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1. (US20080205501) DSL system estimation
Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

Claims
1. A method for estimating a DSL system test loop configuration, the method comprising:
obtaining a test loop parameter vector from the test loop of the DSL system, wherein the test loop parameter vector comprises one or more loop-dependent parameter values;
selecting a reference parameter vector corresponding to a reference loop configuration;
computing the difference between the test loop parameter vector and the reference parameter vector; and
estimating the test loop configuration based on the computed difference between the test loop parameter vector and the reference parameter vector.
2. The method of claim 1 wherein the test loop parameter vector comprises at least one of the following:
channel attenuation per tone;
channel attenuation averaged over a group of tones;
loop attenuation;
signal attenuation;
LATN;
SATN;
estimated upstream power back-off electrical length;
UPBOKLE;
HLOG[n]; or
receiver noise per tone estimated assuming a channel attenuation per tone corresponding to a straight loop.
3. The method of claim 1 further comprising:
selecting the reference loop configuration to correspond to a reference loop with no bridged taps;
locating peaks in the difference between the test loop parameter vector and the reference parameter vector;
estimating the size of any located peaks; and
declaring the presence of a bridged tap on the DSL system test loop based on the location and estimated size of any located peaks.
4. The method of claim 3 further comprising estimating the length of the bridged tap based on the location of the peaks.
5. The method of claim 3 wherein identifying the presence of a bridged tap comprises:
declaring a positive peak when the size of a detected peak is larger than a positive peak size threshold;
declaring a negative peak when the size of a detected peak is smaller than a negative peak size threshold;
counting the number of declared positive peaks;
counting the number of declared negative peaks;
declaring the presence of a bridged tap if:
the number of declared positive peaks exceeds a positive peak count threshold; and
the number of declared negative peaks exceeds a negative peak count threshold.
6. The method of claim 5 further comprising adjusting at least one of the following:
the positive peak size threshold;
the negative peak size threshold;
the positive peak count threshold; or
the negative peak count threshold.
7. The method of claim 4 wherein estimating the length of the bridged tap comprises at least one of the following:
estimating the length of a bridged tap that corresponds to the detected location of at least one positive peak; or
estimating the length of a bridged tap that corresponds to the detected location of at least one negative peak.
8. The method of claim 1 wherein the test loop parameter vector comprises a test loop echo-dependent parameter vector obtained from operational data collected from the test loop;
further wherein the reference loop configuration comprises a reference loop configuration with no bridged tap;
further wherein the reference parameter vector comprises a reference echo-dependent parameter vector corresponding to the reference loop configuration with no bridged tap;
further wherein the method further comprises:
computing the difference between the test loop echo-dependent parameter vector and the reference echo-dependent parameter vector;
wherein the method comprises estimating the location of a bridged tap from the computed difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector.
9. The method of claim 8 wherein the echo-dependent parameter vector comprises at least one of the following:
an echo response;
a loop impedance; or
a receiver noise per tone.
10. The method of claim 1 wherein the reference loop configuration has no bad splice;
further wherein the method further comprises:
computing a difference between the test loop parameter vector and the reference parameter vector; and
declaring the presence of a bad splice in the test loop if the computed difference is larger than a first threshold.
11. The method of claim 1 wherein the reference loop configuration has no bad splice;
further wherein the method further comprises:
detecting a frequency set for which the difference between the test loop parameter vector and the reference parameter vector is larger than a first threshold; and
declaring a bad splice if the detected frequency set is within a first frequency range.
12. The method of claim 10 wherein the test loop parameter vector comprises at least one of the following:
channel attenuation per tone;
channel attenuation averaged over a group of tones;
loop attenuation;
signal attenuation;
LATN;
SATN;
estimated upstream power back-off electrical length;
UPBOKLE;
HLOG[n]; or
receiver noise per tone estimated assuming a loop with no bad splice.
13. The method of claim 10 wherein the test loop parameter vector comprises an echo-dependent parameter vector based on operational data collected from the DSL system;
further wherein the reference parameter vector comprises a reference echo-dependent parameter vector corresponding to the reference loop configuration;
further wherein the method comprises:
computing the difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector; and
estimating the location of a bad splice from the computed difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector.
14. The method of claim 13 wherein the echo-dependent parameter vector comprises at least one of the following:
an echo response;
a loop impedance; or
a receiver noise per tone.
15. A method for detecting a missing micro-filter in a DSL system loop, the method comprising:
generating a first operational parameter vector based on operational data of the DSL system;
storing the first parameter vector;
generating a second operational parameter vector based on operational data of the DSL system; and
comparing the first operational parameter vector to the second operational parameter vector.
16. The method of claim 15 wherein each of the first and second operational parameter vectors comprises at least one of the following:
channel average attenuation measurements;
LATN;
SATN;
estimated upstream power back-off electrical length;
UPBOKLE;
channel bit distributions;
channel transmit power levels;
reported current data rates;
reported maximum attainable data rates;
reported error-correction-parity;
reported use of trellis codes;
measured channel insertion loss;
HLOG[n];
measured channel gain;
measured channel phase;
inferred data regarding individual users' power levels;
operational data regarding individual users' power levels;
inferred data regarding individual users' PSD levels;
operational data regarding individual users' PSD levels;
inferred data regarding individual users' code settings;
operational data regarding individual users' code settings;
inferred data regarding the parameterized shaped PSDs of potential noises;
operational data regarding the parameterized shaped PSDs of potential noises;
the frequency/tone index of highest noise change in a recent time interval;
the total number of bit-swaps occurring in a recent time interval;
the distribution of FEC errors, code violations or errored seconds violations over several successive sub-intervals of a time interval;
measured noise power variations;
measured peak-to-average power ratio;
measured channel logarithmic magnitude;
measured quiet-line noise levels;
measured active-line noise levels;
mean square error per tone;
MSE[n];
signal-to-noise ratio per tone;
SNR[n];
count of ATM or other protocol cells;
measured higher-level protocol-throughput;
count of retraining;
count of failed synchronization attempts;
reported carrier mask;
reported tone-shaping parameters;
inferred data regarding vectored or matrix channel characterization;
echo response;
received echo noise; or
loop impedance.
17. The method of claim 15 further comprising declaring a missing micro-filter if the difference between first operational parameter vector and the second operational parameter vector exceeds a certain threshold.
18. The method of claim 17 wherein declaring a missing micro-filter is performed only if phone call record information indicates that the phone state changed between generating the first operational parameter vector and the second operational parameter vector, wherein a change in the phone state comprises the phone changing from an on-hook state to an off-hook state or the phone changing from the off-hook state to the on-hook state.
19. The method of claim 15 further comprising declaring a missing micro-filter if the first operational parameter vector and the second operational parameter vector indicate that a retrain occurred between generating the first operational parameter vector and generating the second operational parameter vector; and
if phone call record information indicates that the phone state changed between the first collection and the second collection, wherein a change in the phone state comprises the phone changing from an on-hook state to an off-hook state or the phone changing from the off-hook state to the on-hook state.
20. The method of claim 15 further comprising declaring a missing micro-filter if the first operational parameter vector and the second operational parameter vector indicate that, between generating the first operational parameter vector and generating the second operational parameter vector, at least one of the following occurred:
a large number of code violations; or
a large number of FEC corrections; and
if phone call record information indicates that the phone state changed between the first collection and the second collection, wherein a change in the phone state comprises the phone changing from an on-hook state to an off-hook state or the phone changing from the off-hook state to the on-hook state.
21. A computer program product comprising:
a machine readable medium and program instructions contained in the machine readable medium, the program instructions specifying a method for estimating a DSL system test loop configuration, the method comprising:
obtaining a test loop parameter vector from the test loop of the DSL system, wherein the test loop parameter vector comprises one or more loop-dependent parameter values;
selecting a reference parameter vector corresponding to a reference loop configuration;
computing the difference between the test loop parameter vector and the reference parameter vector; and
estimating the test loop configuration based on the computed difference between the test loop parameter vector and the reference parameter vector.
22. The computer program product of claim 21 with the method further comprises:
selecting the reference loop configuration to correspond to a reference loop with no bridged taps;
locating peaks representing the difference between the test loop parameter vector and the reference parameter vector;
estimating the size of any located peaks; and
declaring the presence of a bridged tap on the DSL system test loop based on the location and estimated size of any located peaks.
23. The computer program product of claim 21 wherein the test loop parameter vector comprises a test loop echo-dependent parameter vector obtained from operational data collected from the test loop;
further wherein the reference loop configuration comprises a reference loop configuration with no bridged tap;
further wherein the reference parameter vector comprises a reference echo-dependent parameter vector corresponding to the reference loop configuration with no bridged tap;
further wherein the method further comprises:
computing the difference between the test loop echo-dependent parameter vector and the reference echo-dependent parameter vector; and
wherein the method comprises estimating the location of a bridged tap from the computed difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector.
24. The computer program product of claim 21 wherein the reference loop configuration has no bad splice;
further wherein the method further comprises:
computing a difference between the test loop parameter vector and the reference parameter vector; and
declaring the presence of a bad splice in the test loop if the computed difference is larger than a first threshold.
25. The computer program product of claim 24 wherein the test loop parameter vector comprises an echo-dependent parameter vector based on operational data collected from the DSL system;
further wherein the reference parameter vector comprises a reference echo-dependent parameter vector corresponding to the reference loop configuration;
further wherein the method further comprises:
computing the difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector; and
estimating the location of a bad splice from the computed difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector.
26. A computer program product comprising:
a machine readable medium and program instructions contained in the machine readable medium, the program instructions specifying a method for detecting a missing micro-filter in a DSL loop, the method comprising:
generating a first operational parameter vector based on operational data of the DSL system;
storing the first parameter vector;
generating a second operational parameter vector based on operational data of the DSL system; and
comparing the first operational parameter vector to the second operational parameter vector.
27. A controller comprising:
a data collection unit coupled to a data analysis unit and a control signal generator coupled to the data analysis unit, wherein the data collection unit, the data analysis unit and the signal generator are configured to:
obtain a test loop parameter vector from a test loop of a DSL system, wherein the test loop parameter vector comprises one or more loop-dependent parameter values;
select a reference parameter vector corresponding to a reference loop configuration;
compute the difference between the test loop parameter vector and the reference parameter vector; and
estimate the test loop configuration based on the computed difference between the test loop parameter vector and the reference parameter vector.
28. The controller of claim 27 wherein the data collection unit, the data analysis unit and the signal generator are further configured to:
select the reference loop configuration to correspond to a reference loop with no bridged taps;
locate peaks in the difference between the test loop parameter vector and the reference parameter vector;
estimate the size of any located peaks; and
declare the presence of a bridged tap on the DSL system test loop based on the location and estimated size of any located peaks.
29. The controller of claim 27 wherein the test loop parameter vector comprises a test loop echo-dependent parameter vector obtained from operational data collected from the test loop;
further wherein the reference loop configuration comprises a reference loop configuration with no bridged tap;
further wherein the reference parameter vector comprises a reference echo-dependent parameter vector corresponding to the reference loop configuration with no bridged tap;
further wherein the data collection unit, the data analysis unit and the signal generator are further configured to:
compute the difference between the test loop echo-dependent parameter vector and the reference echo-dependent parameter vector;
wherein the method comprises estimating the location of a bridged tap from the computed difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector.
30. The controller of claim 27 wherein the reference loop configuration has no bad splice;
further wherein the data collection unit, the data analysis unit and the signal generator are further configured to:
compute a difference between the test loop parameter vector and the reference parameter vector; and
declare the presence of a bad splice in the test loop if the computed difference is larger than a first threshold.
31. A controller comprising:
a data collection unit coupled to a data analysis unit and a control signal generator coupled to the data analysis unit, wherein the data collection unit, the data analysis unit and the signal generator are configured to:
generate a first operational parameter vector based on operational data pertaining to a DSL system;
store the first parameter vector;
generate a second operational parameter vector based on operational data of the DSL system; and
compare the first operational parameter vector to the second operational parameter vector.