CATV ne wo k e olu ion
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CATV NETWORK EVOLUTION
J. Hlubík, L. Schwa z, V. Ho ma
Uni e si y o Zilina, Facul y o Elec ical Enginee ing, Depa men o Telecommunica ions
Uni e zi na 1, 010 26 Zilina, Slo ak Republic
hlubik@ el.u c.sk, schwa z@ el.u c.sk, ho ma @ el.u c.sk
Summa y Cable ele ision (CATV) dis ibu ions a e ansmissions sys ems assigned o ecei ed and dis ibu ion ele isions
(TV) and adios (R) signals. This pa ag aph is abou indi idual s ages o e olu ion o his dis ibu ion. I begins by classic CATV
ne wo k by using coaxial cable hen i con inues by mode niza ion o op ical ib e. I desc ibes s uc u e and wo-way
communica ion o in e ac i e TV cable dis ibu ion ame and i desc ibes in elligence o his ne wo k. By implemen a ion
in e ac i i y we can no unde s and i as he CATV ne wo k as only dis ibu ions sys em which ans e s only TV and R signals
bu like mul i unc ional sys em which can ans e in o ma ion by bo h di ec ions.
1. INTRODUCTION
Tele ision cable dis ibu ion CATV was sugges ed as
dis ibu ion sys em which should ans e analog
ele isions canals o maximum coun s o cus ome s in
lowes possible cos s. In nine ie h wi h coming DBS
(Di ec B oadcas Sa elli e) and DSL (Digi al
Subsc ibe Line) ope a o s p o ided cable TV mus
igh wi h his compe ing echnologies o posi ion on
he ma ke . DBS ope a o s o e ed mo e op ions and
be e ision quali y ia digi al echnology, while
DSL echnology sugges ed oice, ideo and da a
ans e h ough DSL. Wo ies o loss pa icipa ion
on he ma ke o ced ope a o s CATV o o e bigge
op ions o se ices. A he p esen ime he ambi ion
o CATV is o dis ibu e no only ele ision TV and
adio R signal bu also o e use s in e ac i e access
o hei se ices as e.g. a e elec ical mail,
ideophone, ideo-con e ence, in e ac i e
in o ma ions sea ching, ideo on demand (VoD) e c.
The ambi ion is also o implemen so wa e and
ha dwa e equipmen o he ne wo k, which gua an ee
speci ic in elligence o his ne wo ks.
2. TELEVISION CABLE NETWORK WITH
COAXIAL CABLES - CATV
Coaxial cable echnology is used om he beginning
o cable dis ibu ion. I s big ad an age is inancial
unp e en iousness conce ning ne wo k building-up.
TV and R signals assigned o ans e o CATV
membe s a e eed in o main s a ion h ough head-end
om indi idual an ennas, e en ually by cable splice,
adio elay splice e c. In main s a ion a e his signals
p ocessed, ampli ied and changed in o ano he
equency posi ion acco ding he need. On exi main
s a ion a e his signals se in o he channel acco ding
espec i e s anda d and a e ansmi ed h ough di ec
b oadcas channel. This b oadcas channel is on his
exi main s a ion connec ed on one e en ually on
mo e coaxial cables, which a e pa o dis ibu ion
ne wo k (Fig. 1).
Dis ibu ion ne wo k is usually ealized in hie a chal
o de in ee s uc u e, wi h g adual b anching om
main s a ion.
I s le els a e:
1. P ime ne wo k - sa egua ds ans e o signals on
bigge dis ances.
2. Seconda y ne wo k - sa egua ds ans e o
signals on smalle dis ances, usually di ec ly o
indi idual objec s o o g oups o objec s
(house).
3. Te ia y ne wo k - sa egua ds ans e o signals
on pa icipan s socke s, which a e inpu spo s
Ad ances in Elec ical and Elec onic Enginee ing
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o cable TV and h ough which a e signals
eeding di ec ly on TV and R ecei e .
3. HYBRID TELEVISION CABLE NETWORK -
HFC
By in luence o cus ome ising, by incoming o da a
se ices and by dis ibu ion sa eli s TV chanells ha e
coaxial cables insu icien wa e-lengh s and big
signal damping, which mus be s onge . This
p oblem can be emo ed by using op ical ibe which
ha e b oadband, small abso bing signals, no spu ious
adia ion, small pa ame e s, e c. HFC ne wo k is
c ea ed by op ical ibe om he main s a ion o he
op ical node (op ical-elec ic con e e ) and by
coaxial cable om he op ical node o he pa icipan .
Op ical pa o ne wo k consis s o op ical
ansmi e s, op ical ibe and om op ical accep o s.
I can con ain ano he componen s oo, e.g. op ical
ampli ie s, op ical couple s, e c.
We know 3 ypes o op ical sys em con igu a ions
(OS):
1. Simple OS – can eplace coaxial cable in
maximum le el o dis ibu ion ne wo k
(Fig. 2).
Can be con igu a ion:
• poin o poin
• poin - o mul ipoin
2. OS wi h epea ing – allows o ealize bigge
ne wo k con igu a ions on sho e dis ance
(Fig. 3).
3. OS wi h op ical ampli ie – is possible class also
se e al ampli ie o cascade and so ealize
la ge CATV ne wo ks (Fig. 4). [2]
On Fig. 5 is one om possible ealiza ions o hyb id
ne wo k, whe e p ime ne wo k is sol ing by op ical
ing s uc u e wi h 1550 nm o wa e-leng h. Op ical
sys ems in dis ibu i e nodes con inue by 1310 nm o
wa e-leng h. These can be sol ing by ing o s a
s uc u e. On op ical node a e a ached sho coaxial
ne wo ks up o he cus ome .
CATV ne wo k e olu ion
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4. INTERACTIVE TELEVISION CABLE
NETWORK - ICATV
In e ac i e ele ision cable dis ibu ions a e sys ems,
which o e o pa icipan an in e ac i e access o
in o ma ions. In e ac i e access o se ices is ealized
on he basis o equisi ions om pa icipan s o main
s a ion. I pa icipan wan o ha e an access o
in o ma ions mus be ICATV ne wo k equipped by
back-channel and by echnical acili ies, which
minimally p o ide:
• Manage in o ma ion ans e in s aigh and
back di ec ion
• Selec i e access o in o ma ion sea ching
and i s heading o pa icipan
• P o ec he in o ma ion agains abuse by
illegal access
Fo p o ision o in e ac i e se ices a e necessa y
wo ypes o ansmission channel:
1. Downs eam - is headed om main s a ion o
pa icipan .
2. Ups eam – is headed om pa icipan o
main s a ion. By i a e ans e ed eques s o
cus ome s abou se ices. [3]
S uc u e ICATV ne wo k which p o ides in e ac i e
access o pa icipan s o in o ma ions is on he Fig. 6.
Concep ion o his ICATV ne wo k is de ined as open
wo-s age sys em.
• Fi s s age is cha ac e ized as he cen e o TV
cable dis ibu ion CCATV, which is
“concen a o o se ices”. I allows access
o uppe le el o ne wo k, manage
ansmission be ween CCATV and managing
cen e o home ne wo k MCHN.
• Second s age is cha ac e ized as g oup o inal
pa icipan s bo de lines EUB (End use box)
connec ed o MCHN. Managing cen e o
home ne wo k om in o ma ion aspec
con ains subse o se ices concen a ed in
CCATV and comple e se o se ices connec
o da abase o pa icipan s, who a e indi idual
EUB. Managing cen e o home ne wo k
manages communica ion wi hin second s age,
whe e EUB allows selec i e access o
pa icipan s o se ices and da a in MCHN.
Two-di ec ional communica ion in ICATV ne wo ks
Two-di ec ional is secu ed by equency mul iplex o
backwa d and s aigh ansmission. Swi ches a e
sol ing by pa allel combina ion o high pass H (in
s aigh di ec ion) and low pass il e D (in back
di ec ion).
S uc u e o wo-di ec ional communica ion in ICATV
ne wo k
1. Sha ing o one e ace zone by all pa icipan s
connec ed o one main s a ion. Typical o
olde o smalle CATV ne wo k wi h small
eques o ansmission in e ace and o wo-
di ec ional communica ion (Fig. 7.a).
2. Hyb id s uc u e wi h selec i e ansmission o
indi idual zone o e ace (Fig. 7.b).
3. Hyb id s uc u e wi h ne wo k pa i ion in o he
segmen s in which can by ans e signals o
wo-di ec ional communica ion (Fig. 7.c).
To sol e wo-di ec ional communica ion a e a ailable
di e en solu ions om simple o small a ic ill o
mo e complica ed and s ong a ic wi h big numbe o
pa icipan s wi h high equi emen s o in o ma ion
con en . [2]
Ad ances in Elec ical and Elec onic Enginee ing
30
5. INTELLIGENT ICATV NETWORK
In elligence is ac s ecogni ion and esea ch, i is
analyse and educ ion o logical esul s. Te m
in elligen ICATV ne wo k is no new ne wo k,
which is sepa a e om al eady exis ing ICATV
ne wo k, bu is concep ion, which will ill exis ing
ICATV ne wo k abou new unc ions o cus ome s.
By applica ion o o he se ices will be c ea e
condi ions o mo e ex ensi e using o ne wo k by
cus ome s and also ise in ea nings o pa icipan s o
cable dis ibu ion. [4] Cons uc ion and se ice o
in elligen ICATV ne wo k equi es ela i ely no
much new echnical de ices owa d cons uc ion
ICATV whe e we mus exp essi ely in e ene in o
he s uc u e o ne wo k by building backwa d
channel and also by plan and building CCATV and
MCHN. New unc ions o ne wo k a e ealized
mos ly by p og am de ices implemen in o he
al eady exis ing de ices. To be concep ion o
in elligen ICATV able o change as acco ding he
cus ome s, i mus ha e e icien lexible managemen
de ices. Block o se ices managemen ealizes con ol
o se ice p og ess, and also managemen o se ice.
As example o conc e e unc ions is possible p esen
da abase adminis a ion, da a eques s abou ne wo k,
and also con olling and es ing he ne wo k. In elligen
communica ion ne wo k mus be a leas able o p o ide
and communica e wi h su oundings, make decision,
use and e ec i ely manage he ne wo k de ices.
6. CONCLUSION
Ne wo k in elligence will e ol e h ough g ow h in
compu a ional powe and h ough he accumula ion o
knowledge abou he ypes o inpu da a needed o
making decisions conce ning expec ed esponse, and
abou he algo i hmic p ocessing equi ed in a complex
and changing communica ions en i onmen .
Inc easingly sophis ica ed ne wo k in elligence makes
possible lookahead planning, managemen be o e
esponding and easoning abou he p obable esul s o
al e na i e ac ions. These in elligen ne wo k
capabili ies can p o ide se ice p o ide s wi h
compe i i e and ope a ional ad an ages o e adi ional
ne wo ks. [5] Ne wo k in elligence will be de elop wi h
inc eased powe o compu e echnique, wi h capaci y
da a inc ease o incoming s a emen s, which a e
nessece y o c ea ion solu ion abou expec ed esul and
equi ed algo i hm which eac s o change o
communica ion su oundings.
Acknowledgemen
The au ho s g a e ully acknowledge suppo om he
VEGA p ojec No. 1/2043/05 ” The Sys ems o
In eac i e Cable Tele ision ICATV”.
REFERENCES
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k/i o_doc/cable.h m
[2] Dianiška, S.: Sie e káblo ej ele ízie – Pa ame e a
š uk ú y, Vyda a es o NOI B a isla a, 2001
[3] Ho ma V.: Výkonnos ný model ýpo o ých
sys émo sie e ITKR, yda a es o ŽU, 2004
[4] Bluna , K.: Telekomunikané Sie e, EDIS –
yda a es o ŽU, 2000
[5] Volne , R.: BioMedical In elligence Secu i y Home
Ne wo k – ATM/IP CATV Ne wo k, Czech
Technical Uni e si y in P ague, 2004