CA2092297C - Passive optical network - Google Patents
Passive optical networkInfo
- Publication number
- CA2092297C CA2092297C CA002092297A CA2092297A CA2092297C CA 2092297 C CA2092297 C CA 2092297C CA 002092297 A CA002092297 A CA 002092297A CA 2092297 A CA2092297 A CA 2092297A CA 2092297 C CA2092297 C CA 2092297C
- Authority
- CA
- Canada
- Prior art keywords
- head
- receiver
- transmitter
- data
- end station
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
- H04B10/0795—Performance monitoring; Measurement of transmission parameters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/27—Arrangements for networking
- H04B10/272—Star-type networks or tree-type networks
Abstract
A head-end station (1) for a passive optical network system arranged to transmit and receive TDMA frames comprising a header portion and a plurality of basic frames, each basic frame comprising traffic bits and control bits. The head-end station (1) includes a data transmitter which assembles and transmits downstream frames and also generates a diagnostic signal for transmission in a downstream frame, the station being switchable to a diagnostic mode in which it transmits the diagnostic signal in a downstream frame in the absence of other traffic, and also including a data receiver which receives upstream frames and detects a return of the diagnostic signal. In a preferred example, the head-end station (1) may transmit a diagnostic signal in the header portion (H) of each downstream frame. Also, in a test mode the transmit signal is looped back to the receiver to enable testing of the transmit/receive function. Loop back is provided at three levels, namely the transmitter drive level, the monitored output level and at the laser output/receiver input level.
Description
92/07432 ~ g 3 2 2 ~ 7 PCT/GB91/01815 PA5S}V~ o~r~r. N~:lWOR~
The present lnvent~on ~ela;es to a passive op~ical network ~PON) system, and ~n par-~cular to a head-end qtation for use in such a PON sys.em.
The present applLcan~ nas deveiope~ a bi- ~_ansport system (BTS~ 40r use _-. a TP~N ~Tetephony on a Passive Optical Netwosk) SyStQm. .n th;s 3~S, a head-enc seat~on broadca~ts tl~e di-~isio. m~!~;-!e access (TDMA~ C_3mes eo all the term~nations o~. the ne;-~o~k. The ~ransmitted fr~m-s inc~ude both t-a'~ ata and control data. ~ach termination recoqnlses and -Q5pOnd, ~e an appro?r.ate!~
addressed por-~on of the ~ata L-. ~.-e oroadcast ~:ame and ignores thQ remaindQ: o' .~e f_amQ
In ehe upse:eam ~.rsc~:e-.. Qach tsrm~nation :ransmlts daea ~n a prQdQte:m.nQd -~mQ s~oe and ~hg data 1$ f~om the diffQrQn- ~QsmlnaaLons are assQm~Led at hQad-Qnd ln~o a TDM~ f,ame o' ~:adqc~rminQd format.
Acccrdlng 'o ~ha ?:QSan' ~nventian. ~hes~ LS
p~ovlded a head-snd stae~3n ~a- ~ pass~vQ opt~ca~ n~e~o-~sy-t~m arranaQA to ~~ansmL~ 3nd _4C9i VQ TOP~ '.ames 20 comp~islng a heed~s po:~.on anc~ a plura~lt~ o' oesLc 'rames, ~ach bas~ ~:a;~e ~ p~ na 3 ~lur~ ; o~
e:af~c ~ts and a ~a~ ca~.e:o' ~L-'S ~ o~d-Qnd sea~on ~Q~ng ~wLec~a~ 4ew~Qn an opora-Lonal modQ
L n W~li C ~ .. a nl: mL ~ 4 ~ g .. ~ 0~ ~ -~m~ s ~l n~l ~
The present lnvent~on ~ela;es to a passive op~ical network ~PON) system, and ~n par-~cular to a head-end qtation for use in such a PON sys.em.
The present applLcan~ nas deveiope~ a bi- ~_ansport system (BTS~ 40r use _-. a TP~N ~Tetephony on a Passive Optical Netwosk) SyStQm. .n th;s 3~S, a head-enc seat~on broadca~ts tl~e di-~isio. m~!~;-!e access (TDMA~ C_3mes eo all the term~nations o~. the ne;-~o~k. The ~ransmitted fr~m-s inc~ude both t-a'~ ata and control data. ~ach termination recoqnlses and -Q5pOnd, ~e an appro?r.ate!~
addressed por-~on of the ~ata L-. ~.-e oroadcast ~:ame and ignores thQ remaindQ: o' .~e f_amQ
In ehe upse:eam ~.rsc~:e-.. Qach tsrm~nation :ransmlts daea ~n a prQdQte:m.nQd -~mQ s~oe and ~hg data 1$ f~om the diffQrQn- ~QsmlnaaLons are assQm~Led at hQad-Qnd ln~o a TDM~ f,ame o' ~:adqc~rminQd format.
Acccrdlng 'o ~ha ?:QSan' ~nventian. ~hes~ LS
p~ovlded a head-snd stae~3n ~a- ~ pass~vQ opt~ca~ n~e~o-~sy-t~m arranaQA to ~~ansmL~ 3nd _4C9i VQ TOP~ '.ames 20 comp~islng a heed~s po:~.on anc~ a plura~lt~ o' oesLc 'rames, ~ach bas~ ~:a;~e ~ p~ na 3 ~lur~ ; o~
e:af~c ~ts and a ~a~ ca~.e:o' ~L-'S ~ o~d-Qnd sea~on ~Q~ng ~wLec~a~ 4ew~Qn an opora-Lonal modQ
L n W~li C ~ .. a nl: mL ~ 4 ~ g .. ~ 0~ ~ -~m~ s ~l n~l ~
2~ dla~nostic modo ~n W~o~ ns-aeQ~ nnd c:ansm~Lts a d~a~ost~ al ~n~ * ~s~ aL ~.Q'''~O:'.~ sy5eQm and d-tocts any :~eu~n o~ C~.4 ~a~nost~c ~na~.
Con~or~:' onaL L ~;. wno n -.,Q..~ .-3 ~1 comp' Q c a:Qa~ :r.
tho notwor~ so e~ae e~e e~anomLss~s~ ~se~n t~4 h~Dd-~
30 statlon an~ :orm~natLons c~nn~c~4i to tho n~ewo-.~ is ineorruptod~ tt~ hoad ~nd seae~o.. ls ~lsa~LQd and dod~catQd tQSt ~uLpm~ne c~nn~cc~ to t~9 nQew3rk _..
ordor to locate ehQ ~aul~ Q ~r~sQn- ~nv~nt~3n provides a head-end stat:on wh~c~. is itself able to locate a faul~ in t;~e netwo~ s.ng a diagnostic mode which funct~ons in ~he absence of normal data transmissior.. Preferably, .he d~agnostic mode is entered automaticaily upon senslng ~he absence of upstream frames, whereby the faul_ ~caeLon ~s known and can be relayed to ~ainter.ance ,eaf' ;~_~aally ~mmediatel.- :he fault has occurred.
Prefer~bl~ e ..sa--sn~ s~at_cn incl ~dgs means C3 generate an autoco__ei3:~s O~ ?-obe as thQ dLagnos~c slgna}.
~ he ?ressrt a?p_~_a~.~ , _-.~~nat~o~.al .~p?_.ca~;3n No. GB90/01758 (?uDl.cae;on !lo. ~0~ 0882i ! d~scLoses a structure fo- e~e head-~nd s~a~:on ;n ~hich ~ -on~-o~
!5 procsssor a-ran~ed ~s .gc~ ontrol data ~C~ QS a parallei data ~np~ m ~ _ont_~l data à~ and a traffic in~erfacQ _9CQ~QS n_om~ng e affic data serial-to-parallal con~e -:4 _ ~ 4CQ~VQS ~nco~
frames, ~he parallel ouC?u~ ~ o~ Ch~ serLal~-a ?arall Qi convereer be~ng connQce~d .~. ~a~allQL eo th~ ~Qspac-~a LnPUtS Of C~a _On~-Q da;~ a~l'e- and C~ aflt.C
~neerfaCQ. .~ COm?1qm4n;ar~ ~e_~ re LS a~Qae~ j'O. a ~ata eransmL:e~- ~n cn~ n~d-~n~ s~aeLan Pref~r~ a~-~r.~ C L ~ 3 e a transm~et~s and daea .Q-~L'~ a-Q ~ncn:QnL;9~ ~~Lt~ a ~tc~a~ a~ b~t~ n~ -Q_ ~3nd :Q ~ ~ L ~Q -such ehae .n an apQra:.~n~l mod~ e~Q e;~Ln~ o~ C~Q
SQC Q L VQ: ~ t ~ Q ~ Q ~ a c ~ ~ - Q - ~.Q '~ L - - 9-- b'; 3 por~o~ ~on~ral'~; Qq~ ';~Q ~ a~ 0 ~0 ~y~tQ~, an~ 4S~ i'i9 ~La~ àQ-~Q~ .Q
tran~mlttQr and t~ rqc~L~*~ ub~eane~all~f Q~;mLnaeQd so ehat daea e:an~mLttQ~ ~s~m ens e:anqmLetQr an~ !oopQd-back Co th~ rQcR~vQr ~s a~L~n~d at ~Q ~-amQ ~4VQL.
92/07432 J - - ' J ;J 7 PCT~GB91/0181~
~ he present lnven~lon .:--ouc;~ :he use of upstream and downstream frames ~nlch are ~dentical ;n the~r general structure, althoug;~ di 'e:~ng ~n some detalls, makes it posslble to p~ovLde a loop-back test mode, n whlch ~y connectlng th_ ou-?~ e t_ansmlt:er ~o the input of the rece ve:, a-,d S~'-.C;-:0-.15' ng ;ne t:ming o-.he ~~ansml~er and -ece_~e~ ec~ compa~:so?. o.
~ransmL_~e~ ar.d -ece~e~ a c~ e made.
~ head-snd s~a~~ r,~o wl~ .e ?-esent iO ~:lVen~lOn Wl_' now oe aes--:oec .. leta_l wle.. _efe~ence ~o the accompany_ng drawL-,ss _-,~
~lgure : ~s a blo~;~ d a _~m ,,.ow:n, a ~?~ s~s~em:
Figure 2 ~s a d:ag_a.~ .o~ e ss_~_c ~~e o~
downs~_~am ~MA ~_ame:
:; Flgure 2 3now~ 3 '=~ n,.n~_~~ed ....... a d~ag~.o;~_ mode;
Figure ; ls a bloc.~ d.35~3m showing Cho n~ad-en~
station in greater deta~l:
Flaure 5 ~s a dia~ si~owL..~ ehe '~on~-~nd a' :~a head-en~ sta~'on; a..d 5 3 ~ _3~-a~ ~ow~ ata ~ransm~ttor and daea '4~ agQ3 n ~ Loop-ba~;~
conf i ~urae: o-~ T~a~ "~,'3 ee~ a~a~ ,3~
num3~ o~ ~Q-:~na~ n~ ~ 3a~L~ .Q
w~r ~ nk ~ q~ - 4 n~ ; ~a ~ L ~ ~ 2 . ~L~
tor:TLnae~on~ ~ Ale~o~ n~ 'or ~' a:L~ enLy ~r4e ~ ~ r .~ t ~ o ~ 9 g ~ .t'.~ 4 ~a~
t~rm;~nat~on$ ar~ conn~ e 4a~ s~n~' ~ n~a~-~nd o ~ t a t . ~ i r ~ ~ 7' ~ ' ~ '' ' ' a 10C~ p~o~a ~ an~ an~ ~.q -s~ naeLon~ .. a:e sl~b~crl~cr seat:ons ~n doa~ese~c a~ ~3~m~rcLal ~:Qmls~s or in ~e~-~e ca~in4es n c~ -.4~ a~ n00d o~t e'.-~s .~eal Qxc~lance .
? ~2?J97 ~ ~
The head-end statlon b-oadcasts data over the fibre network 3 as tlme dlvis on ~ultiple access frames (TDMA), the frames havlng a ~redetermined format. The frames include control channei, addressed to spec~C~c ; ones of the terminations ~ -3 control, amon~st other parameters, the ampl~t-~e an~ ng of .he opt_cal slgnals t_ansmitted on_o ~ho :b-e network 3 by ,:e term~nat~ons 2.
~ he u?stre ~ d -o-~_~-.. each ~er. n2~' C-. 2 ~ransm~ts data in a ?rnde~e_m:-.e- ~me slot. The data assembled ln~o a ~DMA f-ame a~ ~he nead-end s~a~ ~n :
T~e t'~lng o~ t:ansm~ss:3ns '~3..~ ~he ~orm~a~ or.s ' _, con~roiled to compensa~e ~ e d~ffer~n~ dei~, associated w~~;~ the c._f'e-e-.~ poss~'o~s of :~.e termlnatlons 2 on ~he f_b_e no~~o_:~ 3 Figure ~ shows ~;e s~_us-~~e o' -~o -.ead-s-.d station 1 The hsad-snd s~a~_3~. Lâ coupl~d -o ~hn ~ibrQ
nstwork 3 ~y an optica' ~nt~r~3ce ~'~? whic~ _ncludQs an optical 50urce and a pho~o-asnsi:_~e dQtec~o A 3T5 mas~sr aM comprlsQs a ~~a ~-3..sm~ whic~ 3~s~mblss lncomlng t-afflc r9C4;VQ~ '.'La an n~4 n nto downs;r~am T~A framQs~ A ~a~a r9CQi~Qr ~ ~3:-:QS
out thQ c~nvQrs 4 ?r~C45 S ~4mu_ :; ?i Q~; n~ ~nC~mL -.~ A
~-am~s a~ 3U-~U-' ~ 3 ~ e~an~ a~
25 XI/F.
Fl~ura ~ sho~s ~;-.Q ~ 4~ 9 ~ewe~n e;-4 ~ n~
of tha roc~Lv~r RX and op~ n~Qr~ac~ ~"~ Q
a~ ln-lLnQ ~mpll'LQ: ~ Q~ a ~
30 ana~oqu~ u~ ~ Q ~ 4~.~ A
callbratod mark~r pulse tq~o:atQd ~y a cLmL~g ~n:~ ;s rlmpo~od by an amplL ~La: ' l~ ~n eh~ sLqnal ac the analoguQ ~npu~ and ths ~ssuL~:~.q s~nal s~nc e~ a hLqh-spQQd ~JD convartar ~hLc~. ,ampi~s ~ anaL~u~ s.gnaL at ~5 a $amplin~ raee consLdQra~ nLqh~: c~an c'n~ ata of I~J ~ V ~ rd ~ 7 -;
the data making up the 'rame. The output of the A~D
co~verter lS processed by a host ~rocessor to recover any returned diagnostic s~g~al. The signal from the digital input is resampled by flip-flop ~ setimed by the master clock at the frame bit rate to p-ovLde the input for a signal recovery stage.
Figure 2 shows ths st-~c~l:e of a downs~:eam TDMA
frame assem~led b~f t~e _-3~sm:~ s;de of the ~S master.
The ~-affl~ is ca:r~e~ n a s-- es of 80 bas.c C-ames ~Fl, BF2 ,.... ~F80. As -~ei as '~52 traff__ b;t,, eac-basic f-ame contains Ln ad~-~_o~. ~44 con~roi Di~ ese contsol bits can ~e use~. aman.gs~ other ' nc::ons, ;o control the ampli~uàe a~ mLng of ~ransmlss;ons ~n the upstream di:èc~~cn f_~m ~~ 3at~0ns connectQd to t~e network, The seriss of 30 ~35~C 'rames is prQceded ~y ~
h~ader ~. 5'he p_ima-y pU:~OSQ O~ ehis hQadQ: is ;e prov~de a synchronisa~:~n ~:ame ~aving a pr~dec~ :mL ned ~1x~d bi~ pate~rn whLc;-~ ~s ~co~n_sed by t~e e~rm_naeLons and usqd to r~co~sr C~e syse~m cloc~ ~his 2C sync~ron~sation ~3et~:~. _-.C.'i~Q5. in e~e ~:~sene sm~odlmQne, a S9:LQ5 o~ t ?~ n~ i. Q. ~Q:O ~L
immedlaeoly prscQdi ng D e o t ~e ~as L c ':a~as 3Fl~
5'hQ daea '-ansm.;-~ ciuda~ mQanS tor gQnqrat~n~ as ~are c' e.-.g ~r4dgt9~.r~LnQd ~L' ~ae Q:n ' n 2S e~o h-ador, a d~agnose_~ sL~na~ s d~agnQs~c ;~nal ~ e~-n era~ :4~ 4 nQe~ w~e.~ a~ ue~Ln~
TD~A fram-. T~on ~ r~ LS pa::~al dlscon~~nu~ey .n ~ n4ewor.~ . a~ s~ ; a~ p4:~ç~
al~gn-d coupl~r, or a !'Law w~ n an op:~cai ~ ra. e~o d~a~nost~c s~nal ~s .çf'oc-ç~ ~,om -~9 ~areiai dlscone~nu~ey ~ack eowar~s eno 'noa~-ond seatLon. whQr4 L' ~s dot-ctQd by t~Q data :OC~L~4. ~X. ~Q ~Qad-ond ~eat~on is ar:angod eo ~n~raeo an approp~iaes 31arm s~gnal w~-n ~uc~. a fau~t _s ~oeoceo~
o ~
The diagnostl~ slgnal .akes the form of an autocorrelative OTD~ probe. It L5 encoded on the b~t seguence preceding the Ig6 nulls l-. the header H. The incoming slgnals a- the rece~ver .2X, including anv return of the OTDR probe are, as alrea~ escr~bed, sampled at high speea, ~he res~ data are then processed to aetect any occur-ence _c ~~e -e~u-.ed probe. '.~here suc;-a ret~-n LS ?resent, ~ co~.p_:ses not oniy ~;.e ~3ui~
response Oc _he ~e~~c-.- , s_~ ~ also :~.cl_~es ~e--~s ~0 correspondln~ ~o ~he enc3~Ln- Cunc~lon o~ e sutocorrela~ve ~i- p2~e~~. _' ~;~e ~ata ~s ;..e-. :.ea_e~
wlt~ a filter ma;chod :s :;~e ~-.c3~:ng _ ~nc~_3~ ese terms are ef.ec~:veiy co3ve~ed _n.~o ~he autoco_~elatLo~.
funct~ on of- .he enco~ se~uence. ~Q encod~5 Se~UQnCQ
1~ is chosen so tha. ~ s ~u~oco-relatLon ~~unc~Lon approximates ~o a s~mple del;a 'u..c:Lon, allow~n~ o~~
recovery of ~he Lmp~Lse -~soonse o~ thQ nQtwo~ om this recovered respons4. ~~e 30s~Lon and ~a~ de af thQ partial discontLn~L~~ can '~ d4Ce:m~nQd~
OCCasLonaii-~ e~Q may ~ a complet~ a~ .n ~
nQtwork. In ~QSQ ~_:sums~anc~s ~h~ normal ~-3~5mLS-~O
of data bs~ween tha hQad-on~ scaeion : and -~Q
~.~rmLnat~ons ~ ?~9~ A --~Q h~ad-mus t c ~a~ ~ C ~~s mL ~ Q
doeece~ ;~Q a~o..cQ o~ ~se:4am ~ramas and ;.. r~s?ons~
automatical'S sw~:c~.as ~ a A~agnoseLc ~o~o. A
manually-op-raeQd swLe~.~ can ~o p:o~id~d so e~ae an op~raec: ~ar. manua.'~ .o hQad-an~ ~n:o .-;
dlagnoselc mod-. ~n pLac~ o~ e~o no:~aL do~ns-:oam ~-amQ
Con~or~:' onaL L ~;. wno n -.,Q..~ .-3 ~1 comp' Q c a:Qa~ :r.
tho notwor~ so e~ae e~e e~anomLss~s~ ~se~n t~4 h~Dd-~
30 statlon an~ :orm~natLons c~nn~c~4i to tho n~ewo-.~ is ineorruptod~ tt~ hoad ~nd seae~o.. ls ~lsa~LQd and dod~catQd tQSt ~uLpm~ne c~nn~cc~ to t~9 nQew3rk _..
ordor to locate ehQ ~aul~ Q ~r~sQn- ~nv~nt~3n provides a head-end stat:on wh~c~. is itself able to locate a faul~ in t;~e netwo~ s.ng a diagnostic mode which funct~ons in ~he absence of normal data transmissior.. Preferably, .he d~agnostic mode is entered automaticaily upon senslng ~he absence of upstream frames, whereby the faul_ ~caeLon ~s known and can be relayed to ~ainter.ance ,eaf' ;~_~aally ~mmediatel.- :he fault has occurred.
Prefer~bl~ e ..sa--sn~ s~at_cn incl ~dgs means C3 generate an autoco__ei3:~s O~ ?-obe as thQ dLagnos~c slgna}.
~ he ?ressrt a?p_~_a~.~ , _-.~~nat~o~.al .~p?_.ca~;3n No. GB90/01758 (?uDl.cae;on !lo. ~0~ 0882i ! d~scLoses a structure fo- e~e head-~nd s~a~:on ;n ~hich ~ -on~-o~
!5 procsssor a-ran~ed ~s .gc~ ontrol data ~C~ QS a parallei data ~np~ m ~ _ont_~l data à~ and a traffic in~erfacQ _9CQ~QS n_om~ng e affic data serial-to-parallal con~e -:4 _ ~ 4CQ~VQS ~nco~
frames, ~he parallel ouC?u~ ~ o~ Ch~ serLal~-a ?arall Qi convereer be~ng connQce~d .~. ~a~allQL eo th~ ~Qspac-~a LnPUtS Of C~a _On~-Q da;~ a~l'e- and C~ aflt.C
~neerfaCQ. .~ COm?1qm4n;ar~ ~e_~ re LS a~Qae~ j'O. a ~ata eransmL:e~- ~n cn~ n~d-~n~ s~aeLan Pref~r~ a~-~r.~ C L ~ 3 e a transm~et~s and daea .Q-~L'~ a-Q ~ncn:QnL;9~ ~~Lt~ a ~tc~a~ a~ b~t~ n~ -Q_ ~3nd :Q ~ ~ L ~Q -such ehae .n an apQra:.~n~l mod~ e~Q e;~Ln~ o~ C~Q
SQC Q L VQ: ~ t ~ Q ~ Q ~ a c ~ ~ - Q - ~.Q '~ L - - 9-- b'; 3 por~o~ ~on~ral'~; Qq~ ';~Q ~ a~ 0 ~0 ~y~tQ~, an~ 4S~ i'i9 ~La~ àQ-~Q~ .Q
tran~mlttQr and t~ rqc~L~*~ ub~eane~all~f Q~;mLnaeQd so ehat daea e:an~mLttQ~ ~s~m ens e:anqmLetQr an~ !oopQd-back Co th~ rQcR~vQr ~s a~L~n~d at ~Q ~-amQ ~4VQL.
92/07432 J - - ' J ;J 7 PCT~GB91/0181~
~ he present lnven~lon .:--ouc;~ :he use of upstream and downstream frames ~nlch are ~dentical ;n the~r general structure, althoug;~ di 'e:~ng ~n some detalls, makes it posslble to p~ovLde a loop-back test mode, n whlch ~y connectlng th_ ou-?~ e t_ansmlt:er ~o the input of the rece ve:, a-,d S~'-.C;-:0-.15' ng ;ne t:ming o-.he ~~ansml~er and -ece_~e~ ec~ compa~:so?. o.
~ransmL_~e~ ar.d -ece~e~ a c~ e made.
~ head-snd s~a~~ r,~o wl~ .e ?-esent iO ~:lVen~lOn Wl_' now oe aes--:oec .. leta_l wle.. _efe~ence ~o the accompany_ng drawL-,ss _-,~
~lgure : ~s a blo~;~ d a _~m ,,.ow:n, a ~?~ s~s~em:
Figure 2 ~s a d:ag_a.~ .o~ e ss_~_c ~~e o~
downs~_~am ~MA ~_ame:
:; Flgure 2 3now~ 3 '=~ n,.n~_~~ed ....... a d~ag~.o;~_ mode;
Figure ; ls a bloc.~ d.35~3m showing Cho n~ad-en~
station in greater deta~l:
Flaure 5 ~s a dia~ si~owL..~ ehe '~on~-~nd a' :~a head-en~ sta~'on; a..d 5 3 ~ _3~-a~ ~ow~ ata ~ransm~ttor and daea '4~ agQ3 n ~ Loop-ba~;~
conf i ~urae: o-~ T~a~ "~,'3 ee~ a~a~ ,3~
num3~ o~ ~Q-:~na~ n~ ~ 3a~L~ .Q
w~r ~ nk ~ q~ - 4 n~ ; ~a ~ L ~ ~ 2 . ~L~
tor:TLnae~on~ ~ Ale~o~ n~ 'or ~' a:L~ enLy ~r4e ~ ~ r .~ t ~ o ~ 9 g ~ .t'.~ 4 ~a~
t~rm;~nat~on$ ar~ conn~ e 4a~ s~n~' ~ n~a~-~nd o ~ t a t . ~ i r ~ ~ 7' ~ ' ~ '' ' ' a 10C~ p~o~a ~ an~ an~ ~.q -s~ naeLon~ .. a:e sl~b~crl~cr seat:ons ~n doa~ese~c a~ ~3~m~rcLal ~:Qmls~s or in ~e~-~e ca~in4es n c~ -.4~ a~ n00d o~t e'.-~s .~eal Qxc~lance .
? ~2?J97 ~ ~
The head-end statlon b-oadcasts data over the fibre network 3 as tlme dlvis on ~ultiple access frames (TDMA), the frames havlng a ~redetermined format. The frames include control channei, addressed to spec~C~c ; ones of the terminations ~ -3 control, amon~st other parameters, the ampl~t-~e an~ ng of .he opt_cal slgnals t_ansmitted on_o ~ho :b-e network 3 by ,:e term~nat~ons 2.
~ he u?stre ~ d -o-~_~-.. each ~er. n2~' C-. 2 ~ransm~ts data in a ?rnde~e_m:-.e- ~me slot. The data assembled ln~o a ~DMA f-ame a~ ~he nead-end s~a~ ~n :
T~e t'~lng o~ t:ansm~ss:3ns '~3..~ ~he ~orm~a~ or.s ' _, con~roiled to compensa~e ~ e d~ffer~n~ dei~, associated w~~;~ the c._f'e-e-.~ poss~'o~s of :~.e termlnatlons 2 on ~he f_b_e no~~o_:~ 3 Figure ~ shows ~;e s~_us-~~e o' -~o -.ead-s-.d station 1 The hsad-snd s~a~_3~. Lâ coupl~d -o ~hn ~ibrQ
nstwork 3 ~y an optica' ~nt~r~3ce ~'~? whic~ _ncludQs an optical 50urce and a pho~o-asnsi:_~e dQtec~o A 3T5 mas~sr aM comprlsQs a ~~a ~-3..sm~ whic~ 3~s~mblss lncomlng t-afflc r9C4;VQ~ '.'La an n~4 n nto downs;r~am T~A framQs~ A ~a~a r9CQi~Qr ~ ~3:-:QS
out thQ c~nvQrs 4 ?r~C45 S ~4mu_ :; ?i Q~; n~ ~nC~mL -.~ A
~-am~s a~ 3U-~U-' ~ 3 ~ e~an~ a~
25 XI/F.
Fl~ura ~ sho~s ~;-.Q ~ 4~ 9 ~ewe~n e;-4 ~ n~
of tha roc~Lv~r RX and op~ n~Qr~ac~ ~"~ Q
a~ ln-lLnQ ~mpll'LQ: ~ Q~ a ~
30 ana~oqu~ u~ ~ Q ~ 4~.~ A
callbratod mark~r pulse tq~o:atQd ~y a cLmL~g ~n:~ ;s rlmpo~od by an amplL ~La: ' l~ ~n eh~ sLqnal ac the analoguQ ~npu~ and ths ~ssuL~:~.q s~nal s~nc e~ a hLqh-spQQd ~JD convartar ~hLc~. ,ampi~s ~ anaL~u~ s.gnaL at ~5 a $amplin~ raee consLdQra~ nLqh~: c~an c'n~ ata of I~J ~ V ~ rd ~ 7 -;
the data making up the 'rame. The output of the A~D
co~verter lS processed by a host ~rocessor to recover any returned diagnostic s~g~al. The signal from the digital input is resampled by flip-flop ~ setimed by the master clock at the frame bit rate to p-ovLde the input for a signal recovery stage.
Figure 2 shows ths st-~c~l:e of a downs~:eam TDMA
frame assem~led b~f t~e _-3~sm:~ s;de of the ~S master.
The ~-affl~ is ca:r~e~ n a s-- es of 80 bas.c C-ames ~Fl, BF2 ,.... ~F80. As -~ei as '~52 traff__ b;t,, eac-basic f-ame contains Ln ad~-~_o~. ~44 con~roi Di~ ese contsol bits can ~e use~. aman.gs~ other ' nc::ons, ;o control the ampli~uàe a~ mLng of ~ransmlss;ons ~n the upstream di:èc~~cn f_~m ~~ 3at~0ns connectQd to t~e network, The seriss of 30 ~35~C 'rames is prQceded ~y ~
h~ader ~. 5'he p_ima-y pU:~OSQ O~ ehis hQadQ: is ;e prov~de a synchronisa~:~n ~:ame ~aving a pr~dec~ :mL ned ~1x~d bi~ pate~rn whLc;-~ ~s ~co~n_sed by t~e e~rm_naeLons and usqd to r~co~sr C~e syse~m cloc~ ~his 2C sync~ron~sation ~3et~:~. _-.C.'i~Q5. in e~e ~:~sene sm~odlmQne, a S9:LQ5 o~ t ?~ n~ i. Q. ~Q:O ~L
immedlaeoly prscQdi ng D e o t ~e ~as L c ':a~as 3Fl~
5'hQ daea '-ansm.;-~ ciuda~ mQanS tor gQnqrat~n~ as ~are c' e.-.g ~r4dgt9~.r~LnQd ~L' ~ae Q:n ' n 2S e~o h-ador, a d~agnose_~ sL~na~ s d~agnQs~c ;~nal ~ e~-n era~ :4~ 4 nQe~ w~e.~ a~ ue~Ln~
TD~A fram-. T~on ~ r~ LS pa::~al dlscon~~nu~ey .n ~ n4ewor.~ . a~ s~ ; a~ p4:~ç~
al~gn-d coupl~r, or a !'Law w~ n an op:~cai ~ ra. e~o d~a~nost~c s~nal ~s .çf'oc-ç~ ~,om -~9 ~areiai dlscone~nu~ey ~ack eowar~s eno 'noa~-ond seatLon. whQr4 L' ~s dot-ctQd by t~Q data :OC~L~4. ~X. ~Q ~Qad-ond ~eat~on is ar:angod eo ~n~raeo an approp~iaes 31arm s~gnal w~-n ~uc~. a fau~t _s ~oeoceo~
o ~
The diagnostl~ slgnal .akes the form of an autocorrelative OTD~ probe. It L5 encoded on the b~t seguence preceding the Ig6 nulls l-. the header H. The incoming slgnals a- the rece~ver .2X, including anv return of the OTDR probe are, as alrea~ escr~bed, sampled at high speea, ~he res~ data are then processed to aetect any occur-ence _c ~~e -e~u-.ed probe. '.~here suc;-a ret~-n LS ?resent, ~ co~.p_:ses not oniy ~;.e ~3ui~
response Oc _he ~e~~c-.- , s_~ ~ also :~.cl_~es ~e--~s ~0 correspondln~ ~o ~he enc3~Ln- Cunc~lon o~ e sutocorrela~ve ~i- p2~e~~. _' ~;~e ~ata ~s ;..e-. :.ea_e~
wlt~ a filter ma;chod :s :;~e ~-.c3~:ng _ ~nc~_3~ ese terms are ef.ec~:veiy co3ve~ed _n.~o ~he autoco_~elatLo~.
funct~ on of- .he enco~ se~uence. ~Q encod~5 Se~UQnCQ
1~ is chosen so tha. ~ s ~u~oco-relatLon ~~unc~Lon approximates ~o a s~mple del;a 'u..c:Lon, allow~n~ o~~
recovery of ~he Lmp~Lse -~soonse o~ thQ nQtwo~ om this recovered respons4. ~~e 30s~Lon and ~a~ de af thQ partial discontLn~L~~ can '~ d4Ce:m~nQd~
OCCasLonaii-~ e~Q may ~ a complet~ a~ .n ~
nQtwork. In ~QSQ ~_:sums~anc~s ~h~ normal ~-3~5mLS-~O
of data bs~ween tha hQad-on~ scaeion : and -~Q
~.~rmLnat~ons ~ ?~9~ A --~Q h~ad-mus t c ~a~ ~ C ~~s mL ~ Q
doeece~ ;~Q a~o..cQ o~ ~se:4am ~ramas and ;.. r~s?ons~
automatical'S sw~:c~.as ~ a A~agnoseLc ~o~o. A
manually-op-raeQd swLe~.~ can ~o p:o~id~d so e~ae an op~raec: ~ar. manua.'~ .o hQad-an~ ~n:o .-;
dlagnoselc mod-. ~n pLac~ o~ e~o no:~aL do~ns-:oam ~-amQ
3~ ~t:~C~US~ oad~as~ t~m4 ~ a.~ a~-~3se~
s~gna~ but wle~oue any ~asLC ~amos. ~or 4aso of lmpl-m-neae~on~ t~a dLa~no~tic si~nal may ~OmprLS~ 9Lmply t~o ~ama hoad-r us-d in e~a convoncional ~ownstraam ~ramo. T~ arrang4mane ~s s~own ~n ~Lguca ~.
3S Aleornael~ol$~t~Q d~agno~e~c ~LgnaL may comp;Lsq a sLng~
G rt ~ " ~ 7 ~YO92/07432 PCT/CB91/0181~
,~ ", ,~
pulse. As a further alternat~e~ ~he frame may use a difSerent, more extendeh ?roDe aeGuence, effectively provlding a h-gher slgnal ~o ~o~se -a;io on any return, and so increasLng the apeed Wlt~ ~n c:~ the fault can be ; analyse~.
~i,aure o shows ~-.e da.a ~-ans~itte~ anc ~ata recelver n tno head-~nd s:a_:~.. : ~~r.nec~ed _n a loop-back conSigur~-lor.. Sucn a co-.~ on lS use~ eat the '~nc~ ~c_.g ~ .e ~ d-e-.~ ,ta:~on ! ~~- ~he output from the .:ansm~ - s~aae ~X Deln,a conne~a2c d~rec_Ly to ;;ne ir.?~ o. .-._ -oceLve: ~X. The 3ut?u~ of the transml;:er s;aae T''~ ~asses ~;-_~uah a sc_am~ler w~.ic.-changes the b:. orcer _~ acco~~an_e ~lth a pseudo-random b~nary sequence (~3S~ ~efo-è p3ss:-g the si~nal ~Q an !5 opto-siect~on;c s~a~e ~ ~;. outputs ar. o?~a' signal. ~he scramD'_~.g e~ :.._ ~~p_~ serves ~o;h :~ a_~
clock _~cover~ 3~ eh~ s:gra~ and also ~a e-o~;~e addle~onal SQCur'~ r.~~.-ar.~sation ~gna~ i;
transmltted ':om ~he t:~nsm.-'e- -_~:..g un~t ~.~ec-'~ eo thQ recelvQr -:~n~ r.;~ ma~ e synch~a.._3a~0r.
~ignal .s a::ar.g~d ~Q eha~ -he ~-a-~sm~eeer and ~
are aligned a- :he bLe _*~Qi ~ no a~ ehs ~_amQ L~'~QL.
'n normal ~?Qra.L~n - .4_~ ~, a ~Ql a~ ~ew~e.~ -n~
::an~m~ r a~ -n~ e mQ: ~ua -. ~u-a~Lon ~a ~a~a.
25 ~a~c framos. ~ 4ia',~' CainpQn~ 5 'ar "i~4 .~a~ ia~
o' :h~ TPO~ S~Qe~ 3P-~a~ Q
Ln F:gUrQ 0, t~Q 5~Yn~nrOn._Sa:;~n ~L~na1 ~:O,m e~Q
:an~ Q- ~ &~ SC~ -~La~
:ran~m~ teQr and r4C4~ a:~ ai ~n~ ' the ~'-aa~e L~
~0 d~ w~ ~4~ ~n~ ~si~- Wr.L-i~.
~s normall$t .neroduc4d~ n wh4n eh~ out2u~ Q
eSansm~ttar L~ fQ~ Lneo eina ..gC~L~4: a d~rsce ~;t~by-~Le compar~on ~ay b4 mad~ o~ e~n4 ~e~oin~ snd Lnc~minq fram-~ eo pro~Lds ~ -apL~i ~n~ 4CeL'5~ tQS- Oi~
op-rac~on of ~o naad-~n~ ~eatLon .
WO 92/07432 PCI/GB91/0181~
9'l ~ -In the example sho~n ln ~ sre 6, connections are provided for us~ng differen~ loop sources. Loop excludes the optical staqe and connects the output of the scrambler directly to the serl~i-to-parallel converter o~
the recelver stag~e.
~ oop 3 includes _he _?,~cal staqe of ~he -ransmltter but omits ;~_ o~_;~a_ ~.age of ehe receiver~
Semlconducto- lase- _e~__es _~ ~he ~ype used cO, ;.~e optlcal out?ue sta~e ~~m~onl~ ;nclude a mOnL~O.
photodiode. '~hen 1oo? 3 _, _,e', ,he elect_~c~l ou~p_e from t.~is mon~to: photod~ods _, connected ~~ the SQriai-to-parallel converte_ o' ;;~e _on~rter. The third loop at the head-snd s~a~:on. _3~3 -, _ncludes ~he f~
optlcal i~put and ou~p~: stag~es. A~ ex~sr~a' i5 ~umper/atte~uator _s used ~a ~onnec: ~he opt~cal sta~e o' the ~-ansmitte- to the o?e:_a' s~ace o' the rsce~sr.
I~ addit~on ~o e~s ~ .e-.: 'oops avall3bLe ae ehs hea~-end s~atior. '~ Loo?-~ac,~ ~ay bQ ~rc~id~d a- ~e termlnaelons o. a' 0~9~ , o_n~~ he n~e~or,~ .n 20 general t~.e di f ~Csrsn~ ~,e3?s ~ _ - ha~ e di ~f~ren- delays as~ociat~d w~h ehs;n ~nd acca~~ng'~ ehe cQcQLt~e~ ing stage l~ ar~ang~d eo ,el~ce d' ''QrQnt 1 a~? dQlays appropriaeQ ea eh~ d~''a~~n~ oop SOt~..CQ9 SO ~hae ;n eae~.
casa ehe ~n~om~ ng an~ o~ o_n~ 9t5 ar~ G3i~3n~ Gl~ ~Ot;.'' 2 5 ~ m Q ~ Q V ~ L a ;~ 4 . ~
s~gna~ but wle~oue any ~asLC ~amos. ~or 4aso of lmpl-m-neae~on~ t~a dLa~no~tic si~nal may ~OmprLS~ 9Lmply t~o ~ama hoad-r us-d in e~a convoncional ~ownstraam ~ramo. T~ arrang4mane ~s s~own ~n ~Lguca ~.
3S Aleornael~ol$~t~Q d~agno~e~c ~LgnaL may comp;Lsq a sLng~
G rt ~ " ~ 7 ~YO92/07432 PCT/CB91/0181~
,~ ", ,~
pulse. As a further alternat~e~ ~he frame may use a difSerent, more extendeh ?roDe aeGuence, effectively provlding a h-gher slgnal ~o ~o~se -a;io on any return, and so increasLng the apeed Wlt~ ~n c:~ the fault can be ; analyse~.
~i,aure o shows ~-.e da.a ~-ans~itte~ anc ~ata recelver n tno head-~nd s:a_:~.. : ~~r.nec~ed _n a loop-back conSigur~-lor.. Sucn a co-.~ on lS use~ eat the '~nc~ ~c_.g ~ .e ~ d-e-.~ ,ta:~on ! ~~- ~he output from the .:ansm~ - s~aae ~X Deln,a conne~a2c d~rec_Ly to ;;ne ir.?~ o. .-._ -oceLve: ~X. The 3ut?u~ of the transml;:er s;aae T''~ ~asses ~;-_~uah a sc_am~ler w~.ic.-changes the b:. orcer _~ acco~~an_e ~lth a pseudo-random b~nary sequence (~3S~ ~efo-è p3ss:-g the si~nal ~Q an !5 opto-siect~on;c s~a~e ~ ~;. outputs ar. o?~a' signal. ~he scramD'_~.g e~ :.._ ~~p_~ serves ~o;h :~ a_~
clock _~cover~ 3~ eh~ s:gra~ and also ~a e-o~;~e addle~onal SQCur'~ r.~~.-ar.~sation ~gna~ i;
transmltted ':om ~he t:~nsm.-'e- -_~:..g un~t ~.~ec-'~ eo thQ recelvQr -:~n~ r.;~ ma~ e synch~a.._3a~0r.
~ignal .s a::ar.g~d ~Q eha~ -he ~-a-~sm~eeer and ~
are aligned a- :he bLe _*~Qi ~ no a~ ehs ~_amQ L~'~QL.
'n normal ~?Qra.L~n - .4_~ ~, a ~Ql a~ ~ew~e.~ -n~
::an~m~ r a~ -n~ e mQ: ~ua -. ~u-a~Lon ~a ~a~a.
25 ~a~c framos. ~ 4ia',~' CainpQn~ 5 'ar "i~4 .~a~ ia~
o' :h~ TPO~ S~Qe~ 3P-~a~ Q
Ln F:gUrQ 0, t~Q 5~Yn~nrOn._Sa:;~n ~L~na1 ~:O,m e~Q
:an~ Q- ~ &~ SC~ -~La~
:ran~m~ teQr and r4C4~ a:~ ai ~n~ ' the ~'-aa~e L~
~0 d~ w~ ~4~ ~n~ ~si~- Wr.L-i~.
~s normall$t .neroduc4d~ n wh4n eh~ out2u~ Q
eSansm~ttar L~ fQ~ Lneo eina ..gC~L~4: a d~rsce ~;t~by-~Le compar~on ~ay b4 mad~ o~ e~n4 ~e~oin~ snd Lnc~minq fram-~ eo pro~Lds ~ -apL~i ~n~ 4CeL'5~ tQS- Oi~
op-rac~on of ~o naad-~n~ ~eatLon .
WO 92/07432 PCI/GB91/0181~
9'l ~ -In the example sho~n ln ~ sre 6, connections are provided for us~ng differen~ loop sources. Loop excludes the optical staqe and connects the output of the scrambler directly to the serl~i-to-parallel converter o~
the recelver stag~e.
~ oop 3 includes _he _?,~cal staqe of ~he -ransmltter but omits ;~_ o~_;~a_ ~.age of ehe receiver~
Semlconducto- lase- _e~__es _~ ~he ~ype used cO, ;.~e optlcal out?ue sta~e ~~m~onl~ ;nclude a mOnL~O.
photodiode. '~hen 1oo? 3 _, _,e', ,he elect_~c~l ou~p_e from t.~is mon~to: photod~ods _, connected ~~ the SQriai-to-parallel converte_ o' ;;~e _on~rter. The third loop at the head-snd s~a~:on. _3~3 -, _ncludes ~he f~
optlcal i~put and ou~p~: stag~es. A~ ex~sr~a' i5 ~umper/atte~uator _s used ~a ~onnec: ~he opt~cal sta~e o' the ~-ansmitte- to the o?e:_a' s~ace o' the rsce~sr.
I~ addit~on ~o e~s ~ .e-.: 'oops avall3bLe ae ehs hea~-end s~atior. '~ Loo?-~ac,~ ~ay bQ ~rc~id~d a- ~e termlnaelons o. a' 0~9~ , o_n~~ he n~e~or,~ .n 20 general t~.e di f ~Csrsn~ ~,e3?s ~ _ - ha~ e di ~f~ren- delays as~ociat~d w~h ehs;n ~nd acca~~ng'~ ehe cQcQLt~e~ ing stage l~ ar~ang~d eo ,el~ce d' ''QrQnt 1 a~? dQlays appropriaeQ ea eh~ d~''a~~n~ oop SOt~..CQ9 SO ~hae ;n eae~.
casa ehe ~n~om~ ng an~ o~ o_n~ 9t5 ar~ G3i~3n~ Gl~ ~Ot;.'' 2 5 ~ m Q ~ Q V ~ L a ;~ 4 . ~
Claims (21)
1. A head-end station for a passive optical network system arranged to transmit TDMA data frames comprising a header portion and a plurality of basic frames, each basic frame comprising a plurality of traffic bits and a plurality of control bits, the head-end station including means switchable upon detection of an abnormality between an operational mode in which it transmits and receives TDMA data frames and a diagnostic mode in which transmission of data frames is terminated and said means generates and transmits a diagnostic signal onto the passive optical network system and detects any return of the diagnostic signal.
2. A head-end station as in claim 1, including means to generate an autocorrelative OTDR probe as the diagnostic signal.
3. A head-end station as in claim 1, including means for encoding a header portion of a TDMA frame transmitted in the operational mode with a diagnostic signal.
4. A head-end station as in claim 1, in which the absence of received upstream data frames is sensed and in response thereto the head-end station automatically switches from the operational mode to the diagnostic mode.
5. A head-end station according to claim 1, in which the passive optical network system exhibits a loop delay timing between transmission of data from the head-end station and reception of TDMA data from a remotely situated termination, said head-end station including a data transmitter and data receiver synchronised with a switchable delay between the transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
6. A head-end station as in claim 2, including means for encoding a header portion of a TDMA frame transmitted in the operational mode with the diagnostic signal.
7. A head-end station as in claim 2, in which the absence of received upstream data frames is sensed and, in response thereto, the head-end station automatically switches from the operational mode to the diagnostic mode.
8. A head-end station as in claim 3, in which the absence of received upstream data frames is sensed and, in response thereto, the head-end station automatically switches from the operational mode to the diagnostic mode.
9. A head-end station as in claim 6, in which the absence of received upstream data frames is sensed and, in response thereto, the head-end station automatically switches from the operational mode to the diagnostic mode.
10. A head-end station as in claim 2, in which the passive optical network system exhibits a loop delay timing between transmission of data from the head-end station and reception of network TDMA data from a remotely situated termination, said head-end station including a data transmitter and data receiver synchronized with a switchable delay between the transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
11. A head-end station as in claim 3, in which the passive optical network system exhibits a loop delay timing between transmission of data from the head-end station and reception of network TDMA data from a remotely situated termination, said head-end station including a data transmitter and data receiver synchronized with a switchable delay between the transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
12. A head-end station as in claim 4, in which the passive optical network system exhibits a loop delay timing between transmission of data from the head-end station and reception of network TDMA data from a remotely situated termination, said head-end station including a data transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
13. A head-end station as in claim 6, in which the passive optical network system exhibits a loop delay timing between transmission of data from the head-end station and reception of network TDMA data from a remotely situated termination, said head-end station including a data transmitter and data receiver synchronized with a switchable delay between the transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is alignedat the frame level.
14. A head-end station as in claim 7, in which the passive optical network system exhibits a loop delay timing between transmission of date from the head-end station and reception of network TDMA data from a remotely situated termination, said head-end station including a data transmitter and data receiver synchronized with a switchable delay between the transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
15. A head-end station as in claim 8, in which the passive optical network system exhibits a loop delay timing between transmission of data from the head-end station and reception of network TDMA data from a remotely situated termination, said head-end station including a data transmitter and data receiver synchronized with a switchable delay between the transmitter and receiver such that in said operation mode the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
16. A head-end station as in claim 9, in which the passive optical network system exhibits a loop delay timing between transmission of data from the head-end station and reception of network TDMA data from a remotely situated termination, said head-end station including a data transmitter and data receiver synchronized with a switchable delay between the transmitter and receiver such that in said operational mode-the timing of the receiver is delayed with respect to the transmitter by a period approximately equal to the loop delay time of the passive optical network system, and in a test mode the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
17. A method for operating a head-end station of a passive optical network said method comprising the steps of:
transmitting from the head-end station TDMA data frames of optical signals, said data frames including a header portion and a plurality of basic frames, each basic frame having a plurality of traffic bits and a plurality of control bits; and switching upon the detection of an abnormality between (a) an operational mode in which the head-end station transmits and receives TDMA
data frames of optical signals and (b) a diagnostic mode in which transmission of data frames is terminated and the head-end station generates and transmits a diagnostic signal onto the passive optical network system and detects any return of the diagnostic signal.
transmitting from the head-end station TDMA data frames of optical signals, said data frames including a header portion and a plurality of basic frames, each basic frame having a plurality of traffic bits and a plurality of control bits; and switching upon the detection of an abnormality between (a) an operational mode in which the head-end station transmits and receives TDMA
data frames of optical signals and (b) a diagnostic mode in which transmission of data frames is terminated and the head-end station generates and transmits a diagnostic signal onto the passive optical network system and detects any return of the diagnostic signal.
18. A method as in claim 17, wherein said diagnostic signal is generated as an autocorrelative OTDM probe signal.
19. A method as in claim 17, including encoding a header portion of a TDMA frame transmitted in the operational mode with the diagnostic signal.
20. A method as in claim 17, including sensing the absence of received upstream data frames and, in response thereto, automatically switching the head-end station from said operational mode to said diagnostic mode.
21. A method as in claim 17, wherein the passive optical network system exhibits a loop delay time between transmission of data from the head-end station and reception of returned TDMA data from a remotely situated termination, said method including:
synchronizing a data transmitter with a data receiver at the head-end station with a switchable delay between the transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respectto the transmitter by a period approximately equal to the loop delay time of the passive optical network system; and, in a test mode, the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
synchronizing a data transmitter with a data receiver at the head-end station with a switchable delay between the transmitter and receiver such that in said operational mode the timing of the receiver is delayed with respectto the transmitter by a period approximately equal to the loop delay time of the passive optical network system; and, in a test mode, the delay between the transmitter and receiver is substantially eliminated so that data transmitted from the transmitter and looped-back to the receiver is aligned at the frame level.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB909022681A GB9022681D0 (en) | 1990-10-18 | 1990-10-18 | Passive optical network |
| GB9022681.2 | 1990-10-18 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2092297A1 CA2092297A1 (en) | 1992-04-19 |
| CA2092297C true CA2092297C (en) | 1997-12-23 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002092297A Expired - Fee Related CA2092297C (en) | 1990-10-18 | 1991-10-17 | Passive optical network |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5548432A (en) |
| EP (1) | EP0559659B1 (en) |
| JP (1) | JPH06505134A (en) |
| AU (1) | AU8737291A (en) |
| CA (1) | CA2092297C (en) |
| DE (1) | DE69129992T2 (en) |
| GB (1) | GB9022681D0 (en) |
| WO (1) | WO1992007432A1 (en) |
Families Citing this family (26)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992010036A1 (en) * | 1990-11-22 | 1992-06-11 | British Telecommunications Public Limited Company | Test apparatus |
| US5519830A (en) * | 1993-06-10 | 1996-05-21 | Adc Telecommunications, Inc. | Point-to-multipoint performance monitoring and failure isolation system |
| US5528579A (en) * | 1993-06-11 | 1996-06-18 | Adc Telecommunications, Inc. | Added bit signalling in a telecommunications system |
| US5453737A (en) * | 1993-10-08 | 1995-09-26 | Adc Telecommunications, Inc. | Control and communications apparatus |
| AU701959B2 (en) * | 1994-03-29 | 1999-02-11 | British Telecommunications Public Limited Company | Optical telecommunications network |
| DE69533274T2 (en) * | 1994-08-12 | 2005-08-18 | Nippon Telegraph And Telephone Corp. | Optical time compression multiplex transmission system |
| US6334219B1 (en) | 1994-09-26 | 2001-12-25 | Adc Telecommunications Inc. | Channel selection for a hybrid fiber coax network |
| USRE42236E1 (en) | 1995-02-06 | 2011-03-22 | Adc Telecommunications, Inc. | Multiuse subcarriers in multipoint-to-point communication using orthogonal frequency division multiplexing |
| US7280564B1 (en) | 1995-02-06 | 2007-10-09 | Adc Telecommunications, Inc. | Synchronization techniques in multipoint-to-point communication using orthgonal frequency division multiplexing |
| US5760940A (en) * | 1995-10-27 | 1998-06-02 | Lucent Technologies Inc. | Methods for monitoring optical path characteristics in an optical communication system |
| US5790293A (en) * | 1995-10-27 | 1998-08-04 | Lucent Technologies Inc. | Systems for monitoring optical path characteristics in an optical communication system |
| CA2304280C (en) | 1997-09-29 | 2003-07-08 | Tollgrade Communications, Inc. | Frequency agile transponder |
| US6144472A (en) * | 1998-01-20 | 2000-11-07 | Lucent Technologies Inc. | Upgrading a power-splitting passive optical network using optical filtering |
| US6151144A (en) * | 1998-01-20 | 2000-11-21 | Lucent Technologies, Inc. | Wavelength division multiplexing for unbundling downstream fiber-to-the-home |
| US7181142B1 (en) | 2002-04-09 | 2007-02-20 | Time Warner Cable Inc. | Broadband optical network apparatus and method |
| US20090016714A1 (en) * | 2003-03-03 | 2009-01-15 | Alexander Soto | System and method for performing in-service fiber optic network certification |
| US9312953B2 (en) | 2003-03-03 | 2016-04-12 | Alexander Ivan Soto | System and method for performing in-service optical network certification |
| US8655166B2 (en) * | 2003-03-03 | 2014-02-18 | Alexander I Soto | System and method for performing in-service optical fiber network certification |
| US7428382B2 (en) * | 2003-03-03 | 2008-09-23 | Soto Alexander I | System and method for performing in-service fiber optic network certification |
| US20060147203A1 (en) * | 2004-12-30 | 2006-07-06 | Thinguldstad Arthur M | Optical network element with remote access capability |
| CN100438434C (en) * | 2005-10-20 | 2008-11-26 | 华为技术有限公司 | Method for isolating rejection service source and its passive optical network system |
| US7716540B2 (en) * | 2007-01-03 | 2010-05-11 | Dell Products L.P. | Standalone data storage device electromagnetic interference test setup and procedure |
| WO2015006623A1 (en) * | 2013-07-10 | 2015-01-15 | Neophotonics Corporation | Optical network communication system with embedded optical time domain reflectometer and method of operation thereof |
| US9602311B2 (en) | 2014-02-06 | 2017-03-21 | The Board Of Trustees Of The Leland Stanford Junior University | Dual-mode network |
| US9948399B2 (en) | 2015-01-09 | 2018-04-17 | Time Warner Cable Enterprises Llc | Methods and apparatus for removing beat interference from splitters/combiners |
| US9674591B2 (en) | 2015-06-08 | 2017-06-06 | Time Warner Cable Enterprises Llc | Methods and apparatus for asymmetric distribution of mixed content via a network |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1287603B (en) * | 1965-03-17 | 1969-01-23 | ||
| US4451916A (en) * | 1980-05-12 | 1984-05-29 | Harris Corporation | Repeatered, multi-channel fiber optic communication network having fault isolation system |
| GB8528890D0 (en) * | 1985-11-23 | 1986-01-02 | Int Computers Ltd | Data transmission system |
| US4749247A (en) * | 1986-04-03 | 1988-06-07 | The Mitre Corporation | Self-monitoring fiber optic link |
| GB8727846D0 (en) * | 1987-11-27 | 1987-12-31 | British Telecomm | Optical communications network |
| GB8807050D0 (en) * | 1988-03-24 | 1988-04-27 | British Telecomm | Communication system |
| GB8828408D0 (en) * | 1988-12-06 | 1989-01-05 | British Telecomm | Loss detector |
| JP3100386B2 (en) * | 1990-06-19 | 2000-10-16 | 住友電気工業株式会社 | Optical communication system |
| US5285305A (en) * | 1991-12-12 | 1994-02-08 | At & T Bell Laboratories | Optical communication network with passive monitoring |
-
1990
- 1990-10-18 GB GB909022681A patent/GB9022681D0/en active Pending
-
1991
- 1991-10-17 WO PCT/GB1991/001815 patent/WO1992007432A1/en active IP Right Grant
- 1991-10-17 AU AU87372/91A patent/AU8737291A/en not_active Abandoned
- 1991-10-17 JP JP3516900A patent/JPH06505134A/en active Pending
- 1991-10-17 EP EP91918331A patent/EP0559659B1/en not_active Expired - Lifetime
- 1991-10-17 DE DE69129992T patent/DE69129992T2/en not_active Expired - Fee Related
- 1991-10-17 CA CA002092297A patent/CA2092297C/en not_active Expired - Fee Related
-
1995
- 1995-02-28 US US08/395,539 patent/US5548432A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0559659B1 (en) | 1998-08-12 |
| US5548432A (en) | 1996-08-20 |
| EP0559659A1 (en) | 1993-09-15 |
| DE69129992T2 (en) | 1999-01-21 |
| DE69129992D1 (en) | 1998-09-17 |
| WO1992007432A1 (en) | 1992-04-30 |
| JPH06505134A (en) | 1994-06-09 |
| GB9022681D0 (en) | 1990-11-28 |
| AU8737291A (en) | 1992-05-20 |
| CA2092297A1 (en) | 1992-04-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |