Evolutionary architecture for an all‐services ATM access network

Abstract

AbstractThis paper presents a flexible concept for a broadband subscriber access network which minimizes investment costs by predominantly using the existing network infrastructure. The target network may consist of either a coaxial tree‐and‐branch structure or symmetrical copper pairs to the subscriber, and is connected to the central head station with the aid of optical feeder lines which can be implemented or enhanced by a passive optical network (PON). In the event of an increase in bit rate requirements, the coaxial network can be expanded by dividing it into smaller, optically fed subnetworks or by supplementing it with optical overlay systems. Flexibility, expandability and low costs are achieved through the standard ATM format implemented for the signals of all interactive services down to the network termination units on the subscriber side. Those signals are transmitted in the coaxial network in frequency bands above the CATV band in accordance with a multiple of the CATV channel width to ensure that the modulation and demodulation is implemented in a cost‐efficient manner while providing ‘bit rate on demand’ for a suitably high number of subscribers. Separation of the network termination unit from the customer premises equipment enables a flexible, cost‐efficient subscriber configuration to be selected, existing domestic wiring to be used and several completely different subscriber terminals to be simultaneously connected.