Subscriber loop topology classification by means of time-domain reflectometry

Qualifying a subscriber loop for xDSL transmission can be done in many ways. Amongst all ways, methods that don´t require an expensive truck-roll to the customer are preferred. In this paper we provide a method for an intelligent automated interpretation of reflectometric 1-port measurements at the central office. First, we focus on how reflectograms can be characterised. Next, we build up intelligence in the system to deal with the uncertainty on the characteristics and to infer the topology by means of a belief network. Eventually, we combine in an artificial intelligent way, by means of a rule-based expert system all available knowledge and derive the basic loop properties i.e. the topology and the delays of the individual line sections.