lecture 13 is95 fwdchannels

8/12/2019 Lecture 13 IS95 FwdChannels

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Advanced Wireless and Mobile

Communications

Lecture 13

IS-95 Forward Channels

Dr. Mohammed Usman


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IS-95 Forward Channels

Forward Channels

Downlink channelsDefined using 64 Walsh codes

Forward channel contains

One pilot channel defined by Walsh code 0One sync channel defined by Walsh code 32

e!en paging channels Walsh codes "#$

%% traffic channels &W' to W3" ( W33 to W63)

Forward traffic channels support two rate sets *" and *2


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IS-95 Pilot Channel

+sed for synchroni,ation and tracking4#6 d- stronger than all other logical channels &about 2./ of

total base station power)

pread using Walsh code 0

Consists 01 binary seuence with period 32$6' &2"%) also

called as short code

t "22'' 5cps it corresponds to a period 2666$ 7s

8ranslates to pilot channel repeating $% ti7es e!ery 2 seconds

5obile recei!er needs to 7onitor only the pilot channel while

recei!ing data o!er different traffic channels


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IS-95 Sync Channel parameters

Parameter Value

Data rate&bps) "2..

Code sy7bolrepetition period

2

Code rate ;

5odulation sy7bolrate

4'..

01 chips per

7odulation sy7bol

2%6

01 chips per bit ".24

01 chip rate&5cps) "22''

+sed to acuire initial ti7e

synchroni,ation 9nfor7ation contained in sync

channel data

yste7 identification 1etwork identification yste7 ti7e :ocal ti7e offset Data rate used by the paging

channel &4' kbps or


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IS-95 Paging Channel parameters

Parameter Value 1 Value 2

Data rate&bps) 4'..


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IS-95 Paging Channel processing

Baseband

filter

Baseban

d filter

Walsh

code 1..

1.2288

Mcps

I-channel pilot PN

sequence at 1.2288

Mcps

Pain channel

data at /.8+.3 bps

!-channel pilot PN

sequence at 1.2288Mcps

"o !P#$

%odulator

'on(olutional

)ncoder *1+2

rate,

#&%bol

epetition

Bloc

Interlea(e

r

.3+1.2 bps

1.2 bps

4on

code

enerator

4on code

deci%ator

4on code

pain %as

3/ 5 11.2288Mc s

1.2 bps


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IS-95 Forward Traffic Channel parameters for RS1

Parameter Value 1 Value 2 Value 3 Value 4

+ser data rate&bps) "2.. 24.. 4'..


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IS-95 Forward Traffic Channel processing for RS1

Baseband

filter

Baseban

d filter

Walsh

code !

1.2288

Mcps

I-channel pilot PN


6ser data

*#1,

!-channel pilot PN


"o !P#$

%odulator

'on(olutional

)ncoder *1+2

rate,

#&%bol

epetition

Bloc

Interlea(e

r1.2 bps

4on

code

enerator

4on code

deci%ator

4on code %as

3/ 5 11.2288Mc s

4on code

deci%ator

2/ 5 1

1.2 bps

M67

800

bps

Poer 'ontrolbits 800 bps


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IS-95 Forward Traffic Channel parameters for RS2

Parameter Value 1 Value 2 Value 3 Value 4

+ser data rate&bps) "'.. 36.. $2.. "44..

Code sy7bolrepetition period

' 4 2 "

Code rate ; ; ; ;

0uncturing rate 4>6 4>6 4>6 4>6

?ffecti!e code rate @ @ @ @

5odulation sy7bolrate

"


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IS-95 Forward Traffic Channel processing for RS2

-aseband

filter

-aseband

filter

Walsh

code !

"22''

5cps

9#channel pilot 01

seuence at "22'' 5cps

+ser data &*2)

A#channel pilot 01

seuence at "22'' 5cps

8o A0B

7odulator

Con!olutional?ncoder &">2 rate)

y7bol

*epetition

-lock

9nterlea!er

"


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ifferent codes !sedWalsh codes

64 orthogonal codes of length 64 chips

Chip rate is "22'' 5cps

tored in a 64 64 7atri

hort codes

97ple7ented using shift register of length "%

0eriod E 2"% chips

"22'' 5cps

:ong codes

97ple7ented using shift register of length 42

0eriod E 242 chips

"22'' 5cps

:ong codes do not spread the signal

lecture 13 is95 fwdchannels

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