Single-ended Line Testing – A White Box Approach

P. Boets, L. Van Biesen, T. Bostoen (Belgium), and D. Gardan (France)


Channel Estimation, System Capacity Analysis


A measurement, modelling and identification system is proposed to qualify a subscriber line with the constraint that only measurements can be conducted at the Central Office. The system uses the one-port scattering parame ter as a base measurement of the loop. The time domain version of this scattering parameter will be pre-processed so that the features, which are the start, maximum and end positions of a reflection, are clearly visible and hence de tectable. These features are used by the interpreting expert system which performs a topology estimation of that loop. Once the topology is known, a loop model, based on the physical properties of a twisted pair line, is build and the loop can be identified using a Maximum Likelihood Esti mator. Next, the end-to-end transfer function will be calcu lated. The results and observations of a measurement cam paign using a France Telecom cable plant will illustrate the proposed Single-Ended Line Testing approach.

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