High grade copper/optical fibre hybrid cable technology for investment safe broadband access networks

摘要

In order to take over most modem digital transmission systems, a reliable balanced copper cable design for the transmission of high data rates and broadband signals is necessary for the use in the rapidly growing advanced access networks. At the same time, the "fibre-to-the-home-philosophy" has to be considered for the cable design. Thus only a combination of copper and fibre stranding elements offers a good compromise between today's system demands and near future challenges in particular with respect to economical aspects. Generic cabling for the access link section is highly advisable in order to avoid repeated and cost intensive cable network installations, i.e. current and upcoming transmission systems are respected by this new cable plant concept. Therefore, this paper concentrates on cable delivery lenghts, manufactured regarding the mentioned transmission characteristics. Due to the strong trend towards high grade digital transmission systems, in particular the development of adequate copper transmission elements for xDSL- circuits are described here. The performance of the copper cabling for customer application is specified, as there are for long times no international requirements available for the access network cabling using copper technology. Networks carriers are now about to install copper outdoor cables which guarantee the essential minimum transmission quality, for instance with respect to xDSL-systems. This paper describes the particular design aspects for outdoor cables, enabling broadband transmission similar to generic cabling for customer premises up to at least 30 MHz. Transmission parameters like attenuation, crosstalk attenuation, longitudinal conversion loss, return loss, characteristic impedance will be examined. It will be shown that high grade copper outdoor cables can be used for xDSL-systems if certain design criteria are taken into account. Finally a few system applications were connected to completed cable links in order to prove correlation between cable properties and channel behavior. The global concept of copper/hybrid technologies will be described in particular regarding technical and economical aspects.