basic cellular ed2

7/26/2019 Basic Cellular Ed2

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Cellular principles & radio propagation

basics

ND Competence Centre

February 2009


2/73

Agenda

1. Cellular Concept

2. Multiple Access Tecni!ues

". #adio$%ropagation

. Cell Co'erage Calculation

(. Cluster )i*e Calculation


3/73

All #igts #eser'ed + Alcatel$,ucent 2009- ND CC

Cellular Concept

1


4/73


Cellular Concept

ntroduction

Fundamental /eatures o/ a cellular system

Wireless connection'oice data to %)TN or %DN /or te subscribers in te ser'ice

area

%ro'ision o/ su//icient capacity/or o//ering ser'ice to a large number o/ users on a

large geographical area3it a limited spectrum

Call/session continuity3en users are mo'ing in te ser'ice area

Scalability/or capacity and introduction o/ new services

)econd 4eneration systems

4)M 900 and 1500 4%#) 6D46 in 6urope

D$AM%) )$9( %C)$1900 in 7)

Tird generation systems

7MT) FDDTDD

CDMA 18#TT- 6$D:- 6$D


5/73


Cellular Concept

Fre!uency #euse

12 /re!uencies in te area

1285;9< circuits in te area

://ered load is 5 6rl in te area

2 500 subscribers in te area

" /re!uencies per cell

"85;2 circuits per cell

://ered load is 1= 6rl per cell

(=0 subscribers per cell

< 50 subscribers in te area

Serving areaconsists in

contiguous cells

5 users ma8 /re!uency

"0m6rl subscriber

4o) ; 2>

/1- /2- /"- /- /(- /


6/73


Cellular Concept

Cellular Co'erage and Cell Dimensions


7/73All #igts #eser'ed + Alcatel$,ucent 2009- ND CC

Cellular Concept

#euse Factor

Reuse Factor of 7Reuse Factor of 1

f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!

f1 f2f5f6 f7

f f!f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!

f1 f2f5f6 f7

f f!

Set of available fre"uencies#f1 f2 f! f f5 f6 f7

f1 f2f5

f6 f7

f f!

$ll availablefre"uenciesare use% in

each cell



Cellular Concept

Cell Cluster

Ad?acent cells use di//erent ortogonal sets o/ /re!uencies

For best spectrum e//iciency- a gi'en set o/ /re!uency is used repeatedly

A group o/ cells using all a'ailable spectrum is a cluster

Number o/ cells in a cluster and its sape 'ary

)maller te cell- greater te number o/ cells in a gi'en cluster

Ma8imum T8 po3er determines ma8imum cell si*e

Co$cannel inter/erence per/ormance determines te minimum cell si*e



Cellular Concept

:mni$directional Macrocells

#euse Factor ; 12 i;?;2

:ne tier o/ inter/ering cells

< inter/ering cells

)er'ing cell)er'ing cell

nter/ering cellsnter/ering cells


10/73


Cellular Concept

)ectori*ed Macrocells



" inter/ering cells


&e'agonal area %ivi%e%into ! sectori(e% cells



11/73


Multiple Access Tecni!ues

2


12/73



Duple8ing

Duplexing = techniques of achieving 2 ways simultaneous communications

)**@ Time Di'ision Multiple8ing

ot directions use te same /re!uency band during di//erent time inter'als

F**@ Fre!uency Di'ision Multiple8ing

)eparate /re!uency bands are permanently allocated to eac direction o/

transmission


13/73



Duple8ing $ FDD

T

)

Subscribertrans+itonF2

,Strans+it

onF1

,S capable offull RF %uple'

operation

)*-$ subscribersoperate in RF half

%uple' +o%e


14/73



Duple8ing $ TDD

,S trans+it to -S -S trans+it to ,S ,S trans+it to -S

T

)

T

)

T

)

Temporal guard band

)i+e


15/73



Duple8ing 's. Co'erage

For cellular communications@

For3ard linB or do3nlinB@ /rom ) to M)

acB3ard linB or uplinB@ /rom M) to )

FDD is te most commonly used tecni!ue 3it FDMA- TDMA and CDMA /or largeco'erage systems

TDD is ad'antageously used /or sort range co'erage systems but is also recently

used in macro$cellular systems 7MT)$TDD- iMA


16/73



Duple8ing $ Conclusion

)**

7, and D, transmission separated in

time

)ame /re!uency /or 7, and D,transmission

Mostly used 3it TDMA

Multicannel calls easy to implement

)uitable /or small cells apps

68. D6CT- 7MT)$TDD- iMA

F**

7, and D, transmissions on di//erent

/re!uencies

Mostly used 3it FDMA- TDMA and CDMA

systems

)uitable /or large cell systems

68. 4)M- )$1"


17/73



Multiple8ing

Multiplexing: Technique for dividing the available resources

)*-@ Time Di'ision Multiple8ing

Allocated band3idt is sared by di//erent ser'ices or co'erage *ones during

time inter'als

F*-@ Fre!uency Di'ision Multiple8ing

%ortions o/ allocated band3idt are allocated to di//erent ser'ices or co'erage

*ones /or long durations


18/73


19/73



Multiple Access )cemes 22

Multiple Access can be@

Con/lict /ree

A cannel is reser'ed /or a connection

Contention based

Data pacBets are sent on te cannel 3o reser'ation

Con/lict /ree

)tatic Fre!uency- time- time and /re!uency based

Dynamic temporary reser'ations and toBen passing

Contention based

)tatic or dynamic contention resolutions


20/73



Con/lict Free Multiple Access )cemes

F*-$

Allocated band3idt is di'ided into smaller and eac

acti'e users get one cannel during period o/ acti'ity

)*-$

6ac FDM cannel is subdi'ided in units o/ time and eac

acti'e user gets a time unit and /re!uency during acti'ity

period

C*-$

)ignal spreading codes are used to separate signals o/

di//erent users


21/73



FDMA

Caracteristics and constraints

Transmitter Beeps a /re!uency all along in te call

Fre!uency guard band re!uired bet3een cannels

6asy implementation no syncronisation re!uired

Applications 7sed in analog systems

,imited system capacity and limited 'ariety o/ ser'ice

%er/ormance

A'ailable number o/ cannels

BT: total available BW

BC: channel BW

a: factor depending on propagation

C/I: required carrier to interference ratio

IC

BB

N C

T

FDMAC

=)(


22/73



TDMA 12

Caracteristics and constraints

Transmitter user o/ /re!uency /or a /raction o/ time

4uard time re!uired bet3een di//erent transmission

T8$#8 syncronisation needs transmission o/ system in/ormation

#e!uires po3er s3itcing during guard time

Applications

Digital systems /or speec and data transmission

7se/ul /or po3er sa'ing and inter/erence reduction

4ood o'erall per/ormance


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TDMA 22

%er/ormance

)ame /ormulation as FDMA.

NCis increased in proportion to te TDMA /actor i/ Cis maintained

Trade$o// and discussion

iger C G$H lo3er capacity

,o3er carrier G$H iger capacity

,o3er carrier G$H iger re!uired C /or good system operations

A Compromise bet3een Cand C is re!uired

68ample@

4)M@ C;200 B*- N;5- C;9 d

DAM%)@ C;"0 B*- N;"- C;15 d


24/73


#adio Mobile %ropagation

!


25/73



A Di'ersity o/ Applications


26/73



A Di'ersity o/ 6n'ironments

6ac system operates in an application speci/ic en'ironment

Di//erent /re!uency band

)peci/ic cannel types

)peci/ic mecanisms to assess re!uired Io) o/ te application


27/73



Designing a #adio$Mobile )ystem

)ystem Constraints

Iuality o/ )er'ice a'ailability call !uality trougput

Fre!uency band

6n'ironment type J co'erage...

Design %arameters modem K pysical layer $

Modulation Demodulation spectral e//iciencyJ )ignal to Noise ratio J 6# J

nter/erence protection J comple8ity

6!uali*ation correction o/ cannel imper/ections

Cannel code F6C and interlea'ing trade$o// cannel ser'ice %rotocol re$transmissionE


28/73



Digital Transmission Cain

4ood Bno3ledge o/ te propagation is mandatory /or@

Appropriate modem design

Cell co'erage estimation

Cannel6ncoder

&

nterlea'er

Modulator

%ropagation

Cannel

Demodulator

De$interlea'er

&

Cannel

decoder

6!uali*ern/ormation

n/ormation


29/73



#adio )ignal

#adio signal at te recei'er comes /rom di//erent pats 3it di//erent@

#e/le8ion J Di//ractions J )cattering

B

T

S

1

4 3

2


30/73



#ecei'ed )ignal Caracteri*ation

6ac pat is a//ected by@

Attenuation

%ase rotation

Fre!uency si/t Doppler e//ect

ig 'ariation o/ recei'ed signal

)tatistical approac is needed

Function o/ te en'ironment urban J rural J indoorE


31/73



Model /or #adio %ropagation

)uperposition o/ tree attenuation types

%at loss

Llarge scale obser'ations se'eral 1

)ado3ing e//ectattenuation due to obstacles

Lmedium scale obser'ation 2 to 1

Attenuation due to multiple re/lections and scattering on local obstacles Lsort scale obser'ation or%er of

Distinct pysical penomena modeled 3it distinct la3s


32/73



L,arge )cale Attenuation 12

)tatistical models

Medianattenuation 'alues

)tandard de'iation around < d

%o3er Attenuation- A

2 G nG ( /or dG 20 Bm

n;".5 in urban en'ironment

nKdA


33/73



L,arge )cale Attenuation 22

Con'entional models

ATA

7rban- suburban- rural en'ironments

Fre!uency range@ 1(0 to 1 (00 M*

C:)T$2"1 ATA

7rban- suburban en'ironments

Fre!uency range@ 1 (00 to 2 000 M*

C:)T$2"1 A,F)$O64AM

Metropolitan and urban en'ironments

Fre!uency range@ 500 to 1 (00 M*


34/73



L,arge )cale Attenuation $ ATA Model a

Application range@

Fre!uency@ 1(0 to 1 (00 M*

Aase@ "0 to 200 m

Mobile@ 1 to 10 m

Distance base $ mobile@ 1 to 20 Bm

4eneral e8pression@

/unction o/ Aase@

A depends on se'eral en'ironment parameters /- Aase- Mobile- en'ironment

type

kmp dBAL log

)(log..

mBasehB 556944


35/73



L,arge )cale Attenuation $ ATA Model b

7rban area

aMobile@ correction coe//icient null /or G 1.(m

)uburban area

Deserted area

#ural area

not included in te original document but 'alid 3it a 10 d margin

AD

MobileBaseMHz hahfA mlog82.13log16.2655.69

4.528

log2

2

MHzS

fAA

94.40log33.18log78.4 2MHzMHzD ffAA

]

94.30log33.18log78.4 2 MHzMHzR ffAA

d b l


36/73



L,arge )cale Attenuation $ C:)T$2"1 ATA

Application range@

Fre!uency@ 1 (00 to 2 000 M*

:ter parameters similar to ATA model

@ similar to ATA model

A@

Cme!uals@

0 /or small cities and suburban areas

" /or metropolitan centers

mMobileBaseMHz ChahfA m log82.13log9.333.46

# di M bil % i


37/73



L,arge )cale Attenuation $ C:)T$2"1 A,F)$O64AM

Application range@

Fre!uency@ 500 to 2 000 M*

Aase@ to (0 m abo'e roo/$top

Mobile@ 1 to " m

Distance base $ mobile@ 20 m to ( Bm

ery accurate street dimensions and angle o/ arri'al o/ recei'ed signal are

accounted /or

# di M bil % ti


38/73



L,arge )cale Attenuation $ Micro$cellular Models an e8ample

alid 3en antennas are belo3 roo/$top

)'

0 2 %,

r

%%bpt %corner

n1 3246

n2 3

n!3

mhbh2bkptd =

68ample@ b;"m J m;1.(m J /;900M* dbBpt;5(m

b;


39/73



LMedium )cale Attenuation 12

en a'eraging te recei'ed po3er on 20 to 100 - along a circular pat

centered on te )- a 4aussian distribution o/ %#is obser'ed

d

# di M bil % ti


40/73



LMedium )cale Attenuation 22

Te recei'ed signal is a//ected by multiple random attenuation addition in

d. Central limit teorem gi'es te normal la3@ log$normal attenuationnormal la3 3it 'alues in d.

,arge scale models median attenuation- amoy

%robability tat actual attenuation is less tan A0@

7sed /or cell dimensioning

Typical 'alues /or @ 2 to 5 d

[ ]

daaa

AAPA

moy

0

2

2

02

exp2

1

# di M bil % g ti


41/73



L)ort )cale Attenuation 1(

Due to mobile mo'ements- /ast local signal le'el 'ariations are obser'ed

inter/erence /ringes

Function o/ radio 3a'elengt-

Function o/ mobile speed

:ne /ading e'ery 2

)ignal pase is uni/ormly distributed on P0 J 2Q

T3o models@

mobile and ) are not in line$o/$sigt

#ayleig distribution /or te signal en'elop

mobile and ) are in line$o/$sigt

#ice distribution /or te signal en'elop



42/73



L)ort )cale Attenuation 2(

#ayleig@

s2@ a'eraged recei'ed signal po3er

#ice@

A@ peaB signal po3er in line$o/$sigt

0@ modi/ied essel /unction

2

2

2 2exp

p

202

22

2 2exp

AI

Ap

a A0

b A1

c AR



43/73


n te /re!uency domain- a signal /re!uency band 3idening is obser'ed multiplication by A/ @

/d@ Doppler /re!uency

2

12

1

=

d

d

f

ff

fA

!fd

=

)pectral 3idening due to Doppler si/t


L)ort )cale Attenuation "(



44/73



L)ort )cale Attenuation (

Time dispersion due to re/lectionsE

A'erage delay spread@

#.M.). delay spread@

Coerence band3idt band3idt /or 3ic cannel is /lat@

Time e'olution o/ te cannel Doppler spread

Coerence time@

=

22

k

kk

a

a

=

2

22222 ~~

k

kk

a

aa!e"

5.05

1;9.0

50

1==

pourBpourB cc

max

1

dC

fT



45/73



L)ort )cale Attenuation ((

Short scale fa%ing

Flat fa%ing Fre"uency selective fa%ing

relati'e to delay spread

1. )ignalG Cannel

2. Delay spread G T)

1. )ignalH Cannel

2. Delay spread H T)

Short scale fa%ing

Fast fa%ing Slow fa%ing

relati'e to Doppler spread

1. ig Doppler si/t

2. TCG T)". Cannel 'ariations H base

band signal 'ariations

1. )mall Doppler si/t

2. TCH T)". Cannel 'ariations G base

band signal 'ariations



46/73



L)ort )cale Attenuation $ 68ample o/ 4)M cannel

Typical 4)M cannels consists in se'eral taps di//erent delay and attenuations

68ample T7 pro/ile@

$10(.0 6bNo G 9d

A margin is re!uired

Cell Co'erage Calculation


60/73


g

Co'erage Area@ Margin /or )ado3ing

)ado3ing e//ect log$normal distribution

For a better co'erage- a margin- M- is taBen@

mportant parameter is@

68ample@

=

>

02

2

00

00

0

2exp

2

1P

N

#d

N#

N#

N

#

N

# S

N

#

moy

SS

Min

SS

S

8.0P7.0m!"00

=

>

N

#

N

#M SS

M

MN

#

N

# S

moy

S

=

m!"00



61/73


Co'erage Area@ 6bNo's. Margin

M

>

m!"

P00 N

#N# SS



62/73


Co'erage Area@ 6bNoA'eraged on te Cell 12

Attenuation is a'erage on te cell area

etter !uality is acie'ed near te )

Io) criterion@ 90> o/ cell area H 9 d

margin o/ = d /or pat loss d$".5and ; 10 d

#emarB@ /or acie'ing 99 > co'erage- 2( to "0 d margin is re!uired



63/73


Co'erage Area@ 6bNoA'eraged on te Cell 22

Cell

SS

N#

N#

>

m!"

P00

M

# 10 %B


64/73


Cluster )i*e Calculation

5



65/73


#euse Factor 12

Reuse Factor of 7Reuse Factor of 1

f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!

f1 f2f5

f6 f7

f f!

Set of available fre"uencies#f1 f2 f! f f5 f6 f7

f1 f2f5

f6 f7

f f!

$ll availablefre"uenciesare use% ineach cell



66/73


#euse Factor 22

#euse Factor K=i!i"!"@number o/ cells using di//erent /re!uencies

#euse Distance D; "O r@

distance bet3een 2 co$cannel cells

)ome #euse Factors@

Cluster o/ = cellsFirst tier o/

inter/ering cells

Reuse Factor 7 3i2 / 1

i ?

ii

i

i i?

?

?

?

?

2*

2r

& ! ' (

1 1 0 1.7 d

3 1 1 3.0 d

4 2 0 3.5 d

7 2 1 4.6 d

9 3 0 5.2 d

12 2 2 6.0 d

13 3 1 6.2 d

16 4 0 6.9 d

19 3 2 7.5 d

21 4 1 7.9 d

25 5 0 8.7 d

27 3 3 9.0 d



67/73


:mni$directional Macrocells



< inter/ering cells





68/73


:mni$directional Macrocells $ #euse Distance

*

R

81

82

8!

8

85

86

I PeDC PeR

C

I

D

RK

=

=

6

1

6

1

63

/ C is /i8ed- O can be deri'ed

A.N. @ g; ".(

C ; 9 dO ; C ; 15 d O ; 12

en # and O are determined- D can be deri'ed



69/73


K=21

:mni$directional Macrocells $ C distribution

)ame T8 po3er

No %C

D, inter/erence analysis

%at loss model@ d$".(

s ; = d

9( > o/ cell area H 9 d

X dB

P(C/I

basic cellular ed2

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