Is 95 Standard

7/31/2019 Is 95 Standard

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02PearsonEducation,

Inc.Commercialuse,

distribution,or

saleprohibited.

IS 95 occupies 1.25 MHz of spectrum on

each one way link

Different modulation and spreading

technique for the forward and reverse link On forward link user data transmits

simultaneously along with pilot carrier

All mobile use coherent detection


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02PearsonEducation,

Inc.C

ommercialuse,

distribution,or

saleprohibited.

On reverse link all mobiles respond in

asynchronous fashion and have constantpower level

IS 95 uses Qualcomm 9600 bps QCELPcoder


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Inc.C

ommercialuse,

distribution,or

saleprohibited.


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ommercialuse,

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Frequency and channelspecification

Forward link 869-894

reverse link 824-849 Forward link and reverse link separated by

45 MHz

Maximum user data 9.6kb/s

On the forward link user data is encoded

using rate convolution code,interleaved, and spread by one of sixtyfour orthogonal spreading sequence


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ommercialuse,

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The base station and subscriber uses

RAKE receiver to resolve multipathcomponents

The soft handoff is given from base station,the mobile receives the signal from twobase station and processed as multipath

components


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ommercialuse,

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FORWARD CDMA CHANNEL Pilot channel

acquire timing for the forward CDMAchannel

phase reference for coherent detection

provides each mobile with a means forsignal strength comparison for handoff

Synchronization channel Broadcasts synchronization message to all

mobiles at 1200bps


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ommercialuse,

distribution,orsaleprohibited.

Paging channel

send control information and pagingmessages from base station to mobiles

,operates at 9600,4800,and2400bps. The forward traffic channel

It supports variable user data rates

9600,4800,2400 or 1200 bps


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Convolutional encoder and repetion circuit

encoded using half rate convolutional encoderwith constant length 9

generator vectors Go(753) octal and G1(561)

constant base band symbol rate 19.2kbps

4800 repeat one time

2400 repeat three time1200 repeat seven times


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Long PN sequence Direct sequence

PN sequence long 242 -1 chips period P(x)=x42+x35+x33+x31+x27+x26+x25+x22+x21+

x19+x17+x16+x10+x7+x6+x5+x3+x2+s1+1

Intial state id 1after 41 consecurive 0s

Two types of mask

public mask-ESNPrivate mask-MIN


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ommercialuse,


Public long code

M41 through M32 is set to 1100011000

M31 through M0 is permutated ESN

Private long codeM41 and M40 set 01

M39 through M0 are set by privateprocedure


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ommercialuse,

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rsaleprohibited.

Data scrambler

1.2288 MHz PN sequence is applied to adecimator, keeps only first bit of every sixty fourconsecutive PN sequence

Power control sub channel

Power control updates are sent by basestation for every 1.25ms

increase or decrese in 1dB steps


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ommercialuse,

distribution,o

rsaleprohibited.

Power control


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ommercialuse,

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Orthogonal covering

spreaded with a walsh function with afixed chip rate of 1.2288Mcps

64 binary sequence length of 64 all areorthogonal to each other

the walsh sequence repeats every

52.083 s,equal to one coded data symbol


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Inc.C

ommercialuse,

distribution,o

rsaleprohibited.

64 by 64 walsh function Hadamard matrix

H1=0 H2= 0 0

0 1

H4= 0 0 0 0 H2N= HN HN0 1 0 1

0 0 1 1 HN HN

0 1 1 0


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ommercialuse,

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rsaleprohibited.

Quadrature Modulation 215-1 is used for modulation

The short spreading sequence

PI(x) =x15+x13+x9+x8+x7+x5+1

PQ(x)= x15+x12+x11+x10+x6+x5+x4+x31


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Reverse CDMA channel AC Acess channel

RTC Reverse traffic channel RTC/AC identified by long distinct user code

AC mobile to initiate call and respond to paging

channel

32 ACs per supported paging channel

ACs fixed data rate 4800bps

RTC variable data rate


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Inc.Commercialuse,

distribution,o

rsaleprohibited.

Convolutional encoder

557,663,771 Block interleaver

span 20ms array with 32 rows and 18 columns

64 walsh functionwalsh function is selected according to

c0+2c1+4c2+8c3+16c4+32c5

Transmitted at rate of 28.8kbpsx64walsh chips/6coded bits=307.2kbps


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Is 95 Standard

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