA-95-B Narrowband System
Occupies the Same 1.23 MHz Bandwidth as TIA/EIA-95-B
Forward Link:99Add s Fast Power Contro lAdds Fast Power Contro l
99Quick Paging Channel to Improve Standby TimeQuick Paging Channel to Improve Standby Time
99Uses QPSK Modu lat ion Rather than Dual BPSK to:Uses QPSK Modulat ion Rather than Dual BPSK to:
Use 3/8 Rate Convolutional Encoder instead of 3/4 for 14.4 Service(improves error correction)
128 Walsh Codes to Handle More Soft Handoffs for 9.6 service
Reverse Link:
99Uses Pi lot Aided BPSK to A l low Coherent Demodulat ionUses Pi lot Aided BPSK to A l low Coherent Demodulat ion
99Uses 1/4 RateUses 1/4 RateConvolut ionalConvolut ionalEnco der Instead o f 1/2 or 1/3Encoder Instead o f 1/2 or 1/3
99Uses HPSK Spreadin gUses HPSK Spreading
Doubles System Voice Capacity
SR1 F d R di C fi ti
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SR1 Forward Radio Configurations
Radio Configuration 1 - Required
99Backwards compat ible mode with TIA/EIABackwards com pat ible mode with TIA/EIA --9595--BB
99Based on 9,600 bp s Traff ic(RS1)Based on 9,600 bp s Traff ic(RS1)
Radio Configuration 2
99Backwards compat ible mode with TIA/EIABackwards com pat ible mode with TIA/EIA --9595--BB
99Based on 14,400 bp s Traff ic(RS2)Based on 14,400 bps Traff ic(RS2)
Radio Configurations 3, 4, and 599Al l use new cdm a2000 cod ing fo r imp roved capaci tyAl l use new cdma2000 cod ing fo r impro ved capaci ty
99RC3 is based on 9,600 bps and goes up to 153,600 bpsRC3 is based on 9,600 bps and goes up to 153,600 bps
99RC4 is based on 9,600 bps and goes up to 307,200 bpsRC4 is based on 9,600 bps and goes up to 307,200 bps
99RC5 is based on 14,400 bps and goes up to 230,400 bpsRC5 is based on 14,400 bps and goes up to 230,400 bps
SR1 F d Ch l
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SR1 Forward Channels
F-Pilot (Using TIA/EIA-95-B Coding)
F-Sync (Using TIA/EIA-95-B Coding)
Up to 7 F-Paging (Using TIA/EIA-95-B Coding) IS-2000 Rev.0
0 to 3 F-QPCH (Quick Paging Channel)
IS-2000 Rev.A/B 0 or 8 F-BCH (Broadcast Channel) 0 to 4 F-CPCCH (Common Power Control Channel)
0 to 7 F-CACH (Common Assignment Channel)
0 to 7 F-CCCH (Common Control Channels)
Many F-Traffic Channels, Each Consisting of:99 0 or 1 F0 or 1 F--DCCH (Dedicated Con trol Channels)DCCH (Dedicated Cont rol Chann els)
99 1 F1 F--FCH (Fundamental Chann el)FCH (Fundamental Channel)
99 0 to 7 F0 to 7 F--SCCH (Supplemental Code Channels for RC1 & RC2)SCCH (Supplemental Code Channels for RC1 & RC2)
99 0 to 2 F0 to 2 F--SCH (Supplemental Chann el for RC3, 4, 5)SCH (Supplemental Chann el for RC3, 4, 5)
B St ti V i bl R t V d
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Base Station Variable Rate Vocoder
Base Stations Do Not Pulse TX Channels
How Does the Base Station Handle Variable
Rate Vocoding? Repeats Data Bits When Transmitting at
Reduced Rates
Repeating Data Adds 3 dB Coding Gain
Lowers the TX Power 3dB for Each Lower
Rate
Forward Link Traffic Channel Physical Layer
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Walsh CodeGenerator
Forward Link Traffic Channel Physical Layer
(RC1,RC2)
1/2
Rate
3/4
Rate
P.C.
Mux
Vocoded
SpeechData
20 msec
blocks
ConvolutionalEncoder
InterleaverLong Code
Scrambling
Power
ControlPuncturing
800 bps Walsh
Coder9.6
kbps
14.4
kbps
19.2kbps
19.2
kbps
Long Code
19.2
kbps
19.2
kbps
19.2
kbps
19.2kbps
1.2288 Mbps
1.2288 Mbps
1.2288
Mbps
1.2288
Mbps
Short Code Scrambler
800
bps
FIR
FIR
I
Q
I Short Code
Q Short Code
Forward FCH Physical Layer
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Forward FCH Physical Layer
RC3 (9.6 kbps)
OptionalCan be Carried by F-DCCH
8.6 kbps
1228.8 kbps
Long Code
Decimator
Interleaver
38.4 ksps
1/4 Rate Conv.
Encoder
38.4 ksps
9.6 kbps
Long Code
Generator
38.4 kbps
Power
Control
Puncture
Walsh 64
Generator
1228.8 kcps
1228.8 kcps
1228.8 kbps
1228.8kbps
Q
I
S -P
800 bps
PCUser Long
Code Mask
Q
I
PC
Dec
1228.8 kcps
Q Short Code
I
Q
1228.8 kcps
Complex
Scrambling
Q
I
FIR
FIRI Short Code
Orthogonal
Spreading
1228.8 kcps
1228.8 kcps+
+
+
-
38.4
ksps
19.2 ksps
19.2 ksps
P.C. Bits
Decimate by
Walsh Length/2
Gain
Gain
Puncture
Timing
Full Rate
Data BitsAdd CRC and
Tail Bits
800 bps
CDMA Vocoders
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CDMA Vocoders
Vocoders Convert Voice to/from Analog Using DataCompression
There are Three CDMA Vocoders: IS-96A Variable Rate (8 kbps maximum)
CDG Variable Rate (13 kbps maximum)
EVRC Variable Rate (improved 8 kbps)
Each has Different Voice Quality: IS-96A - moderate quality
EVRC - near toll quality
CDG - toll quality
CDMA Frame Formats
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15
24 bits in a ms frame
39
79
171 266
124
54
201200 bps
Frame8
Mixed Mode BitInformation Bits
1-bit
Reserved
8
8
88
12 12 8
10 8
6
88
8
Mixed Mode Bit
Mixed Mode Bit
Mixed Mode Bit
Information Bits
Information Bits
Information Bits
2400 bps
Frame
9600 bps
Frame
4800 bps
Frame
192 bits in a ms frame
96 bits in a ms frame
48 bits in a ms frame
1800 bps
Frame
3600 bps
Frame
7200 bps
Frame
14400 bps
Frame
288 bits in a ms frame
144 bits in a ms frame
72 bits in a ms frame
36 bits in a ms frame
1-bit
Reserved
1-bit
Reserved
1-bit
Reserved
Mixed
Mode Bit
Mixed
Mode Bit
Mixed
Mode Bit
Mixed
Mode Bit
Encoder
Tail Bits
CRC
CRC
Encoder
Tail Bits
Encoder
Tail Bits
Encoder
Tail Bits
Information Bits
Information Bits
Information Bits
Information BitsEncoder
Tail Bits
Encoder
Tail Bits
Encoder
Tail Bits
Encoder
Tail Bits
CRC
CRC CRC
CRC
CDMA Frame Formats
Forward Error Protection
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Forward Error Protection
Uses Half-Rate Convolutional Encoder
Outputs Two Bits of Encoded Data for Every Input Bit
Data Out
9600 bps
Data Out
9600 bps
D DDDD D D D
+
+
Data In
9600
bps
zzzz z zz
14 4 Traffic Channel Forward Link
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14.4 Traffic Channel Forward Link
Modifications Replaces 8 kbps Vocoder with a
13 kbps Vocoder(both Variable
Rate)
Effects:
Provides Toll Quality Speech
Uses a 3/4 Rate Encoder
Reduces Processing Gain 1.76 dB
Results in Reduced Capacity or
Smaller Cell Sizes
3/4rate
Vocoded
Speech
Data
ConvolutionalEncoder
20 msec
blocks
14.4
kbps
19.2
kbps
Interleaver
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384 symbols are sequentially written in an input array
Interleaved symbols are then read from the output array
19.2 ksps9.6 ksps4.8 ksps2.4 ksps
SymbolRepetition
19.2 ksps
384 Symbols
20 ms
Block
InterleaverInput
Array /output
Array
16 x 24 Array
Interleaved
Output
16
24
Interleaver
Process of permuting a sequence of symbols to achieve time
diversity
CDMA uses block interleaving with 20 ms blocks
CDMA System Time
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54
CDMA System Time
How Does CDMA Achieve
Synchronization for Efficient
searching?
Use GPS Satellite System
Base Stations Use GPS Time
via Satellite Receivers as a
Common Time Reference
GPS Clock Drives the LongCode Generator
112
2
3
45
67
8
9
1011
Long Code Generation
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55
Modulo-2 Addition
Long Code Output
Long Code Generator
1
User Assigned
Long Code Mask42 bits
24 342 41 5
Long Code Generation
Long Code Generation
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56
Long Code Generation
Modulo-2 Addition
Long Code Output
34 12
User Assigned
Long Code Mask
42 bits4142 5
Long Code Generator(Driven by System Time)
1100011000 Permuted ESN
41 32 31 0
Long Code Mask
Long Code Scrambling
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g g
Users Long Code Mask is
Applied to the Long Code
Masked Long Code is
Decimated Down to 19.2 kbps
Decimated Long Code is
XORed with Voice Data Bits
Scrambles the Data to Provide
Voice Security
Encoded
Voice Data
Long Code
Generator
Long Code
Decimator
XOR
1.2288 Mbps
19.2 kbps
19.2 kbps
19.2 kbps
Closed Loop Power Control Puncturing
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58
19.2 kbps
p g
Long Code is Decimated
Down to 800 bps
Decimated Long Code
Controls the Puncture
Location
Power Control Bits Replace
Voice Data Voice Data is Recovered by
the Mobiles Viterbi Decoder
Long Code
Scrambled
Voice Data
Long CodeDecimated
Data
Closed Loop
Power
Control Bits
P. C.
Mux
Long Code
Decimator
800 bps
800 bps
19.2 kbps
19.2 kbps
Power Control Bit Puncturing
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59
g
z 19.2 ksps: 384 symbols / 20ms frame
z Each 20ms frame is divided into 16 power control
group (1.25 ms each)
z 24 modulation symbols in each power control group
Long Code DecimatedData
Decimator19.2 ksps
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
4 symbols = 16 combinations
20ms
1.25ms
If [20,21,22,23]=[1,1,0,1],then puncture bit 11,12
SR1, RC4 (152.4 kbps) F-SCH
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60
Payload
Data Bits
1228.8 kbps
Long Code
Decimator
Interleaver
1/2 Rate
Convolutional
Encoder
307.2 ksps
Channel
Coder
Add CRC and
Tail Bits
153.6 kbps
Long Code
Generator
User Long
Code Mask
Decimate by
Walsh Length/2
307.2 ksps
307.2 ksps
307.2 ksps
GainWalsh 8
Generator
1228.8 kcps
1228.8 kcps
1228.8 kbps
1228.8kbps
Q
I
S -P
Q
I
1228.8 kcps
Q Short Code
I
Q
1228.8 kcps
Complex
Scrambling
FIR
FIRI Short Code
Orthogonal
Spreading
1228.8 kcps
1228.8 kcps
+
+
+
-
153.6 ksps
153.6 ksps
152.4 kbps
( p )
Walsh Codes
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W=0 0
0 1
W = 0
0 0 0 0
0 1 0 1
0 0 1 10 1 1 0
W=
1
2
4
=nn
nn
n
WW
WWW2
Checking for Orthogonality
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2 Match - 2 dont = 0
W =4
0 0 0 00 1 0 1
0 0 1 1
0 1 1 0
0 0 0 00 0 1 1
Y Y N N
Cross
Correlation= Nagreements
- Ndisagreements
N total_number_of_digits
Effects of Using Variable Length Walsh Codesf S di
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SF=16SF=2 SF=4 SF=8
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 -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 -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 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 -1 1 1 1 1 -1 -1 -1 -11 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
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 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 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 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 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 1 -1 1 1 -1
1 -1 -1 1 -1 1 1 -1 -1 1 1 -1 1 -1 -1 1
for Spreading
Using Shorter
Walsh Codes
Precludes Using
all Longer CodesDerived from the
Original
Shorter Codes on
a Branch mapinto Longer
Codes
Walsh Code Spreading
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64
Encoded
Voice Data
Walsh Code
Generator
19.2 kbps
1.2288 Mbps
1.2288 Mbps
What is the
Spread ing Rate
Inc rease ?
Why Spread Again with the Short Sequence
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65
Provides a Cover to Hide the
64 Walsh Codes
Each Base Station is Assigned
a Time Offset in its ShortSequences
Time Offsets Allow Mobiles to
Distinguish Between Adjacent
Cells Also Allows Reuse of All Walsh
Codes in Each Cell
Walsh Coded
Data at1.2288 Mbps
1.2288 Mbps
1.2288 Mbps I Channel ShortSequence Code
Generator
Q Channel Short
Sequence CodeGenerator
To I/Q
Modulator
Multi-Layer Code Assignment Short Code
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Walsh Code layer (spreading code)
Full codeset per cell
W64,1
W64,2
W64,0
Cells A/Sector A
W64,1
W64,2
W64,0
Cells B/Sector B
PN 0
PN 1
Convolutional
Encoder
Long code
Walsh Code
CDMA as an OnionCDMA as an Onion
Short Code (PN) Generation
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z PN sequence codes are generated using 15-bit shift
registers
z PN sequence pattern repeats every 26.666 ms
z 75 PN sequences repetition occur every 2 seconds
z On every even second clock, MS will get PN sequence
initial state
Jan 6, 1980 00:00:00
1, 0, 0, 0.............. 0R1,R2,R3,R4..........R15
( initial state of 15 registers )
PN Code Combinations: 215 = 32768
Clock Rate = 1.2288 McpsReturn of Initial State = 26.666 ms
32768
32768
1
274
7532
768
2 sec26.666ms
PN Offsets
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Each BS scrambles PN sequence with data by sometime offset
Time offsets are in intervals of 64 clock chips (52.08us) from even second clock
512 unique offsets arecreated (32768/64 = 512)
Each BS is allotted
an offset for PNsequence scrambling
PN 0
PN 120
PN 237
PN 511
PN 489
Short Code Correlation
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Short Codes are Designed to
Have:
Strong Auto-Correlation at Zero
Time Offset
Weak Auto-Correlation at Other
Offsets
Good Auto-Correlation in Very
Poor Signal-to-Noise RatioEnvironments
Allows Fast Acquisition in Real
World Environment
Auto-Correlation Versus
Time Offset With 17 dB Noise Added
0 10 205 15 25 30
Chip Offset
Forward Link Channel Format
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Convert to I/Q
& PN
Spreading
FIR LP Filter &
D/A Conversion
I Data
Q Data
1228.8 kbps
Walsh Code 0
Pilot Channel All 0s
Convert to I/Q
& PN
Spreading
FIR LP Filter &
D/A Conversion
I Data
Q Data
1228.8 kbps
Walsh Code 32
Sync Channel 4.8 kbps
Convert to I/Q
& PN
Spreading
FIR LP Filter &
D/A Conversion
I Data
Q Data
1228.8 kbps
Walsh Codes 1 to 7
Paging Channels1 up to 7 Channels
19.2 kbps
Convert to I/Q
& PN
Spreading
FIR LP Filter &
D/A Conversion
I Data
Q Data
1228.8 kbps
Walsh Codes 8-31,33-63
Traffic Channels1 up to 55 Channels
19.2 kbps
I
Q
Walsh Coding Example
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71
W2=0 0 -User A
0 1 -User B
-1
-2
+1+2
-1
+1Channel A
Walsh Encoded
Voice Data
+1
-1
Channel A
Voice Data
For a 1 Input
Use Code 11
+1
-1
For a 0 Input
Use Code 00
User A User B
For a 0 Input
Use Code 01
For a 1 Input
Use Code 10
Channel B
Voice Data
Channel B
Walsh Encoded
Voice Data
Sum of A & B
Walsh Encoded
Data Streams
0 0
1 1
0 0 1 1 0 0 0 0
+1
-1
+1
-1
0 1
1 0
-1
+1
1 0 0 1 0 1 1 0
+0
+1
1 0 0 1
+1
0
1 0 0 1
Walsh Decoding Example
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72
Correlation Coefficient
fi
(t) r fj
(t) dtzi j
=1
T
+1
01 0 0 1
+1
-1
+2
-2
Original User B Voice Data
User A & B Walsh Data
Multiply Summed Data with Desired Walsh Code
+1
01 0 0 1
+1
-1
+2
-2
Original User A Voice Data
User A & B Walsh Data
Multiply Summed Data with Desired Walsh Code
+1
-1
+2
-2
X
+1
-1 1 1
+1
-1
+2
-2 -1+1
-1
+2
-2
+1
-11 0 1
+1
-1
+2
-2
= = = =+
0T
What if Walsh Codes are Not Time Aligned ?
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Channel B
Walsh
EncodedVoice Data -1
+1
1 0 0 1 0 1 1 0-1
+1Channel A
Walsh
EncodedVoice Data
0 0 1 1 0 0 0 0
-1
-2
+1Sum of A & B
Walsh EncodedData Streams
Original Data Was
0 (-1), We Have
Interference Now!
Multiply Summed Data with Desired Walsh Code
+1
-1
+2
-2
+1
-11 1
+1
-1
+2
-2
-0.75
Original Time Delayed
+
X = =
Pilot Channel Physical Layer
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74
Walsh
Modulator
1.2288 Mbps
1.2288 Mbps
1.228
8
Mbps
1.228
8Mbps
Short Code Scrambler
FIR
FIR
I
Q
Walsh Code
Generator Q Short Code
I Short Code
All 0
Inputs
19.2
kbps
WalshCode 0
Uses Walsh Code 0:
All 64 bits are 0
All Data into WalshModulator is 0
Output of WalshModulator is therefore all
0s Pilot Channel is just the
Short Codes
Sync Channel Physical Layer
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75
1/2
Rate2x
ConvolutionalEncoder Interleaver
Walsh
32
Coder
1.2
kbps
2.4
kbps
4.8
kbps
1.2288 Mbps
1.2288 Mbps
1.2288
Mbps
1.2288
Mbps
Short Code Scrambler
FIR
FIR
I
Q
Sync
Channel
Message
Data
Symbol
Repetition
4.8
kbps
Walsh CodeGenerator Q Short Code
I Short Code
Paging Channel Physical Layer
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Paging Channel
Long Code
1/2
Rate
ConvolutionalEncoder
Interleaver
4.8kbps 9.6kbps 19.2kbps
Paging
Channel
Message
Data
2x
Symbol
Repetition
19.2kbps
Walsh1 to 7
Coder
1.2288 Mbps
1.2288 Mbps
1.2288
Mbps
1.2288
Mbps
Short Code Scrambler
I
Q
Walsh Code
Generator QShort Code
Long Code
Scrambling
19.2kbps
19.2
kbps
FIR
I Short Code
FIR
SR1 Reverse Radio Configurations
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77
Radio Configuration 1 - Required
99 Backwards compat ible mode with TIA/EIABackwards compat ible mode with TIA/EIA --9595--BB
99 Based o n 9,600 bps Traff icBased on 9,600 bps Traff ic
Radio Configuration 2
99 Backwards compat ible mode with TIA/EIABackwards compat ible mode with TIA/EIA --9595--BB
99 Based on 14,400 bps Traff icBased on 14,400 bps Traff ic
Radio Configurations 3 and 4
99 Al l use new ISAl l use new IS--2000 cod ing fo r imp roved capaci ty2000 cod ing fo r imp roved capaci ty
99 RC3 is based on 9,600 bps and g oes up to 307,200 bpsRC3 is based on 9,600 bps and goes up to 307,200 bps
99 RC4 is based on 14,400 bps and goes up to 230,400 bpsRC4 is based on 14,400 bps and goes up to 230,400 bps
SR1 Reverse Channels
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Each Mobile Transmits Several
Channels: 1 R1 R--Pi lotPi lot(Reverse Pilot)99 Includes Power Control SubIncludes Power Control Sub--ChannelChannel
1 R1 R--ACH or RACH or R--EACHEACH(Access or Enhanced Access Channel)
99 Used to Init iate CallsUsed to Init iate Calls
0 or 1 R0 or 1 R--CCCHCCCH(Common Control Channel)
99 Used to Init iate Calls in the Reservation Ac cess ModeUsed to Init iate Calls in the Reservation A ccess Mode
0 or 1 R0 or 1 R--DCCHDCCH(Dedicated Control Channel)
99 Prov ides Signaling while a Traff ic Channel is Ac tiveProvid es Signaling while a Traff ic Channel is Ac tive
0 or 1 R0 or 1 R--FCHFCH(Reverse Fundamental Channel)99 Primary Channel, usually VoicePrimary Channel, usu ally Voice
0 to 2 R0 to 2 R--SCHsSCHs(Reverse Supplemental Channels)
99 Carries High Speed DataCarries High Speed Data
R-FCH Coding for SR1(RC1,RC2)
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79
1/2Rate
Vocoded
SpeechData
20 msec
blocks
Convolutional
Encoder
Interleaver
9.6
kbps
14.4
kbps
28.8
kbps
28.8
kbps
28.8
kbps
1.2288 Mbps
1.2288
Mbps
Short Code Scrambler
I
Q
1/3
Rate
Long Code
64-ary
Modulator
1 of 64
Walsh Codes
Walsh
Code 2
Walsh
Code 63
Walsh
Code 62
Walsh
Code 61
Walsh
Code 1
WalshCode 0
Long Code
Modulator
307.2
kbps
1.2288
Mbps1.2288 Mbps
Q Short Code
FIR
I Short Code
FIRt/ 2
1/2 Chip Delay
Reverse Error Protection
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Uses Third-Rate Convolutional Encoder
Outputs Three Bits for Every Input Bit
Data Out
9600 bps
D DDDD D D D
+
+
Data
Out
9600
bps
+
Data In
9600kbps
Data Out
9600 bps
z z z z z z z z
z
z
z
14.4 Traffic Channel Reverse LinkModifications
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Replaces 8 kbps Vocoder with
a 13 kbps Vocoder (both
Variable Rate)
Effects: Provides Toll Quality Speech
Uses a 1/2 Rate Encoder
Reduces Processing Gain 1.76
dB Results in Reduced Capacity
or Smaller Cell Sizes
1/2Rate
Vocoded
Speech
Data
20 msec
blocks
ConvolutionalEncoder
14.4
kbps28.8
kbps
64-ary Modulation
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Every 6 Encoded Voice Data
Bits Points to one of the 64
Walsh Codes
Spreads Data from 28.8 kbps to307.2 kbps
(28.8 kbps * 64 bits) / 6 bits =
307.2 kbps)
Is Not the Channelization forthe Reverse Link
307.2kbps
28.8kbps
>
Walsh
Code 2
Walsh
Code 1Walsh
Code 0
Walsh
Code 63
Walsh
Code 62
Walsh
Code 61
Why Arent Walsh Codes Used for ReverseChannelization ?
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All Walsh Codes Arrive
Together in Time to All Mobiles
From the Base Station
However, Transmissions fromMobiles DO NOT Arrive at the
Same Time at the Base Station
Reverse Channel Long Code Spreading
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Long Code Spreading
Provides Unique Mobile
Channelization
Mobiles are Uncorrelated butnot Orthogonal with Each Other
Long Code
Generator
WalshModulated
Voice Data
XOR
307.2 kbps 1.2288 kbps
1.2288 kbps
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Data Burst Randomizer
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86
Algorithm
At 2400 bps rate ,
Transmission should occur on the PCG's numbered:
b0 if b8 = 0, or 2 + b1 if b8 = 1 (i.e. 1 out of PCG 0...3)
4 + b2 if b9 = 0, or 6 + b3 if b9 = 1 (i.e. 1 out of PCG 4...7)
8 + b4 if b10 = 0, or 10 + b5 if b10 = 1 (i.e. 1 out of PCG 8...11)
12+b6 if b11 = 0, or 14 + b7 if b11 = 1 (i.e. 1 out of PCG 12..15)
(Example)
( 25% Gated-On, 25% Gated-Off )
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
At 1200 bps rate ,
Transmission should occur on the PCG's numbered:
b0 if (b8 = 0 and b12=0), or 2 + b1 if (b8 = 1 and b12=1)
or 4 + b2 if (b9 = 0 and b12=0), or 6 + b3 if (b9 = 1 and b12=1) (i.e. 1 out of PCG 0...7)
8 + b4 if (b10 = 0 and b13=0), or10 + b5 if (b10 = 1 and b13=1)or 12 + b6 if (b11 = 0 and b13=0), or14 + b7 if (b11 = 1 and b13=1) (i.e. 1 out of PCG 8..15)
(Example)
(12.5% Gated-On, 12.5% Gated-Off)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Gated-On and Gated-Off Power
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87
7 us 7 us
20 dB or to
the noise
floor (-60dBm)
3 dB
1.247 ms
Mean output of theensemble average
Ensemble average: Average of power control groups,
all with the same output power
Reverse Channel Short Sequence Spreading
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88
Same PN Short Codes Are
Used by Mobiles
Short Sequence spreading Aids
Base Station Signal Acquisition Extra 1/2 Chip Delay is Inserted
into Q Path to Produce OQPSK
Modulation to Simplify Power
Amplifier Design
1.2288 Mbps
Short Code Scrambler
I
Q
1.2288 Mbps
I Short Code
FIR
I Short Code
FIRt/ 2
1/2 Chip Delay
1.2288
Mbps
OQPSK Modulation
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89
QPSK Makes oneSymbol Change EveryPeriod
OQPSK Makes twoSymbol Changes EveryPeriod if Q DataChanges
Example Symbol Patternis:
- 00,10,01,11
I
Q
n
n n
n00 01
10 11
I
Q
n
n n
n00 01
10 11
CDMA Modulation Formats
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90
Filtered Offset QPSKFiltered QPSK
I I
Mobile Station TX
Base StationPilot Channel TX
Reverse Pilot/Power Control Multiplexing(RC3,4)
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91
MUX
Pilot Data
Power
Control Bits
To I Channel
Summer
One Power Control Group
Pilot PilotPilot PC Bits
312.5 us 312.5 us 312.5 us 312.5 us
1.25 ms
There are 16 Power Control Groups per 20 ms Frame
Each Power Control Group is Split into 4 Sub-Groups
1 Power Control Bit is Sent per Power Control Group Pilot and Power Control are Multiplexed Together
SR1, RC3 R-FCH Coding(RC3,RC4)
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92
R-FCH
Data Bits
8.6 kbps
Walsh Code
Generator
1 Frame1/4 Rate
Convolutional
Encoder
38.4 ksps
Channel
Coder
Add CRC and
Tail Bits
9.6 kbps
Interleaver
1,1, 1, 1,-1, -1, -1, -1, 1,1, 1, 1,-1, -1, -1, -1
R-FCH Coding for a 20 ms Frame
Orthogonal
Spreading
Spread
Factor = 16
2 Reps
Symbol
Repeat
38.4 ksps 76.8 ksps 1228.8 kcps
R-FCH Carries Voice Information
Uses a 20 ms Frames Length
Using rate convolutional coding
ComplexR-SCH 2 Gain
SR1 Reverse Channel Spreading(RC3,RC4)
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1,1,1,1,1,1,1,1,-1,-1,-1,-1,-1,-1,-1,-1
I Channel
Short Code
Generator
User Long
Code Mask
ComplexScrambling
Q
I+
+
+
-R-DCCH
R-Pilot +
Power
Control
R-SCH 1
orR-EACH
or
R-CCCH
R-FCH
Walsh 16
Generator
1,1, 1, 1 -1,-1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1
Walsh 2/4/8
Generator
1,-1 or 1 -1 1,-1, or 1,1,-1,-1,1,1,-1,-1
Walsh 16
Generator
1228.8 kcps
R-SCH 2
Walsh 4/8
Generator
1, 1, -1, -1 or 1, 1, -1, -1, -1, -1, 1, 1
Walsh 2
Generator
1,-1
Gain
Scale
GainScale
Gain
Scale
GScale
Deci
by 21228.8 kcps
1228.8 kcps
1228.8 kcps
1228.8 kcps
1228.8 kcps
1228.8 kcps
1228.8 kcps
1228.8 kcp
Q Channel
Short Code
Generator
1228.8 kcps
1-Chip
Delay
Long Code
Generator
1,1,1,1,-1,-1,-1,-1 for
R-EACH or R-CCCH
Channelization Summary
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94
Function
9.6 kbpsConvolutional Encoder
14.4 kbps
Convolutional Encoder
Walsh Coding
Long Code
Spreading
Short Code
Spreading
Forward Link
(Base to Mobile)
1/2 Rate(9600 in 19200 out)
3/4 Rate
(14400 in 19200 out)
Channelization
Voice Privacy
Base Station
Identification
Reverse Link
(Mobile to Base)
1/3 Rate(9600 in 28800 out)
1/2 Rate
(14400 in 28800 out)
64-aryModulation
Channelization
Aid Base Station
Searching
CDMA Multiplex Sublayer
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Layer 1Physical Layer
Channel Data - 9600 bps or 14400 bps
Multiplex SublayerTraffic Channel
Layer 2Link Layer
Paging & Access
Channels
Layer 2Primary Traffic
Layer 2Signaling
Layer 3
Call Processing & Control
Station Class Mark (SCM)
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Extended SCMIndicator
7 Band Class 0 0XXXXXXXBand Class 1 1XXXXXXX
Dual Mode 6 CDMA Only X0 XXXXXXDual Mode X1XXXXXX
Slotted Class 5 Non-Slotted XX0XXXXXSlotted XX1XXXXX
IS- 54 Power Class 4 Always 0 XXX0XXXX
25 MHz Bandwidth 3 Always 1 XXXX1XXX
Transmission 2 Continous XXXXX0XXDiscontinous XXXXX1XX
Power Class for Band
Class "0" AnalogOperation( For CDMA only "00")
1- 0 Class I XXXXXX00
Class II XXXXXX01Class III XXXXXX10Reserved XXXXXX11
Function Bit(s) Setting
Ten Minutes in the Life of a CDMA MobilePhone
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Turn-on
System Access
Travel
Idle State Hand-Off
Initiate Call
System Access
Continue Travel
Initiate Soft Handoff
Terminate Soft Handoff
End Call
CDMA Turn On Process
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Find All Receivable Pilot Signals Choose Strongest One
Establish Frequency and PN TimeReference (Base Station I.D.)
Demodulate Sync Channel
Establish System Time
Determine Paging Channel Long CodeMask
Sync Channel Message
C t i th F ll i D t
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Contains the Following Data:
Base Station Protocol Revision
Min Protocol Revision
Supported
SID, NID of Cellular System
Pilot PN Offset of Base Station
Long Code State
System Time
Leap Seconds From Start of
System Time
Local Time Offset from System
Time
Daylight Savings Time Flag Paging Channel Data Rate
Channel Number
SYNC
Read the Paging Channel
D d l t th P i
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Demodulate the Paging
Channel:
Use Long Code Mask Derived
from the Pilot PN Offset Givenin Sync Channel Message
Decode Messages
Register, if Required by Base
Station Monitor Paging Channel
Pagin
g
CDMA Idle State Handoff
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No Call In Progress
Mobile Listens to New Cell
Move Registration Location ifEntering a New Zone
Access Procedures
Controlled b BS b broadcasting Access Parameters
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Controlled by BS by broadcastingAccess ParametersMessage on the paging channel
Access attempt is the process of sending one message and
receiving (or failing to receive) an ACK for that message= groups of access probe sequence
Access probe sequence = groups of access probes
Access probe = each transmission in an access attempt
Access Probe
Access Probe (or Access Channel Slot)
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Access Channel Message
40 - 880 bits
Padding
as reqd
Frame Body
88 bits
T
8
Frame Body
88 bits
T
8
Access Channel Message Capsule
Access
Chan Frame96 b/20ms
Access
Chan Frame96 b/20ms
Access
Chan Frame96 b/20ms
Access
Chan Frame96 b/20ms
Access
Chan Frame96 b/20ms
Access
Chan Frame96 b/20ms
( )( 4 + PAM_SZ + MAX_CAP_SZ) x 20ms [ Max value = 26 frames ]
Preamble
(1 + PAM_SZ) x 20ms[ max = 16 frames ]
Access Channel Message Capsule
(3 + MAX_CAP_SZ) x 20 ms[ Max = 10 frames ]
Preamble
96 bits 0s
Preamble
96 bits 0s
PAM_SZ = No. of preamble frames
MAX_CAP_SZ = No. of message capsule frames
Access Probe Sequence
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Access Probe Sequence
AccessProbe 1
Access
Probe 2
Access
Probe 3
Access
Probe n
TA TA TART RT RT
Preamble + Access Message Capsule
Max = 26 frames
RN RN RN RN
IP
P1
P2
P3
IP = Open Loop Power + NOM_PWR + INIT_PWR
where Open Loop Power = -( Received Power ) - 73
Access Attempt
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RS : Backoff delay, which is random value between 0 to BKOFF slots
Process for Response MessagesProcess for Response Messages
message ready for
transmission
Access
Probe
Sequence
Access
Probe
Sequence
Access
Probe
Sequence
Access
Probe
Sequence
Access AttemptMAX_RSP_SEQ
RS RS RS
Access Attempt
P f R t MP f R t M
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PD: (Persistence Delay) resulted from a pseudo-random test by MS; the first access probe of thesequence begins in the slot only if the test passes within that slot
The test result depends on the ESN, reason for attempt (call origination, register, etc.) and theaccess overload class of the MS, and a PSSIST value broadcasted by BS for that access class. If
the PSSIST is all 1s for some access class, the test for that access class will always fail
Process for Request MessagesProcess for Request Messages
message ready for transmission
Access
Probe
Sequence
AccessProbe
Sequence
AccessProbe
Sequence
AccessProbe
Sequence
Access AttemptMAX_REQ_SEQ
RS PD RS PDRS PDPD
Access Channel Messages
Registration Message
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Registration Message - for registration as well as GlobalChalleng Authentication Process
Order Message - for transmission of order messages (e.g., BSchallengeorder, SSD update confirmation, MSacknowledgement order, etc.)
Data Burst Message - to get a trigger from the user to send amessage to BS (information message likeSMS)
Origination Message-MS information
Page Response message
Authentication Challenge Response Message
Status Response Message - response to BS status requestorder which may include MS terminalinformation, station class mark, service optionsupported, multiplex option support, IMSI, ESN,etc.
CDMA Call Initiation
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Dial Numbers, Then Press Send Mobile Transmits on a Special Channel Called the
Access Channel
The Access Probe Uses a Long Code Mask
Based On:bAccess & Paging Channel NumbersbBase Station ID
bPilot PN Offset
CDMA Call Completion
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Base Answers Access Probe using theChannel Assignment Message
Mobile Goes to A Traffic Channel Based on
the Channel Assignment MessageInformation
Base Station Begins to Transmit andReceive Traffic Channel
CDMA Soft Handoff Initiation
Mobile Finds Second Pilot of Sufficient Power (exceeds
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(
T_add Threshold)
Mobile Sends Pilot Strength Message to First Base Station
Base Station Notifies MTSO
MTSO Requests New Walsh Assignment from Second Base
Station
If Available, New Walsh Channel Info is Relayed to First
Base Station
Hard, Soft, and Softer Handoffs
Hard Handoff f2
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Break before make.
Soft Handoff
Make before break.
MS communicates with more
than one BS at a time.
Improves reception on cell
boundaries.
MS will receive different powercontrol from the two BSs.
Softer Handoff
MS communicates with more
than one sector of a cell. MS will receive identical power
control from both sectors.
f1
2
Hard Handoff
f1
f1
Soft Handoff
f1
Softer Handoff
Pilot Ec/ I0
cdma2000 CONCEPT: Soft Handoff
Terms:
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T_ADD
BS1 BS2
Pilot Ec/ I0
T_DROP
BS1 BS2
Active Set: MS is in soft
handoff.
Candidate Set: MS identifies asstrong.
Parameters:
T_ADD
T_COMP T_DROP
T_TDROP
Pilot Ec/ I0
0.5xT_COMP
BS1 BS2
CDMA Soft Handoff Completion
First Base Station Orders Soft Handoff with new Walsh
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Assignment
MTSO Sends Land Link to Second Base Station
Mobile Receives Power from Two Base Stations
MTSO Chooses Better Quality Frame Every 20 Milliseconds
MTSO
Base Station 1
Land Link
Vocoder/ Selector
Base Station 2
Ending CDMA Soft Handoff
First BS Pilot Power Goes Low at Mobile Station (drops
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below T_drop)
Mobile Sends Pilot Strength Message
First Base Station Stops Transmitting and Frees up Channel
Traffic Channel Continues on Base Station Two
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cdma2000 Standards Overview - TIA/EIA-98-D/E
I.e.3GPP2 C.S0011-A/B:
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Recommended Minimum Performance Standards for
cdma2000 Spread Spectrum Mobile Stations.
Important test sections:
2 Standard Radiated Emissions Measurement Procedure
3 CDMA Receiver Minimum Standards
4 CDMA Transmitter Minimum Standards
Covers both SR1 and SR3
No Minimum Standards specified for SR3.
This presentation only covers SR1 testing.
CDMA Service Options
Service Options Are:
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9911--Voice Using 9600 bp s ISVoice Using 9600 bps IS--9696--AA VocoderVocoder
9922--Rate Set 1Rate Set 1LoopbackLoopback(9600 bp s)(9600 bp s)
9933--Voice Usin g 9600 bps (EVRC)Voice Usin g 9600 bps (EVRC)
9944--Asy nch ronous Data Service (c i rcui t sw i tched)Asynch ronou s Data Service (c i rcui t sw i tched)
9955--Group 3 FaxGroup 3 Fax
9966--Sho rt Message Service (9600 bps )Sho rt Message Service (9600 bps )
9977--Internet Standard PPP Packet DataInt ernet Standard PPP Packet Data
9988--CDPD Over PPP Packet DataCDPD Over PPP Packet Data
9999--Rate Set 2Rate Set 2LoopbackLoopback(14400 bps)(14400 bp s)
991414--Sho rt Message Service (14400 bps)Sho rt Message Service (14400 bp s)
9932,76832,768--Voice Usin g 14400 bps (CDG)Voice Usin g 14400 bps (CDG)
Section 3 - Receiver Test
Receiver Test
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3.1 Frequency Coverage Requirements
3.4.1 Demod of Fwd Traffic Channel with AWGN
3.4.2 Demod of Fwd Traffic Channel with Multipath Fading
3.5.1 Receiver Sensitivity and Dynamic Range
3.5.2 Single Tone Desensitization
3.5.3 Intermodulation Spurious Response Attenuation3.5.4 Adjacent Channel Selectivity
3.5.5 Receiver Blocking Characteristics
3.7.1 Supervision Paging Channel
Section 4 - Transmitter Test
Transmitter Test
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4.1 Frequency Accuracy
4.2 Handoff
4.3 Modulation Requirements4.4 RF Output Power Requirements
4.4.14.4.1Range of Open Loop Output PowerRange of Open Loo p Outpu t Power
4.4.2 Time Response of Open Lo op Power Con trol4.4.2 Time Response of Open Lo op Power Con trol
4.4.3 Acc ess Probe Outpu t Pow er4.4.3 Access Probe Ou tpu t Pow er
4.4.4 Range of Closed Loop Pow er Control4.4.4 Range of Closed L oop Power Con trol
4.4.5 Maximum RF Outpu t Pow er4.4.5 Maximum RF Outpu t Pow er
4.4.6 Minimum Control led Outp ut Power4.4.6 Minimum Control led Outp ut Power
4.4.7 Standby Outpu t Power and Gated Ou tpu t Power4.4.7 Standb y Ou tput Power and Gated Ou tput Power
4.4.8 Pow er Up Funct ion Outpu t Power4.4.8 Power Up Func t ion Outpu t Power
4.4.9 Code Channel to Reverse Pilot Channel Output Power A ccu rac4.4.9 Code Channel to Reverse Pi lot Channel Outpu t Pow er Acc uracyy
4.4.10 Reverse Pilot Channel Transm it Phase Discon tinu ity4.4.10 Reverse Pilot Channel Transm it Phase Discon tinu ity
4.4.11 Reverse Traff ic Channel Outpu t Power During Changes in Da4.4.11 Reverse Traff ic Channel Outpu t Power During Changes in Datata
RateRate
CDMA Conclusions
New Access Method
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Code Based
Designed for Use in Interfering Environment
Uses Multipath to Improve Reception in Fading Conditions
cdma2000 is Backwards Compatible with TIA/EIA-95-B
Provides 2x Capacity Improvement Over TIA/EIA-95-B
99Improved CodingImproved Coding
99 Improved Modulat ionImproved Modulat ion
99 Coherent Reverse Link Demodulat ion (Mobi le Pilot)Coherent Reverse Link Demodulat ion (Mobi le Pi lot)
99 Fast Forward Lin k Power Contro lFast Forward Link Power Contro l
Has Options for Green Field and Overlay Operation:99 Direct Spread for Green Field Spectrum Appl icat ionsDirect Spread for Green Field Spectrum Appl icat ions
Supports High Speed Data for New Applications