Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO ~/21215 2 ~ 8 7 ~ ~ 2
"CELL-TYPE TELEP~ONE SYSTE~ WITK rXTENDED CELL"
Background of the Invention
Field of the lnvention
The present Inventian gener~lly relates ro cell-
type tclepnonc systems ~nd. mor~ spcclfically, to ~ cell-type
~ lcphone system having an ex-en~e~ cell which i~
particul~rly suita~le for use in rural areas.
~cscription of thc Prior Ar-
Generally, the pro~L~ion of an efficient
telophon~ system for ~ural areas poses a numoer of problemc,
~mong whicn are :
(1) low papula~ian ~onsity due ~o natural
disperslon of peoplo;
~ ii) great ~is~ances -o be cove~e~ wnic~
practically ~r~ng a~out expenslvn ~mplemencae~on of a ca~le
telephone network servin~ all prospectlve use~s; and
~ iil) d~fficuity ~ stretching and maincain~n~
telephane netwar~ ca~les. ~n vLew of ~eographlc profiles.
ln vlew ~f s~ch difriculCies e~ere ~s. Lnter
al~a, a greae een~ency towar~s e~e ~se of ~adioeel pn~ny fo~
the supply of telecommunicat~on eo ~ural areas.
Tlplcally, a ~u~al ~a~i~telephone ¢y~Cem such 3
the one prcsently ln ~se comp~ses interconnece~n~ small
v111ages ar settlemene~ ~nrougn ra~ioeelepnony an~. ae
g1ven s1te, conne~eln~ 3~ a~ioeelephone sy~eem eo ene
national telecommunicatLcn necwo~.
Th~s solutlon~ ~owe~e~, apare from noc ~eten~n~
all prospectlv~ u~e~ lso ?~esene. ~^rlou~ p~e~Lc~mene~
malnly rel~eed tO e~e nl~nly e~pen~Lve ~nsCallseLon of ene
~0 whole lnfra~truccu~e ~a~L~e~ ve~y ~m~ll v~L~a~ c~
seetlement and tne compLec~ t ~o~ of p~ cy ~n tne
communlcation, ~nce anyone m~ inC-~epG B ~ven c~ll Lf ne
ls provlde~ wlcn a ~u~e~}e ^~uLpm~ne.
Alm~ng tO ~ol~e ~ ove-~sc~s3e~ p~o~lem~ an~
~5 pro~l~e ~n efficienc eelecommun~c3t~0n ~ysCem for r~ral
areas, It was proposed eo use a cel1~eype eelephone ~yster.:.
Br~efly, a c~lL-Cyp~ CeL~pnone s~em ~g 3
raalotelep~one ~vstem in wnicn Ch~ dvsil~ale f.~3unnc~ ~an~
WO92/21215 2 ~ 8 ~ 2 PCTIBR92/~WK~
;. ''' ~
is divided into ~roups of frecucinc-es diisignated as cells,
which ce~ls are geographically distrisu~e~ in such a way that
groups of frequencies from twa adj~cent cells always differ
from each othcir in ordcir ~o -l_minate any possible
interference in the communication.
Similarly, the f-ci~uonc~es in a given group of
frequencies are only rep-~~ed when ~:ne distancci ~etween Che
cells is enou~h t~:o assure t'nat :i~.ere ~ no morci be any
interferonce betwecin such f-~i~uenc.~ic in a c~ill and ~-te same
froquencles used in anothor ^~
Sincci oV~ t~ it~ Wi'i~''i a ~,_'i-i-, rj-"'i?
of frequencies, it is p~ssi~ile tCi perform or conduc~ a
cer~ain numcer ~f simul'ai-ie3u~ c~-r~ri-,a~~3ns. Yowevci~, a~ -`ho
areas coverod ~y each cei; ".~ sen~ differen~ .e!e?nono
trafflc loads, the dimensian cif ChQ cslls may chan3e in
accordance wlth the fluctuat~on of said telephone t~affic
load. In other words, dependin~ on ~he traffic loa~. c~e si~e
of the cell may have a radius ~etweon approximatsly l and
km ~one and five kilomeeers~.
Thou~ the smallest siz~ of the cell is limiced
by the presently avsila~le ~oc;nnot~gy to a r3dlus of
approx~mately ' km ~one ~ meter`l. since ~elow s~c~ lim~t
enere may arl3e lntsrfsrenoo pro~lnms whicn can no~ ~e ~olve~
w~thi~ eh~ g~oup of f~e~n_ios ~o~. th~ hi3h~C'. ~ of ~n~
cell now depen~s on th~ usor'~ ro~oiv~r dee~etiQn ~pa_i r~,
ene ~ntènn~ of wn~ch of~ n ~ee~en~ low ~o~oc~l~n power.
Thus, the aver~e size of c~Ll~ n e~ pr~onel~ ~n~wn ~
type telepnone syst~ms incorpor~e~ i w~ehin ~ ^~n~e of S
to 15 ~m ( flve to f~fe^en '~iomn~er-~.
~0 T~p~ o~ lL-~.y~n ~ nn
!~y9tem compr~3es:
~ mm~ n~ n.
c~nne~t~ th~o~h ~a~ n~ n~ ph~ n~ ~W~ n~
Ln commun~cation w~e~ .~evoJr~l e~o11~7 a~ io wa~os;
~5 ~ reCelv~n~ ~n`~ reGransmiccin~ o~e radio
~e~tion (ERB~ ~n e~èry cel~ m~sing a ~,~wor an~ an
antenna array: and
(lLil a pll~L~ L~ m~ n-C
W092/21215 3 2 ~ 8 7 ~ ~ 2 PCT/BR92/nWK~
O
~rovided with low detection power ~ntennas and able to
establish radiofrequency communicatian with every b~se r~dio
st~tion r~ferred to in the precedin~ paragrapn.
In view of tho ~ov~-discussed problema- related
to traffic load, cell siz_ and interferenca between
f~e~uencies, con~ention~l ce~l-ty~e telephone sys~ems. in
their ~se r~dio stationC. use l~w power antennas ~ssemsla~
on rel~tiveiy low towers prefer3~ly conatructod on not ~oo
elevated sites, in order o avai i a_ much as pOSa~bl any
interference ~etween the fro~uenc ~a of each grou~.
Summary of ~he Inven~l~r.
Thus, there is ~ need to provide an efficieQ~
telephona system for rur3l ~rO~ ;-. c-. i. one af ~~.e e~e-~C
of the present invention.
Anaeher o~Jac ~f ~he ?~esent Lnvencion is tne
provlsion of such an efficient tolep~one system Sor rural
areas whlch may 3erve all prospec~iva users.
An addition~l o~ec~ of the p~esent inveneion is
the provlsion of such an efficien~ radiotelephone syseem for
20 ru~al ~ress wnlcn doec not p~es~nt the a~ovo ~iscussed
pro~lems relsted to hi~hlv expensive inseall~on ~n~
difflcult ca~le seretchin3 ~nd ma~n~enanca.
Stlll anot~e~ o~ece of tne presenc invention is
tne prov1s1on of such ~ tolophono Cystem for ~u~al ~n3s
25 wnicn does not present er~ ovo-~iscusse~ pt~o~lams ~elato~
to expen~l~^ lmplemenc~c~on of infra3truceuro for
conventlon~l ~ural radioeelep~ony.
One addieional o~ece oC Cha inven~lon is ehe
pro~lslon of suc~ a t~lepnone ~y~e m for rural areas whLcn
does noe pre~ene en~ ~a~ u~e~ ~o~lem~ rel~ee~ eo 1~CK
of prlv~cy ln the communLc~eLon.
Accor~ln~ eo 5~e preS~Qe ~ nveneion, ;a~ accs
are fulfllled Gv tn~ pra~ L~n oC a call-eypa ra~io-~lep~one
syscem p~rc~cularly ~e~inei ~ ~a t~ed in rtl~al areag,
~5 cnaracterlza~ ~y compr~in~ a a~m~taeion an~ conerQl unit
connected to tne natLan~l ~elaonone netwoF~ an~ in
communlcatlon wltn ~evaral caLl~: a r a ~v~ng and
retran~mittin~ ba~e radi~ ~t~e:~n n e~er~ nll. aa~d ~3~a
W092/2l215 ~ 4 PcT/BR9~WKK
~, . . . ..
20%75g2 ~
radio station being comprisea o, ~ ~ower and an antenna
array, said tower being pr~f~ra~ly a large one and
constructed on an elova~e~ site an~ provided with high power
antennas in ordar to cover 3 gre~r ~rea; and a plurality of
fixed tarminal stations distribut-d wl:nin the reach of eacA
a~ove-m~ntioned ~ase r~dio staeia~, each fixed torminal
station ~eing provided with 3 ;~igh deteceion power
directional antenn3 coupl~td ~s sama ~r.ich is ~irecse~ towards
said baset radio station.
According to ~ha pre~n- invention, the base
radio s~3tion 3ntann~ powa- nc~a3_ct, ~heir ins~a.la~io., on
an elevated site and tha lncraase in rhe detecrion car,acity
of fixed termir,al s;atior., wn.e~. 3~a row ccuple~ ~o a ;n.~h
det~ctlon power ~irac~iorai an~-nna -~hi_h is ~irnc~e~ s~wa~C
lS t~e ~ase radio station, maka ,- p~ssi~le to increasa ehe si~ct
of each individual cell to a ra~ius of approxim~tnly 60 km
(slxty kilometers~ on a fla- surfaca, pracrically
qua~ruplicating the radius of ehe iarg~st cells in cnll-type
ra~lotelephone syscems of Che prio~ are.
Thus, ~y inve~t~ng the ~asic princlplas ~f call-
type ra~lotelephone syseems of e~e prior art, ~.~o si~a of
each cell may ~e extaertde~ C~ ~ne naCu~3L ga~gr~ohical
~oundarles wiehout po~in~ any inc_r fnranc_ pro~lnm ~aeween
groups of fr~aqu~ncies of ewo ~ a~ar.~
Addleionally an~ ^anerar~ t.o wh~t. ~ r~ln~ ~.n
conventlonal c~ typ~ ra~iotai~aphona ~y~tAmS~ th~a ~as~a -~io
~e~eion aneenna power incr~sa ~o~s not ~mply 3ny
interferenc~ pro~lem, sLnce en~ e 3n~ iis~ Q~on of
cells ln addiCion ea tne low ~ p~or.~ ~r~fri~ loa~ norm~lly
oG~erve~ in rural ~re~3 el~m~na-e ~.n~s ~in~ ef ~ro~ n~~,
~rlef Descrlption o~ Dr~win~s
Tne pr^~ent ~n~n-ior. wi~ n~ hara n
after in Rre~ter ~eea~} wie~ r~rerence ~ ~he non L`~ ve
em~odiment ehercof ~h~wn ir. ~.h~ ~eeached ~r~ n~ ~s ~n
ex~mple, in wn~cn :
Figure L ls ~ sc~am~ r~?r~en~.~e~n ~f ~ ~oll-
type radlotelepnone ~ystam ~c_i~r~i.n~ t~ eh~ prosen~ nvanel3n
snOwing a central~o~ conf i~r~e~?.~ n~
WO92~21215 5 2 ~ 8 7 ~ 4 2 PCT/B W2/~N~
. .. ..
Figure 2 is ~ schem~ c r~rasentation of a cell-
type radiotelephone system accordin~ eo the present invention
showing ~ decentr31ized confi~ur~tion.
~escription of the Prefarr~d ~mbodi~ent
With referenco now more particularly to the
dr~win~s, 3 c~ typ~ r~dio~eleonano system havin~ an
extended cell ~cco~din~ eo the presen~ invention is shown in
Figures 1 ~nd 2, The syse m comprises, basically,
commutation and control uni~ CC~. ~ ?lurality of ~ase r3dio
qtations E~B and a plurality of fixed cerminal stations ETF.
The commuta~ic-. ~n~ .o ~ni~ C~C ic a ii~ ~31
electronic commutation e~uipmen~ which uses ~istributed
processing and stored pra~r3m c3n~~0 ape~ati~nal eechni~ue-c
to control ~as~ radio s,ations _~3 and fix~d :erminai
stàtlons ETF in or~er to provi~e an efficient communication
system.
Prsfera~ly, t~e cammueaelon and control unlt CCC
19 of ~ type known in e~e seate a~ tne art whic~ is a~le Co
commutàte volce and daea c~rcuitry ~nd perform analag~ itsl
~A/~) and dlgltal-analog (D/A~ conversions and tnus it shall
not be descrl~ed ln details ~elaw. T~e ob~ectiv_ of tne
commutation and control unie CC~ ~ 3 eo provi~e an interface
~etween ~ase radio stat~ons E~8 in t~e ce;l-type
ra~lotelephone 3yseem nav~n~ an axc~n~e~ cell ~cc3r~n~ eo
the present invenelon an~ cna naeianal t~laphone natwor~
tnrou~n RNT caGlè~. Sai~ ~nte~face may ~e ~oen local and
trafflc ~epen~ent.
Thus, enrou~ C~a comm~tae~on ~nd con~rQ~ unlt
CCC i t 19 poggl~l~ tO affor~ an ~tom~t~e ineerc~nnc^tion
~etw~en a flx~d e~m~n~l sc~e~on ~ an~ a cele~h~r. central
0tatlon of both naelonal ~n~ ~nt^~n~cionaL ~xtene.
The commueae~on an~ conC,ol un~t C~ is 3a ically
comp~se~ of a m~ln cone~ol un~C CCP and a commutatian unlt
CC. The funceion of e~e m~n cont~ol ~n~t CCP i5 eo
eJta~lish an interfaca ~eeween e~e ~pe~rato~ 3ni th~ syscem.
for wnlcn purpose it is pro~e~ w~C~ a ~ata ~ank for tne
whole system, and allow ~Q~ e~ perfo~m3nc~ o~ s~seem
managemene an~ maint~nan~o func~.3ns ~ro~gh prosocol~
W092/21215 ~~ 6 PCT/BR92/~WXK
208~42 ~
designed for man-machine communica-ion. On the other han~.
the objective of the commutation ~nie CC is to control call
processin~, monitor base radio sta~ion ERB equipment and
perform management and mainrenanc~ fu~o~ionc commencA~ ei~her
at peripheral equipment in the main con~rol unit CCP or at ;
local t~rminal interface o~ ~h~ c~m~u~3eion uni~ CC ~s_lf.
Additionally, the cammut~tion uni~ CC ic
responsi~le for all call connec-.ion and disconnec~ion phases
including signaling, supe~vision. commutation and a}loca-l~n
of radlofrequency channels.
The oase ra~lo ;ba:i3ns --Ra which ~efiî.e
individual cells are conn~c~e~ ~o ~he commutation an~ conerol
unlt CCC Oy means of a four w~re analcg or ~i~i~al ci^.ann-!.
the communicatlon between ce~ls oa~n3 carried ou~ -hrou3n
radlofrequency, PCM ~eam or o?~ica} f~berâ, in ~ccor~anco
w~th the speclfication of eacn pro~ecC. ~n such a
communlcatlon system eher~ is a ~oice and data flow. ~owever
wlth a spec~Slc data l~n~ for Qen~ing and rec~iving conc~ol.
supervl~lon and lnformativa me~sa~es.
The maln funceion of each base radio stat~on ERB
19 to lnterface local su~scr i~ers wieh one anoeho~ snd/or
interface local â~cacr~e~s w~th na~ional telephonn nerwork
RN~ su~scrl~ers.
For r.hlS purpase eh~ ~ase ra~io ~eac.on E~B
snoul~ preferaoly compr~s~ ab ~ CwO racks ~n~i~n~tea as
radiofrequency and ord~n~ nes w`n~^n ara ~onnn~ee~ ~s ewo
omnldlrectlonal antennas as~em~la~ at ~ suita~le heL~e wnLcn
may affor~ a complete covera~e w~tn~n an ~varag~ r3~us of ~0
km (slxty kllometer~ a~oun~ e~e ~e ~a~o seat/oQ ~3. ~nus
conflguraeln~ an excen~e~ c~Ll.
~ no commun~c~e~on of ~n~ oa~e radlQ ~cacion -~B
w~th flxed eerm~nal ~cac~on~ r~ i~ c~rrl~ ou `nrou~n
raalofrequency c~anne~ w~Lch u~ sCan~rd proc~cols ~s~
sendln~ ~nd recelv~ng concr~l ~aea ~n!~ ~o~ca ~nals~ such
commun~cation ~eing car~^a ouc e~rou3~ fr~aquenc~ mo~ulaei~n
ln a radlo system operacing wiC~n Che ~00 ~2 ~n~n. ~n
other words, t~e communLcae~on ~ecwe~n C~a ~sa r3~ eaelOn
ERB and a g~ven fixaa C~rmin~l ~caci~n ~T~ 3rrL~ ~u-
WO92/21215 7 PCTIBR92/~HXK
~ 2~7~-~2
through control and voice channels.
~ he control ch~nnel supplios data between the
~ase radio station ER~ contrcller 3nd the fixed terminal
stations ETF of each cell, ~nd i ta functions aro to: send
information to fixed torminal sta; ans and monitor their
registers, inclu~ing messa~o regis~o- parameters and tho
frequency transmitte~ to fixe~ ~erminai stations; control
st~rted and completed calls; and datormine the avai~abil7ty
of fixed terminal stations ~o~ raceiving a call.
The voice channel pravides an audio interfaco
~etween fixed torminal sta iona ~ and the commuta ior. uri~
CC, Through the volca channo' are 30nt the audio supe~ision
tone TSA and Cho signalins -ono TS.
The voic~ channels 3~ 'O supply the 3udio li~k
and signal converslon to 3~s~.3ir. ehe call; ~oni~o~ -ha
radlofrequency slgn~l intensity; monitor ehe fixed ~armina}
statlon for access of facilities to subsc~i~er: and
dlsconnect the audlo super~ision eone ~SA during the c~ll.
The flxed terminal scacions ETF comp~e a low
power transrecelver coupled eo a ~i~actional antenn~ whlc~ ~s
dlrected towar~ ene ~ase ~a~lo seaeion and is ~lso provided
wlth the s~bscri~ers~ te~mlnaL. whic~ L5 fixed and ~f ~peciai
~nterest to the cell-ty~c te~aphone ~ystem of th~ pfesene
~nventlon.
2S ~he oper~Clon o~ tne ceL!-type e lnp~one ~yseem
wlth exeen~ed cell accor~n~ e3 e~ p~ sene in~ene.~n ~all
~e descrl~e~ nereln as foLlows w~e~ refsrence eo e~ree ~in~s
of call~ ~ one call f~o~ a f~xe~ e~mlnal ~e~tLon '~F eo t~e
natlon~1 telepnone neewor~ RNT: on~ call tram e~e nac~ona}
telepnone networ~ RTN to ~ f~x ~ ~erminal st~elon _TF; and
on~ call from a flxe~ Ce~m~n~L ~e~e~an ETF eo ~notner f~xed
t~rminal station TF.
In tne call from 3 f~e~ Cermln~l ~t~eion TF to
the nacional telep~one neewor~ RTN. ~nen e~e f~xe~ ee~minal
seation ETF 3u~scri~er starC~ e~- call, Che ~ase radlo
staclon ERB r~cel~e~ and L~eneL~es t~e re~uesc ~roug~ the
control cnannel and ~en~ sam~ e~ e~e commueaG i on unie CC
to~et`ner w1tn all otner ~nformaci~n rAqui~e~ e~ ~mpLete cne
WO92/21215 2 ~ g ~ ~ 2 PCT/BK92/0X~
call, ~iz: the subscriber's ~-laphone number, the
subscriber's se~ial number and the diaied number.
Th~ commutation unit CC ~hen selects a vacant
channel tO b~ used in the eall 3nd signals the base radio
station ERB to instruct the Lixe~ ~erminal station ETF to use
the selectad channel. Addi~io~al~-f, ~ha commutation unit CC
carries out the v~lldation of ~he dialed numbers to assure
that the su~scriber can then make ~he call an~ to ~etermine
the required route as well aâ :h_ ~ype of call.
1~ The connection estaDiishe~ throu~h the digiea
commu~ation the commutaTian uni- C_u -^omplatas the ~oica :in'~
from the ~ixed terminal s~ati3n _T~ and the base r-~io
station ERB with the nationai 'ei~phone network ~TN.
Alte~natlvel~, in ~r~e~ ~o p~ovide a low cost
iS route, the call may ~e rû~e~ ~y c~e ~ommutaCion un~C CC f~om
the cell-type telephone system to another commutation unie CC
ln another cell-type tele~hone system to then ~each ehe
natlonal telephone netwo~ RT~ acc~ding to the ~ecent~al~ed
sy3tem shown in Figure 2.
When t~e call is cQmplete~, any of cne pareins
who dlsconnect the commutation unit CC ~eleases all ~esou~ces
used ln the call. The ~e~iseer co~esponding Co ~ei~ call is
then t~ansmlteed eo the ~in conC~ol unie CCP to ~e use~
su~sequently in th~ p~oducti~n of ~ho ratin~ taoe ~nd t~af~ic
analy~ls.
When a call is m~e ~~~m. tne naeiona~ ~olephon~
networ~ RNT to a fixe~ CermLnal seaei~n ~T~. C~ n~C~nsl
eelephone necwor~ RTN acces3es ~ Cr~n~ in t~e c3mmuCaion and
conerol unlt CCC an~, tn~ou~n ~ ital swiCc~, san~s cne
correspondlng inormaclve ~igi~ e~ e~^ fi~a~ e~rmina: seaei3n
ETF suCscr~er.
T~ commueac~on an~ c~ne~31 un~t ~ earrias out
tne validatlon an~ d~LC Cr~n~l~Cion an~ LnsCru~ eno ~ase
~adlo qtatlon ER3 corre~pon~Ln~ to Che 1~caCa~ area co
actlvaee, ~hrou~ e~e control e~nn~}, t~e f~e~ ~ermin~l
statlon ETF selected, in ~r~e. C~ ena~l~ iC~ ~inl~c~ge wicn Che
nat~onal telept~one network RTN.
~ ~e ~ L ;~ ~ ~ a ~ !. X ~. ~J
WO92/21215 9 PCT/BR92/OWK~ ~
`~2~7~2
terminal st~tion ETF through the control channel and, when
the latter answers the call, tha commutation unit CC is
instructed by the ~ase radio station E~B to select the vacant
voice channel to ~e used in the cal}. The fixed terminal
station ETF is informed ~bout the s~lacted channel by the
bas~ radio st~tion ER3, ~nd th~ commutation unit CC connects
the correspondin~ di~ieal swiCch wnen the ~ixea ~erminal
~tation ETF is ready to recaive the c~ll.
Thus, the base r~dio sta~on ERB is inst~ucted to
alert the su~scriber, and the tele?hone set in the fixed
termlnal s~at~on E~B starts o rin~. W~en the fixed earmina~
statlon subscrlbe ~nswers ~he call, ~he voice link in ehe
natlonal ta7ephane netwa~k ~T~ am?ieeed.
Again, when the cali is completad, 3ny of thA
parties who disconnec~ tne commueae~on unit CC rele3ses al~
r~sourses used ln the call an~ generates a register
correspondlng to sald cal}, which register is sent ~o ehe
maln control unlt CCP to ~e u~e~ su~seQuently in the
productlon af ene rating tape and trsff~c analysis.
wnen a call is ma~e ~rom a fixed termLnal seation
ETF to anotner flxed term~nal ~tat~on ESF, wnen 3 f~xe~
su~scrlber start~ tne cal!, it ~s ~rocassed as aDove une~l
the dlglt translatlon sCep. ~t e~is point, C~a co~mucaC~on
unlt. CC datermlnes t~rough ~es ~a~a ~ank if ena calL was
2S dlreceed toward8 anotner f~xed eermlnal station ETF.
~ cn~s oeher ~xe~ e~ninai staeL~n ~ i9
~crved ~y the same commutatLon un~ t ~C, ene call 13 pro~essed
ln a regular way. On the ~ontrar~. Lf et~e suoscr~er i9
served by anoe~er commut~t~on ~nLe CC, a vacane e~un~ ls
~es~gnatc~ for the call an~ ~e L3 ensn proc~3~ f~xed
eermlnal ~taeion ETF eo a ~iK~ e~rminal ~taelon ~F cype
call.
The ~uDscr~ call~ s locate~ ~n~, ~y
answerlng tne eall, a voLc~ ~annel Ls ~eSlgnar~e~ eo
e~ea~ h the volce llnk ~eeween ehe 3tatlons. ~ai~ voLC~
llnk 14 esta~lls~ed ~esre~ng fr~m t~e comm~taclon unle CC of
the base radlo station E~3 eo~$pondLn~ e3 e~e fLxe~
~ermlnal statLon ETF wn~ch ~L~inat~ th~ ~al1 e~ eh~
WO92/21215 ~1l; lO PCT/BR92/~WXK
2~g~2 0
commu~ation unit CC in th~ oase r~o station ERB of tnn
fixed terminal station ETF ~ime~ at.
When ~ call is compl-t~ ny of the parties who
disconnect the commutation un~t CC rel~ases all resourses
used in the call and the rn~ist_r corrnsponding tO said call
is goneratnd in th~ ori~in ~as- ^ad.o station _R3 ~o bn
transmltted to the main contr3l UQie CCP tO be u~e~
subsequently ln the production ~f the rating tape and eraffic
analysis.
In thls syseem. ~he calls may be made ehrough a
flxed terminal statior. ~. wnor~ ^hn~n is room i~ ehe d~ea
bank avallablo for the rog~gto- 0~ calls made by every
subscriber.
An importan~ ~e3~r~ n cnll_~y?n ~~nphonn
system with extended cnll a__o~r.g ~~ ~e ?resen~ 1nvon~n
is the possibility of its ex3ansi3n t~rou~h secto~ng andfor
dl~lslon of cells.
Thus, t~roug~ a p~edo~n~~ined pro~ec~. iC ~s
possl~le to canfigurate t~e cells roquired for the ~itial
coverage of a given area, prec~s~!y d~torminin~ the location
and the n~m~er of cell~, and thu3 ~h base radi~ 3cae~ons
ERB~ requlred ln Che 3~'~ o~'Vel~. To suppore such
trafflc, groups of channeL~ ar~ aLL~cated for 3C~
always proport~ns} eo c~ ma~lLmum e~pact~nd t~a~f~
Hawever, c~e celL-eypo Cel~phone ~yse~m ~ h
extended cell of t~e proson' ~n~en~ion, ~ecau~e of 5~n
num~er of sucqcrl~er3, t^~Q~ono -r 3f f ~ C loa~ ~n~ ~the~
fac~ors lnclu~n~ topo~rap~ie ones. al~ows for ~ec~r~g an~
dl~l~lon of every cell ~n a sec~n~ ~ea~.
-~0 In tne former c a~ n e~ll iS ~ nto
sector~ w~ic~ e~en be~n co ~ w~c~ ~y 5~e ~ommueasion
and control unit C~C a~ now cell~ ~n~, ~n sne l~cer _a~e,
t~e cell eo ~e ~lvi~ g ic~ e~u_g~ ~y th~
eransmitted power decre~se. ~ em~/ning ~rea ~u~ 3eing
covered t,~ a new cell, w~ic~. ~es~!~s ~n ~^ve~l ~Lcrocells
lnstead of one macrocell.
T~e invention ~ein~ d~scri~e~. it ~hall ~e
understood t~at several mo~ n~ ~n~ v~rl~ ons may ~
W092/21215 11 PCT/BR92/~WXK
2~87~2
made thereto, provided that such mod-f_c tions and variations
do nat depart from the spir~t ~n~ scope of the invention as
defined in the appended claims.
