3-cdma-channels structure.ppt

7/29/2019 3-CDMA-Channels STRUCTURE.ppt

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Copyright 2003, ZTE CORPORATION

CDMA CHANNEL

STRUCTUREAND MODULATION

2004.10.3


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Upon completion of this lesson, the student will be able tomaster:

Objectives

-- The forward channel in IS-95

Pilot ;Sync ; Paging and Traffic

-- The reverse channel in IS-95Access; Traffic

-- CDMA Call Processing

-- New Channels in CDMA20001X


3/60


CDMA Forward Traffic

Channels

Used for the transmission of user and signalinginformation to a specific mobile station during a call.

Maximum number of traffic channels: 64 minus one

Pilot channel, one Sync channel, and 1 Paging channel. This leaves each CDMA frequency with at least 55 traffic

channels.

Unused paging channels can provide up to 6 additional channels.

Forward Traffic Channel


Sync

Paging



Pilot

CDMA Cell Site


4/60



Generation

8 kb Vocoding

Walshfunction

PowerControl

Bit

I PN

9600bps4800 bps2400 bps1200 bps(Vocoder) Convolutional

EncodingandRepetition

1.2288McpsLong PN Code

Generation800Hz

R=1/2, K=9

Q PN

Decimator DecimatorUserAddress

Mask(ESN-based)

19.2ksps

1.2288Mcps

Scrambling

bits symbols chips

19.2ksps

CHANNEL ELEMENT

MUX

BlockInterleaving


5/60


Rate 1/2, k=9 Convolutional

Encoding

Symbols generated as the information bits transit through the encoder, are relatedto all the bits currently in the register.

Each information bit contributes to multiple symbols.

Pattern of inter-relationships helps detect and correct errors.

The length of shift register is called constraint (K=9) length.

The longer the register, the better coding can correct bursty errors

Reduces power required to achieve same accuracy with coding

Here, two symbols are generated for every bit input (Rate 1/2).

CodeSymbolOutput

1 2 3 4 5 6 7 8

g0

g1

c0

c1

DataBitInput


6/60


Symbols areWritten In

Symbols areRead Out

1 25 49 73 97 121 145 169 193 217 241 265 289 313 337 361

2 26 50 74 98 122 146 170 194 218 242 266 290 314 338 362

3 27 51 75 99 123 147 171 195 219 243 267 291 315 339 363

4 28 52 76 100 124 148 172 196 220 244 268 292 316 340 364

5 29 53 77 101 125 149 173 197 221 245 269 293 317 341 365

6 30 54 78 102 126 150 174 198 222 246 270 294 318 342 366

7 31 55 79 103 127 151 175 199 223 247 271 295 319 343 367

8 32 56 80 104 128 152 176 200 224 248 272 296 320 344 368

9 33 57 81 105 129 153 177 201 225 249 273 297 321 345 369

10 34 58 82 106 130 154 178 202 226 250 274 298 322 346 370

11 35 59 83 107 131 155 179 203 227 251 275 299 323 347 371

12 36 60 84 108 132 156 180 204 228 252 276 300 324 348 372

13 37 61 85 109 133 157 181 205 229 253 277 301 325 349 373

14 38 62 86 110 134 158 182 206 230 254 278 302 326 350 374

15 39 63 87 111 135 159 183 207 231 255 279 303 327 351 375

16 40 64 88 112 136 160 184 208 232 256 280 304 328 352 376

17 41 65 89 113 137 161 185 209 233 257 281 305 329 353 377

18 42 66 90 114 138 162 186 210 234 258 282 306 330 354 378

19 43 67 91 115 139 163 187 211 235 259 283 307 331 355 379

20 44 68 92 116 140 164 188 212 236 260 284 308 332 356 380

21 45 69 93 117 141 165 189 213 237 261 285 309 333 357 381

22 46 70 94 118 142 166 190 214 238 262 286 310 334 358 382

23 47 71 95 119 143 167 191 215 239 263 287 311 335 359 383

24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384

16 Columns

24Rows

Full Rate Block Interleave Array

The 384 modulation symbols in a frame are input into a 24 by 16 blockinterleave array read down by columns, from left to right

The modulation symbols are then read out of the array in rows


7/60Copyright 2003, ZTE CORPORATION

Full Rate Block Interleave

Adjacent symbols are now separated in time This separation combats the effect of fast fading

A burst of errors could effect the area in red above and after the frame iswritten into the block de-interleave function at the mobile we see the

errors are spread out instead of being in consecutive order.

Symbols areWritten In

Symbols areRead Out

1 25 49 73 97 121 145 169 193 217 241 265 289 313 337 361

2 26 50 74 98 122 146 170 194 218 242 266 290 314 338 362

3 27 51 75 99 123 147 171 195 219 243 267 291 315 339 363

4 28 52 76 100 124 148 172 196 220 244 268 292 316 340 364

5 29 53 77 101 125 149 173 197 221 245 269 293 317 341 365

6 30 54 78 102 126 150 174 198 222 246 270 294 318 342 366

7 31 55 79 103 127 151 175 199 223 247 271 295 319 343 367

8 32 56 80 104 128 152 176 200 224 248 272 296 320 344 368

9 33 57 81 105 129 153 177 201 225 249 273 297 321 345 369

10 34 58 82 106 130 154 178 202 226 250 274 298 322 346 370

11 35 59 83 107 131 155 179 203 227 251 275 299 323 347 371

12 36 60 84 108 132 156 180 204 228 252 276 300 324 348 372

13 37 61 85 109 133 157 181 205 229 253 277 301 325 349 37314 38 62 86 110 134 158 182 206 230 254 278 302 326 350 374

15 39 63 87 111 135 159 183 207 231 255 279 303 327 351 375

16 40 64 88 112 136 160 184 208 232 256 280 304 328 352 376

17 41 65 89 113 137 161 185 209 233 257 281 305 329 353 377

18 42 66 90 114 138 162 186 210 234 258 282 306 330 354 378

19 43 67 91 115 139 163 187 211 235 259 283 307 331 355 379

20 44 68 92 116 140 164 188 212 236 260 284 308 332 356 380

21 45 69 93 117 141 165 189 213 237 261 285 309 333 357 381

22 46 70 94 118 142 166 190 214 238 262 286 310 334 358 382

23 47 71 95 119 143 167 191 215 239 263 287 311 335 359 383

24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384

16 Columns

24

Rows



Data Scrambling

Every 64th PN chip is modulo-2 added to a symbol

Randomize transmitted data Effects of all 1s or 0s' traffic (impulse-like) is reduced

Eliminates probability of Pilot Reuse Error Mobile might demodulate a distant cell with same PN offset

BlockInterleaver

Long

Code PNGenerator

19.2 KspsModulationSymbols

User Address

Mask (ESN)Decimator

Divideby 64

19.2Ksps

1.2288Mcps

19.2Ksps

To PowerControl Mux



Power Control Subchannel

Base station receiver estimates received signal strength of mobileover a 1.25 ms period (800/s)

A power control subchannel is transmitted continuously A power up/down command is sent 800 times a second

A puncturing technique sends Power Control Bits at full power anduncoded

19.2 Kspsfrom BlockInterleaver

1.2288 Mcps

User LongCode

Decimator

ScrambledModulationSymbol orPowerControl Bit19.2

Ksps

Decimator

Data ScramblingMUX

800 Hz Mux

Timing

Power ControlBit (800 bps)



Orthogonal Spreading

Each symbol output from the Mux is exclusive ORd bythe assigned Walsh function

Walsh function has fixed chip rate of 1.2288 Mcps Result is 64 chips output for each symbol input

Channels are distinguished from each other by Walshfunction

Bandwidth used greatly exceeds source rate

To QuadratureSpreading19.2

Ksps

MUX

1.2288Mcps

Walsh Functionfrom Index

Wt800 Hz Mux

Timing

Power ControlBit (800 bps)

ScrambledData



Quadrature Spreading

& Baseband Filtering

The forward traffic channel is combined with twodifferent PN sequences: I and Q

Baseband filtering ensures the waveforms are containedwithin the 1.25 MHz frequency range

The final step is to convert the two baseband signals toradio frequency (RF) in the 800 MHz or 1900 MHzrange

ConvolutionalEncoding

Code SymbolRepetition

VocoderProcessing

Baseband Trafficto RF Section

PCM Voice

BlockInterleaving

Data Scrambling

Power ControlSubchannel

OrthogonalSpreading

QuadratureSpreading

BasebandFiltering

(SymbolPuncturing)

WalshFunction

1.2288Mcps

19.2 kspsfrom PowerControl Mux

I-Channel Pilot PN Sequence1.2288 Mcps

BasebandFilter

Baseband

Filter

I

Q

I

Q

Q-Channel Pilot PN Sequence1.2288 Mcps

cos(2pfct)

sin(2pfct)

GAIN



Composite I and Q

Each CHM hasa combiner andworks in a serialarray to

combine the Iand Q signalsfor all forwardchannels in a

partition sector

or cell.

Pilot

Channel

WalshCode

SyncChannel

WalshCode

Paging

Channel(s)

WalshCode

Forward Traffic

Channel(s)

WalshCode

IPN Code

QPN Code

CompositeI

CompositeQ



Quadrature Phase Shift Key

(QPSK) Modulation

Q1 sin (2 fct) + Q2 sin (2 fct) = ( Q1 + Q2 ) sin (2 fct)

I1 cos (2 fct) + I2 cos (2 fct) = ( I1 + I2 ) cos (2 fct)

: XOR

S: Analog sum

: Baseband x Carrier

Every

Channel

Walshcode

Q PN Code

I PN Code

Basebandfilter

Basebandfilter

cos (2pfct)

sin (2pfc

t)

S

S

S

Gain

Control




Generation (13 kb Vocoding)

Walshfunction

PowerControl

Bit

I PN

14400bps7200 bps3600 bps1800 bps(Vocoder) Convolutional

EncodingandRepetition

1.2288Mcps

Long PN CodeGeneration 800Hz

R=1/2, K=9

Q PN

Decimator Decimator

UserAddress

Mask(ESN-based)

19.2ksps

1.2288

McpsScrambling

bits symbols chips

28.8ksps

CHANNEL ELEMENT

MUX

BlockInterleaving

SymbolPuncturing(13 kb only) 19.2

ksps



Forward Channel Demodulation

Three elements must be capable of demodulating multipathcomponents

One must be a searcher that scans and estimates signal

strength at each pilot PN sequence offset

IS-95A/J-STD-008 requires a minimum of four processing elements thatcan be independently directed:

DigitalRake Receiver

ReceiverRF SectionIF, Detector

TransmitterRF Section

Vocoder

Traffic Correlator

PN xxx Walsh xx

Traffic Correlator

PN xxx Walsh xx

Traffic Correlator

PN xxx Walsh xx

Pilot SearcherPN xxx Walsh 0

ViterbiDecoder

CPUDuplexer

TransmitterDigital Section

Long Code Gen.

Open

Loop

Transmit Gain Adjust

Messages

Messages

Audio

Audio

Packets

Symbols

SymbolsChips

RF

RF

AGC



Pilot Channel Used by the mobile station for initial system acquisition

Transmitted constantly by the base station

The same Short PN sequences are shared by all base stations

Each base station is differentiated by a phase offset

Provides tracking of:

Timing reference

Phase reference

Separation by phase provides for extremely high reusewithin one CDMA channel frequency

Acquisition by mobile stations is enhanced by:

Short duration of Pilot PN sequence

Uncoded nature of pilot signal Facilitates mobile station-assisted handoffs

Used to identify handoff candidates

Key factor in performing soft handoffs



Pilot Channel Generation

The Walsh function zero spreading sequence is applied to the Pilot

The use of short PN sequence offsets allows for up to 512 distinct Pilots

per CDMA channel

The PN offset index value (0-511 inclusive) for a given pilot PN

sequence is multiplied by 64 to determine the actual offset Example: 15 (offset index) x 64 = 960 PN chips

Result: The start of the pilot PN sequence will be delayed

960 chips x 0.8138 microseconds per chip = 781.25 microsecond

PilotChannel(All 0s)

1.2288Mcps

I PN

Q PN

Walsh

Function 0



Pilot Channel Acquisition

The mobile station starts generating the I and Q PN shortsequences by itself and correlating them with the received

composite signal at every possible offset. In less than 15 seconds (typically 2 to 4 seconds) all possibilities

(32,768) are checked.

The mobile station remembers the offsets for which it gets thebest correlation (where the Ec/Io is the best.

The mobile station locks on the best pilot (at the offset that resultsin the best Eb/N0), and identifies the pattern defining the start ofthe short sequences (a 1 that follows fifteen consecutive 0s).

Now the mobile station is ready to start de-correlating with aWalsh code.

0001 0001 0001 0001 0001 0001

Pilot Channel(Walsh Code 0)



What is Ec/Io? Ec/Io

Measures the strength of the pilot Foretells the readability of the

associated traffic channels

Guides soft handoff decisions

Is digitally derived as the ratio of goodto total energy seen by the searchcorrelator at the desired PN offset

Never appears higher than Pilotspercentage of serving cells transmittedenergy

Can be degraded by strong RF fromother cells, sectors

Can be degraded by noise

Ec/Io dB

-25 -15 -10 0

Ec

Io

Energy ofdesired pilot alone

Total energy received



Sync Channel

Used to provide essentialsystem parameters

Used during system acquisitionstage

Bit rate is 1200 bps

Sync channel has a frameduration of 26 2/3 ms

Frame duration matches theperiod of repetition of thePN Short Sequences

Simplifies the acquisition of

the Sync Channel once thePilot Channel has beenacquired

Mobile Station re-synchronizesat the end of every call

(Acquired Pilot)

Sync Channel



Sync Channel Generation

1200 bps

Walsh Function 32

1.2288 Mcps

IPN

ConvolutionalEncoderand

RepetitionBlock

Interleaver

R=1/2 K=9

ModulationSymbols

4800 sps 4800 sps

Bits Chips

QPN



Sync Channel Message

Body Format

MSG_TYPE (00000001)

P_REV

MIN_PREV

SID

NID

PILOT_PN

LC_STATE

SYS_TIME

LP_SECLTM_OFF

DAYLT

PRAT

CDMA_FREQ

8

8

8

15

16

9

42

36

86

1

2

11

FieldLength(bits)

Total : 170



Sync Message Parameters Message Type (MSG_TYPE) Identifies this message and

determines its structure (set to the fixed value of00000001)

Protocol Revision Level (P_REV) Shall be set to 00000001

Minimum Protocol Revision Level (MIN_P_REV) 8-bit unsignedinteger identifying the minimum protocol revision level required tooperate on the system. Only mobile stations that support revisionnumbers greater than or equal to this field can access the system.

System ID (SID) 16-bit unsigned integer identifying the system

Network ID (NID) 16-bit unsigned integer identifying the networkwithin the system (defined by the owner of the SID)

Pilot PN Sequence Offset Index (PILOT_PN) Set to the pilot PNoffset for the base station (in units of 64 chips), assigned by thenetwork planner

Long Code State (LC_STATE) Provides the mobile station with thebase station long code state at the time given by the SYS_TIME field,generated dynamically

System Time (SYS_TIME) GPS system-wide time as 320 ms afterthe end of the last superframe containing any part of this message,minus the pilot PN offset, in units of 80 ms, generated dynamically


24/60


Sync Channel Message

Parameters (cont.)

Leap Seconds (LP_SEC) Number of leap seconds that have occurredsince the start of system time (January 6, 1980 at 00:00:00 hours) asgiven in the SYS_TIME field, generated dynamically

Local Time Offset (LTM_OFF) Twos complement offset of localtime from system time in units of 30 minutes, generated dynamically

Current local = SYS_TIME LP_SEC + LTM_OFF

Daylight savings time indicator(DAYLT) Determined by thenetwork planner

1 if daylight savings in effect in this base station

0 otherwise

Paging Channel Data Rate (PRAT) The data rate of the pagingchannel for this system, determined by the network planner

00 if 9600 bps

01 if 4800 bps

CDMA Frequency Assignment (CDMA_FREQ)


25/60


Paging Channels

There is one paging channel per sector per CDMAcarrier

The Paging Channel uses Walsh function 1

Two rates are supported: 9600 and 4800 bps

Paging Channel

Used by the base station totransmit system overhead informationand mobile station-specific messages.


26/60


Paging Channel Generation

Walsh code #1 is used to spread the data. This results in an increase to 1.2288Mcps

That is, 24,576 9600 [4800] bps x 0.020 s = 192 [96] bits in a PagingChannel frame.

The Rate 1/2 convolutional encoder doubles the bit rate, resulting 384 [192]

code symbols in a Paging Channel frame.

If the 4800 bps rate is used, the repetition process doubles the rate again, so that,at either rate, 384 modulation symbols per Paging Channel frame result

384 modulation symbols per frame times 50 frames per second = 19.2 Ksps

chips per Paging Channel frame, or 128 [256] chips per original bit at 9600[4800] bps

9600 bps

4800 bps

Walshfunction

1.2288Mcps

Q PN

1.2288Mcps

19.2Ksps

19.2KspsPaging Channel

Address Mask

R = 1/2 K=9

Decimator

ConvolutionalEncoder &Repetition

I PN

BlockInterleaving

Scrambling

Long PN CodeGenerator


27/60


Paging Channel Time Slot Structure

7

6

5

4

3

2

1

0

SCI 163.84 s

T 2SCI

SCI = Slot Cycle IndexT = Slot Cycle Length in 1.28 sunits 80 ms

1.28 s


28/60


MS How to Watch Paging Channel

System Time

Paging Channel Slots

2047 0 1 2 3 4 12 13 14 15 16 17

1.28 seconds

Mobile Stationin Non-Active State

Assigned PagingChannel Slot

Re-acquisition ofCDMA System

Mobile Stationin Non-Active State

80 ms

Paging Channel O erhead


29/60


Paging Channel Overhead

Messages

Mobile-Station-DirectedMessages

OverheadMessages

Access Parameters Message

System Parameters Message

CDMA Channel List Message

Extended System Parameters Message

Extended Neighbor List Message

ConfigurationParameterMessages

Global Service Redirection Message

PagingMessages

ACC_MSG_SEQ

CONFIG_MSG_SEQ


30/60


CDMA Reverse Traffic

Channels

Used when a call is in progress to send: Voice traffic from the subscriber

Response to commands/queries from the base station

Requests to the base station

Supports variable data rate operation for:

8 Kbps vocoder Rate Set 1 - 9600, 4800, 2400 and 1200 bps

13 Kbps vocoder

Rate Set 2 - 14400, 7200, 3600, 1800 bps

Reverse Traffic Channel


31/60


9600 bps4800 bps

2400 bps1200 bps

28.8ksps

R=1/3,K=9

1.2288McpsUser Address

Mask

LongPN Code

Generator

28.8ksps OrthogonalModulation

Data BurstRandomizer

307.2kcps

1.2288

Mcps

Q PN(no offset)

I PN(no offset)

D

1/2 PNChipDelay

DirectSequenceSpreading


BlockInterleaver


Generation at 8 kb Vocoding


32/60


+

+

+

g0

g1

g2

Information bits(INPUT)

Code Symbols(OUTPUT)



1 2 3 4 5 6 7 8

Rate 1/3 Convolutional

Encoder


33/60


28.8 kspsFrom Coding& SymbolRepetition

28.8 ksps toOrthogonalModulation

Input Array(Normal

Sequence)32 x 18

Output Array(ReorderedSequence)

32 x 18


Block Interleaving

20 ms symbol blocks are sequentially reordered

Combats the effects of fast fading

Separates repeated symbols at 4800 bps and below

Improves survivability of symbol data

Spreads the effect of spurious interference


34/60


Reverse Traffic Channel:

64-ary Orthogonal Modulation

For every six symbols in, 64 Walsh Chips are output

Six symbols are converted to a decimal number from 0-63

The Walsh code that corresponds to the decimal number becomes theoutput

1 0 1 1 0 0 1 0 0 0 1 1

Symbols

3544 Walsh Lookup TableWalshChipwithina WalshFunction

01234567

11

8901

1111

2345

1111

6789

2222

0123

2222

4567

2233

8901

3333

2345

3333

6789

4444

0123

4444

4567

4455

8901

5555

2345

5555

6789

6666

0123

0

1

2

3

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

4

5

6

7

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

8

9

10

11

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

12

13

14

15

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

Wals

16

17

18

19

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

h

Fu

20

21

22

23

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

ncti

24

25

26

27

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

onI

2829

30

31

00000101

0011

0110

11111010

1100

1001

11111010

1100

1001

00000101

0011

0110

11111010

1100

1001

00000101

0011

0110

00000101

0011

0110

11111010

1100

1001

00000101

0011

0110

11111010

1100

1001

11111010

1100

1001

00000101

0011

0110

11111010

1100

1001

00000101

0011

0110

00000101

0011

0110

11111010

1100

1001

ndex

32

33

34

35

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

36

37

38

39

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

40

41

42

43

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

44

45

46

47

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

48

49

50

51

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

52

53

54

55

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

56

57

58

59

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

60

61

62

63

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

0000

0101

0011

0110

1111

1010

1100

1001

0000

0101

0011

0110

1111

1010

1100

1001

1111

1010

1100

1001

0000

0101

0011

0110

1 0 0 0 1 . . . 1 1 0 1 0

64 Chip Pattern ofWalsh Code # 35


35/60


Reverse Traffic Channel:

Direct Sequence Spreading

Output of the randomizer is direct sequence spread by the

long code The mobile station can use one of two unique long code

masks:

A public long code mask based on the ESN

A private long code mask

1.2288Mcps

User AddressMask

LongCode PN

Generator


307.2kcps To Quadrature

Spreading

1.2288Mcps


36/60


Offset Quadrature Spreading &

Baseband Filtering

The channel is spread by a pilot PN sequence with a zerooffset

Baseband filtering ensures that the waveform is containedwithin the required frequency limits

Baseband signals converted to radio frequency (RF) inthe 800 MHz or 1900 MHz range

1.2288Mcps

I-Channel Pilot PN Sequence1.2288 Mcps

PN

I

Q

I

Q

cos(

2

pfct)

sin(2 fct)PN chip

1.2288 Mcps

FromData BurstRandomizer

RF Converters

D

1/2 PN ChipTime Delay

BasebandFilter

BasebandFilter


37/60


14400 bps7200 bps

3600 bps1800 bps

28.8

ksps

R=1/2,K=9

1.2288McpsUser Address

Mask

LongPN Code

Generator

28.8

ksps OrthogonalModulation


307.2

kcps

1.2288Mcps

Q PN(no offset)

I PN(no offset)

D

1/2 PNChipDelay

Direct

SequenceSpreading


BlockInterleaver


Generation at 13 kb Vocoding


38/60


Reverse Channel Demodulation

IS-95A/J-STD-008 requires a process that is complementary to the mobilestation modulation process

CDMA processing benefits from multipath components

Signals from several receive elements can be combined to improvereceive signal quality

U/DCommand

De-InterleaverSpeechOutput

C

ombiner

BTS Receiver BSC

Power ControlDecision

ViterbiDecoder

Vocoder

Demodulator SearchCorrelator


Demodulator

Search

Correlator


PN+ tUser Long Code


39/60


Access Channels

Used by the mobile station to: Initiate communication with the base station

Respond to Paging Channel messages

Has a fixed data rate of 4800 bps

Each Access Channel is associated with only one Paging

Channel Up to 32 access channels (0-31) are supported per Paging

Channel

4800 bps


40/60


28.8kspsConvolutional

Encoder &Repetition

R = 1/3

1.2288Mcps

Access ChannelLong Code Mask

Long PN CodeGenerator

28.8ksps Orthogonal

Modulation

307.2kcps

1.2288Mcps

Q PN (No Offset)

I PN (No Offset)

D

1/2 PNChipDelay

BlockInterleaver

Access ChannelInformation

(88 bits/Frame)

4.8 kpbs

DirectSequenceSpreading

Access Channel Generation

Message attempts are randomized to reduce probability ofcollision

Two message types:

A response message (in response to a base stationmessage)

A request message (sent autonomously by the mobile

station)


41/60


Access Channel Long Code MaskAn Access Channel is scrambled by the longcode, offset by a mask constructed as follows:

Where:

ACN is the Access Channel Number,

PCN is the Number of the associated Paging ChannelBASE_ID is the base station identification number, and

PILOT_PN is the Pilot short PN code offset index

1 1 0 0 0 1 1 1 1 PCNACN BASE_ID PILOT_PN

41 33 32 028 27 25 24 9 8


42/60


Access Channel Probing

AccessProbe 1

Access

Probe 1

Access

Probe 1

Access

Probe 1

Access Probe

1 + NUM_STEP

(16 max)

System

Time

TA RT TA RT TA RT TA

PI

PI

PI

IP(InitialPower)

See previous

figure

ACCESS

PROBE

SEQUENCE

Select Access Channel (RA)

initialize transmit power


43/60



System

Time

See previousfigure

ONE ACCESS CHANNEL SLOT

ACH Frame(20 ms)

ACCESS CHANNELPREAMBLE

(Modulation Symbol 0)

ACCESS CHANNELMESSAGE CAPSULE

ACTUAL ACCESS PROBE TRANSMISSION

PN Randomization Delay = RN chips = RN x 0.8138 s

ACCESSPROBE

1 + PAM_SZ(1 - 16 frames)

3 + MAX_CAP_SZ(3 - 10 frames)

4 + PAM_SZ + MAX_CAP_SZ(4 - 26 frames)

Access ChannelSlot and Frame

Boundary


44/60



Seq 2 Seq 3

Seq MAX_REQ_SEQ(15 max)

RSRS

Access Attempt

PD

System

Time

Access ProbeSequence 1

REQUEST

ATTEMPT

Request messageready for transmission

PD PD

Seq 2 Seq 4Seq 3Seq MAX_RSP_SEQ

(15 max)

RSRS

Access Attempt

RS

System

Time

Access ProbeSequence 1

RESPONSEATTEMPT

Response messageready for transmission



45/60



Parameters RA - Access Channel Number. Random value between 0 and ACC_CHAN; generated before

every sequence (maximum range is 0 - 31).

IPInitial Open-Loop Power. Calculated in dBm as follows:

IP = k - Mean Input Power (dBm) + NOM_PWR (dB)

- NOM_PWR_EXT x 16 (dB) + INIT_PWR (dB)

where k = -73 for 800 MHz Cellular and -76 for 1900 PCS.

PIPower Increment. Equal to PWR_STEP in dB (range is 0 to 7 dB). TAAcknowledgment Response Timeout (timeout from the end of the slot). Calculated in ms

as follows (range is 160 to 1360 ms):

TA = 80 x (2 + ACC_TMO)

RTProbe Backoff. Random value between 0 and 1 + PROBE_BKOFF; generated before

every sequence (maximum range is 0 - 16 slots).

RSSequence backoff. Random value between 0 and 1 + BKOFF; generated before everysequence (except the first sequence). Maximum range of values is 0 to 16 slots

PDPersistence delay. (Value used to implement the persistence test).

RNPN Randomization Delay. (0 to 511 chips) . Generated before every sequence, between

0 and 2 PROBE_PN_RAN - 1, by hash, using ESN_S.


46/60


CDMA MS Call ProcessingPower-Up

Initialization

Idle

SystemAccess

Traffic

Mobile stationhas fully acquired

system timing

Mobile station receives a PagingChannel message requiring ACK

or response, originates a call, orperforms registration

Mobile station is directedto a Traffic Channel

Mobile station ends useof the Traffic Channel

Mobile station receives an ACK toan Access Channel transmission

other than an Origination Messageor a Page Response Message

Mobile station is in idle handoffwith NGHBR_CONFG equal to

011 or is unable to receivePaging Channel Message


47/60


Mobile Station Originated Call

Allocatesresources

Mobile Station Base Station

Detects user-initiated call

Sends Origination Message

ACCESS

(FW null traffic is arriving but themobile station does not know onwhat channel; therefore, the mobile

station cannot start decoding it)

Sends message with thisinformation to the switch

Sends Base Station Acknowledge-ment Order

FW TRAFFIC

Allocates resources for ServiceOption 1

Begins transmitting null ReverseTraffic Channel Data

Sends Service Request Messagefor Service Option 1 RV TRAFFIC

Acquires the Reverse TrafficChannel


FW TRAFFIC

Sets up Traffic Channel

Receives N5m=2 consecutive validframes

Begins sending the Reverse TrafficChannel Preamble

Sends Channel AssignmentMessage

PAGING

RV TRAFFIC

Switch


Begins sending null traffic

Stops probingPAGING


48/60


Mobile Station Originated Call

(User Conversation)

Optional

Applies ring back from audio path

Optional

Removes ring back from audio path

Begins processing primary traffic inaccordance with Service Option 1

Sends Service ConnectCompletion Message

Optional

Sends Origination ContinuationMessage

RV TRAFFIC

RV TRAFFIC

Optional

Sends Alert With InformationMessage (ring back tone)

Optional

Sends Alert With InformationMessage (tones off)

Message sent to the switchindicating that the mobile stationis ready

FW TRAFFIC

FW TRAFFIC

Completesthe call

(User Conversation)


Sends Service Connect Message

Mobile Station Base Station Switch

FW TRAFFIC

M bil S i T i d C ll


49/60


Mobile Station Terminated Call

Stops probing

(FW null traffic is arriving but themobile station does not know onwhat channel; therefore, the mobilestation cannot start decoding it)


Begins sending null TrafficChannel data

Acquires the Reverse TrafficChannel



Receives N5m=2 consecutivevalid frames

Begins sending the ReverseTraffic Channel Preamble

Begins transmitting null TrafficChannel data

Sends General Page Message

Sends Page Response Message ACCESS

PAGING

RV TRAFFIC

FW TRAFFIC

PAGING

FW TRAFFIC

RV TRAFFIC

Switch

Mobile Station Base Station

Sends Channel AssignmentMessage


Sends message to switchindicating that the mobile stationhas responded

Allocates

resources

PAGING

Switch


50/60


Mobile Station Terminated Call

Sends Alert With InformationMessage (ring)

Begins processing primary traffic inaccordance with Service Option 1

Sends Service ConnectCompletion Message

Starts ringing

User answers call

Stops ringing

Sends Connect Order

(User Conversation) (User Conversation)

FW TRAFFIC

RV TRAFFIC

RV TRAFFIC

Sends Service Connect MessageFW TRAFFIC

Sends message to the switchindicating that the mobilestation is ready

Call proceeds


Sends Service Response Messageaccepting Service Option 1

RV TRAFFIC

Sends Service Request Msgfor Service Option 1

FW TRAFFIC

Begins transmitting null TrafficChannel data RV TRAFFIC

SwitchMobile Station Base Station


51/60


CDMA20001XRtt

New Channel Structure


52/60


Benefits of the CDMA2000

1x Standards

Increased mobile standby battery life (via Quick Paging

Channel)

Total backward compatibility to reuse switch and call

processing features

2-3 dB better coverage

High speed 153.6 kbps packet data capabilities

CDMA2000 1x = 1.25 MHz Radio Transmission Technology


53/60


Backward Compatible with

IS-95 Air Interface

No need to change any RF infrastructure

Capacity improvements will not be realized until most IS-95 subscribers disappear

IS-95 mobiles are supported in the IS-2000 standardfor 1xRTT:


54/60


Cdma2000 1xRtt Channel(Qualcomm)


55/60


Channel List: 1xRTT vs. IS-95 IS-95B built on the IS-95A channels, and introduced two new channels

Fundamental channel was the same as IS-9A traffic channel

Supplemental code channels assigned to support rates above14.4Kbps

IS-2000 1xRTT continue to build on the IS-95 channels

IS-95 channels continue to be supported in IS-2000 to support IS-95 mobiles

Pilot channelSync channelPaging channel Access channelForward Traffic Channel Reverse Traffic Channel

Fundamental channel Fundamental channelSupplemental Code channel (F-SCCH) Supplemental Code channel (R-SCCH)

Supplemental channel (F-SCH) Supplemental channel (R-SCH)Quick Paging channel (F-QPCH) Reverse Pilot channel (R-PICH)

IS-95B

1xRTT

IS-95A

Forward Reverse

F d S l t l


56/60


Forward Supplemental

Channel (F-SCH) Assigned for high-speed packet data (>9.6 kbps) in the forward

direction; (FCH is always assigned to each call)

Up to 2 F-SCH can be assigned to a single mobile

SCH cannot exist without having a fundamental channelestablished

F-SCH supports Walsh code lengths of 4 - 1024 depending on data rateand chip rate

SCH-1 File transfer at 144 kbps

FCH Voice, power control and link continuity

Mobile 1


57/60


Reverse Supplemental

Channel (R-SCH) Used for high-speed packet data (>9.6 kbps)

Difference between F-SCH and R-SCH is in Walsh code basedspreading

F-SCH supports Walsh code lengths of 4 to 128 (1xRTT) or 1024

(3xRTT) depending on data rate and chip rate R-SCH uses either a 2-digit or 4-digit Walsh code; rate matching

done by repetition of encoded and interleaved symbols

Walsh code allocation sequence is pre-determined andcommon to all mobiles

Users are differentiated using long PN code with user mask


58/60


Reverse Pilot Channel

(R-PICH)

Mobile transmits well-known pattern (pilot)

Allows base station to do timing corrections withouthaving to guess where mobile is (in search window)

Mobile can transmit at lower power, reducing interference

to others


59/60


Quick Paging Channel

(F-QPCH) More efficient monitoring of paging channel by mobile, enhancement

to slotted paging

Mobile monitors QPCH to determine if there is a page forthcoming on

paging channel in its slot (looks at 1-bit paging indicator)

If no flag, then mobile goes back to sleep; if flag, then mobile monitors

appropriate slot and decodes general page message

Without QPCH, mobile must monitor regular paging channel slot and

decode several fields to determine whether page is for it or not; this

drains mobile batteries quickly

The main purpose of QPCH is to save mobile battery life.


60/60

The End!

3-cdma-channels structure.ppt

Documents