British Telecommunications Public Limited Company

David M Rohlfing

Paul Benyon

Stephen A Cassidy

Philip M Bull

Botond Virginas

Kjeld Jensen

Phil Bull

Ian Horsley

Ashley Pickering

Philip Antony Everett

Mark Andrew Fletcher

Phillip Bull

This invention provides a computer-implemented method of modifying an algorithm operating on a computing system, and a device for implementing said method, the method comprising the steps of: applying the algorithm to a first set of inputs; determining a relevance score for a first input of the first set of inputs based on: a first effectiveness value of the first input, wherein the first effectiveness value represents a contribution of first input to the algorithm, and a first computational cost of the first input, wherein the 1 first computational cost represents the computational resources of using the first input in the algorithm; defining a second set of inputs based on the determined relevance score of the first input; and applying the algorithm to the second set of inputs.

Computer-implemented method of modifying an algorithm operating on a computing system

This invention provides an autonomic method for controlling an algorithm on a multi-terminal computing system, wherein the algorithm is configured to analyse diagnostic data for each terminal and an outcome of the analysis is a first action or a second action, and a device for implementing the method, the method comprising the steps of: receiving a first set of data for the multi-terminal computing system; applying the algorithm to the first set of data to classify each terminal in the multi-terminal computing system as being associated with either a first action or second action; re-classifying a first subset of terminals classified as being associated with the first action as being associated with the second action; and applying the first actions, second actions, and reclassified second actions respectively to each terminal in the multi-terminal computing system.

Autonomic method for managing a computing system

A method is presented of determining whether a digital subscriber line is susceptible to radio frequency interference. The method measures the signal to noise ratio (SNR) margin on the digital subscriber line over a number of 24 hour periods. The measured SNR margin over a given 24 hour period is then compared to a reference function of SNR margin over time (24 hours), where the SNR margin of the reference function is higher during the day and lower during the night, and also repeats daily. A measure of the interference susceptibility is generated based on the degree of similarity between the measured SNR margin and the reference function.

DSL line interference susceptibility

The invention relates to a method of estimating an electrical length of a line, which is the signal loss measured at a predetermined frequency such as 1 MHz, compensated for impairments on the line. Firstly, the H log(f) data representing the attenuation plotted against frequency is gathered for the line. Secondly, data transformation is performed on the H log(f) data, such as by dividing by the square root of frequency. This compensates for changes in the loss as a function of frequency, allowing values of the loss from a broader range of frequencies to be used. Thirdly, data spike removal is performed on the transformed data, removing spikes that can arise from a number of factors such as excessive noise. The resulting data is then used to estimate a value for compensated k10.

Estimating the electrical line length of a digital subscriber line

The operation of base stations in a wireless network whose areas of coverage do not overlap are synchronized by taking timing values from mobile units that travel from one area of coverage to another. A base station receiving a timing value from a mobile unit entering its area of coverage adapts its timing value and that of any mobile units in its coverage area, including the newly-arrived mobile unit, to a become a value intermediate between its existing timing value and that indicated by the mobile unit. The use of an intermediate value instability in the system that might result from an inability of the base stations to communicate directly with each other in real time.

Base station time synchronization in a wireless network

The present invention presents a method of identifying faults in a DSL line using upstream and downstream attenuation measurements, which can be obtained directly from the DSLAM or CPE, thus requiring no specialist test equipment nor disrupting service. A downstream over upstream attenuation ratio is calculated for a line, with calculations repeated over a population of lines. The distribution of ratios, as well as upper and lower thresholds, is determined based on the population. A line is identified as being potentially faulty if it has an attenuation ratio above the upper threshold or below the lower threshold. Specifically, an attenuation ratio below the lower threshold is identified as having a high resistance joint fault (caused by an imperfect connection or corrosion at a joint in at least one of the pairs of a line), and a ratio above the upper threshold as a shunt (caused by degradation of the insulation between the pairs of a line, and often coupled with water ingress).

Fault identification using line attenuations

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.

Estimating line rate

The invention presents a method of identifying faults on a DSL line, typically intermittent faults arising from unstable joints in the DSL line. The method collects errored seconds data at the DSLAM and at the customer's premises equipment (CPE, typically a home hub or router). The error data collected at the DSLAM are termed near-end errors, and the error data collected at the CPE are termed far-end errors. The near-end and far-end data is then analyzed by applying regression analysis to determine if there is a correlation or match between the two sets of data. Matching data patterns are indicative of unstable or bad joints in the DSL line, and are typically intermittent and located near the customer's premises.

Identifying line faults using regression analysis on near and far end errors

A method is proposed for calculating a line performance, or stability, measure for a telephone line. Various physical parameters associated with the line, such as insulation resistance, capacitance and DC voltages, are measured. The values for each of the parameters are compared to expected values, which are based on historical values measured for that line. Individual performance measures for each parameter are calculated based on the difference between the actual and expected values, normalised by the deviation of that parameter. The deviation accounts for general fluctuations across all the lines. A weighting value is also applied, based on knowledge of values relevant to the good operation of lines. The deviation effectively gives a scaling, and the weighting gives a context to the measured values for a single line. The individual performance measures are summed to get the final performance measure for the line. Thus, the performance measure for the line gives an indication of the stability of that line, based on analysis of the past performance of that line, and taking into account the general fluctuations seen over all lines.

Line performance measure

A method of measuring the performance of a DSL line provides an indication of potential faults in the line. Analysis of broadband DSL is less straightforward than for other technologies, since 'normal' behavior depends on a number of factors, including line length and line quality, where normal behavior for a long line could be regarded as poor for a short line. The data transmission characteristics of a DSL line under test are measured with reference to its upstream line attenuation, then the results are compared with the model for the corresponding data transmission characteristic. A performance measure is calculated for each characteristic indicative of the difference between the measured characteristic and the observed 'average' for other lines having the same upstream line attenuation. A final line performance indicator is calculated based on the combination of all the individual performance measures, which provides a quantitative measure of a line's performance.

Measuring line performance

A method of fault diagnostics in a case based reasoning system, wherein said case based reasoning system comprises a plurality of cases, each case having an associated solution and a case weight, said method comprising the steps of: receiving data associated with a fault; determining a case match indicative of the degree of matching between the received data and each of the plurality of cases; providing a solution associated with one of the plurality of cases in dependence on its case match and case weight; receiving an actual solution to the fault; increasing the case weight of the case associated with the provided solution if the actual solution is equal to the provided solution; and adding a new case to the plurality of cases if the actual solution is not equal to the provided solution, wherein the actual solution is associated with the new case.

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Ipswich, United Kingdom

David M Rohlfing