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Atm applications over hybrid optical fibre coax


The global objective of ATHOC is to enable in the short term a wide introduction of broadband communication and multimedia services, by providing bidirectional communication paths with flexible bandwidth (up to 34 Mbit/s), via existing cable infrastructure. The terminals will be PC's or workstations connected to the coaxial Cable TV network (CATV). This network will be interconnected at the Head End with the public SDH/ATM network. Gateways to other networks (e.g. Internet) will also be provided. The applied transfer mode is ATM. The project provides the transport platform, and on top of it, the higher layer protocols, services and applications.
By the end of the 2nd project year (1996) the following major results have been achieved:
( Overall system concept and system evolution, containing mainly multiple access techniques and MAC protocols;
( Specifications for the network elements of the evolutionary step 1, with 2 Mbit/s upstream bitrate per channel;
( Implementation of the key network elements needed for installation at the headend, and for termination of the coaxial cable at the user side, as well as adaptation to the terminal via an ATM Forum interface at 25.6 Mbit/s;
( Selection and definition of middleware, services and applications planned for installation at the trial sites;
( Demonstration of a subset of services and applications (news on demand, teleinformation, telesurveillance, collaborative working) on an ATM platform;
( Detailed plans for the trials in Stuttgart, Antwerp, Aveiro and Zurich to be started during 1997.

Expected Future Achievements
The global expected project result is the introduction of broadband communication and multimedia services on existing hybrid optical fibre-coax CATV networks.
Expected Impact
The availability of the novel network elements developed in the project enables the upgrade of the existing coaxial CATV networks towards an access network suitable for broadband communication, and in particular bidirectional communication.
By the use of ATM from end to end, a generic service independent broadband access network will be available in the short term. The higher layer protocols, services and applications installed on the transport platform enable the creation and installation of further applications, leading to increased acceptance of the system.

Approach for the Higher Layer Protocols

Main contributions to the programme objectives:
Main deliverables
Prototype of Hybrid Fiber Coax System (HFC) based on ATM and IP as multiservice platform
Contribution to the programme
Enabling the introduction of broadband multimedia services for residential and business users by upgrading existing
Technical Approach
The project objectives will be reached in two evolutionary steps.
In step 1 the envisaged modulation technique in the downstream direction is 64QAM. The total provided bitrate per carrier is about 34 Mbit/s, which is shared among the active subscribers, typically with up to 6 Mbit/s per user. In the upstream direction a QPSK or DQPSK modulation technique is foreseen, providing a capacity of about 2 Mbit/s, to be shared among the simultaneously active users. Alternative multiple access techniques will be elaborated and compared with respect to the required effort and their efficiency.
Step 2 will provide an increased upstream capacity, respecting however, robustness against noise. The techno-economical limit of the maximum capacity will be elaborated. This maximum bitrate is expected in the range of 10-20 Mbit/s. The full upstream capacity is shared dynamically among the simultaneously active users. In the overall network ATM is applied as transfer mode, thus all types of communications can be offered at the ATM user interface.
Work has been started on the overall concept of the technological platform, followed by the specifications of the needed equipment, taking into account the requirements of the different test environments. In parallel with this work definitions and implementations of higher layer protocols, services and applications are being performed. The network elements are being implemented and integrated in the laboratory, followed by the installation, test and operation in the field.
Summary of Trial
The technology will be tested in field environments of CATV networks in 4 European countries (Germany, Belgium, Switzerland, Portugal), providing access to Internet, to servers, to ATM/SDH research networks and a supercomputing centre. The networks in these four countries that are upgraded with ATHOC technology form a platform for installing all kinds of broadband services.
Key Issues
Network aspects
( Flexible bidirectional broadband communication on a tree and branch coax network, coexisting with CATV;
( Privacy and conditional access for ATM based user to user communication;
( Efficient use of the limited bandwidth for the upward direction in the coaxial tree network;
( Establishment and release of connections in the heterogeneous network.

Network/terminal interfaces
( Unified and standardised network/terminal interfaces;
( Protocols and software platform for applications;
( Adequate higher layer protocols will be selected, adapted and installed on the provided platforms.

Provision of services and content
( A few selected applications, e.g. collaborative working, news on demand etc., will be implemented on the test platforms.

Network operation
( The developed system and services will be delivered to various test platforms.


Alcatel SEL AG
Holderaeckerstr. 35
70499 Stuttgart

Participants (13)

AUTOR Tecnologias Multimedia Lda
Alcatel BELL
Centro de Estudos Comunicacoes
Communication Technology Lab
Instituto de Engenharia de Sistemas e Computadores
Integan CV
Multimedia Kommunikations AG
North West Labs Ltd
Pixelpark Multimedia Produkt. ges
Rechenzentrum Universitaet Stuttgart
Rediffusion AG
Verbraucherzentrale Baden-Wuerttemberg