Granted Patent B2

US 7,924,736 · App. 11/995,194 · Granted Apr 12, 2011

Abstract

Claims (178)

1. A method for estimating a DSL system test loop configuration, the method comprising:

collecting operational data from a DSL system test loop comprising a first DSL transceiver at a near end of the test loop and a second DSL transceiver at a far end of the test loop, wherein the operational data is a result of transmissions between the first and second transceiver;

generating a test loop parameter vector from the collected operational data, wherein the test loop parameter vector comprises one or more loop-dependent parameter values, further wherein the test loop parameter vector includes parameters directly collected or derived from the operational data;

selecting a reference parameter vector corresponding to a reference loop configuration, wherein the reference parameter vector includes reference values characterizing the presence or absence of a condition on a hypothetical or ideal loop free from the condition, wherein the condition is a bridged tap or the condition is a bad splice;

comparing the test loop parameter vector and the reference parameter vector; and

detecting the condition on the test loop, based on the comparison 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 (LATN); signal attenuation (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 loop with no bridged taps.

3. The method of claim 1 wherein comparing the test loop parameter vector and the reference parameter vector comprises computing the difference between the test loop parameter vector and the reference parameter vector, the method further comprising:

selecting the reference loop configuration to correspond to a reference loop with no bridged taps, wherein the condition is the presence of a bridged tap;

locating peaks in the computed 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 declaring the presence of a bridged tap comprises:

identifying a positive peak when the size of a located peak is larger than a positive peak size threshold;

identifying a negative peak when the size of a located peak is smaller than a negative peak size threshold;

counting the number of identified positive peaks;

counting the number of identified negative peaks;

declaring the presence of a bridged tap when:

the number of identified positive peaks exceeds a positive peak count threshold, and

the number of identified 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 identified location of at least one positive peak; or

estimating the length of a bridged tap that corresponds to the identified 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 condition is the presence of a bridged tap, and 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 a 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 condition is the presence of a bad splice, and 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 when the computed difference is larger than a first threshold.

11. The method of claim 1 wherein the condition is the presence of a bad splice, and 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 when 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 (LATN);

signal attenuation (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 problem with a micro-filter in a DSL system loop, the method comprising:

generating a first operational parameter vector based on operational data of the DSL system, the operational data providing a state of the DSL system loop when a phone that shares the DSL system loop is in an on-hook state;

generating a second operational parameter vector based on operational data of the DSL system, the operational data providing a state of the DSL system loop when a phone that shares the DSL system loop is in an off-hook state;

comparing the first operational parameter vector to the second operational parameter vector; and

declaring a problem with the micro-filter based on the comparison of the first and second operational parameter vectors, wherein declaring a problem with the micro-filter comprises confirming from phone call record information that the phone state changed between an on-hook state and an off-hook state between the generation of the first operational parameter vector and the generation of 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;

loop attenuation (LATN);

signal attenuation (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' power spectral density (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 forward error correction (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;

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 wherein declaring a problem with the micro-filter based on the comparison of the first and second operational parameter vectors comprises declaring a missing micro-filter when the difference between the first operational parameter vector and the second operational parameter vector exceeds a threshold.

18. The method of claim 15 wherein declaring a problem with the micro-filter based on the comparison of the first and second operational parameter vectors comprises declaring a missing micro-filter when:

the first operational parameter vector and the second operational parameter vector indicate that a retrain occurred between the generation of the first operational parameter vector and the generation of the second operational parameter vector.

19. The method of claim 15 wherein declaring a problem with the micro-filter based on the comparison of the first and second operational parameter vectors comprises declaring a missing micro-filter when the first operational parameter vector and the second operational parameter vector indicate that, between the generation of the first operational parameter vector and the generation of the second operational parameter vector,

a large number of code violations, or a large number of FEC corrections occurred.

20. A computer program product comprising:

a non-transitory 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:

collecting operational data from a DSL system test loop comprising a first DSL transceiver at a near end of the test loop and a second DSL transceiver at a far end of the test loop, wherein the operational data is a result of transmissions between the first and second transceiver;

generating a test loop parameter vector from the collected operational data, wherein the test loop parameter vector comprises one or more loop-dependent parameter values, further wherein the test loop parameter vector includes parameters directly collected or derived from the operational data;

selecting a reference parameter vector corresponding to a reference loop configuration, wherein the reference parameter vector includes reference values characterizing the presence or absence of a condition on a hypothetical or ideal loop free from the condition, wherein the condition is a bridged tap or the condition is a bad splice;

comparing the test loop parameter vector and the reference parameter vector; and

detecting the condition on the test loop, based on the comparison between the test loop parameter vector and the reference parameter vector.

21. The computer program product of claim 20 wherein comparing the test loop parameter vector and the reference parameter vector comprises computing the difference between the test loop parameter vector and the reference parameter vector, and wherein the method further comprises:

selecting the reference loop configuration to correspond to a reference loop with no bridged taps, wherein the condition is the presence of a bridged tap;

locating peaks representing the computed 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.

22. The computer program product of claim 20 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 condition is the presence of a bridged tap, and 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 a location of a bridged tap from the computed difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector.

23. The computer program product of claim 20 wherein the condition is the presence of a bad splice, and 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 when the computed difference is larger than a first threshold.

24. The computer program product of claim 23 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.

25. A computer program product comprising:

a non-transitory machine readable medium and program instructions contained in the machine readable medium, the program instructions specifying a method for detecting a problem with a micro-filter in a DSL loop, the method comprising:

generating a first operational parameter vector based on operational data of the DSL system, the operational data providing a state of the DSL system loop when a phone that shares the DSL system loop is in an on-hook state;

generating a second operational parameter vector based on operational data of the DSL system, the operational data providing a state of the DSL system loop when a phone that shares the DSL system loop is in an off-hook state;

comparing the first operational parameter vector to the second operational parameter vector; and

declaring a problem with the micro-filter based on the comparison of the first and second operational parameter vectors, wherein declaring a problem with the micro-filter comprises confirming from phone call record information that the phone state changed between an on-hook state and an off-hook state between the generation of the first operational parameter vector and the generation of the second operational parameter vector.

26. A controller comprising:

a data collection unit coupled to a data analysis unit and a control signal generator coupled to the data analysis unit, to:

obtain a test loop parameter vector from operational data collected from a test loop of a DSL system comprising a first DSL transceiver at a near end of the test loop and a second DSL transceiver at a far end of the test loop, wherein the operational data is a result of transmissions between the first and second transceiver, wherein the test loop parameter vector comprises one or more loop-dependent parameter values, further wherein the test loop parameter vector includes parameters directly collected or derived from the operational data;

select a reference parameter vector corresponding to a reference loop configuration, wherein the reference parameter vector includes reference values characterizing the presence or absence of a condition on a hypothetical or ideal loop free from the condition, wherein the condition is a bridged tap or the condition is a bad splice;

compare the test loop parameter vector and the reference parameter vector; and

detect the condition on the test loop, based on the comparison of the test loop parameter vector and the reference parameter vector.

27. The controller of claim 26 wherein the compare of the test loop parameter vector and the reference parameter vector computes a difference between the test loop parameter vector and the reference parameter vector, and wherein the data collection unit, the data analysis unit and the signal generator further:

select the reference loop configuration to correspond to a reference loop with no bridged taps, wherein the condition is the presence of a bridged tap;

locate peaks in the computed 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.

28. The controller of claim 26 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 condition is the presence of a bridged tap, and 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 to:

compute the difference between the test loop echo-dependent parameter vector and the reference echo-dependent parameter vector; and

estimate a location of a bridged tap from the computed difference between the echo-dependent parameter vector and the reference echo-dependent parameter vector.

29. The controller of claim 26 wherein the condition is the presence of a bad splice, and the reference loop configuration has no bad splice;

further wherein the data collection unit, the data analysis unit and the signal generator further:

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 when the computed difference is larger than a first threshold.

30. 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:

generate a first operational parameter vector based on operational data pertaining to a DSL system, the operational data providing a state of the DSL system loop when a phone that shares the DSL system loop is in an on-hook state;

generate a second operational parameter vector based on operational data of the DSL system, the operational data providing a state of the DSL system loop when a phone that shares the DSL system loop is in an off-hook state;

compare the first operational parameter vector to the second operational parameter vector; and

declare a problem with the micro-filter based on the comparison of the first and second operational parameter vectors when phone call record information indicates that the phone state changed between an on-hook state and an off-hook state between the generation of the first operational parameter vector and the generation of the second operational parameter vector.

Assignments (11)