05-tm2106euo1_eg0001-cdma in fixed wireless systems

8/12/2019 05-Tm2106euo1_eg0001-CDMA in Fixed Wireless Systems

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CDMA in Fixed wireless systems [WLL] Siemens

CDMA in Fixed wireless systems [WLL]

Contents

11.11.21.31.41.51.5.11.5.21.5.31.61.6.11.6.2

1.6.31.6.41.6.51.71.7.11.1.!1.1"

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Wireless L#$%l L##& 'WLL( A$$ess te$)n#l#*ies+ist#ri$%l ,%t)-ene its # WLL systemsC/rrent St%t/s # WLLWLL &r#&%*%ti#n F%st %din* 0ew # str/$ti#ns %in %ll+#w d#es WLL w#r WLL n$#din* S&ee$) en$#din*

rr#r $#rre$ti#n $#din* %nd interle% in* Ci&)erin* M/lti&le A$$essD C8 %s WLL 8e$)n#l#*y D C8 S&e$i i$%ti#nsC)%n*in* /ser dem%nd,redi$ti#ns #r WLLCDMA t# d#min%te

8)e di eren$e etween WLL %nd $ell/l%r

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Siemens CDMA in Fixed wireless systems [WLL]

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Introduction

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1 Wireless Local Loop (WLL)

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M#st &e#&le %re %mili%r wit) $ell/l%r r%di#< m#st re%ders will )% e /sed % $ell/l%r &)#ne %ts#me time in t)eir li e. Wireless l#$%l l##& 'WLL(= w)i$) is t)e /se # r%di# te$)n#l#*y t#&r# ide % tele&)#ne $#nne$ti#n t# t)e )#me= is % less well n#wn $#n$e&t. WLL systems

)% e % ery simil%r >%r$)ite$t/re? %nd simil%r &r# lems t# $ell/l%r systems. -e #reex&l%inin* t)e simil%rities etween t)e tw# systems= we will &r# ide s#me %$ *r#/ndin #rm%ti#n #n WLL systems %nd w)y t)ey %re # interest.

e$ent &redi$ti#ns r#m % n/m er # ey tele$#mm/ni$%ti#ns %n%lysts )% e s)#wn t)%t t)eWLL m%r et is set #r dr%m%ti$ *r#wt) in t)e next ew ye%rs. ,er)%&s m#st st%rtlin* %re t)e&redi$ti#ns t)%t y 2""2 t)e n/m er # wireless lines inst%lled w#rldwide will ex$eed t)en/m er # wired lines. Des&ite t)e dr%m%ti$ &redi$ti#ns # *r#wt)= WLL rem%ins % little/nderst##d t#&i$= # ten $#n /sed wit) $ell/l%r #r $#rdless tele&)#ny.

+ist#ri$%lly= t)e w%y t)%t )#mes were $#nne$ted int# t)e tele&)#ne netw#r w%s /sin*$#&&er $% le /ried in t)e *r#/nd #r $%rried #n # er)e%d &yl#ns. 8)is $#nne$ti#n is n#wn

%s the local loop @l##& e$%/se e%$) $#nne$ti#n re /ires tw# wires t)%t l## li e % l##&w)en dr%wn #n % di%*r%m %nd l#$%l t# distin*/is) t)e $#nne$ti#ns t# )#mes r#m$#nne$ti#ns m%de etween di erent swit$)es. WLL re&l%$es t)e l#$%l l##& se$ti#n wit) %r%di# &%t) r%t)er t)%n % $#&&er $% le. Bt is $#n$erned #nly wit) t)e $#nne$ti#n r#m t)edistri /ti#n int 'ty&i$%lly % /n$ti#n #x %l#n*side t)e street $#nne$tin* s/ s$ri ers wit)in% r%di/s # 1 m( t# t)e )#/se< %ll #t)er &%rts # t)e netw#r %re %s #r % tr%diti#n%l wired%rr%n*ement.

Bn % WLL system= t)e distri /ti#n int is $#nne$ted t# % r%di# tr%nsmitter re$ei er= % r%di#tr%nsmitter re$ei er is m#/nted #n t)e side # t)e )#/se= %nd % $% le is r/n d#wn t)e side# t)e )#/se t# % s#$ et inside t)e )#/se. 8)is is % s#$ et identi$%l t# t)e #ne int# w)i$)/sers $/rrently &l/* t)eir )#me tele&)#nes. +en$e= %&%rt r#m % sm%ll tr%nsmitter re$ei er#n t)e side # t)eir )#/se= t)e )#me s/ s$ri er d#es n#t n#ti$e %ny di eren$e.9sin* r%di# r%t)er t)%n $#&&er $% le rin*s % n/m er # %d %nt%*es %s will e seen l%ter.

An # er iew # % ty&i$%l WLL netw#r %r$)ite$t/re is s)#wn in t)e next i*/re= w)ere itssimil%rity wit) % $ell/l%r netw#r is # i#/s.

-r#%dly= t)e netw#r $#nsists # t)ree ey elementsE t)e %se st%ti#ns= t)e swit$)= %nd t)es/ s$ri er /nits. 8)ere is %ls# % netw#r m%n%*ement system= w)i$) m#nit#rs %ll /n$ti#ns# t)e netw#r .

WLL systems %re ein* de&l#yed in % r%n*e # di erent l#$%ti#ns= # ten $)%r%$teri ed %sde el#&in* $#/ntries li e :G,8 %nd s#me A ri$%n $#/ntries= %stern /r#&e%n $#/ntries%nd de el#&ed $#/ntries.

Bn de el#&in* $#/ntries t)ere is little tele&)#ne in r%str/$t/re %nd WLL is seen %s t)em#st $#st e e$ti e w%y t# &r# ide #i$e tele&)#ny t# t)#se w)# $/rrently d# n#t)% e %$$ess t# t)e ,S80. 8)e m% #r di i$/lty is # ten w)et)er t)e l#$%l &/l%ti#n$%n % #rd t# &%y #r tele&)#ny.

Bn %stern /r#&e%n $#/ntries t)ere is # ten % l#n* w%itin* list #r tele&)#ny %ndWLL is seen %s t)e m#st r%&id w%y t# &r# ide %si$ tele&)#ny= wit) &er)%&s limitedd%t% $%&% ilities= t# # er$#me t)e w%itin* list.

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Bn de el#&ed $#/ntries #&er%t#rs %re %ttem&tin* t# &r# ide $#m&etiti#n t# t)e

existin* wired #&er%t#r %nd see WLL %s t)e l#west $#st me%ns # &r# idin* t)%t%ltern%ti e. +ere= l#w $#st $#/&led wit) *##d d%t% $%&% ilities %re seen %s essenti%lin #rder t# t% e m%r et s)%re r#m t)e in$/m ent #&er%t#r.

Fi*.1

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1.1 Access technolo ies

An %$$ess te$)n#l#*y is % me%ns # $#nne$tin* % )#me int# t)e ,S80= #r &r# idin* it wit)%$$ess t# t)e ,S80. 9ntil re$ently= t)ere w%s #nly #ne %$$ess te$)n#l#*y= n%mely= t)e$#&&er wirin* t)%t lin s m#st )#mes in t)e de el#&ed w#rld int# t)e tele&)#ne netw#r .M#re re$ently= #t)er tenti%l %$$ess te$)n#l#*ies )% e een de ised. B y#/ %re in #l edin WLL ser i$es it is imrt%nt t# /nderst%nd w)%t %$$ess te$)n#l#*ies %re % %il% le sin$et)ese will #rm t)e $#m&etiti#n t# WLL %nd will )% e % si*ni i$%nt e e$t #n t)e &r# it% ility # t)e netw#r .Bt is imrt%nt t# di erenti%te etweenbearers %nd access te$)n#l#*ies.

8)e $#&&er wire #r r%di# &%t) is % %si$ e%rer= w)ere%s % &%rti$/l%r $#m&/ter sendin* %si*n%l # er t)%t e%rer mi*)t #rm t)e %$$ess te$)n#l#*y. +en$e= t)ere %re ty&i$%lly m#re%$$ess te$)n#l#*ies t)%n t)ere %re e%rers. 8)e ey e%rers %re t)e $#&&er $% les

el#n*in* t# t)e tele&)#ne netw#r = t)e $% les el#n*in* t# t)e $% le 8H netw#r s= m# ilenetw#r s= %nd WLL netw#r s.

Bt is wit) t)e $#&&er $% les t)%t t)ere is t)e widest r%n*e # di erent te$)n#l#*ies % le t#/se t)e e%rer= r#m %si$ $#nne$ti#ns # er w)i$) m#dems $%n &r# ide % m#der%te d%t%

r%te= t)r#/*) s# $%lled BSD0 lines t)%t &r# ide % medi/m d%t% r%te %nd will e ex&l%inedl%ter= t# t)e )i*) d%t% r%te te$)n#l#*ies &r#sed s/$) %s Asymmetri$ Di*it%l S/ s$ri erLines 'ADSL(. ADSL is % $#m&li$%ted me%ns # *ettin* m/$) )i*)er d%t% r%tes d#wntele&)#ne lines. S/$) % )i*) s&eed te$)n#l#*y w#/ld %ll#w t)e n%ti#n%ltele$#mm/ni$%ti#ns $#m&%ny t# deli er ser i$es s/$) %s ide# #n dem%nd t)r#/*) existin*$#nne$ti#ns.

C% le 8H netw#r s %re ein* /&*r%ded t# &r# ide )i*) it r%tes &er s/ s$ri er %nd #rm %een $#m&etit#r t# #t)er %$$ess netw#r s. Cell/l%r r%di# is %ls# % $#ntender #r t)e l#$%l

l##&= %lt)#/*) re$ent initi%ti es y $ell/l%r #&er%t#rs t# en$#/r%*e s/ s$ri ers t# /se %m# ile &)#ne in &l%$e # t)eir ixed &)#ne )% e *ener%lly %iled d/e t# #r #i$e /%lity%nd )i*) $#sts. +#we er= %s t)e $ell/l%r m%r et e$#mes in$re%sin*ly $#m&etiti e= m#res/$) initi%ti es mi*)t emer*e.

An#t)er %ltern%ti e %$$ess te$)n#l#*y= $l#sely %li*ned t# WLL= is t)e ide# distri /ti#nsystem t)%t is % %il% le in % r%n*e # %ri%nts n#wn %s mi$r#w% e ide# distri /ti#nsystem 'MHDS(= mi$r#w% e m/ltiint distri /ti#n system 'MMDS(= %nd l#$%l m/ltiintdistri /ti#n system 'LMDS(. 8)ese systems %re widely de&l#yed in t)e 9nited St%tes /tless s# elsew)ere %nd &r# ide 5" #r s# 8H $)%nnels t# % sm%ll %eri%l m#/nted #n t)e side# t)e )#/se@t)ey di er #nly in t)e re /en$y %t w)i$) t)ey #&er%te %nd w)et)er t)ey /se%n%l#*/e #r di*it%l tr%nsmissi#n. Bt is w#rt) ex&l%inin* )#w t)ese di er r#m WLL. At t)e# er iew le el t)ere is n# di eren$e< #t) /se *r#/nd %sed r%di# systems t# send si*n%lst# re$ei ers m#/nted #n t)e side # )#/ses. 8)e di eren$es lie in t)e ser i$es e%$) systemis t%il#red t# &r# ide. -e$%/se WLL systems d# n#t re /ire t)e wide %ndwidt)s needed #r

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ide# distri /ti#n= t)ey $%n e %$$#mm#d%ted %t l#wer r%di# re /en$ies wit) res/ltin*

*re%ter r%n*e= less ex&ensi e s/ s$ri er e /i&ment= %nd )en$e l#wer $#st. B ide#distri /ti#n is n#t re /ired= WLL $/rrently &r# ides % less ex&ensi e %nd etter /%litytele&)#ne ser i$e t)%n ide# distri /ti#n systems.

8% le 1

Bt is $le%rly %&&%rent r#m t)e t% le t)%t WLL is n#t $#m&etiti e in terms # &r# idin* )i*) itr%tes t# s/ s$ri ers. 8)e ey r#le /l illed y WLL is w)ere t)ere is % limited re /irement #r )i*) d%t% r%tes #r= m#re &re$isely= w)ere m#st /sers %re n#t &re&%red t# &%y m#re #r)i*)er d%t% r%tes t)%n t)ey %re $/rrently /sin*. Bt is %s % rel%ti ely l#w d%t% r%te e%rer t)%tWLL systems %re ein* de&l#yed %r#/nd t)e w#rld= wit) s/ s$ri ers ein* # ered l#wert%ri s t)%n t)#se # t)e existin* ixed line #&er%t#r.

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1.! "istorical #ath A rie l## %t t)e )ist#ri$%l &%t) )%s een s/mm%ri ed r#m el#w E

Early 1950s . Sin*le $)%nnel H+F s/ s$ri er e /i&ment w%s &/r$)%sed r#m M#t#r#l%= /tt)e m%inten%n$e $#sts were t## )i*) %s % res/lt # t)e %l e te$)n#l#*y /sed %nd t)ewer $#ns/m&ti#n t## )i*). 8)e tri%l w%s dis$#ntin/ed %nd t)e s/ s$ri ers were$#nne$ted y wire

Mid-1950s . %yt)e#n w%s *i en seed /nds t# de el#& 6 :+ %nd e /i&ment= w)i$)w#/ld )% e % etter reli% ility %nd % l#wer wer $#ns/m&ti#n. 8)e desi*ners %iled t#%$)ie e t)#se *#%ls %nd t)e system still &r# ed t## ex&ensi e

ate 1950s . S#me e /i&ment $%&% le # &r# idin* m# ile ser i$e t# r/r%l $#mm/nities w%s&/t #n tri%l. 9sers were &re&%red t# &%y % &remi/m #r m# ile /se= /t t)e system still

&r# ed t# e t## ex&ensi e in % ixed %&&li$%ti#n #r w)i$) /sers were n#t &re&%red t# &%y% &remi/m.

Early 1960s . Systems % le t# #&er%te #n % n/m er # r%di# $)%nnels were de el#&ed=elimin%tin* t)e need #r e%$) /ser t# s)%re % s&e$i i$ $)%nnel %nd t)/s in$re%se $%&%$ity.8)e *ener%l l%$ # $)%nnels %nd )i*) $#st= )#we er= m%de t)ese systems /n%ttr%$ti e.

Early 1970s . A C%n%di%n m%n/ %$t/rer de el#&ed e /i&ment #&er%tin* %t 15" M+ t)%t&r# ed s/$$ess /l in ser in* ixed s/ s$ri ers #n t)e isl%nd # L% e S/&eri#r. 8)e l%$ #

re /en$ies in t)e %nd= )#we er= &re$l/ded its wides&re%d /se.

ate 1970s . 8)e r%di# e /i&ment r#m se er%l 9S m%n/ %$t/rers w%s lin ed t# &r# ideser i$e t# is#l%ted ,/ert# i$%n ill%*es. 8)e ser i$e w%s ssi le #nly e$%/se t)e*e#*r%&)i$%l l#$%ti#n %ll#wed t)e /se # %dditi#n%l $)%nnels= &r# idin* *re%ter $%&%$ityt)%n w#/ld )% e een ssi le elsew)ere.

Early 19!0s . C#mm/ni$%ti#n s%tellites were ex%mined #r r/r%l %&&li$%ti#ns /t werere e$ted %s ein* t## ex&ensi e.

19!5" 8ri%ls # % int t# m/ltiint r%di# system /sin* di*it%l m#d/l%ti#n &r#miseds/ i$ient $%&%$ity %nd reli% ility t# m% e WLL l## &r#misin*.

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Fi*.2

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1.$ %ene&its o& WLL systems

8)e ey %ttr%$ti#n # WLL is sim&le@it $%n &r# ide %n e /i %lent l#$%l l##& $#nne$ti#n t#$#&&er $% le %t % l#wer $#st. Bt d#es n#t ne$ess%rily &r# ide % etter #r di erent ser i$e=sim&ly #ne t)%t is less ex&ensi e= %ll#win* t)e new #&er%t#r /sin* WLL t# $#m&ete #n &ri$e%*%inst t)e in$/m ent. 8)e e$#n#mi$s # ixed ers/s wireless %re rel%ti ely sim&le t#/nderst%nd. 8)e ey ints t# n#te %re t)%tE

8)e $#st # inst%llin* wired systems is r#%dly de&endent #n t)e $#st # l% #r 't# di*/& t)e r#%ds(= w)i$) tends t# rise %t % r%te *re%ter t)%n in l%ti#n. 8)e $#st # wirelessde&ends r#%dly #n t)e $#st # t)e s/ s$ri er /nits= w)i$) tends t# %ll # er timewit) in$re%sin* e$#n#mies # s$%le.

8)e $#st # wired systems is $riti$%lly de&endent #n t)e dist%n$e etween )#/ses%nd t)e &enetr%ti#n le els %$)ie ed= w)ere%s t)e $#st # wireless is r#%dlyinde&endent # t)ese %$t#rs.

B % s/ s$ri er m# es t# % di erent #&er%t#r= in t)e $%se # wired %$$ess t)ein estment is l#st w)ere%s in t)e $%se # wireless t)e s/ s$ri er /nit is ty&i$%lly

rem# ed %nd inst%lled elsew)ere. 8)e $#st # wired systems is in$/rred &ri#r t# m%r etin* t# t)e /sers= w)ere%s m/$)

# t)e $#st # wireless is n#t in$/rred /ntil t)e /sers s/ s$ri e t# t)e netw#r .

Bn t)e &%st= t)e $#st # t)e ele$tr#ni$s re /ired #r WLL )%s een *re%ter t)%n t)e $#st #l%yin* $% les= )en$e t)e re%s#n w)y m#st tele&)#ne lines %re wired r%t)er t)%n wireless.Inly in t)e l%st ew ye%rs= wit) t)e e$#n#mies # s$%le *ener%ted y $ell/l%r= )% e &ri$es

%llen t# le els w)ere WLL )%s e$#me e$#n#mi$= wit) /rt)er %lls li ely in $#min* ye%rs.8)is will res/lt in %n in$re%sin* trend t#w%rd WLL %s t)e &red#min%nt me%ns # &r# idin*s/ s$ri er $#nne$ti#n int# t)e ,S80.

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8)e #ll#win* i*/re s)#ws t)e rel%ti e $#sts # $% le %$$ess %nd wireless %$$ess #r %

medi/m density en ir#nment. 8)e %d %nt%*es # WLLw)ere &enetr%ti#n is l#w %re $le%rly# i#/s. Sim&ly= t)is s)#ws t)e ey r#les # WLL.

8)e i*/re s)#ws WLL &r# idin* % less ex&ensi e %$$ess te$)n#l#*y t)%n $% le #r l#w&enetr%ti#n le els. As wireless system $#sts %ll in $#min* ye%rs= %ny di eren$e is li ely t#in$re%se. In$e t)e rel%ti e m%inten%n$e $#sts %re in$l/ded= t)ese di eren$es e$#mee en *re%ter. Bn m#st $%ses #&er%t#rs will e w#r in* %t l#w &enetr%ti#n le els %s t)ey$#m&ete wit) t)e existin* tele&)#ne &r# iders.

Bt $%n e seen t)%t t)e ex&ense # &r# isi#nin* ser i$e i% WLL is n#t % e$ted y t)edist%n$e etween t)e s/ s$ri er %nd t)e $entr%l # i$e '/& t# % int(= WLL is m#re $#ste e$ti e t)%n wireline #&er%t#r ser i$e &r# ider #r %t le%st 2" &er$ent # t)e ser i$e lines

de&l#yed in % netw#r 'see Fi*/re 4(.WLL )%s % m/$) l#wer in$rement%l in estment $#st t)%n $#&&er= %nd it is m/$) $)e%&er t#de&l#y %t l#wer s/ s$ri er densities. As s)#wn in Fi*/re 5= t)e $#st # de&l#yin* t)e l%stmile # $#nne$ti ity will $#ntin/e t# %ll #r wireless w)ile rem%inin* $#nst%nt #r $#&&er wirenetw#r s.

Fi*.3

Fi*.4

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Fi*.5

1.' C rrent tat s o& WLL8)r#/*)#/t t)e w#rld # tele$#mm/ni$%ti#ns &r# essi#n%ls t)ere )%s een % dr%m%ti$ risein interest in t)e WLL te$)n#l#*y. Bn t)e l%te 2" t) $ent/ry= ind/stry %n%lysts &redi$ted t)%tt)e *l# %l WLL m%r et w#/ld re%$) milli#ns # s/ s$ri ers y t)e ye%r 2""". 8)e WLLm%r et is ex&e$ted t# *r#w r#m J563 milli#n in 1!!6 t# %t le%st J6.3 illi#n in 2""2.

M/$) # t)is *r#wt) is #$$/rrin* in emer*in* e$#n#mies w)ere )%l t)e w#rldKs &/l%ti#nl%$ s &l%in #ld tele&)#ne ser i$e ',I8S(. De el#&in* n%ti#ns li e C)in%= Bndi%= -r% il=

/ssi%= %nd Bnd#nesi% %re l## in* t# WLL te$)n#l#*y %s %n e i$ient w%y t# de&l#y ,I8S#r milli#ns # s/ s$ri ers wit)#/t t)e ex&ense # /ryin* t#ns # $#&&er wire.

Bn de el#&ed e$#n#mies= WLL will )el& /nl#$ $#m&etiti#n in t)e l#$%l l##&= en% lin* new#&er%t#rs t# y&%ss existin* wireline netw#r s t# deli er ,I8S %nd d%t% %$$ess.

Sin$e t)e %d ent # t)e tele&)#ne system= $#&&er wire )%s tr%diti#n%lly &r# ided t)e lin int)e l#$%l l##& etween t)e tele&)#ne s/ s$ri er %nd t)e l#$%l ex$)%n*e. -/t $#&&erKs)eyd%y in t)e l#$%l l##& is $#min* t# %n end. $#n#mi$

WLL ser i$e #r 172 milli#n t# 3"7 milli#n s/ s$ri ers /t t)%t %$t/%l ser i$e will e&r# ided #r 5" milli#n t# 6" milli#n s/ s$ri ers y t)e ye%r 2"""

Bn de el#&ed e$#n#mies= wireless te$)n#l#*yKs rel%ti ely l#w de&l#yment %nd m%inten%n$e$#sts %nd le%rnin* $/r e %d %nt%*es m% e WLL % $#m&etiti e y&%ss s#l/ti#n %nd % i% le

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%ltern%ti e t# wireline netw#r s #r ,I8S %nd d%t% %$$ess. 8w# iss/es will determine )#w

/i$ ly WLL will e de&l#yed in de el#&ed m%r etsE $#st %nd %ndwidt).8)e &redi$ti#ns %ry dr%m%ti$%lly= s)#win* t)e $/rrent l%$ # ex&erien$e wit) WLL= /t %n% er%*e # t)e ind/stry #re$%sts m%de in 1!!7 s/**ests t)%t t)e m%r et will e %r#/nd 1""milli#n )#mes $#nne$ted= #r >lines? y t)e ye%r 2"""= re&resentin* % m%r et # J1"" illi#n# er t)e t)ree ye%r &eri#d. -ey#nd 2"""= e en )i*)er *r#wt) is ex&e$ted.

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Fi*.6

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1.* WLL propa ation

WLL &r#&%*%ti#n is m#stly t)e s%me %s m# ile r%di# &r#&%*%ti#n. 8)e di eren$es *ener%llyres/lt in t)e &r#&%*%ti#n ein* sim&ler %nd less &r# lem%ti$ t)%n #r m# ile r%di#. WLLsystems %re *ener%lly desi*ned t# )% e % LIS &%t)= w)i$) is liter%lly /st w)%t it s%ys< itme%ns t)%t i y#/ &/t y#/r )e%d w)ere t)e tr%nsmittin* %ntenn% is= t)en y#/ $%n see t)ere$ei er. Bn m# ile r%di#= % LIS etween t)e m# ile %nd t)e %se st%ti#n is % r%re#$$/rren$e. +#we er= WLL systems ty&i$%lly need t# e desi*ned s/$) t)%t % LIS is m#re

re /ently %$)ie ed e$%/se= %t t)e re /en$ies /sed #r WLL r%di#= w% es d# n#t end

'>di r%$t?( well %r#/nd # st%$les. +en$e= %ny # st%$le tends t# m#re #r less l#$ t)esi*n%l= res/ltin* in in%de /%te si*n%l stren*t) #r *##d re$e&ti#n. F/rt)erm#re=WLLsystems need t# &r# ide % #i$e /%lity $#m&%r% le wit) ixed systems= /nli e $ell/l%r=w)i$) is % le t# &r# ide %n in eri#r #i$e /%lity. Bn #rder t# # t%in % )i*) /%lity= % str#n*si*n%l is re /ired t)%t is ty&i$%lly #nly %$)ie ed t)r#/*) % LIS &%t). 8)is is n#t t##&r# lem%ti$ #r WLL e$%/se t)e re$ei er /nits $%n e &l%$ed #n r## s w)ere % LIS ism/$) m#re li ely t)%n w#/ld e t)e $%se #r m# ile r%di#. st% lis)in* w)et)er t)ere is %LIS $)%nnel is str%i*)t #rw%rd. Wit) WLL t)ere %re ewer $)%n*es t# t)e si*n%l sin$e m#st# t)e si*n%l $#mes i% % LIS &%t) t)%t will n#t e l#$ ed y m# in* # st%$les. +#we er=t)e si*n%l d#es %ry %nd t)ere %re t)ree ey re%s#ns w)y t)is #$$/rsE

F%st %din*. 0ew # str/$ti#ns. %in %ll.

1.*.1 Fast &adin

-r#%dly= i t)ere is n#t % LIS &%t)= #r t)ere %re &%rti$/l%rly str#n* re le$ti#ns= t)en w)enl%r*e # e$ts m# e in t)e i$inity # t)e re$ei er t)e %din* &%ttern will $)%n*e. Bn t)e w#rst$%se= t)e si*n%l mi*)t de$%y m#ment%rily t# er# d/rin* % %de e #re ein* rest#red t# /llstren*t). 8)ere is little t)%t t)e &l%nnin* en*ineer $%n d# t# # er$#me t)is &r# lem.Bnste%d= t)e r%di# e /i&ment desi*ner m/st ens/re t)%t t)e e /i&ment is % le t# $#rre$t t)eerr#rs #$$/rrin* r#m t)ese &)en#men%.

1.*.! +ew o,str ctions

0ew # str/$ti#ns $%n #$$%si#n%lly %rise. 8)e m#st # i#/s ex%m&le is t)e $#nstr/$ti#n # %new /ildin* etween t)e tr%nsmitter %nd t)e re$ei er= l#$ in* % &re i#/s LIS &%t). S/$)

l#$ in* is # ten $%t%str#&)i$ in renderin* t)e re$ei ed si*n%l t## we% t# e # /se.Cle%rly= t)ere is little t)%t t)e r%di# &l%nner #r r%di# desi*n en*ineer is % le t# d# % #/t t)is&r# lem. 8)e extent # t)e &r# lem will %ry de&endin* #n t)e r%te # /ild in t)e %re%. 8)eWLL #&er%t#r s)#/ld e %w%re # new /ildin*s /nder $#nstr/$ti#n %nd m#del t)eir e e$t in

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#rder t# l## #r ssi le s#l/ti#ns= s/$) %s /sin* re le$ti#ns= /ildin* %n %dditi#n%l $ell #r

re&e%ter= #r %li*nin* t)e re$ei er t#w%rd t)e %se st%ti#n in %n %d %$ent $ell.

1.*.$ -ain&all

%in %ll $%n e % &r# lem. %di# si*n%ls %re %tten/%ted y m#ist/re in t)e %tm#s&)ere.8)e le el # %tten/%ti#n %ries wit) t)e $%rrier re /en$y= t)e /%ntity # r%in %llin*= %nd t)edist%n$e # t)e tr%nsmitter r#m t)e re$ei er. 8)e %ri%ti#n # %tten/%ti#n wit) re /en$y is&%rti$/l%rly str#n* %nd in$re%ses ery dr%m%ti$%lly %t )i*)er re /en$ies. At 3 :+ = t)e)i*)est %tten/%ti#n is %r#/nd "."6 d- m< #r % ty&i$%l WLL &%t) # s%y 6 m= t)e%tten/%ti#n is #nly ".36 d- '".36 d- is e /i %lent t# % l#ss # #nly in t)e si*n%lstren*t)(. +#we er= %t 1" :+ = t)e %tten/%ti#n $#/ld= in extreme $%ses= e %s )i*) %s 5d- m= #r /& t# 3" d- # er % ty&i$%l lin . S/$) % l#ss # si*n%l w#/ld %lm#st $ert%inly m% et)e lin /n/s% le. +en$e= % # e %r#/nd 5 :+ = in $#/ntries w)ere )e% y r%in %ll $%n eex&erien$ed= r%in %din* is % tenti%l &r# lem. -r#%dly= t)e )e% ier t)e r%in= t)e we% ert)e re$ei ed si*n%l.

%in %de res/lts in %n in$re%sed red/$ti#n in si*n%l stren*t) &er meter< )en$e t)e /rt)er%w%y t)e re$ei er= t)e *re%ter t)e &r# lem. Sim&ly= t)#se re$ei ers #n t)e ed*e # $ells will

e irst t# s/ er d/rin* )e% y r%in.

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1. "ow does WLL wor/0

Sin$e WLL systems %re ixed= t)e re /irement #r inter#&er% ility # % s/ s$ri er /nit wit)di erent %se st%ti#ns is less strin*ent t)%n t)%t #r m# ile ser i$es. As % res/lt= t)ere exist% %riety # st%nd%rds %nd $#mmer$i%l systems. %$) st%nd%rd '#r $#mmer$i%l system( )%sits #wn %ir inter %$e s&e$i i$%ti#n= system %r$)ite$t/re= netw#r elements= %nd termin#l#*y.M#re# er= %lt)#/*) t)e netw#r elements in di erent systems )% e t)e s%me termin#l#*y=t)e /n$ti#ns # t)e elements m%y di er %$$#rdin* t# systems. 8)e ixed s/ s$ri er /nit'FS9( is %n inter %$e etween s/ s$ri erKs wired de i$es %nd WLL netw#r . 8)e wiredde i$es $%n e $#m&/ters #r %$similes %s well %s tele&)#nes. Se er%l systems /se #t)er%$r#nyms #r FS9 s/$) %s t)e wireless %$$ess ixed /nit 'WAF9(= t)e r%di# s/ s$ri er /nit' S9(= #r t)e ixed wireless netw#r inter %$e /nit 'FW0B9(. FS9 &er #rms $)%nnel$#din* de$#din*= m#d/l%ti#n dem#d/l%ti#n= %nd tr%nsmissi#n re$e&ti#n # si*n%l i% r%di#=%$$#rdin* t# t)e %ir inter %$e s&e$i i$%ti#n. B ne$ess%ry= FS9 %ls# &er #rms t)e s#/r$e$#din* de$#din*.

8)ere %re % %riety # FS9 im&lement%ti#ns. Bn s#me ty&es # $#mmer$i%l &r#d/$ts= %nFS9 is inte*r%ted wit) )%ndset. 8)e %si$ /n$ti#ns # t)is inte*r%ted FS9 %re ery simil%rt# t)#se # t)e )%ndset #r m# ile $#mm/ni$%ti#ns= ex$e&t t)%t it d#es n#t )% e % ri$) set# /n$ti#ns #r m# ility m%n%*ement.

FS9 is $#nne$ted wit) t)e %se st%ti#n i% r%di# %nd w)i$) is se er%l )/ndreds # M+ #r%r#/nd 2:+ . Sin$e WLL is % ixed ser i$e= )i*) *%in dire$ti#n%l %ntenn%s $%n e /sed

etween FS9 %nd t)e %se st%ti#n= ein* %rr%n*ed y line # si*)t '%t le%st= ne%rly(.

8)e %se st%ti#n is im&lemented /s/%lly y tw# &%rts= t)e %se st%ti#n tr%ns$ei er system'-8S( %nd t)e %se st%ti#n $#ntr#ller '-SC(. Bn m%ny systems= -8S &er #rms $)%nnel$#din* de$#din* %nd m#d/l%ti#n dem#d/l%ti#n %s well %s tr%nsmissi#n re$e&ti#n # si*n%l

i% r%di#. -8S is %ls# re erred t# %s t)e r%di# rt ' ,( #r t)e r%di# tr%ns$ei er /nit ' 89(. A -SC $#ntr#ls #ne #r m#re -8Ss %nd &r# ides %n inter %$e t# t)e l#$%l ex$)%n*e 'swit$)(in t)e $entr%l # i$e. An imrt%nt r#le # -SC is t# tr%ns$#de etween t)e s#/r$e $#des/sed in wired netw#r %nd t)%t %t t)e %ir inter %$e. Fr#m t)e % # e r#les= % -SC is # ten$%lled t)e r%di# rt $#ntr#l /nit ' ,C9( #r t)e tr%ns$#din* %nd netw#r inter %$e /nit'809(. WLL systems d# n#t need t# # er m# ile ser i$es %si$%lly= e en i s#me systems&r# ide limited m# ile ser i$es. 8)/s= #r ex%m&le= t)ere is n# )#me %nd isit#r l#$%ti#nre*ister '+L HL ( in % WLL system %nd its # er%ll %r$)ite$t/re m%y e sim&ler t)%n t)%t # t)e m# ile systems. As seen r#m Fi*/re= t)e WLL ser i$es de&end n#t #nly #n t)e

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/n$ti#n%lity # FS9= -8S= -SC= %nd %ir inter %$e s&e$i i$%ti#n /t %ls# #n t)e ser i$ee%t/res &r# ided y t)e swit$) in t)e $entr%l # i$e. F#r ex%m&le= w)en WLL is /sed %s %

tele&)#ny system= t)ere %re t)e %si$ tele&)#ny ser i$es 'e.*. $%ll #ri*in%ti#n= $%ll deli ery=

$%ll $le%rin*= emer*en$y $%ll= et$.( %nd t)e s/&&lement%ry ser i$es 'e.*. $%ll w%itin*= $%ll#rw%rdin*= t)ree w%y $%llin*= $%llin* n/m er n%me deli ery= et$.(. Bn %dditi#n= %s in t)ewired systems= t)e e%t/res s/$) %s $/st#m $%llin* e%t/res= Centrex e%t/res= $/st#m l#$%l%re% si*n%lin* ser i$es 'CLASS( $%n e s/&rted y t)e swit$) . B t)e %ir inter %$e&r# ides % tr%ns&%rent $)%nnel t# t)e swit$)= t)ese ser i$e e%t/res de&end t#t%lly #n t)eswit$) /n$ti#ns.

Fi*.7

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1. .1 WLL ncodin

As WLL is % wireless te$)n#l#*y it is reli%nt /n F t# &r#&%*%te d%t%. Bn t)is WLL systemwe need t# e % le t# *et d%t% ' #i$e( t# t)e ,S80 %nd t)is &r#$ess m/st t% e int# %$$#/nt% n/m er # %$t#rsE

S% ety. Se$/rity. Minim/m # err#rs. M#st e i$ient d%t% tr%ns er.

1. .! peech encodin

Bn di*it%l r%di# systems it is ne$ess%ry t# t/rn #i$e si*n%ls= w)i$) %n%l#* int# % di*it%l d%t%stre%m. S&ee$) en$#din* is % )i*)ly $#m&lex t#&i$ %nd % /ll tre%tment is well ey#nd t)e

#/nds # t)is ess%y. 8)e sim&lest s&ee$) en$#ders %re essenti%lly %n%l#* t# di*it%l$#n erters. 8)e %n%l#* s&ee$) w% e #rm is s%m&led &eri#di$%lly= %nd t)e inst%nt%ne#/s

#lt%*e le el %ss#$i%ted wit) t)e s&ee$) is $#n erted int# % di*it%l le el. 8)e tw# m%in&%r%meters %reE )#w re /ently t)e s&ee$) is s%m&led s%m&le r%te %nd )#w m%nydi erent its %re /sed t# des$ri e t)e #lt%*e le el.

1. .$ rror2correction codin and interlea3in

Bn #rm%ti#n tr%nsmitted i% % r%di# $)%nnel is li% le t# e $#rr/&ted. Bnter eren$e= %din*%nd r%nd#m n#ise $%/se err#rs t# e re$ei ed= t)e le el # w)i$) de&ends #n t)e se erity# t)e inter eren$e. rr#r $#rre$ti#n is widely de&l#yed in m# ile r%di#= w)ere %st %din* is%lm#st /ni ers%lly &resent. Bt is less $riti$%l in WLL= w)ere t)e LIS &%t) res/lts in lessse ere &r# lems. 0e ert)eless it is still ne$ess%ry= es&e$i%lly #r $#m&/ter d%t% tr%ns er.

rr#r $#rre$ti#n systems w#r y %ddin* red/nd%n$y t# t)e tr%nsmitted si*n%l. 8)e re$ei er $)e$ s t)%t t)e red/nd%nt d%t% is %s ex&e$ted< i it is n#t= t)e re$ei er $%n m% e err#r$#rre$ti#n de$isi#ns. rr#r $#rre$ti#n met)#d#l#*ies %ll int# tw# $%te*#ries= l#$ $#din*

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#r $#n #l/ti#n%l $#din*. -#t) %re )i*)ly in #l ed %nd m%t)em%ti$%l %nd %re ey#nd t)es$#&e # t)is ess%y.

1. .' Cipherin

Alm#st %ll m#dern r%di# systems rely #n s#me #rm # $i&)erin* t# &r# ide se$/retr%nsmissi#n. 8)e /se # s/$) se$/rity te$)ni /es #t) re%ss/res t)e /ser t)%t t)e$#n ers%ti#n $%nn#t e # er)e%rd %nd %ll#ws t)e #&er%t#r t# %/t)enti$%te t)e /ser. M#st$i&)erin* s$)emes %re rel%ti ely str%i*)t #rw%rd. 8)e %se st%ti#n %nd t)e s/ s$ri er /nit%*ree #n % m%s #n % $%ll y $%ll %sis. 8# t)e $# ert listener= w)# d#es n#t n#w t)em%s = t)e d%t% is in$#m&re)ensi le.

1. .* M ltiple Access

WLL te$)n#l#*ies )% e di ered # er t)e ye%rs in t)e m/lti&le %$$ess te$)n#l#*ies t)%t t)ey/se. A de$isi#n % #/t w)i$) te$)n#l#*y t# %d#&t will de&end /n t)e %&&li$%ti#n. %$)#&er%t#r )%s % *i en %m#/nt # r%di# s&e$tr/m t# di ide %m#n* its /sers.

8)e m#st widely /sed %$$ess te$)n#l#*y /sed t#d%y #r WLL is CDMA.

Fi*.

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1.4 D C5 as a WLL 5echnolo y

8)e system %r$)ite$t/re # % D C8 WLLsystem is s)#wn in Fi*/re .

8)e m%in $#mnents # t)e system %re t)e -SCs= t)e -Ss= %nd t)e s/ s$ri er /nits. 8)e-SCs %re n#rm%lly in % di erent l#$%ti#n r#m t)e %se st%ti#ns= %nd )en$e t)ere %re 8 Ns

t# $#mm/ni$%te etween t)em. 8)ese tr%nsmitters eit)er send t)eir si*n%l d#wn % le%sed$% le #r /sin* % mi$r#w% e r%di# lin < #t) ty&es %re s)#wn #n t)e i*/re= wit) t)e r%di#&%t) %t t)e t#&. 8)e -SC is %t t)e )e%rt # t)e system< it $#ntr#ls $%lls #ri*in%tin* #rtermin%tin* in t)e r%di# netw#r %nd &r# ides $#nne$ti#n t# t)e l#$%l ,S80 ex$)%n*e. Ine-SC $%n )%ndle 6" sim/lt%ne#/s $%lls %nd /& t# 6"" s/ s$ri ers.

Bn % ty&i$%l de&l#yment % n/m er # -SCs %re re /ired. 8y&i$%lly= t)ey will e l#$%ted %t t)el#$%l ex$)%n*e site e$%/se t)e lin etween t)e %se st%ti#n %nd t)e -SCs sends #i$e/sin* 32 O its s $#din*= w)ile t)e lin r#m t)e -SCs int# t)e netw#r /ses 64 O its s$#din*. +en$e= t)e tr%nsmissi#n res#/r$es re /ired %re red/$ed i t)e %se st%ti#ns %rede&l#yed in t)is %s)i#n. 8)e %se st%ti#n $#nsists # % sm%ll $% inet %nd tw# %ntenn%s=s&%$ed %r#/nd 2m %&%rt t# %$)ie e s/ i$ient s&%ti%l di ersity. 8y&i$%lly= #mnidire$ti#n%l%ntenn%s %re /sed= %lt)#/*) dire$ti#n%l %ntenn%s m%y e re /ired w)ere )i*) r%n*e isneeded. %$) $% inet $#nt%ins six D C8 tr%ns$ei ers %nd % $#ntr#l /nit t)%t # ersees t)etr%ns$ei ers %nd m/lti&lexes t)e $%ll tr% i$ #n t)e $#nne$ti#n %$ t# t)e %se st%ti#n$#ntr#ller i% t)e wire= i er= #r mi$r#w% e r%di# tr%nsmissi#n res#/r$e. 8)e /nit inst%lled %tt)e s/ s$ri erPs &remises is $#msed # %D C8 tr%ns$ei er= % line inter %$e /nit= %n%ntenn%= % wer s/&&ly= %nd % %ttery %$ /&. 8)e line inter %$e %ll#ws %n #rdin%ry %n%l#*tele&)#ne t# e $#nne$ted int# t)e /nit. M/lti&le line /nits '/& t# 12( $%n e e%sily &r# ided

y $#nne$tin* m#re line inter %$es int# t)e D C8 tr%ns$ei er.

D C8 %ls# )%s t)e ssi ility # de&l#yin* re&e%ter /nits. 8)ese m%y e /se /l i m# ility isneeded in % limited %re% s/$) %s %n # i$e #r s)#&&in* m%ll. 8)e re&e%ter /nit w#r s yre$ei in* t)e d%t% in #ne time sl#t d/rin* t)e re$ei e )%l # t)e8DD r%me %nd

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F#r % n/m er # ye%rs % ter t)e st%nd%rd w%s intr#d/$ed= D C8 %iled t# t% e # . +#we er=in re$ent ye%rs &enetr%ti#n )%s in$re%sed s/ st%nti%lly= &%rti$/l%rly in :erm%ny. Bt m%y et)%t wit) s/$$ess in t)e WLL m%r et D C8 will sell s/ st%nti%lly %r#/nd t)e w#rld.

Bt w%s s)#wn t)%t= BSB $#/ld limit t)e r%n*e # D C8 systems t# #nly %r#/nd 3""m.+#we er= in t)e $%se # WLL= w)ere dire$ti#n%l %ntenn%s %re /sed %t t)e s/ s$ri ere /i&ment= t)e r%n*e $%n e s/ st%nti%lly extended. Fi*/re s)#ws t)%t= wit) % dire$ti#n%l%ntenn% wit) %n # er%ll e%mwidt) # 2" de*rees= t)e s/ s$ri er /nit $%n e siti#nedm/$) /rt)er r#m t)e %se st%ti#n e #re BSB will e$#me &r# lem%ti$ 'sim&le m%t)em%ti$ss)#ws t)%t t)e dist%n$e t# t)e s/ s$ri er /nit $%n e in$re%sed t# 23 m in t)is $%se(.D C8 )%s % rel%ti ely l#w tr%nsmit wer= %nd )en$e it is m#re li ely t)%t t)e r%n*e in %

WLL de&l#yment w#/ld e $#nstr%ined y in%de /%te si*n%l stren*t) r%t)er t)%n BSB.

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1.4.1 D C5 peci&ications

D C8 w%s st%nd%rdi ed wit)in /r#&e d/rin* t)e e%rly 1!!"s= initi%lly #r /se %s % wireless# i$e ,A-N. Bt )%s re$ently %ls# een s/**ested #r de&l#yment in WLL netw#r s %s well%s $#rdless %&&li$%ti#ns. Bts ey stren*t)s %re *##d #i$e /%lity< t)e % ility t# &r# ide %)i*) %ndwidt) t# t)e /ser= %ll#win* t)em t# send l%r*e $#m&/ter iles /i$ ly< %nd t)e% #id%n$e # re /en$y &l%nnin*.

D C8 )%s %n %d %nt%*e # er m%ny # t)e #t)er $#rdless %nd $ell/l%r te$)n#l#*ies= n%mely=t)e % %il% ility # /nli$ensed %nd st%nd%rdi ed s&e$tr/m. Bn m#st $#/ntries= es&e$i%lly in

/r#&e= t)e 1. t# 1.! :+ re /en$y %nd )%s een set %side #r D C8. 8)ere #re=#&er%t#rs $%n e%sily *%in %$$ess t# s&e$tr/m %nd m%n/ %$t/rers %re % le t# %$)ie e *##de$#n#mies # s$%le wit) t)eir e /i&ment. 9sin* t)e *eneri$ %$$ess &r#t#$#l ':A,(=$/rrently ein* de el#&ed= s/ s$ri er e /i&ment r#m #ne m%n/ %$t/rer s)#/ld e % le t#interw#r wit) netw#r e /i&ment r#m % di erent m%n/ %$t/rer= e%sin* $#n$erns # erm/ltis#/r$in*.

D C8 tr%nsmits /sin* 8DMA in % simil%r m%nner t# :SM. %di# $)%nnels %re s&%$ed2 M+ %&%rt. %$) r%di# $)%nnel is di ided int# 24 timesl#ts. 0#min%lly= 12 %re #r %sest%ti#n t# s/ s$ri er tr%nsmissi#n 'd#wnlin ( %nd 12 #r s/ s$ri er t# %se st%ti#n

tr%nsmissi#n '/&lin (= /t t)is $%n e %ried dyn%mi$%lly i t)ere is m#re in #rm%ti#n t# etr%nsmitted in #ne dire$ti#n t)%n t)e #t)er. -e$%/se it tr%nsmits in #t) dire$ti#ns #n t)es%me re /en$y= D C8 is s%id t# e time di isi#n d/&lex '8DD(. Liter%lly= t)e time is di ided

etween t)e di erent d/&lex dire$ti#ns. 8DD %ll#ws sim&ler m# ile desi*n. Bmrt%ntly= t)e%$t t)%t t)e s%me r%di# $)%nnel is /sed in #t) /&lin %nd d#wnlin dire$ti#ns %ls# %ll#ws

t)e /se # %ntenn% di ersity= % te$)ni /e dis$/ssed s/ se /ently. D C8 %ls# )%s DCA.8)is is w)ere t)e %se st%ti#n listens t# %ll t)e re /en$ies % %il% le t# t)e netw#r %nd

inds t)e #ne wit) t)e l#west inter eren$e r#m s/rr#/ndin* $ells. Bt %ll#ws D C8 systems t#exist wit)#/t t)e need #r re /en$y &l%nnin* %nd t# m%ximi e t)e system $%&%$ity in $%sesw)ere t)e inter eren$e r#m s/rr#/ndin* $ells is rel%ti ely l#w.

8)e )i*) d%t% r%te # D C8 $%n $%/se s#me &r# lems wit) BSB. D C8 d#es n#t )% e %ne /%li er /t tr%nsmits d%t% %t % rel%ti ely )i*) r%te '%r#/nd 1.1 M its s(. Any re le$ted&%t)s wit) %n extr% &%t) len*t) # 26"m m#re t)%n t)e m%in &%t) $%n $%/se &r# lem%ti$BSB. W)en %n #mni dire$ti#n%l %ntenn% is /sed in %n /r %n en ir#nment= t)e BSB &r# lem)%s een #/nd in &r%$ti$e t# limit t)e r%n*e # D C8 t# ewer t)%n 3""m re*%rdless # t)ewer t)%t is tr%nsmitted. Ine ey %d %nt%*e # D C8 is t)e sim&li$ity # t)e system=res/ltin* in rel%ti ely inex&ensi e e /i&ment $#sts. -e$%/se )i*)ly $#m&lex r%di#tr%nsmissi#n met)#ds %nd &r#t#$#ls )% e een % #ided= D C8 %se st%ti#ns %re % %il% le%t #nly % r%$ti#n # t)e $#st # $ell/l%r %se st%ti#ns.

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1.6 Chan in ser demand

Bt is # ten s%id t)%t t)e w#rld is e$#min* %n Bn #rm%ti#n S#$iety= wit) )/*e %m#/nts #in #rm%ti#n ein* m%de % %il% le t# indi id/%ls %nd &%ssed r%&idly %r#/nd t)e w#rld. 8)eBnternet is )eld /& %s t)e irst m%ni est%ti#n # s/$) % de el#&ment. B tr/e= /sers willin$re%sin*ly dem%nd %ndwidt)s # me*% ytes &er se$#nd %s ser i$es %re &r# ided t)%tre /ire t)em. Cert%inly= t)e Bnternet is in$re%sin*ly re /irin* )i*) %ndwidt) %$$ess= %nd %s

ile si es %nd )%rd dis s *et in$re%sin*ly l%r*e= it is /ndeni% le t)%t /ser dem%nd #r d%t% isin$re%sin*. +#we er= it is e%sy t# *et $%rried %w%y wit) t)is %&&r#%$). M#st &e#&le rely #n

r#%d$%st entert%inment= w)i$) will in$re%sin*ly &r# ide m#re n/mer#/s $)%nnels %nd%$$#m&%nyin* d%t%. 8)is will e deli ered i% t)e r#%d$%st %nd n#t t)e tele&)#ny$)%nnels. :ener%lly= t)#se w)# re /ire l%r*e iles will #nly re /ire t)em &eri#di$%lly' e$%/se t)ey will need time t# di*est w)%t t)ey )% e re$ei ed(. Fin%lly= %nd m#stimrt%ntly= /sers will #nly w%nt s/$) ser i$es i t)ey $%n e &r# ided %t % l#w &ri$e< #rex%m&le= m#st Bnternet /sers $#/ld ene it r#m %n BSD0 $#nne$ti#n /t d# n#t $)##se t#)% e #ne e$%/se t)e %dditi#n%l $#st ex$eeds t)e %l/e t)%t %n BSD0 line will %dd #r t)em.

8)erein lies t)e &r# lem. 9 i /it#/s &r# isi#n # )i*) %ndwidt) ser i$es will re /ireen#rm#/s /&*r%des t# t)e w#rldPs tele$#mm/ni$%ti#ns netw#r = &%rti$/l%rly swit$)es %nd&%$ et ser ers %nd $ert%in &%rts # t)e inter$#nne$tin* netw#r = n#t t# menti#n t)e %$$essnetw#r . S/$) /&*r%des $#st m#ney %nd %s yet t)ere %re ew /sers w)# %l/e t)eBn #rm%ti#n S#$iety en#/*) t# &%y t)e %dditi#n%l cost required. Within the next 1" t#2" ye%rs t)ere m%y e m%ny /sers w)# w#/ld li e % )i*) s&eed $#nne$ti#n /t ew w)#%re &re&%red t# &%y #r it. 8)e /ser dem%nd will e #r in #rm%ti#n %t % re%s#n% le $#st t)%twill en$#/r%*e in #rm%ti#n &r# iders t# $#m&ress d%t% %nd t# /se *r%&)i$s m#re s&%rin*lyt)%n #t)erwise.

Bndeed= &er)%&s i %rrely= %t t)e m#ment t)e /ser is %$t/%lly &re&%red t# &%y less #r)i*)er %ndwidt) ser i$es. Fi*/re 12 s)#ws %&&r#xim%te $/rrent le els &%id &er min/te #r% r%n*e # di erent ser i$es y t)#se in de el#&ed $#/ntries.As $%n e seen in Fi*/re 12=t)e )i*)est %l/e ser i$es %re ty&i$%lly %ls# t)#se t)%t $%n e %$)ie ed y existin*n%rr#w %nd systems. Wit) t)e &resent set # ser i$es= /sers %re #nly &%yin* s#met)in* li e1 1"""t) # t)e %m#/nt &er $)%nnel #r r#%d %nd ser i$es w)en $#m&%red t# n%rr#w %ndser i$es. Sin$e t)e $#st # &r# isi#n *#es /& in line wit) t)e %m#/nt # %ndwidt) 'sin$et)e %ndwidt) $#/ld e /sed #r m/lti&le n%rr#w %nd ser i$es r%t)er t)%n #ne wide %ndser i$e(= t)ere is &resently % m%ssi e */l etween $#st # &r# isi#n %nd ex&e$t%ti#n #$#st.

8)is will sl#w t)e wides&re%d %d#&ti#n # r#%d %nd ser i$es #r s#me ye%rs t# $#me.

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Alt)#/*) t)e dem%nd #r )i*) %ndwidt) &r# isi#n m%y n#t rise dr%m%ti$%lly= t)e /se # t)e

%$$ess netw#r #r %&&li$%ti#ns #t)er t)%n #i$e will $)%n*e si*ni i$%ntly. Bnternet %$$ess=in$l/din* %&&li$%ti#ns s/$) %s )#me s)#&&in*= will dr%m%ti$%lly in$re%se t)e tr% i$*ener%ted y % )#me in t)%t t)e &)#ne line will n#w e /sed #r % m/$) *re%ter &er$ent%*e# t)e d%y. M#dems will e$#me % st%nd%rd it wit)in $#m&/ters %nd &r# % ly %ls# wit)intele isi#ns. 8)is will /el t)e dem%nd #r tw# #r m#re lines &er )#/se %nd will %ls# in$re%set)e re en/e re$ei ed &er line y t)e #&er%t#r.

Ine in%l %re% w#rt)y # menti#n is t)e in$re%sed en ir#nment%l %w%reness t)%t will m% et)e l%yin* # %dditi#n%l $% les in$re%sin*ly &r# lem%ti$.

Alre%dy= $% le #&er%t#rs %re $riti$i ed #r d%m%*in* tree r##ts.

Fi*.12

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1.7 #redictions &or WLL

At t)e st%rt # 1!!7= % n/m er # %n%lysts s/$) %sI /m%nd ,A m%de &r# e$ti#ns # t)eWLL m%r et&l%$e. 8)ese s/**ested t)%t y t)e ye%r 2""" # er 1" # %ll lines ein*inst%lled will e wireless= w)ile #t)ers )% e &redi$ted t)%t t)e n/m er # wireless linesinst%lled &er ye%r $#/ld # ert% e wired lines e #re t)e ye%r 2""5.

Findin* t)e re%s#ns #r s/$) #&timisti$ &redi$ti#ns is n#t di i$/lt.

8)e ey %$t#rs %reE 8)e $#st &er line #r WLL is $/rrently l#wer t)%n #r wired systems %nd will %ll /rt)er

wit) e$#n#mies # s$%le< 8)e dem%nd #r tele$#mm/ni$%ti#ns %r#/nd t)e w#rld will in$re%se si*ni i$%ntly in

$#min* ye%rs< Fr%*ment%ti#n %nd t)e de el#&ment # m%r et ni$)es in t)e tele$#mm/ni$%ti#ns

m%r et will %ll#w % r%n*e # di erent #&er%t#rs t# $#exist.

8)e &redi$ti#ns d# n#t )in*e #n %ny te$)ni$%l #r $#mmer$i%l re% t)r#/*)= %lt)#/*) t)eyd# re /ire t)%t #t)er %$$ess te$)n#l#*ies d# n#t de el#& /nex&e$tedly.I $#/rse= t)ere will e s#me &r# lems. S#me #&er%t#rs will %il in t)e irst ew ye%rst)r#/*) % mis/nderst%ndin* # t)e m%r et #r t)r#/*) t)e de&l#yment # in%&&r#&ri%tee /i&ment. ,r# lems will s##n emer*e wit) l%$ # r%di# s&e$tr/m %nd t)is will= e e$ti ely=in$re%se t)e $#st # r%di# s&e$tr/m= eit)er dire$tly= t)r#/*) %/$ti#ns= #r indire$tly t)r#/*)t)e imssi ility # # t%inin* m#re= #r$in* *re%ter netw#r $#sts %s sm%ller $ells %rede&l#yed. 8)is will e &%rti%lly s#l ed %s )i*)er re /en$ies %re /sed< /t %s wit) m# iler%di#= s)#rt%*es # s&e$tr/m will rem%in % &erm%nent &r# lem= limitin* s/ s$ri er n/m ers%nd t)e d%t% r%tes t)%t $%n e # ered.

0#net)eless= t)e /t/re # WLL is $ert%in t# e % ri*)t #ne.

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1.18 CDMA to dominate

Bt $%me t# &%ss t)%t in 1!!! WLL seemed t# )% e %llen # t)e r%d%r #r s#me end#rs. Att)%t time t)ey de$ided t# t% e % se$#nd l## %t )#w t)ey were s&endin* t)eir QD d#ll%rs

%nd %t t)%t time 3: w%s l## in* m#re %ttr%$ti e. +#we er= t)e next &)%se # WLL is *#in*ey#nd t)e &re)ist#ri$ n%rr#w %nd %nd )%s st%rted # erin* r#%d %nd ser i$es w)ere %WLL #&er%t#r &r# ided t)e $#m&lete r%n*e # ser i$es n#t /st #i$e.

Bt is elie es t)%t CDMA %sed WLL s#l/ti#ns $%n= %nd will= $#ntin/e t# &r# e $#m&etiti eAs t)e $#st # m# ile te$)n#l#*y de$re%ses= it is e$#min* m#re %nd m#re e$#n#mi$ t#

inst%ll K ixedK lines /sin* WLL= . +#we er= #ne # t)e iss/es t)%t needs t# e %ddressed ist)%t t)ere is % l%$ # %de /%te s/&rt #r r#%d %nd ser i$es #n #t) CDMA %nd D C8.t)e ey t# ens/rin* t)%t WLL systems $%n $#m&ete %*%inst ixed wire # erin*s is t# # ere /%l #r s/&eri#r ser i$es. F#r ex%m&le= in t#d%yKs /siness en ir#nment t)e need is #r)i*) s&eed /t l#w $#st Bnternet %$$ess. 8)e #/tl## is t)%t t)is $%n e %$)ie ed /sin*&r#&riet%ry CDMA te$)n#l#*y. 8)is te$)n#l#*y &%r%llels t)e ixed wire ADSL style%&&r#%$)= w)ere t)e /ser d#esnKt )% e t# di%l /& in #rder t# est% lis) % lin t)e Bnternet$#nne$ti#n is %lw%ys t)ere. ADSL still )%s % r#le t# &l%y in t)e r#%d %nd $#mm/ni$%ti#nsm%r et /t WLL te$)n#l#*ists ints #/t t)%t t)ere is % tr%de # etween its r%n*e %nds/&&lied %ndwidt) t)e /rt)er %w%y t)e $#ns/mer is r#m t)e )/ = t)e l#wer t)e

%ndwidt). -y $#ntr%st t)ere is n# s/$) r%n*e restri$ti#n wit) s#me WLL systems= #rex%m&le % WLL system= w)i$) is % le t# deli er 512 it s # er dist%n$es %s *re%t %s 25

il#metres.

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05-tm2106euo1_eg0001-cdma in fixed wireless systems

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