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- Magesacher, Thomas, et al.
(författare)
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Modeling and measurement of short copper cables for ultra-wideband communications
- 2006
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Ingår i: Proc. SPIE OpticsEast Broadband Access Communication Technologies.
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Konferensbidrag (refereegranskat)abstract
- High-speed communication using the copper network, originally installed for telephony, is one of the dominant Internet access techniques. Several variants of a technology referred to as digital subscriber line (xDSL) have been developed, standardized and installed during the last two decades. Essentially, xDSL achieves high rates by exploiting wide bands of the copper cable channel. The shorter the cable, the wider is the band that can be used efficiently for communication. Current xDSL standards use bands up to 18MHz. Cable properties have been studied by means of measurements, characterization and modeling up to frequencies of 30MHz. Recent investigations have shown that is feasible both from technical and from economical point of view to exploit very short cable (up to 300m) even further and use bands above 30MHz. A prerequisite for further evaluation and the design of such ultra-wideband copper (UWBC) systems is the extension of existing cable models to higher frequencies. This paper presents wide-band measurement results of insertion loss and crosstalk coupling in a 10-pair cable of various length values for frequencies up to 400MHz. We compare the results to extrapolations of cable models that are established in the 30MHzrange.
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| 2. |
- Jakovljevic, M., et al.
(författare)
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VDSL Power Back-Off Parameter Optimization for a Cable Bundle
- 2007
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Ingår i: Proceedings European Signal Processing Conference. - Poznan : Poznań University of Technology. - 9788392134022 - 9788392134046 ; , s. 550-554
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Konferensbidrag (refereegranskat)abstract
- To better utilize the capacity of the twisted-pair access networks, operators deploying very high-speed digital subscriber line (VDSL) systems need accurate parameters for power back-off (PBO). However, VDSL standards give almost no guidance on how these parameters should be established for a particular network. In this paper we present a new technique for optimizing PBO parameters for a cable bundle, which is based on the Nelder-Mead simplex search algorithm. In this way each operator can easily calculate PBO parameters that match its actual access network down to the individual cable bundle. Using the properties of the PBO, as defined in the VDSL standard, we show how a normalized FEXT coupling can replace the knowledge of the individual couplings during the optimization of the PBO parameters. By simulations based on measured cable data we show that our approach using cable bundle unique PBO (CUPBO) achieves a significant improvements compared to the performance achieved with the ordinary PBO. © 2007 EURASIP.
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