Radio Engineering - Fading Margin

8/19/2019 Radio Engineering - Fading Margin

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Microa!e Li"k #esi$" %roce

Frequency

Planning

Link Budget

Quality and

Availability

Calculations

Fading

Predictions

Interferenceanalysis

Propagation losses

Branching

losses

Other Losses


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%ro&a$a'io" (osses )ree*s&ace (oss * +e" '+e 'ra"s,i''er a"d recei!er +a!e a c(ear- ."o/s'r.si$+'

Ls(24520(o$20(o$d 7dB8

+ere re9.e"cy G:;

d Ls or R?400,


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5/16


Gas a/sor&'io"C %ri,ari(y d.e 'o '+e a'er !a&or a"d oy$e" i" '+e a',os&+ere i" '+e ra

re$io" T+e a/sor&'io" &eaks are (oca'ed aro."d 23G:; or a'er ,o(ec.'o D0 G:; or oy$e" ,o(ec.(es T+e s&ecic a''e".a'io" dBF,is s'ro"de&e"de"' o" re9.e"cy- 'e,&era'.re a"d '+e a/so(.'e or re(a'i!e +.,ida',os&+ere


6/16


Gas a/sor&'io"C %ri,ari(y d.e 'o '+e a'er !a&or a"d

oy$e" i" '+e a',os&+ere i" '+eradio re(ay re$io" T+e a/sor&'io"&eaks are (oca'ed aro."d 23G:; ora'er ,o(ec.(es a"d 50 'o D0 G:;or oy$e" ,o(ec.(es T+e s&ecic

a''e".a'io" dBF,is s'ro"$(yde&e"de"' o" re9.e"cy-'e,&era'.re a"d '+e a/so(.'e orre(a'i!e +.,idi'y o '+e a',os&+ere


7/16


Rain Attenuation

To 'y&es o a''e".a'i"$ ,ec+a"is,sH

a/sor&'io" a"d sca''eri"$ ca.sed /y '+e rai" dro&s

)a((i"$ rai"dro&

No' ro."d d.e 'o air resis'a"ce

:ori;o"'a((y &o(ari;ed a!es are a''e".a'ed ,ore '+a"!er'ica((y &o(ari;ed a!es


8/16


Rain Attenuation

Rai" i"'e"si'y 7,,F+8

)or '+e ca(c.(a'io"s '+e c.,.(a'i!e dis'ri/.'io" o rai" i"'e"si'y- ie

&erce"'a$e o 'i,e d.ri"$ +ic+ a $i!e" rai" i"'e"si'y is eceededi"'eres'i"$

IT*R &rese"'s '+e c.,.(a'i!e dis'ri/.'io" o rai" i"'e"si'y or 15 drai" ;o"es o" ear'+

T+e reere"ce (e!e( is '+e rai" i"'e"si'y '+a' is eceeded 001 o aR001

de@ is e@ec'i!e &a'+ (e"$'+ i" k, - γ R is s&ecic a''e".a'io" i"

dBFk,

eff R R d A ×= γ


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Rain Attenuation


10/16


Rain Fading

T+e &ro/a/i(i'y '+a' a $i!e" ade ,ar$i" is eceeded- o" a" a"".a(

AR001 is T+e rai" a''e".a'io" eceeded 001 o '+e 'i,e

)M is )ade Mar$i"

++−

=

FM

A x

rain

R

A

$%&$%''&$log%('&$')*%'&$+,-&$-'*&%%

%$


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Rain Fading

o"!ersio" /e'ee" year(y !a(.es a"d ors' ,o"'+ !a(.esH

%,o"'+2K5 %year0KD

%year 03 %year115

)or,.(as /ased o" c(i,a'ic co"s'a"'s


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FADING

)adi"$ is de"ed as '+e !aria'io" o '+e s're"$'+ o a recei!ed radiosi$"a( d.e 'o a',os&+eric c+a"$es a"dFor $ro."d a"d a'er reec'&ro&a$a'io" &a'+ )o.r adi"$ 'y&es are co"sidered +i(e &(a""i"$ (are a(( de&e"de"' o" &a'+ (e"$'+ a"d are es'i,a'ed as '+e &ro/a/i(eceedi"$ a $i!e" ca(c.(a'ed ade ,ar$i"


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FADING

M.('i&a'+ adi"$

)(a' adi"$

)re9.e"cy*se(ec'i!e adi"$


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Li"k #esi$"%rocess

)A#ING)(a' adi"$


15/16


FADING)re9.e"cy*se(ec'i!e adi"$

Atmospheric multipath fading. +e" '+e a',os&+eric co"di'io"'+a' (ayers or s'ra'ica'io"s o di@ere"' de"si'y eis'- as i"dica'ed ed.c'i"$ ca" occ.r I '+e co,&osi'io" o '+e (ayers is s.c+ '+a' '+e ,/ea, is "o' 'ra&&ed- /.' o"(y deec'ed- as i" )i$ 430- '+e ,icroaca" reac+ '+e recei!i"$ a"'e""a /y &a'+s '+a' are di@ere"' ro, '+e

&a'+ T+is ,.('i&a'+ rece&'io" &rod.ces adi"$ /eca.se '+e 'o arare(y recei!ed i" &+ase I '+ey arri!e i" co,&(e'e a"'i&+ase- or a seco"ds a dro& i" recei!ed &oer- +ic+ ca" /e 30 dB or ,ore- is o


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Radio Engineering - Fading Margin

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