It is suggested to detect a single wire interruption (SWI) of a line comprising two wires, wherein such line is part of a vectoring group, comprising (i) determining a capacitance between the single wires of the line; and (ii) determining whether a single wire interruption is present based on the determined capacitance.

Presented is a method of detecting a loop length change in a digital subscriber line. An Uncalibrated Echo Response (UER) trace is obtained from the digital subscriber line by running a Single Ended Line Test (SELT). A historical (baseline) UER trace from the same line is retrieved. A line that has experienced a small change in loop length will have the same overall shape, but be compressed or stretched in the frequency domain. Thus, to detect such a change, a comparison between the two traces is made to determine if the difference between the two traces is less than a threshold but non-zero. Then a range of scale factors are applied in the frequency domain on either one of the traces, before determining which of the scale factors results in the lowest difference between the unscaled and scaled traces. The determined scale factor is above a certain threshold, then the line is determined to have had a loop length change. The value of the scale factor can be used to determine the amount the length has changed.

The invention measures the rates of a whole population of existing lines together with a line characteristic, such as capacitance, that can be measured prior to provisioning. Using these measures, a rating we refer to as a quality figure is generated for each distribution point by looking at the rate of the lines running through that distribution point, and comparing those rates to the rates of other lines having the same line characteristic across the whole population of lines. Distribution points that have lines operating better (faster) than the average for their given line characteristic will have higher quality figures. To estimate the rate of a new line, the quality figure of the distribution point that the new line passes through is used in conjunction with the measured line characteristic as a look up on the whole population of lines.

This invention relates to a method of dynamic line management (DLM) for a digital subscriber line. A quality of experience (QoE) measure is calculated for the digital subscriber line, and the QoE is recorded with the respective DLM line profile and also the line synchronisation rate associated with the line profile. The QoE measure is preferably based on line parameters such as a count of the error rate on the line and loss of synchronisations on the line, averaged over a predetermined period of time. Other line parameters could be used in determining the QoE measure. When DLM exhausts all the available line profiles, the invention checks to see if the QoE associated with the line profile currently being applied is an improvement on the QoE of previously applied line profiles, and if it is an improvement, then the current line profile is maintained. However, if the new QoE is not an improvement to that associated with a previously applied line profile, then the invention reverts the line back to one of the earlier line profiles. The line profile selected to revert back to is one having the same QoE or better, and if there are multiple line profiles satisfying that condition, then the line profile that has the highest associated line synchronisation rate is selected.

A method of determining the location of a disconnection on a digital subscriber line, in particular a VDSL line, where the line has a number of nodes or connection points along it. A statistical model is generated from a population of lines that maps the loop (line) lengths of each of those lines obtained by line test measurements (such as single ended line test tracesSELT traces) against the corresponding loop lengths obtained from inventory data. The model is then used to determine a predicted loop length by mapping a measured loop length (taken from line test measurements) onto an inventory loop length using the model. Knowledge of the node positions on the line is then used to give a probability a line disconnect occurring at a given node by mapping the predicted loop length onto the node positions.

A method of determining when there has been a change in the modem power state of a modem connected to a digital subscriber line. An Uncalibrated Echo Response (UER) trace is obtained from the digital subscriber line by running a Single Ended Line Test (SELT) on the line. This UER trace is compared to a historical (baseline) UER trace from the same line. A difference in the two traces in a higher frequency range (for example, DS3 for a VDSL line), is indicative of a possible modem power state change.

Detecting a short disconnection in a digital subscriber line, for example where the disconnection is near the DSLAM. A SELT UER trace is obtained from the digital subscriber line. The trace is analysed to determine its smoothness, as relatively smooth traces result from shorter lines. The smoothness measure can be calculated by applying some function to the differences of the amplitude between successive frequency tones. Two examples of functions that have been found to work well are a sum and a standard deviation. The result of the function can be compared to a threshold to determine if a short disconnection has occurred. Such a situation can occur when a cable has been disconnected from a patch panel for example.