copyright 2003, zte corporation cdma channel structure and modulation 2004.10.3

Copyright 2003, ZTE CORPORATION

CDMA CHANNEL STRUCTURE

AND MODULATION2004.10.3


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

Objectives

-- The forward channel in IS-95 Pilot ;Sync ; Paging and Traffic -- The reverse channel in IS-95 Access; Traffic -- CDMA Call Processing -- New Channels in CDMA20001X


CDMA Forward Traffic Channels

• Used for the transmission of user and signaling information 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


Forward Traffic Channel Generation

8 kb Vocoding

Walshfunction

PowerControl

Bit

I PN

9600 bps4800 bps2400 bps1200 bps(Vocoder) Convolutional

Encoding andRepetition

1.2288 McpsLong PN Code

Generation 800 Hz

R = 1/2, K=9

Q PN

Decimator DecimatorUser Address

Mask(ESN-based)

19.2ksps

1.2288 Mcps

Scrambling

bits symbols chips

19.2ksps

CHANNEL ELEMENT

MUX

BlockInterleaving


Rate 1/2, k=9 Convolutional Encoding

• Symbols generated as the information bits transit through the encoder, are related to 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


Symbols areWritten In

Symbols areRead Out

1 25 49 73 97 121 145 169 193 217 241 265 289 313 337 3612 26 50 74 98 122 146 170 194 218 242 266 290 314 338 3623 27 51 75 99 123 147 171 195 219 243 267 291 315 339 3634 28 52 76 100 124 148 172 196 220 244 268 292 316 340 3645 29 53 77 101 125 149 173 197 221 245 269 293 317 341 3656 30 54 78 102 126 150 174 198 222 246 270 294 318 342 3667 31 55 79 103 127 151 175 199 223 247 271 295 319 343 3678 32 56 80 104 128 152 176 200 224 248 272 296 320 344 3689 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 37011 35 59 83 107 131 155 179 203 227 251 275 299 323 347 37112 36 60 84 108 132 156 180 204 228 252 276 300 324 348 37213 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 37415 39 63 87 111 135 159 183 207 231 255 279 303 327 351 37516 40 64 88 112 136 160 184 208 232 256 280 304 328 352 37617 41 65 89 113 137 161 185 209 233 257 281 305 329 353 37718 42 66 90 114 138 162 186 210 234 258 282 306 330 354 37819 43 67 91 115 139 163 187 211 235 259 283 307 331 355 37920 44 68 92 116 140 164 188 212 236 260 284 308 332 356 38021 45 69 93 117 141 165 189 213 237 261 285 309 333 357 38122 46 70 94 118 142 166 190 214 238 262 286 310 334 358 38223 47 71 95 119 143 167 191 215 239 263 287 311 335 359 38324 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384

16 Columns

24 R

ow

s

Full Rate Block Interleave Array

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

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


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 is written 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 3612 26 50 74 98 122 146 170 194 218 242 266 290 314 338 3623 27 51 75 99 123 147 171 195 219 243 267 291 315 339 3634 28 52 76 100 124 148 172 196 220 244 268 292 316 340 3645 29 53 77 101 125 149 173 197 221 245 269 293 317 341 3656 30 54 78 102 126 150 174 198 222 246 270 294 318 342 3667 31 55 79 103 127 151 175 199 223 247 271 295 319 343 3678 32 56 80 104 128 152 176 200 224 248 272 296 320 344 3689 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 37011 35 59 83 107 131 155 179 203 227 251 275 299 323 347 37112 36 60 84 108 132 156 180 204 228 252 276 300 324 348 37213 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 37415 39 63 87 111 135 159 183 207 231 255 279 303 327 351 37516 40 64 88 112 136 160 184 208 232 256 280 304 328 352 37617 41 65 89 113 137 161 185 209 233 257 281 305 329 353 37718 42 66 90 114 138 162 186 210 234 258 282 306 330 354 37819 43 67 91 115 139 163 187 211 235 259 283 307 331 355 37920 44 68 92 116 140 164 188 212 236 260 284 308 332 356 38021 45 69 93 117 141 165 189 213 237 261 285 309 333 357 38122 46 70 94 118 142 166 190 214 238 262 286 310 334 358 38223 47 71 95 119 143 167 191 215 239 263 287 311 335 359 38324 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384

16 Columns

24 R

ow

s


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

LongCode PN

Generator

19.2 KspsModulationSymbols

User AddressMask (ESN) Decimator

Divide by 64

19.2 Ksps

1.2288Mcps

19.2 Ksps

To PowerControl Mux


Power Control Subchannel

• Base station receiver estimates received signal strength of mobile over 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 and uncoded

19.2 Ksps from Block Interleaver

1.2288 McpsUser Long Code

Decimator

Scrambled Modulation Symbol or Power Control Bit19.2

Ksps

Decimator

Data ScramblingMUX

800 Hz Mux Timing

Power Control Bit (800 bps)


Orthogonal Spreading

• Each symbol output from the Mux is exclusive OR’d by the 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 Walsh

function• Bandwidth used greatly exceeds source rate

To Quadrature Spreading19.2

Ksps

MUX

1.2288 Mcps

Walsh Function from Index

Wt800 Hz Mux

Timing

Power Control Bit (800 bps)

Scrambled Data


Quadrature Spreading & Baseband Filtering

• The forward traffic channel is combined with two different PN sequences: “I” and “Q”

• Baseband filtering ensures the waveforms are contained within the 1.25 MHz frequency range

• The final step is to convert the two baseband signals to radio frequency (RF) in the 800 MHz or 1900 MHz range

ConvolutionalEncoding

Code SymbolRepetition

VocoderProcessing

Baseband Traffic to RF Section

PCM Voice

BlockInterleaving

Data Scrambling

Power ControlSubchannelOrthogonalSpreadingQuadratureSpreadingBasebandFiltering

(SymbolPuncturing)

Walsh Function

1.2288Mcps

19.2 kspsfrom PowerControl Mux

I-Channel Pilot PN Sequence1.2288 Mcps

BasebandFilter

BasebandFilter

I

Q

I

Q

Q-Channel Pilot PN Sequence1.2288 Mcps

cos(2fct)

sin(2fct)

GAIN


Composite “I” and “Q”

• Each CHM has a combiner and works in a serial array to combine the I and Q signals for all forward channels in a partition sector or cell.

PilotChannel

WalshCode

SyncChannel

WalshCode

PagingChannel(s)

WalshCode

Forward TrafficChannel(s)

WalshCode

“I” PN Code

“Q” PN Code

Composite“I”

Composite“Q”


Quadrature Phase Shift Key (QPSK) Modulation

Q1 sin (2 fc t ) + Q2 sin (2 fc t ) = ( Q1 + Q2 ) sin (2 fc t )

I1 cos ( 2 fc t ) + I2 cos (2 fc t ) = ( I1 + I2 ) cos ( 2 fc t )

: XOR: Analog sum

: Baseband x Carrier

EveryChannel

Walshcode

“Q” PN Code

“I” PN Code

Basebandfilter

Basebandfilter

cos ( 2 fct )

sin (2 fct )

Gai

n C

ontr

ol


Forward Traffic Channel Generation (13 kb Vocoding)

Walshfunction

PowerControl

Bit

I PN

14400 bps7200 bps3600 bps1800 bps(Vocoder) Convolutional

Encoding andRepetition

1.2288 McpsLong PN Code

Generation 800 Hz

R = 1/2, K=9

Q PN

Decimator DecimatorUser Address

Mask(ESN-based)

19.2ksps

1.2288 Mcps

Scrambling

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 multipath components

• 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 that can be independently directed:

Digital Rake Receiver

ReceiverRF SectionIF, Detector

TransmitterRF Section

Vocoder

Traffic CorrelatorPN xxx Walsh xx



Pilot SearcherPN xxx Walsh 0

ViterbiDecoder

CPUDuplexer

TransmitterDigital Section

Long Code Gen.

Op

en

Lo

op

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 delayed960 chips x 0.8138 microseconds per chip = 781.25 microsecond

PilotChannel(All 0’s)

1.2288Mcps

I PN

Q PN

WalshFunction 0


Pilot Channel Acquisition

• The mobile station starts generating the I and Q PN short sequences 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 the

best correlation (where the Ec/Io is the best.• The mobile station locks on the best pilot (at the offset that results

in the best Eb/N0), and identifies the pattern defining the start of the short sequences (a ‘1’ that follows fifteen consecutive ‘0’s).

• Now the mobile station is ready to start de-correlating with a Walsh code.

00…01 00…01 00…01 00…01 00…01 00…01

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 good to total energy seen by the search correlator at the desired PN offset

– Never appears higher than Pilot’s percentage of serving cell’s transmitted energy

– Can be degraded by strong RF from other cells, sectors

– Can be degraded by noise

Ec/Io dB

-25 -15 -10 0

Ec

Io

Energy of desired pilot alone

Total energy received


Sync Channel

• Used to provide essential system parameters

• Used during system acquisition stage

• Bit rate is 1200 bps• Sync channel has a frame

duration of 26 2/3 ms– Frame duration matches the

period of repetition of the PN Short Sequences

– Simplifies the acquisition of the Sync Channel once the Pilot Channel has been acquired

• Mobile Station re-synchronizes at the end of every call

(Acquired Pilot)

Sync Channel


Sync Channel Generation

1200 bps

Walsh Function 32

1.2288 Mcps

I PN

ConvolutionalEncoder and Repetition

BlockInterleaver

R = 1/2 K=9

ModulationSymbols

4800 sps 4800 sps

Bits Chips

Q PN


Sync Channel Message Body Format

MSG_TYPE (‘00000001’) MSG_TYPE (‘00000001’)

P_REV P_REV

MIN_PREV MIN_PREV

SID SID

NID NID

PILOT_PN PILOT_PN

LC_STATE LC_STATE

SYS_TIME SYS_TIME

LP_SEC LP_SEC

LTM_OFF LTM_OFF

DAYLT DAYLT

PRAT PRAT

CDMA_FREQ CDMA_FREQ

88

88

88

1515

1616

99

4242

3636

88

66

11

22

1111

FieldLength(bits)

Total : 170


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

determines its structure (set to the fixed value of ‘00000001’)• Protocol Revision Level (P_REV) – Shall be set to ‘00000001’• Minimum Protocol Revision Level (MIN_P_REV) – 8-bit unsigned

integer identifying the minimum protocol revision level required to operate on the system. Only mobile stations that support revision numbers 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 network

within the system (defined by the owner of the SID)• Pilot PN Sequence Offset Index (PILOT_PN) – Set to the pilot PN

offset for the base station (in units of 64 chips), assigned by the network planner

• Long Code State (LC_STATE) – Provides the mobile station with the base 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 after the end of the last superframe containing any part of this message, minus the pilot PN offset, in units of 80 ms, generated dynamically


Sync Channel Message Parameters (cont.)

• Leap Seconds (LP_SEC) – Number of leap seconds that have occurred since the start of system time (January 6, 1980 at 00:00:00 hours) as given in the SYS_TIME field, generated dynamically

• Local Time Offset (LTM_OFF) – Two’s complement offset of local time 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 the network planner– 1 if daylight savings in effect in this base station– 0 otherwise

• Paging Channel Data Rate (PRAT) – The data rate of the paging channel for this system, determined by the network planner– 00 if 9600 bps– 01 if 4800 bps

• CDMA Frequency Assignment (CDMA_FREQ)


Paging Channels

• There is one paging channel per sector per CDMA carrier

• The Paging Channel uses Walsh function 1• Two rates are supported: 9600 and 4800 bps

Paging Channel

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

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


Paging Channel Generation

• Walsh code #1 is used to spread the data. This results in an increase to 1.2288 Mcps– That is, 24,576 9600 [4800] bps x 0.020 s = 192 [96] bits in a Paging

Channel 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

1.2288 Mcps

Q PN

1.2288 Mcps

19.2Ksps

19.2KspsPaging Channel

Address Mask

R = 1/2 K=9

Decimator

ConvolutionalEncoder &Repetition

I PN

BlockInterleaving

Scrambling

Long PN CodeGenerator


Paging Channel Time Slot Structure

7

6

5

4

3

2

1

0

SCI 163.84 s

T 2SCI

SCI = Slot Cycle Index T = Slot Cycle Length in 1.28 s units 80 ms

1.28 s


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 Overhead Messages

Mobile-Station-Directed Messages

Mobile-Station-Directed Messages

OverheadMessages

OverheadMessages

Access Parameters MessageAccess Parameters Message

System Parameters MessageSystem Parameters Message

CDMA Channel List MessageCDMA Channel List Message

Extended System Parameters MessageExtended System Parameters Message

Extended Neighbor List MessageExtended Neighbor List Message

ConfigurationParameterMessages

ConfigurationParameterMessages

Global Service Redirection MessageGlobal Service Redirection Message

PagingMessages

PagingMessages

ACC_MSG_SEQ

CONFIG_MSG_SEQ


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


9600 bps4800 bps2400 bps1200 bps

28.8ksps

R=1/3,K=9

1.2288McpsUser Address

Mask

LongPN Code

Generator

28.8ksps Orthogonal

Modulation

Data BurstRandomizer

307.2kcps

1.2288Mcps

Q PN(no offset)

I PN(no offset)

D

1/2 PNChipDelay

DirectSequenceSpreading


BlockInterleaver

Reverse Traffic ChannelGeneration at 8 kb Vocoding


+

+

+

g0

g1

g2

Information bits(INPUT)

Code Symbols(OUTPUT)



1 2 3 4 5 6 7 8

Rate 1/3 Convolutional Encoder


28.8 kspsFrom Coding& SymbolRepetition

28.8 ksps toOrthogonalModulation

Input Array(Normal

Sequence)32 x 18

Output Array(Reordered Sequence)

32 x 18

Reverse Traffic ChannelBlock 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


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 the output

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

Symbols

3544 Walsh Lookup TableWalsh Chip within a Walsh Function

0 1 2 3 4 5 6 7 1 18 9 0 1

1 1 1 12 3 4 5

1 1 1 16 7 8 9

2 2 2 20 1 2 3

2 2 2 24 5 6 7

2 2 3 38 9 0 1

3 3 3 32 3 4 5

3 3 3 36 7 8 9

4 4 4 40 1 2 3

4 4 4 44 5 6 7

4 4 5 58 9 0 1

5 5 5 52 3 4 5

5 5 5 56 7 8 9

6 6 6 60 1 2 3

0123

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

4567

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

891011

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

12131415

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

Wals

16171819

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

h

Fu

20212223

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

ncti

24252627

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

on I

28293031

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 0 1 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 0 1 0 0 1

ndex

32333435

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

36373839

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

40414243

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

44454647

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

48495051

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

52535455

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

56575859

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

60616263

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 0 1 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

1 1 1 11 0 1 01 1 0 01 0 0 1

1 1 1 11 0 1 01 1 0 01 0 0 1

0 0 0 00 1 0 10 0 1 10 1 1 0

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

64 Chip Pattern ofWalsh Code # 35


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


Offset Quadrature Spreading & Baseband Filtering

• The channel is spread by a pilot PN sequence with a zero offset

• Baseband filtering ensures that the waveform is contained within the required frequency limits

• Baseband signals converted to radio frequency (RF) in the 800 MHz or 1900 MHz range

1.2288Mcps

I-Channel Pilot PN Sequence1.2288 Mcps

PN

I

Q

I

Q

cos(2

fct)

sin(2fct)PN chip1.2288 Mcps

From Data BurstRandomizer

RF Converters

D

1/2 PN ChipTime Delay

BasebandFilter

BasebandFilter


14400 bps7200 bps3600 bps1800 bps

28.8ksps

R=1/2,K=9

1.2288McpsUser Address

Mask

LongPN Code

Generator

28.8ksps Orthogonal

Modulation


307.2kcps

1.2288Mcps

Q PN(no offset)

I PN(no offset)

D

1/2 PNChipDelay



BlockInterleaver

Reverse Traffic ChannelGeneration at 13 kb Vocoding


Reverse Channel Demodulation

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

• CDMA processing benefits from multipath components– Signals from several receive elements can be combined to improve

receive signal quality

U/DCommand

De-Interleaver SpeechOutput

Co

mb

iner

BTS Receiver BSC

Power Control Decision

ViterbiDecoder

Vocoder

Demodulator SearchCorrelator




PN+ tUser Long Code


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


28.8kspsConvolutional

Encoder &Repetition

R = 1/3

1.2288McpsAccess Channel

Long Code MaskLong PN Code

Generator

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


Access Channel Generation

• Message attempts are randomized to reduce probability of collision

• Two message types:– A response message (in response to a base station

message)– A request message (sent autonomously by the mobile

station)


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

Where:

ACN is the Access Channel Number,

PCN is the Number of the associated Paging Channel

BASE_ID is the base station identification number, and

PILOT_PN is the Pilot short PN code offset index

110001111 PCNACN BASE_ID PILOT_PN

41 33 32 028 27 25 24 9 8


Access Channel Probing

AccessProbe 1

AccessProbe 1

AccessProbe 1

AccessProbe 1

Access Probe1 + NUM_STEP

(16 max)

SystemTime

TA RT TA RT TA RT TA

PI

PI

PI

IP(InitialPower)

See previousfigure

ACCESSPROBE

SEQUENCE

Select Access Channel (RA)initialize transmit power



SystemTime

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 µs

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



Seq 2 Seq 3Seq MAX_REQ_SEQ

(15 max)

RSRS

Access Attempt

PD

SystemTime

Access Probe Sequence 1

REQUESTATTEMPT

Request message ready for transmission

PD PD

Seq 2 Seq 4Seq 3Seq MAX_RSP_SEQ

(15 max)

RSRS

Access Attempt

RS

SystemTime

Access Probe Sequence 1

RESPONSEATTEMPT

Response message ready for transmission


Access Channel Probing Parameters

• RA - Access Channel Number. Random value between 0 and ACC_CHAN; generated before every sequence (maximum range is 0 - 31).

• IP – Initial 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.

• PI – Power Increment. Equal to PWR_STEP in dB (range is 0 to 7 dB).

• TA – Acknowledgment 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)

• RT – Probe Backoff. Random value between 0 and 1 + PROBE_BKOFF; generated before every sequence (maximum range is 0 - 16 slots).

• RS – Sequence backoff. Random value between 0 and 1 + BKOFF; generated before every sequence (except the first sequence). Maximum range of values is 0 to 16 slots

• PD – Persistence delay. (Value used to implement the “persistence test”).

• RN – PN Randomization Delay. (0 to 511 chips) . Generated before every sequence, between 0 and 2 PROBE_PN_RAN - 1, by hash, using ESN_S.


CDMA MS Call ProcessingPower-UpPower-Up

InitializationInitialization

IdleIdle

SystemAccess

SystemAccess

TrafficTraffic

Mobile station has fully acquired

system timing

Mobile station receives a Paging Channel message requiring ACK or response, originates a call, or

performs registration

Mobile station is directed to a Traffic Channel

Mobile station ends use of the Traffic Channel

Mobile station receives an ACK to an Access Channel transmission

other than an Origination Message or a Page Response Message

Mobile station is in idle handoff with NGHBR_CONFG equal to

‘011’ or is unable to receive Paging Channel Message


Mobile Station Originated Call

• Allocates resources


Mobile Station Base Station

• Detects user-initiated call

• Sends Origination Message

• Detects user-initiated call

• Sends Origination Message ACCESS

• (FW null traffic is arriving but the mobile station does not know on what channel; therefore, the mobile station cannot start decoding it)


• Sends message with this information to the switch

• Sends Base Station Acknowledge- ment Order

• Sends message with this information to the switch


FW TRAFFIC

• Allocates resources for Service Option 1


• Begins transmitting null Reverse Traffic Channel Data

• Sends Service Request Message for Service Option 1

• Begins transmitting null Reverse Traffic Channel Data

• Sends Service Request Message for Service Option 1 RV TRAFFIC

• Acquires the Reverse Traffic Channel




FW TRAFFIC

• Sets up Traffic Channel

• Receives N5m=2 consecutive valid frames

• Begins sending the Reverse Traffic Channel Preamble




• Sends Channel Assignment Message


PAGING

RV TRAFFIC

Switch


• Begins sending null traffic


• Begins sending null traffic

• Stops probing• Stops probingPAGING


Mobile Station Originated Call

(User Conversation)

Optional

• Applies ring back from audio path

Optional

• Applies ring back from audio path

Optional

• Removes ring back from audio path

Optional

• Removes ring back from audio path

• Begins processing primary traffic in accordance with Service Option 1

• Sends Service Connect Completion Message

Optional

• Sends Origination Continuation Message



Optional

• Sends Origination Continuation Message

RV TRAFFIC

RV TRAFFIC

Optional

• Sends Alert With Information Message (ring back tone)

Optional

• Sends Alert With Information Message (tones off)

• Message sent to the switch indicating that the mobile station is ready

Optional

• Sends Alert With Information Message (ring back tone)

Optional

• Sends Alert With Information Message (tones off)

• Message sent to the switch indicating that the mobile station is ready

FW TRAFFIC

FW TRAFFIC

• Completes the call

• Completes the call

(User Conversation)


• Sends Service Connect Message


• Sends Service Connect Message

Mobile Station Base Station Switch

FW TRAFFIC


Mobile Station Terminated Call

• Stops probing



• Begins sending null Traffic Channel data






• Begins transmitting null Traffic Channel 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 message to switch indicating that the mobile station has responded


PAGING

Switch


Mobile Station Terminated Call

• Sends Alert With Information Message (ring)

• Sends Alert With Information Message (ring)





• Starts ringing

• User answers call

• Stops ringing

•Sends Connect Order

• Starts ringing

• User answers call

• Stops ringing

•Sends Connect Order

(User Conversation) (User Conversation)

FW TRAFFIC

RV TRAFFIC

RV TRAFFIC

• Sends Service Connect Message• Sends Service Connect MessageFW TRAFFIC

• Sends message to the switch indicating that the mobile station is ready

• Sends message to the switch indicating that the mobile station is ready • Call proceeds• Call proceeds


• Sends Service Response Message accepting Service Option 1


• Sends Service Response Message accepting Service Option 1

RV TRAFFIC

• Sends Service Request Msg for Service Option 1

• Sends Service Request Msg for Service Option 1

FW TRAFFIC

• Begins transmitting null Traffic Channel data

• Begins transmitting null Traffic Channel data RV TRAFFIC

SwitchMobile Station Base Station


CDMA20001XRtt New Channel Structure


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


Backward Compatible withIS-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 standard for 1xRTT:


Cdma2000 1xRtt Channel(Qualcomm)


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 above

14.4Kbps

• 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 channel Sync channel Paging 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


Forward SupplementalChannel (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 channel

established• F-SCH supports Walsh code lengths of 4 - 1024 depending on data

rate and chip rate

SCH-1 File transfer at 144 kbps

FCH Voice, power control and link continuity

Mobile 1


Reverse SupplementalChannel (R-SCH)

• Used for high-speed packet data (>9.6 kbps)• Difference between F-SCH and R-SCH is in Walsh code based

spreading– 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 and

common to all mobiles• Users are differentiated using long PN code with user mask


Reverse Pilot Channel (R-PICH)

• Mobile transmits well-known pattern (pilot)

• Allows base station to do timing corrections without having to guess where mobile is (in search window)

• Mobile can transmit at lower power, reducing interference to others


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


The End!

copyright 2003, zte corporation cdma channel structure and modulation 2004.10.3

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