Alcatel

Alcatel Lucent

Patrick Jan Maria Boets

Thierry Pollet

Tom Bostoen

Leonard Pierre Van Biesen

Mohamed Zekri

Method and apparatus for modeling a network are described in which a 1 port measurement is made on the network by inputting an excitation signal at one port of the network and recording the results reflected back to the port. A 1 port parametric model of the network is generated whereby as much information about the topology of the network is included in calculating initial values of the parameters. Then the values of the parameters of the 1 port parametric model are optimized by reducing the difference between the results of the measurement step and results calculated using the 1-port parametric model and the excitation signal.

Method and apparatus for identification of an access network by means of 1-port measurements

Methods for matching adaptive hybrids () to lines () for making reflectograms of the lines () measure () input impedances (Z) of the lines (), model () characteristic impedances of the lines () via physical models (Z), estimate () parameters of the physical models (Z) via cost functions which depend on the measured input impedances (Z), convert () the modelled characteristic impedances into impedance values (), and set () the adaptive hybrids () with the impedance values (). Unwanted near-end reflections are minimised and wanted reflections can be measured. The physical models depend on frequencies s, Bessel functions Jand parameters arelated to geometrical dimensions A, D and L and material constants &#x3c3;, &#x3b5; and &#x3bc; of the lines (). The method may further model () characteristic impedances of the lines () via rational function models (Z) and estimate () parameters of the rational function models (Z) via further cost functions which depend on outcomes of the physical models (Z).

Method for matching an adaptive hybrid to a line

In the course of a reflectometry-based qualification procedure of a local loop, which connects customer premises to a central office of a telecommunication network, and in the event of being unable to identify the loop termination associated with the customer premises, a second reflectometry measurement of the local loop is carried out with a different impedance load at the customer premises. Next, the two reflectograms are compared with each other in the time domain in order to delineate among all the reflections those at the customer premises and to determine therefrom the position of the customer premises in the local loop.

Localization of customer premises in a local loop based on reflectometry measurements

In the process of estimating attributes of a transmission line from reflectometry measurements, small yet important reflections may be drowned in the immediate reflected signal owing to the mismatch between the reference impedance with respect to which the 1-port scattering parameter of the line has been determined and the characteristic impedance of the line. The major part of the near-end reflections are eliminated by estimating the characteristic impedance of the line, and by converting the 1-port scattering parameter of the line from the reference impedance base to the estimated characteristic impedance base. However, there is still a residual influence of the near-end reflections. It is then highly necessary to determine a time zone wherein the residual near-end reflections are enclosed so as their contribution is further neutralized in the process of estimating attributes of the transmission line.

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Heffen, Belgium

Patrick Jan Maria Boets