PROCEDE D'OPTIMISATION DE LA CAPACITE DE TRANSMISSION DISPONIBLE DE RESEAUX D'ACCES D'ABONNES

METHOD FOR OPTIMIZING THE AVAILABLE TRANSMISSION CAPACITY AT SUBSCRIBER LINE NETWORKS

Abrégé français

Dans des réseaux d'accès d'abonnés par l'intermédiaire desquels les informations sont échangées selon un procédé de transmission xDSL, le problème est posé par le fait que la capacité de transmission maximale possible dépend très fortement des conditions cadres physiques. Si ces dernières sont modifiées, les modems doivent à nouveau s'adapter. Si la capacité de transmission initiale n'est plus atteinte, la ligne xDSL est mise hors service. La présente invention permet de résoudre ce problème grâce à l'établissement d'un canal de communication entre le modem et une logique de commande centrale.

Abrégé anglais

In customer access networks wherein information is exchanged according to a
transmission method xDSL, a problem arises in that the maximum available
transmission capacity is highly dependent on physical conditions of
compatibility. If these conditions are modified, the modems must adapt
themselves again. If the initial transmission capacity is not reached any
longer, the xDSL line is taken out of service. The present invention solves
this problem by establishing a communication channel between the modem and a
central control logic.

Revendications

4
Claims
1. Method for the transmission of information via subscriber line
networks, comprising
a plurality of subscribers (TLN1...TLN n) that are brought together via at
least one
subscriber line network (AN) via which information are routed according to an
xDSL
transmission method, comprising
modem units (M1...M n) that are arranged at both sides of a subscriber line,
and
comprising
a control logic (SN) via which settings in the subscriber line network (AN)
are
undertaken,
characterized in that at least one communication channel (K) is provided
between a
modem unit (M1...M n) and the control logic, information with respect to the
bandwidth present on the allocated subscriber line being conducted thereover.
2. Method according to claim 1, characterized in that the modem units
(M1...M n) are arranged in the subscriber line network (AN).
3. Method according to claim 1, characterized in that the modem units
(M1...M n) are arranged at the subscriber (TLN1...TLN n).
4. Method according to claim 1 through 3, characterized in that the
information exchange via the communication channel (K) ensues periodically.
5. Method according to claim 1 through 3, characterized in that the
information exchange via the communication channel (K) ensues on demand.
6. Method according to one of the preceding claims, characterized in that
the at least one communication channel (K) is transmitted via carrier that are
not
line-bound.

Description

CA 02336274 2000-12-28
1
METHOD FOR OPTIMIZING THE AVAILABLE TRANSMISSION
CAPACITY AT SUBSCRIBER LINE NETWORKS
The invention is directed to a method according to the preamble of patent
claim 1.
In subscriber line networks (access networks), information are exchanged
between subscriber and subscriber line network in the Prior Art according to
an xDSL
transmission method known to a person skilled in the art. For example, the
ADSL or
HDSL transmission method can be employed as xDSL method. In such transmission
methods, the maximally possible transmission capacity is highly dependent on
the
physical boundary conditions that prevail in the subscriber line network
during the
transmission event. Thus, for example, length and diameter of the subscriber
line as
well as the guidance in the bundle with other subscriber lines play a decisive
part.
In typical subscriber line networks, further, all connections are controlled
and monitored by an allocated control logic referred to as service node (SN).
For
example, this service node implements a 'connection admission control' for
each
connection setup request coming from the subscriber or coming from the
network.
This means that a check is undertaken to see whether sufficient transmission
capacity
is available in order to connect the requested connection through to the
subscriber.
The subscriber lines are terminated via modem units at both sides. The
2 0 currently available modems automatically adapt to the physical boundary
conditions
that are present at the time. When these conditions change, for example
because
another xDSL subscriber is added in the same line bundle, then the modems must
re-
adapt since the transmission capacity may potentially be reduced, for example
due to
crosstalk. This leads to a reduction of the available bandwidth.
2 5 When, following the adaptation event, it is not possible to again obtain
the
original transmission capacity, the appertaining xDSL link is taken out of
operation.
This leads to undesired service interruptions.
The invention is based on the object of disclosing a way of how the
transmission of information in subscriber line networks can be more flexibly
designed
3 0 for xDSL subscribers.

CA 02336274 2000-12-28
2
Proceeding from the features recited in the preamble of patent claim 1, the
invention is achieved by the features recited in the characterizing part
thereof.
It is especially advantageous in the invention that no service interruption is
undertaken when a lower bandwidth is available after the adaptation event.
When a
higher bandwidth is available, the user can use this immediately.
Advantageous developments of the invention are recited in the subclaims.
The invention is explained in greater detail below on the basis of a
graphically illustrated exemplary embodiment.
In accord therewith, a subscriber line network AN is shown that is brought
to a plurality of subscribers TLN,...TLNn. Modem units M,...Mn via which
information are communicated to the respectively allocated subscribers
TLN,...TLN~
are arranged in the subscriber line network AN. Only the modem units arranged
in
the network are shown in the Figure. The settings in the subscriber line
network AN
are acquired and administered by an allocated service node SN.
It is inventively proposed that a specific maintenance communication be
produced between an xDSL modem unit MX and the service node. When the physical
boundary conditions change in that, for example, crosstalk occurs in the
bundle from
one of the other subscribers, then the modems re-adapt since the transmission
capacity
may be reduced. In this case, the service node is informed of this fact via
the
2 0 maintenance communication. When the bandwidth is reduced, the new
bandwidth
can be subsequently investigated to see whether newly added connections can
still be
allowed.
The transmission of information is thus continued despite a lower
available transmission capacity. When an increase in the bandwidth occurs,
this does
2 5 not remain unused (as in the Prior Art) but is immediately available for
further
connections. The service interruption time is thus reduced. Further, it is
possible for
the subscriber to continue to use the previous services, albeit to a limited
extent.
Finally, the network operator avoids high revenue losses.
The specific maintenance communication is realized by introduction of a
3 0 maintenance communication channel K between the xDSL modem unit Mx and the
service node SN. The connection control mechanisms can thus remain in the
service

CA 02336274 2000-12-28
3
node. Likewise, the basic architectures of existing and future subscriber line
networks
can remain the same. This involves a considerable reduction in costs for the
network
operator. When a higher transmission capacity derives in a re-adaptation of
the xDSL
link, then this method also allows this capacity to be utilized. The
subscriber is thus
offered a better service and the revenue feasibility of the network operator
is
enhanced.
The coupling between the xDSL modem unit and the service node can
ensue in any desired way. Thus, the maintenance communication channel K can be
connected between the service node SN and the network-side or subscriber-side
modem units. As a result thereof, it is possible to keep xDSL links in
operation even
given modified transmission capacity and to reduce the service interruption
times.
For example, the communication channel can be realized as a separate
time slot in TDM systems and also as a separate ATM channel or as specific ATM
control cells in ATM-based networks. A realization is possible in the same way
or,
on the other hand, via a radio link. It is also conceivable to realize this
communication channel via a TMN connection. The information exchange can
thereby ensue periodically or on demand. It is also provided to allow the xDSL
modem unit to communicate autonomously with the service node or only in
response
to requests. When a plurality of xDSL modem units are situated in the
subscriber line
2 0 network, then the communication channels thereof can be bundled to form a
service
node. Certain minimum transmission rates and/or the change granularity can
also be
prescribed. In the service node, of course, the information about the xDSL
transmission capacity actually available can be employed for purposes other
than the
'connection admission control'.

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