1.Basic qauv ntawm PON
PON (Passive Optical Network)
PON yog ib leeg-fiber bidirectional optical access network siv point-to-multipoint (P2MP) qauv. PON system yog tsim los ntawm cov kab hluav taws xob kho qhov muag (OLT), ib qho kev faib khoom kho qhov muag (ODN), thiab chav tsev kho qhov muag (ONU) ntawm tus neeg siv sab ntawm lub chaw ua haujlwm hauv nruab nrab, thiab yog ib txoj kab hluav taws xob bidirectional. Nyob rau hauv lub downstream kev taw qhia (OLTto ONU), lub teeb liab xa los ntawm lubOLTmus txog ib leegONUlos ntawm ODN.Nyob rau hauv cov kev taw qhia upstream (ONUto OLT), lub teeb liab xa los ntawm lubONUyuav tsuas mus txog lubOLTthiab yuav tsis ncav cuag lwm yamONUsTxhawm rau kom tsis txhob muaj cov ntaub ntawv sib tsoo thiab txhim kho kev ua haujlwm hauv network, cov kev taw qhia uplink txais TDMA ntau hom kev nkag, thiab tswj cov ntaub ntawv xa mus ntawm txhua qhov.ONU. ODN muab optical channels ntawm lubOLTthiab covONU. Cov qauv siv ntawm PON yog qhia hauv daim duab hauv qab no.
PON system siv cov qauv
CovOLTyog nyob rau ntawm lub network sab thiab muab tso rau ntawm qhov chaw ua haujlwm hauv nruab nrab. Nws tuaj yeem yog L2hloovlub l3router, muab kev sib tham hauv network thiab nkag mus, ua kom muaj kev hloov kho qhov muag / hluav taws xob, kev faib bandwidth, thiab kev tswj hwm ntawm txhua txoj kev sib txuas, nrog kev saib xyuas thiab kev tswj xyuas lub sijhawm. Thiab txij nkawm ua haujlwm. CovONUyog nyob rau ntawm tus neeg siv sab los siv kev ua thiab kev tswj xyuas ntawm ntau yam hluav taws xob teeb liab, thiab muab cov neeg siv-sab interface. CovOLTthiab covONUyog txuas los ntawm passive optical splitter, thiab cov optical splitter yog siv los faib cov ntaub ntawv downlink thiab sau cov ntaub ntawv uplink. Ntxiv nrog rau cov khoom siv davhlau ya nyob twg, PON system tsis xav tau cov khoom siv hluav taws xob thiab yog li ntawd tsis muaj zog.
Lub PON txais yuav lub wavelength division multiplexing (WDM) technology nrog downlink 1490 nm / uplink 1310 nm wavelength ua ke ntawm ib qho fiber ntau. Cov kev taw qhia uplink yog hom taw tes rau-taw tes, thiab cov kev taw qhia downlink yog hom tshaj tawm. Daim duab hauv qab no qhia txog cov qauv ntawm PON.
Basic network qauv ntawm PON
Nyob rau hauv lub downstream kev taw qhia, lubOLTxa cov ntaub ntawv rau txhua tusONUsnyob rau hauv ib qho kev tshaj tawm, txhua pob ntawv nqa ib header nrog ib tug kis mus rau qhov chawONUtus cim. Thaum cov ntaub ntawv tuaj txog ntawm lubONU, MAC txheej ntawm lubONUua qhov chaw nyob daws teeb meem, rho tawm cov ntaub ntawv pob khoom uas yog nws tus kheej, thiab pov tseg lwm cov ntaub ntawv pob khoom.
Cov kev taw qhia uplink siv sij hawm Division Multiplexing (TDM) technology, thiab cov ntaub ntawv uplink ntawm ntau yamONUstsim TDM cov ntaub ntawv kwj kom xa mus rauOLT.
2. Optical kab davhlau ya nyob twg (OLT)
Optical kab davhlau ya nyob twg (OLT) ua haujlwm los muab kev sib txuas kho qhov muag ntawm qhov kev pabcuam network thiab ODN, thiab muab ntau yam kev xa mus rau ntau yam kev pabcuam. CovOLTyog sab hauv tsim los ntawm cov txheej txheem tseem ceeb, txheej txheej kev pabcuam, thiab txheej txheej pej xeem. Cov txheej txheem kev pabcuam tsuas yog muab cov chaw nres nkoj pabcuam thiab txhawb nqa ntau yam kev pabcuam; cov txheej txheem tseem ceeb muab kev sib txuas, kev sib txuas, thiab kev sib kis; thiab cov txheej txheem pej xeem muab cov khoom siv hluav taws xob thiab kev tswj xyuas kev ua haujlwm.
Lub xub ntiag ntawmOLTtuaj yeem txo cov kev sib txuas nruj ntawm cov txheej txheem kev pabcuam sab saud thiab cov kev sib txuas tshwj xeeb, tus tuav, kev sib txuas lus, thiab kev tswj xyuas cov cuab yeej siv, thiab tuaj yeem muab kev sib koom ua ke kho qhov muag nkag network tswj interface.
Cov haujlwm tseem ceeb ntawm covOLTsuav nrog: kev sib sau ua ke faib ua haujlwm thiab DN hloov ua haujlwm.
CovOLTkev pab cuam interface muaj xws li: kev pab cuam chaw nres nkoj muaj nuj nqi, kev pab cuam interface adaptation muaj nuj nqi, interface signaling ua, thiab kev pab cuam interface tiv thaiv.
CovOLTCov haujlwm feem ntau suav nrog OAM cov haujlwm thiab cov khoom siv hluav taws xob.
Optical zog emitted los ntawm lubOLTfeem ntau yog siv rau hauv cov chaw hauv qab no.
Splitter: Qhov ntau dua ntawm shunts, ntau dua qhov poob.
l Fiber: qhov ntev ntawm qhov kev ncua deb, qhov poob ntau dua.
l ONU: Tus lej ntau dua, qhov ntau duaOLTxa hluav taws xob xav tau. Txhawm rau kom ntseeg tau tias txhua lub zog ncav cuagONUyog siab tshaj qhov tau txais rhiab heev thiab muaj ib tug tej yam margin, cov peev nyiaj yuav tsum tau raws li qhov tseeb kom muaj nuj nqis thiab geographic faib.
3.Optical faib network
Optical distribution network (ODN) yog ib txoj hauv kev los muab kev sib kis ntawm qhov muagOLTthiab covONU. Nws lub luag haujlwm tseem ceeb yog ua kom tiav cov ntaub ntawv xa tawm thiab kev faib tawm ntawm covOLTthiab covONU, thiab tsim kom muaj qhov kawg-rau-kawg cov ntaub ntawv kis tau tus mob channel ntawm covONUthiab covOLT.
ODN configuration feem ntau yog point-to-multipoint hom, uas yog, ntauONUstxuas nrog ib qhoOLTlos ntawm ib qho ODN, kom ntauONUstuaj yeem qhia qhov nruab nrab kis tau tus mob ntawm qhov muagOLTthiab ODN thiab optoelectronic ntaus ntawv ntawm lubOLT.
(1) Kev sib xyaw ntawm ODN
Lub ntsiab passive Cheebtsam uas ua rau ODN yog: ib hom fiber ntau thiab fiber optic cable, connectors, passive optical splitters (OBD), passive optical attenuators, thiab fiber optic connectors.
(2) Topological qauv ntawm ODN
Lub topology ntawm ODN network feem ntau yog ib qho taw tes-rau-ntau tus qauv, uas tuaj yeem muab faib ua lub hnub qub, tsob ntoo, tsheb npav, thiab lub nplhaib.
ODN network qauv
(3) Cov chaw rau kev tiv thaiv nquag thiab standby
Qhov chaw ua haujlwm / standby tiv thaiv ntawm ODN network feem ntau yog teeb tsa ob qhov kev sib kis kab mob rau cov teeb liab kho qhov muag kis los ntawm ODN network. Thaum thawj channel ua tsis tiav, nws tuaj yeem ua tiavhloovmus rau lwm qhov channel kom xa cov teeb liab kho qhov muag, suav nrog cov fibers optical,OLTs, ONUs, thiab Thawj thiab thaub qab kev tiv thaiv chaw ntawm kev sib kis fiber ntau.
Lub ntsiab thiab standby kis tau tus mob fibers yuav nyob rau hauv tib optical cables los yog nyob rau hauv txawv optical cables. Lub ntsiab thiab thaub qab optical cables tuaj yeem ntsia tau rau hauv cov kav dej sib txawv, kom kev tiv thaiv kev ua tau zoo dua.
(4) Optical kis tus yam ntxwv ntawm ODN
ODN cov qauv tsim yuav tsum xyuas kom meej tias cov kev pabcuam tam sim no tuaj yeem muab tau yam tsis muaj kev hloov pauv loj, qhov yuav tsum tau muaj kev cuam tshuam loj rau cov yam ntxwv ntawm ntau yam passive Cheebtsam. Cov kev cai uas yuav cuam tshuam ncaj qha rau cov yam ntxwv kho qhov muag ntawm ODN yog raws li hauv qab no.
l Optical wavelength transparency: Ntau yam khoom siv kho qhov muag tsis pom kev yuav tsum tsis txhob cuam tshuam qhov pom ntawm cov teeb liab kis tau tus mob. Cov teeb liab kho qhov muag xav tau los ntawm kev tsim kho qhov muag network yuav tsum tau pob tshab, yog li muab kev siv WDM rau yav tom ntej. Lub hauv paus.
l Reversibility: Thaum cov zis thiab cov tswv yim ntawm ODN network hloov pauv, cov yam ntxwv sib kis ntawm ODN network yuav tsum tsis txhob hloov pauv loj, uas yog, kev hloov pauv ntawm kev sib kis bandwidth thiab cov yam ntxwv tsis zoo yuav tsum tsawg. Qhov no simplifies tus tsim ntawm lub network.
l Kev sib raug zoo ntawm kev ua haujlwm hauv lub network: ODN network yuav tsum tuav cov teeb liab kho qhov muag zoo ib yam. Cov yam ntxwv sib kis ntawm ODN network yuav tsum ua raws li tag nrho OFSAN thiab tag nrho cov kev sib txuas lus network. Kev sib kis bandwidth thiab optical poob yam ntxwv yuav tsum haum rau tag nrho OFSAN.
(5) ODN kev ua haujlwm tsis zoo
Cov kev txwv uas txiav txim siab qhov kho qhov muag channel poob kev ua haujlwm ntawm tag nrho cov kab ke yog cov hauv qab no.
l ODN optical channel poob: qhov sib txawv ntawm qhov tsawg kawg nkaus xa hluav taws xob thiab qhov siab tshaj plaws tau txais rhiab heev.
l Qhov siab tshaj plaws tso cai tsis tau channel: qhov sib txawv ntawm qhov siab tshaj plaws xa hluav taws xob thiab qhov siab tshaj plaws tau txais rhiab heev.
l Yam tsawg kawg nkaus tso cai tsis tau: qhov sib txawv ntawm qhov tsawg kawg nkaus xa hluav taws xob thiab qhov qis tshaj tau txais rhiab heev (overload point).
(6) Kev xav ntawm ODN
Qhov kev xav ntawm ODN nyob ntawm qhov rov qab poob ntawm ntau yam khoom uas ua rau ODN thiab txhua qhov kev xav ntawm qhov chaw kho qhov muag. Feem ntau, txhua qhov kev xav tsis sib xws yuav tsum zoo dua—35 dB, thiab qhov siab tshaj plaws discrete reflection ntawm fiber ntau nkag yuav tsum zoo dua—50dB ib.
4. Optical Network Unit (ONU)
Optical network unit (ONU) yog nyob nruab nrab ntawm ODN thiab cov neeg siv khoom siv, thiab muab kev sib txuas kho qhov muag ntawm tus neeg siv thiab ODN thiab ib qho hluav taws xob cuam tshuam nrog cov neeg siv sab los siv kev ua thiab kev tswj xyuas ntawm ntau yam hluav taws xob teeb liab. CovONUyog tsim los ntawm cov txheej txheem tseem ceeb, txheej txheej kev pabcuam, thiab txheej txheej pej xeem. Cov txheej txheem kev pabcuam feem ntau yog hais txog cov neeg siv cov chaw nres nkoj; cov tub ntxhais txheej muab multiplexing thiab optical interfaces; thiab cov txheej txheem pej xeem muab cov khoom siv hluav taws xob thiab kev tswj xyuas.
5. PON daim ntawv thov hom
PON kev lag luam pob tshab yog qhov zoo, thiab hauv txoj cai tuaj yeem siv rau txhua tus qauv thiab tus nqi teeb liab. Piv nrog rau point-to-point active optical networks, PON thev naus laus zis yog tus cwj pwm los ntawm kev saib xyuas yooj yim, tus nqi qis (txuag fiber ntau thiab optical interfaces), kev sib kis bandwidth siab thiab kev ua haujlwm siab tus nqi piv. Cov yam ntxwv no yuav ua rau nws muaj kev sib tw kom zoo dua rau lub sijhawm ntev, thiab PON ib txwm raug suav tias yog kev txhim kho yav tom ntej ntawm kev nkag mus rau hauv lub network.
Daim ntawv thov tsim nyog tshaj plaws rau PON yog: ib feem ntawm kev nkag mus rau lub network ze rau qhov kawg ntawm cov neeg siv khoom; tus neeg siv khoomONUkev pabcuam tsis hais txog qhov xav tau kev rov ua dua lossis kev tiv thaiv hla; tusOLTtuaj yeem teeb tsa ntawm lub node nrog kev ua tau zoo ntawm kev ciaj sia (piv txwv li, lub pob nrog kev tiv thaiv roundabout). Ib qho chaw uas cov neeg siv nyob hauv thaj chaw muaj kev xav. PON feem ntau muaj peb hom kev thov.
(1) Hloov cov txheej txheem sib sau ua ke uas twb muaj lawm: PON tuaj yeem hloov cov txheej txheem 2 uas twb muaj lawmhloovthiab kho qhov muag transceiver, thiab coj tus nkag mus rau hauv lub network ntawm LAN mus rau IP lub nroog cheeb tsam network, raws li qhia hauv daim duab:
PON hloov Layer 2 network uas twb muaj lawm
(2) Hloov cov khoom siv hluav taws xob ntawm cov kab lus cuam tshuam: PON system tuaj yeem hloov qhov uas twb muaj lawm ntawm cov khoom siv kho qhov muag thiab cov khoom siv hloov kho qhov muag, yog li txuag cov khoom siv cable ntawm cov kab lus cuam tshuam, raws li qhia:
PON hloov cov ntu cuam tshuam kom nkag mus rau qhov muag cable
(3) Multi-service access mode (xws li FTTH): Lub PON system tuaj yeem muab ntau qhov kev pabcuam thiab ntau tus nqi nkag uas ua tau raws li QoS cov kev xav tau sib txawv, thiab tuaj yeem hloov mus rau ntau haiv neeg ntawm cov neeg siv thiab tsis paub meej ntawm kev txhim kho kev lag luam, raws li qhia hauv daim duab hauv qab no:
Kev siv ntau yam