METHOD FOR TRANSMITTING INFORMATION SIGNALS IN THE SUBSCRIBER

PROCEDE DE TRANSFERT DE SIGNAUX D'INFORMATION DANS LA ZONE DE RACCORDEMENT D'ABONNE

English Abstract

Transmission speeds are becoming increasingly faster, requiring transmission
techniques that enable optimal utilization of the relevant transmission
medium. Cables are used as a transmission medium in loops. Transmission rates
need to be adapted to the bandwidth of the cable, even during operation.
Transmission methods used in prior art can only meet such requirements to a
limited extent. The invention provides a remedy to this problem by
transmitting information signals (D) and control signals (SCM) in a frame
structure with variably adjustable speeds and the control signals (M) can be
used to adapt the transmission speed to the cable and to meet the requirements
of subscribers.

French Abstract

Dans le cadre de l'augmentation constante des vitesses de transmission se fait ressentir le besoin d'appliquer des techniques de transmission qui permettent une exploitation optimale du moyen de transmission concerné. Dans la zone de raccordement d'abonné, on utilise, comme moyen de transmission, un câble. Les débits de transmission doivent être alors adaptés à la largeur de bande du câble, même pendant le fonctionnement. Les procédés de transmission mis en oeuvre dans l'état antérieur ne peuvent être adaptés à ces exigences qu'avec certaines réserves. L'invention permet de palier cet inconvénient par le fait que des signaux d'information (D) et des signaux de commande (SCM) sont transmis dans une structure à trames à des vitesses pouvant être réglées de façon variable, et par le fait que les signaux de commande (M) peuvent être utilisés pour l'adaptation de la vitesse de transmission au câble et aux besoins de l'abonné.

Claims

claims
1. is method for selectively changing the
transmission speed between two transmission devices,
having a subscriber line network which links a first
transmission devices (MUX) to a plurality of further
transmission devices (T l...T n) and via which information
signals and control signals are routed,
characterized
in that information signals and control signals are
inserted into a frame structure,
in that the frame structure has a management channel
(M) in which information relating to the increase in
the transmission speed is communicated to the remote
station,
in that the sending transmission device transmits the
information signals at an increased transmission speed,
as a result of which the synchronism with the remote
station is lost,
in that, upon receiving the information transmitted in
the management channel (M), the remote station itself
increases the speed until the synchronism with the
sending transmission device is restored.
2. The method as claimed in claim 1,
characterized
in that the frame structure is formed from at least one
superframe having a plurality of single frames.
3. The method as claimed in claim 1,
characterized
in that the first transmission device is in the form of
a multiplex device (MUX).
4. The method as claimed in claim 1,
characterized
in that the further transmission devices are in the
form of subscriber terminate (T l...T n).
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Description

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Description
Method for transmitting information signdl~ in the
subsc~iLer line domain.
The invention relates tV a method in acc.ort3anCe
with the prechard~terizing clause of patent claim 1.
A3 transmission speeds ountinually increase, It
is »seiul to use tran3miESion techniques which permit
optimum utilizafiinn Of the transmission medium. Tn the
subscriber liue domain, the transmission mediul'n used io
cablca. Opt~mmm u'CiliZaLiVii is achieved when the
transmission rate has been mafi.c:hed to the Rdmclwidth. of
the cable. This circumstac~~:e has alroady been taken
into account in the bit-oriented UEH l.tansmission
techniqt~P_ With this tZan3mis3ion technique, however,
it is not por~oible to transmit additional iuFormation,
sur_.h as COntr01 icitvimation fox the user data, for
example.
In additi~m, the IISDL transmission method is
known as a stxuctttrPd baseband tectmi~ue in the prior
art. However, t~tie transmi33ion rate cannot. be matched
to the cable with this method, wlii~l~ means that the
necessary clrcuiL r:vmplenity and costs are high for all
GJ subscribers (even wi f:h a short cable or low demandE on
the transrni5siom rate).
The in«Pnt:l. on is based um the obj cct of
demonstrW rug a way of being ahle Lo tran5u~i L
information sir~nals In vtm subscriber line domain
dynamically at different srppds between l.wo
transmission devices.
The object ie achieved, nn the ba5i~ of the
precharart:Prizirig clause ~f patent claim 1, by t-.he
c:liaracteri~ing features of said Claim.
~i~J~p3/01~1
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Oiie advantage of the iriVenLiu~i is, in
particular, the provi5iun of a frame str»ri-.ure for
various transmicEion ratP~, Within which frame
structu.rp the 3.ndividual information is transmitted. Iri
~l~is context, the framel pss UI_;ri teehnolugy used iri the
grior art has been extended by frames. In this frame
structure, besides the actual user ciatu, information
fnr hyte-oriertt_ea transmiosion, a man2gpment channel
for the interchangQ of control lnfot~tudLion and a CP,C
1(7 channel for d5'essing the quality of the transmission
operation are also transmitted i1i addition. These
individual i L~111s Of information can be transmitted az
various n x H4 kbit/s transmis5iu~~ fates u3ing one and
Lhe scttue stZUCture.
Z5 Tn Addition, this frame structure oan be used
Lu transmit an B kHz information item concurrently at
any dpsirpd transmission rate. This information item is
used, by way of example, in t.hp ISDN for selec~iy
individml 64 kbit/s chantiel~ ~H cha,nnela) . In the
20 malxagament channel, control intorrnation can lj~
i nterchariged. This itilu.emation can be used, by way ~f
Example, fox changing over the transmission rate dutiiig
operation.
Advantageous developmpn~:s of the ittveiil.ioti are
specified in the subclaims.
The invention is c~xplairied iri more d~Lail below
with the aid of ati exemplary embodiment.
In the drawi nr~
Fi~uie 1 show3 the typical stx'itr-.ttlre Of a
30 ~ubscr~.ber line npi:work,
Figure 2 showy the frame strur.t~~rP according t0
the invention.
Figure 1 showE, as a tyr~.ral appliCatiori, a
molt; gl pxer MUX. which iS (:UlltlCC.ted t0 c7 plurality of
35 ~ul:racriber terminalE T1...Tn via nnnnPCtloris Vi...Vn. The
1 at~ter are in zhe fUL'ill Vf permanent connections in thi s
cacc. This mAans that
Z
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the actual data trarismi~sion is maintained conStanLly.
The connection ie set ur or clearmi down only duri ng
inotallation or when tJte speed is changer.! over.
The permanent ~~nneCtionS are now used fi.n
transmi t. the user data wing an fl7SL transtc~ission
tectlttique, in each r2se at ariy desired transmission
ratp_ In this context, the sending and receiving
LLdn5mia3ion devirPS have the Same level of
ani-.horization .1=or setting up or clearing down a
connection. This means that there is no prioritization
as in the ease of the known HUSL tZ'ditsmi3sion
tcohnique, for Pxample. Trte influenco of erronPOUs
settings is thus Significantly rRrluced.
FirJtlrp Z Shows ttie structure of the clat~a
LrailSmission method EDSL. Tti this context, user
information U, frame ittforxnation S for distingtllshinq
indivivlual 64 )cbit/s channel s, management .itiLormation M
and mnni Coring lnfort«.Lion C far ass~ssing the quality
of Lhe tran3miaeion medium are tran9mit~~d. To this
end, spPrtrames era provided in the data transmission
tuethod EDSL. A superframP holds $ sir~ylr frame3. Each _
surprframe is allOC:ated 384 uacr data hi t.s and the
additional bits. An externally supYlied fl kH' clock
signal synchroni~ca the supcrframe. The s»perframe i5
2~ designed such that, at various trausmi5aion rates, it
is given the c:urrect pooition with .r.PSpect Lo the 8 kHa
cloclc signal, which can be output with the correct
phase aqaitt at the reception end_
The surertrame 1S triygcred at the tratzsmissi c~ri
3U end as a zGSUlt of the 8 kHz er.3gps' being counLea. The
length of 't_he Counter .cwquired for this purPcsP iS
Orietil.e~:l toward the lowest speed. Thus, by way of
examrlP, a Superframe contains a total a.f 4E3 bytes
(6 x 0 bytcc) at a transmissiOT1 Speed oL n x 64 Jcbit/s
35 (n = 'I , ~, 4, g, J,6) , since the most 8 kHz edges per
superframc appear at i:his speed. Rl. the next highsst
.spaPd, Lhe l.Ligger puloc is prodttc~.pd only with each
second frame etc., which is qenetally adequate.
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At the receiver end, Lhe suporframe information
itr~m i_s used .iii inverted form for outputting the 8 kHz
cluok signal. To ~:hi3 erid, the counter PrnduCine~ the
~t kHz ClOCk ~iynal i~ in turn triggered Ly the start of
the euperframe, which is lilcewise ariPquate. At a
trarismlssiuii rate of 6d kt~i t/s, the Liiggering occurs
after each 4lith 8 kHz period.
Tlre auperframe is termed by a frame sync wr~r~1
which rPrmits unique allocation of the single frames
and, to this end, is evaluated and monitored by the
synchrnni2ation devi~c at the recept-i~n end. By
~luanging the frame structure (e.g. doubling the
lengths), it is also poosibl~ to implement otlm~ n
multiplex of 64 khit/s,
A single frame has 52 bits in this case. OL the
52 bits, a total nt 4f3 user datz~ bits arc provided and
4 tufther bits. The latter include the sync bit S, 2
management bits M and a CRC hi l: C. The latter is ~ispd
for error ~uu~eitoring. Eight sync hi is form the frame
oync woxd which is received and evaluated at ~:he
reception end. If the rec~ei~rar receives d frame sync
word in full, the frame structure can be restorr~d_
The text below c~emoristrates how the
transmission speed is cliaugGd during the transmission
operation.
Hy way of example, it may be assumed that
iuLvx:mation Signals are transmitted Letween the
mu 1 t i pleXer MUX duct crne of the terminal s Tl . . . '1'" ( a . q .
Tq) at a particular speed. Iri this cane, transmission
takes place ita Loth dircctions_ S~.~hSequeritly, the
information signals noW need t~ Lc transmitted at a
higher speed. Tlic change in speed will. be conLLUlled
from the multirJpx2r MUX; 1t w~ulrl also be possible tn
control iL .Crom the terminal T~_ The multiplexes MUX now
informs the terminal T4, vid the management channel M,
that l,lic tran3miseion speed i s to be incweased. At the
same time ~s this,
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a timer chip :is initlateci, and when it haS tun gut, the
speed is increa:.od in the multiYlexer. The terminal
receives the infolmatiun item relating Lo the opeed
increase via the management chanml M. The terminal Ta
~ubsequeni-.ly retuiw' an acknowledgement signal to the
multiplexer MUX. At the same time as thin, the tr~rmi.nal
T9 inc.rpaseS the speed.
When one of tr,P tran5uti.ssion devices i ncreases
the speed, Whettmr it be the mul t.iplex device ox the
Lerminal, the synchronism im the remote station , 1s
lost_ To this extent, the rem~r.e station necdE to
search for new synchronism. Ti11.5 13 done by virtue of
the sync wvi~l being received. It the new synchror~ism
1'ms been found, t.hP iriformatlon signalE can hp serif at
1.5 an increased speed.
In the ease of ~zroneou;, transmission (e.q. U11
acCOUrit oL lack of bandwidth iri Ll.i~ cable), the
receiver is not able to correct distortions in the
received signal to an adpguaLe extent, and the synn
word is not TeCOqni~~d. The synchronism between the
[lacuna) is thus lost-. After a prescribed time, the
original speed is adopted again.
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Representative Drawing