EP1290836A1

EP1290836A1 - System for the transmission of data

Info

Publication number: EP1290836A1
Application number: EP01940001A
Authority: EP
Inventors: Johann Pfeiffer
Original assignee: Ahead Communications Systems AG
Current assignee: Flextronics International GmbH and Co Nfg KG
Priority date: 2000-05-26
Filing date: 2001-05-25
Publication date: 2003-03-12
Also published as: WO2001093511A1; US20030072311A1; AU2001273721A1; AT410739B; ATA9262000A

Abstract

The invention relates to a system for the transmission of data between a central location (20), connected to a data cell transmission network, for example, an ATM (Asynchronous Transfer Mode) network (50) and a peripheral user-network connector unit (4), connected to the central location (20) by means of a plurality of digital transmission lines (15). A lower data transmission rate may be transmitted over each of said digital transmission lines (15) than the data transmission rate of the transmission network (50), whereby an inverse multiplex unit is provided in each of the central location (20) and in the peripheral user-network connection unit (4). The inverse multiplex unit in the periperhal user-network connection unit (4) may be assembled from a first and optionally one or several further multiplex modules (21, 22, 23, 24), whereby each multiplex module (21, 22, 23, 24) is connected to one of the digital transmission lines (30, 31, 32, 33). At least one unit is provided for the control and synchronisation of partial data cell streams.

Description

System for the transmission of data

The invention relates to a system for the transmission of data between a central location connected to a data cell transmission network and a peripheral subscriber network termination unit connected to the central location via a plurality of digital transmission lines, via which digital transmission lines each have a lower data transmission rate than the data transmission rate of the transmission network is transferable, with in the central location and in the peripheral subscriber network termination unit an inverse multiplex unit for dividing the data line stream to be transmitted over the transmission lines into several partial data cell streams and for merging the over the transmission lines transmitted partial data cell streams are provided.

Packet-wise transmission and transmission of data is already widespread for the transmission of digital information in communication networks, a special type of this form of transmission having become known as ATM (Asynchronous Transfer Mode). In this method, data divided into cells and combined into packets are transmitted either at a constant data rate (CBR) or at a variable data rate (UBR and VBR), and data cells can be received and sent by the user via network termination units. The data pending for transmission are divided into defined packets at the nodes provided for this purpose, with an address and further auxiliary information, such as Failure protection codes, equipped and transmitted in packets to the next node regardless of their origin or destination.

The transmission connections used within such a transmission network contain both copper and fiber optic lines and enable very high data rates. In most cases, however, many private users are connected to these high-speed networks via existing two-wire lines and the transmission services offered for them, such as xDSL, HDSL (High Speed Digital Subscriber Line), ADSL (Asymmetrie Digital Subscriber Line), VDSL (Very High Speed Digital) Subscriber Line) or the like, which enable data rates of, for example, 2 Mbit / s. If there is a need for a higher transmission speed, there is the possibility of combining several such parallel transmission channels and adding them to distribute transmitting information via inverse multiplex (TMA) units to the relevant lines and to transmit them to the user. Since the information to be transmitted is already divided into cells, the distribution of the data on the lines and the combination of the transmitted data to form a data stream can be carried out in a simple manner.

Previously known inverse multiplex units have the disadvantage of low flexibility with regard to their possible uses for the subscriber. This can be satisfied with the relatively low data rate of a single two-wire line or uses an IMA transmission offered by the network operator, in which at least two two-wire lines are combined with a correspondingly high overall data rate. If, on the other hand, the requirements of the subscriber are in a range between one and four lines, a DVIA solution is often oversized and causes high costs and only low utilization because parts of the subscriber network termination unit remain unused, the number of lines mentioned being only an example understand is.

The object of the invention is therefore to provide a data transmission system in which the peripheral subscriber network termination unit can be designed in a variable manner and adapted to the respective requirements.

This is achieved according to the invention in that the inverse multiplex unit of the peripheral subscriber network termination unit can be composed of a first and optionally one or more further multiplex modules, with each multiplex module being assigned one of the digital transmission lines, and that at least one A unit for control and synchronization of partial data cell streams is provided, which divides the data line stream to be transmitted according to the number of multiplex modules and the resulting partial data cell streams to the multiplex modules or respectively the partial data cell stream coming from one of the multiplex modules to the transmitted one Adds data row stream.

Due to the modular design, the inverse multiplex unit can be individually tailored to the needs of the subscriber, in that one or more multiplex modules can be added to the first multiplex module as required. Each multiplex module is connected to one of the transmission lines connected to the central location and sends or receives the data rate defined for this transmission line. If the requirements for the transmission rate at the subscriber increase, the subscriber network termination unit can be retrofitted with one or more multiplex modules.

In a further embodiment of the invention, the data cell transmission network can be formed by an ATM (Asynchronous Transfer Mode) network. Since the ATM switching technology used here has a high degree of distribution, this variant of the invention is suitable for a very large number of applications.

According to a further embodiment of the invention, all multiplex modules can have an equally large data transmission rate, as a result of which the production and storage are inexpensive for this module and each subscriber can increase the transmission rate of his inverse multiplex unit at any time by means of a further module of the same type.

In a further embodiment of the invention it can be provided that the multiplex modules can be connected to one another in series, that each multiplex module has a transmission interface for connection to one of the digital transmission lines, an input / output interface and a forwarding interface, wherein the forwarding interface of the multiplex modules is each connected to the input / output interface of the subsequent multiplex module, and wherein the unit for controlling and synchronizing partial data cell streams branches off a partial data cell stream from the data cell stream to be transmitted and to one of the Forwarding multiplex modules and branching off a further partial data cell stream from the remaining data cell stream and forwarding them to the subsequent multiplex modules.

The simple connection of the multiplex modules via the input / output interfaces and the forwarding interfaces enables, on the one hand, quick assembly and, on the other hand, technically simple manufacture of the multiplex modules.

During the transmission process, a first transmission channel, for example a 2 Mbit / s channel, is hidden from the outgoing data line stream in the first multiplex module and transmitted via the assigned digital transmission line. The remaining data stream is led to the second multiplex module, where a second transmission channel, for example a 2 Mbit / s channel, is faded out and fed to the respectively assigned digital transmission line for transmission. The rest of the data stream is distributed in the same way to the subsequent multiplex modules by branching off from it until nothing is left. Therefore, the number of multiplex modules can be selected that the required total data cell stream is reached. In the opposite transmission direction, the received data cell streams from the individual multiplex modules are put together again to form a total data cell stream.

A further feature of the invention can consist in the fact that the first multiplex unit comprises the unit for the control and synchronization of partial data cell streams, whereby the first multiplex unit represents basic equipment which can be expanded by further modules.

A simplification of the structure of the subscriber network termination unit can also be achieved in that the input / output interface and the forwarding interface have a transmission rate of 25.6 Mbit / s.

The invention further relates to a method for the transmission of data between a data cell transmission network, e.g. an ATM (Asynchronous Transfer Mode) network, connected central location and a peripheral subscriber network termination unit connected to the central location via a plurality of digital transmission lines, via which digital transmission lines each a lower data transmission rate than the data transmission rate of the transmission network can be transmitted is, in the central location and in the peripheral subscriber network termination unit, the data cell stream to be sent is divided into several sub-data cell streams or the sub-data cell streams sent over the transmission lines are combined again to form a data line stream.

The object of the invention is to provide a method of the type mentioned above with which the configuration of the subscriber network termination unit can be adapted to the total data rate to be transmitted.

This is achieved according to the invention in that the inverse multiplex unit of the peripheral subscriber network termination unit is composed of a first and optionally one or more further multiplex modules, and in that the data cell stream to be transmitted corresponds to the number of multiplex modules and their transmission rate divided and the resulting partial data cell streams are fed to the multiplex modules or respectively the partial data cell stream coming from one of the multiplex modules is added to the transmitted data cell stream. In this way, the transmission rate desired by the subscriber can be achieved by assembling a correspondingly large number of multiplex modules, over which the data line stream to be transmitted is divided.

According to a development of the invention, the data cell transmission network can be formed by an ATM (Asynchronous Transfer Mode) network, as a result of which the method according to the invention can be used reliably in very many of the already existing networks.

The invention is explained in detail below on the basis of the exemplary embodiment illustrated in the drawings. It shows

Fig.l is a block diagram of a data transmission system according to the prior art;

2 shows a detail of the data transmission system according to Fig.l and

3 shows a network termination unit with an inverted multiplex unit according to an embodiment of the invention.

Fig.l shows a known system for the transmission of data between a central station 20 connected to an ATM network 50 and a peripheral subscriber network termination unit 4, which is connected to the central station 20 via a plurality of digital transmission lines 15, bidirectional data transmission being required , The data streams within the ATM network 50 are divided into cells, each of which is formed from a cell header or a user data field. Cells of this type are transmitted asynchronously. For the switching of the cells between successive transmission sections, the identifier contained in the cell header is evaluated, by means of which it can be determined which ATM connection currently exists. The division of the data streams into individual identifiable cells is essential, which is why the invention could also be used in other data cell transmission networks.

In addition to the network termination unit 4, further network termination units 1, 2, 3 are connected via digital lines 11, 13, 14 to the central point 20, in which corresponding line cards 5, 6, 7 are provided, each of which has a digital transmission channel available put. The transmission method used on the data lines can vary, for example xDSL, that is HDSL, ADSL, VDSL, SDSL or the like, which enables a data rate of, for example, 2 Mbit / s on the digital lines 5, 6, 7. The digital lines 5, 6, 7 and 15 are realized, for example, by two-wire lines, which are lines between the central point 20, for example one The exchange and the subscribers already exist and therefore do not allow a higher transmission speed.

A higher data throughput is achieved via the network termination unit 4 in that the digital lines 15 are connected to a line card 8 which comprises an in multiplex unit 10 (FIG. 2) in which the distribution of the data via a connecting line 16 from the ATM network 50 coming ATM data cells takes place on the lines 15, via which the partial data cell streams are transmitted in parallel and are merged again in a further inverse multiplex unit of the peripheral subscriber network termination unit 4, four 4 Mbit in the exemplary embodiment shown / s lines 15 allow an overall 8 Mbit / s transmission rate at the subscriber. The partial data cell streams which are brought together again on the subscriber side are then again present on a line 17 as an ATM data cell stream. Due to the subdivision of the ATM data stream into cells, the distribution of these cells on the individual lines 15 can be carried out with the information blocks already provided in the cells, so that the proper composition on the receiving side is correspondingly simple.

In the case of a transmission in the opposite direction, the ATM data cell stream coming from the subscriber is divided in the inverse multiplex unit of the subscriber network termination unit 4, transmitted in partial data cell streams on the lines 15, reassembled in the inverse multiplex unit 10 and over line 16 transferred to the ATM network. Falls e.g. one of the lines 15 for data traffic is automatically transmitted only on the remaining three lines 15, in which case only 6 instead of the 8 Mbit / s possible in the undisturbed case are available.

In this way, a high data rate overall can be made available to the subscriber with the aid of several lines 15 with relatively low transmission rates.

The problem with these known inverse multiplex units is their low flexibility, since not every user can necessarily use the 8 Mbit / s provided, for example, and the costs for such a unit and the provision of the transmission lines 15 are nevertheless relatively high. If the requirements are in the order of magnitude of, for example, 4 or 6 Mbit / s, one or two of the transmission lines 15 are underutilized, but must nevertheless be available, which also reduces the degree of utilization on the part of the central location 20. It is therefore provided according to the invention that the inverse multiplex unit of the peripheral subscriber network termination unit 4 can be composed of a first and optionally one or more further multiplex modules 21, 22, 23, 24.

3 shows an embodiment of the invention in which the inverse multiplex unit of the peripheral subscriber network termination unit 4 is composed of a total of four modules 21, 22, 23, 24, via which 8 Mbit / s can be transmitted.

Each multiplex module 21, 22, 23, 24 has a transmission interface 61, 62, 63, 64 for connection to one of the digital transmission lines 30, 31, 32, 33, which e.g. are designed for 2 Mbit / s, so that each multiplex module is assigned one of the transmission lines and each multiplex module has an equally large data transfer rate, so that similar multiplex modules can be assembled.

Furthermore, each multiplex module 21, 22, 23, 24 has an input / output interface 41, 42, 43, 44 and a relay interface 51, 52, 53, 54, which e.g. are each formed by 25 Mbit / s interfaces.

In this way, the multiplex modules 21, 22, 23, 24 can be connected to one another in series. Depending on requirements, the subscriber can occupy one, two, three or four digital transmission lines, a corresponding number of multiplex modules being connected to one another by the input / output interface of each multiplex module being connected to the forwarding interface of the respective subsequent multiplex module. Module is connected.

In order to carry out a suitable division of the data stream or to merge the incoming data line streams, a unit (not shown) for controlling and synchronizing partial data cell streams is provided, which divides the data cell stream to be transmitted according to the number of multiplex modules 21, 22, 23, 24 and the resulting partial data cell streams are fed to the multiplex modules 21, 22, 23, 24 or respectively add the partial data cell stream coming from one of the multiplex modules 21, 22, 23, 24 to the transmitted data line stream.

The first multiplex unit 21 preferably comprises the unit for controlling and synchronizing partial data cell streams.

3 shows the arrangement of four multiplex units 21, 22, 23, 24 connected in series, the unit for controlling and synchronizing the partial data cell streams supplying the multiplex modules 21, 22, 23, 24 with the data cell stream to be transmitted, by giving each of these data cell streams Branch off partial data cell stream and forward it to one of the multiplex modules 21, 22, 23, 24 and branch off a further partial data cell stream from the remaining data line stream and forward it to the respective subsequent multiplex module. In the opposite transmission direction, the partial data cell stream coming from one of the multiplex modules 21, 22, 23, 24 is added to the data cell stream.

The cell data stream to be transmitted, which in the exemplary embodiment shown is transmitted at 8 Mbit / s, is passed via the input / output interface 41 into the first multiplex unit 21. There, a 2 Mbit / s partial cell data stream is masked out and sent via the transmission line 30 to the inverse multiplex unit 10 in the central location 20. The remaining data stream of 6 Mbit / s is fed via the transfer interface 51 into the input / output interface 42 of the subsequent second multiplex unit 22, from where a 2 Mbit / s partial cell data stream is again sent via the transmission line 31 and the remaining 4 Mbit / s data stream is forwarded to the third multiplex unit 23, in which the process described above is carried out again, until only a 2 Mbit / s subcell data stream remains for the fourth multiplex unit 24 the transmission line 33 is sent. The forwarding interface 54 of the fourth multiplex unit 24 remains unused.

Claims

PATENTA NS PRÜ C HE

1. System for the transmission of data between a central location connected to a data cell transmission network and a peripheral subscriber network termination unit connected to the central location via a plurality of digital transmission lines, via which digital transmission lines each have a lower data transmission rate than that Data transmission rate of the transmission network is transferable, with in the central location and in the peripheral subscriber network termination unit in each case an inverse multiplex unit for dividing the data line stream to be transmitted over the transmission lines into several partial data cell streams and for merging the part transmitted over the transmission lines Data cell streams are provided, characterized in that the inverse multiplex unit of the peripheral subscriber network termination unit (4) consists of a first and optionally one or more further multiplex-M modules (21, 22, 23, 24) can be assembled, each multiplex module (21, 22, 23, 24) being assigned one of the digital transmission lines (30, 31, 32, 33), and that at least one unit for control and synchronization of partial data cell streams is provided, which divides the data line stream to be transmitted according to the number of multiplex modules (21, 22, 23, 24) and their transmission rate and the resulting partial data cell streams to the multiplex modules (21, 22, 23, 24 ) or respectively adds the partial data cell stream coming from one of the multiplex modules (21, 22, 23, 24) to the transmitted data cell stream.

2. Transmission system according to claim 1, characterized in that the data cell transmission network is formed by an ATM (Asynchronous Transfer Mode) network.

3. Transmission system according to claim 1 or 2, characterized in that all multiplex modules (21, 22, 23, 24) have an equally large data transmission rate.

4. 'Transmission system according to claim 1, 2 or 3, characterized in that the multiplex modules (21, 22, 23, 24) can be connected to one another in series, that each multiplex module (21, 22, 23, 24) one Transmission interface (61, 62, 63, 64) for connection to one of the digital transmission lines (30, 31, 32, 33), an input / output interface (41, 42, 43, 44) and a forwarding interface ( 51, 52, 53, 54), the forwarding interface (51, 52, 53, 54) of the multiplex modules (21, 22, 23, 24) each with the input / output interface of the subsequent multiplex module is connected, and the unit for controlling and synchronizing partial data cell streams branches off a partial data cell stream from the data line stream to be transmitted and forwards it to one of the multiplex modules (21, 22, 23, 24) and from the remaining data cell stream in each case a further partial Data cell stream branches and each to the subsequent multipl ex modules (21, 22, 23, 24).

5. Transmission system according to one of claims 1 to 4, characterized in that the first multiplex unit (21) comprises the unit for controlling and synchronizing partial data cell streams.

6. Transmission system according to one of claims 1 to 5, characterized in that the input / output interface (41, 42, 43, 44) and the transfer interface (51, 52, 53, 54) have a transmission rate of 25.6 Mbit / s.

7. A method for transmitting data between a central point connected to a data cell transmission network and a peripheral subscriber network termination unit connected to the central point via a plurality of digital transmission lines, via which digital transmission lines each have a lower data transmission rate than that Data transmission rate of the transmission network is transferable, with the data cell stream to be sent being divided into a plurality of partial data cell streams in the central location and in the peripheral subscriber network termination unit, or the partial data cell streams transmitted over the transmission lines being combined again to form a data cell stream, thereby characterized in that the inverse multiplex unit of the peripheral subscriber network termination unit (4) is composed of a first and optionally one or more further multiplex modules (21, 22, 23, 24), and that the data line stream to be transmitted corresponds to the Number of multiplex modules (21, 22, 23, 24) and their transmission rate divided and the resulting partial data cell streams fed to the multiplex modules (21, 22, 23, 24) or respectively from one of the multiplex modules (21, 22 , 23, 24) incoming partial data cell stream is added to the transmitted data cell stream.

8. The method according to claim 7, characterized in that the data cell transmission network is formed by an ATM (Asynchronous Transfer Mode) network.