System and method for detecting anomalies along telecommunication lines

• US 7,460,498 B2
• Filed: 12/04/2003
• Issued: 12/02/2008
• Est. Priority Date: 12/04/2003
• Status: Active Grant

• Current Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Original Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Inventors: Hunt, Gary, Chu, Fred, Gusler, Lee T. Jr.
• Primary Examiner(s): SINGH, RAMNANDAN P
• Application Number:
  US10/727,411
• Publication Number:
  US 20050123031A1
• Time in Patent Office: 1,825 Days
• Field of Search: 370/286
• US Class Current: 370/286
• CPC Class Codes: H04B 3/238 using initial training sequence
• CPC Class Codes: H04M 3/002 Applications of echo suppressors or cancellers in telephonic connections in two-way loud-speaking telephone systems H04M9/08, echo suppressors or cancellers per se H04B3/20
• CPC Class Codes: H04M 3/085 Fault locating arrangements
• CPC Class Codes: H04M 3/28 Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor

Abstract

An anomaly detection system comprises an echo canceler and anomaly detection logic. The echo canceler has a plurality of taps respectively associated with a plurality of tap coefficients. The anomaly detection logic is configured to determine a difference between a new tap coefficient associated with one of the taps and a previous tap coefficient associated with the one tap. The anomaly detection logic is configured to perform a comparison between the difference and a threshold and to detect an anomaly along a telecommunication line based on the comparison.

Claims

1. An anomaly detection system, comprising:

an echo canceler having a plurality of taps respectively associated with a plurality of tap coefficients; and

anomaly detection logic configured to determine a difference between a new tap coefficient associated with one of the taps and a previous tap coefficient associated with the one tap, the anomaly detection logic configured to perform a comparison between the difference and a threshold and to detect an anomaly along a telecommunication line based on the comparison,

wherein the anomaly causes a resistance at a point on the telecommunication line to vary over time.

2. The system of claim 1, wherein the anomaly detection logic is configured to maintain a histogram of anomaly indications based on comparisons of associated tap coefficients.

3. The system of claim 1, wherein the anomaly detection logic is configured to maintain a running sum of a total number of anomaly indications detected by the anomaly detection logic based on comparisons between tap coefficients associated with the one tap.

4. The system of claim 3, wherein the anomaly detection logic is configured to compare the running sum to a threshold.

5. The system of claim 1, wherein the anomaly detection logic is configured to perform a second comparison between a threshold and a value indicative of an error rate associated with the telecommunication line, the anomaly detection logic further configured to detect the anomaly based on the second comparison.

6. The system of claim 5, wherein the value represents a minimum signal-to-noise ratio detected during a particular time period prior to the second comparison.

7. The system of claim 1, wherein the anomaly is a degraded splice along the telecommunication line.

8. The system of claim 1, wherein the anomaly detection logic is configured to indicate, based on the comparison, a location of the anomaly on the telecommunication line.

9. An anomaly detection system, comprising:

an echo canceler having a plurality of taps respectively associated with a plurality of tap coefficients; and

anomaly detection logic configured to determine when at least one of the tap coefficients fluctuates by at least a specified amount and to detect an anomaly along a telecommunication line based on a detection, by the logic, that the at least one tap coefficient fluctuated by at least the specified amount.

10. The system of claim 9, wherein the anomaly detection logic is further configured to maintain a running sum indicative of a number of times that the logic detects the at least one tap fluctuating by at least the specified amount, wherein the anomaly detection logic is configured to detect the anomaly based on the running sum.

11. The system of claim 10, wherein the anomaly detection logic is further configured to compare the running sum to a threshold.

12. The system of claim 9, wherein the anomaly is a telecommunication line splice that is degrading communication occurring over the telecommunication line between a transmitter at one end of the telecommunication line and a receiver at another end of the telecommunication line.

13. The system of claim 12, wherein the detection is based on a fluctuation of the tap coefficient while the transmitter is communicating with the receiver over the telecommunication line.

14. The system of claim 13, wherein the anomaly detection logic is configured to indicate, based on the detection, a location of the splice on the telecommunication line.

15. An anomaly detection system, comprising:

an echo canceler having a plurality of taps respectively associated with a plurality of tap coefficients; and

anomaly detection logic configured to establish a set of baseline tap coefficients based on the tap coefficients, the anomaly detection logic configured to compute differences between new tap coefficients of the echo canceler and the baseline tap coefficients and to detect, based on the differences, a time varying anomaly along a telecommunication line at a junction of two sections of the telecommunication line.

16. The system of claim 15, wherein the anomaly detection logic is configured to periodically update the baseline tap coefficients.

17. The system of claim 15, wherein the anomaly detection logic is configured to perform comparisons between the differences and a plurality of thresholds, each of the comparisons comparing a respective one of the differences and a respective one of the thresholds, wherein the anomaly detection logic is configured to detect the anomaly based on the comparisons.

18. The system of claim 17, wherein the anomaly detection logic is configured to update at least one of the baseline tap coefficients in response to one of the comparisons.

19. The system of claim 17, wherein the anomaly detection logic is configured to maintain a histogram of the results of the comparisons.

20. An anomaly detection method, comprising the steps of:

determining a difference between a new tap coefficient associated with a tap of an echo canceler and a previous tap coefficient associated with the tap;

comparing the difference to a threshold; and

detecting an anomaly along a telecommunication line based on the comparing step, the anomaly causing a time varying change in a transmission characteristic of a point along the transmission line.

21. An anomaly detection method, comprising the steps of:

monitoring a plurality of tap coefficients of an echo canceler;

determining when at least one of the tap coefficients fluctuates by at least a specified amount; and

detecting an anomaly along a telecommunication line based on the determining step, the anomaly causing a time varying change in resistance at a point along the transmission line.

22. The method of claim 21, further comprising the step of maintaining a running sum indicating a number of times that the at least one tap coefficient fluctuates by at least the specified amount, wherein the detecting is further based on the running sum.

23. The method of claim 22, wherein the detecting step comprises the step of comparing the running sum to a threshold.

24. An anomaly detection method, comprising the steps of:

establishing a set of baseline tap coefficients based on a set of tap coefficients of an echo canceler;

computing differences between the baseline tap coefficients and new tap coefficients of the echo canceler; and

detecting an anomaly along a telecommunication line based on the differences, the anomaly causing a time varying change in resistance at a junction of two sections of the telecommunication line.

25. The method of claim 24, further comprising the step of periodically updating the baseline tap coefficients.

26. The method of claim 24, further comprising the step of comparing the differences to a plurality of thresholds, wherein the detecting step is further based on the comparing step.

27. The method of claim 26, further comprising the step of maintaining a histogram of the results of the comparing step, wherein said detecting step is further based on the histogram.

28. An anomaly detection method, comprising the steps of:

establishing a set of baseline tap coefficients based on a set of tap coefficients of an echo canceler;

computing differences between the baseline tap coefficients and new tap coefficients of the echo canceler;

detecting an anomaly along a telecommunication line based on the differences;

comparing the differences to a plurality of thresholds, wherein the detecting step is further based on the comparing step; and

updating at least one of the baseline tap coefficients in response to a comparison between one of the differences and one of the thresholds.

29. An anomaly detection system, comprising:

an echo canceler having a plurality of taps respectively associated with a plurality of tap coefficients; and

anomaly detection logic configured to determine a difference between a new tap coefficient associated with one of the taps and a previous tap coefficient associated with the one tap, the anomaly detection logic configured to perform a comparison between the difference and a threshold and to detect an anomaly alone a telecommunication line based on the comparison,

wherein the new tap coefficient is based on a first digital signal transmitted from a transmitter at one end of the telecommunication line to a receiver at another end of the telecommunication line, and wherein the previous tap coefficient is based on a second digital signal transmitted from the transmitter to the receiver.

30. A system, comprising:

a receiver coupled to a telecommunication line, the receiver configured to receive digital signals transmitted from a remote transmitter via the telecommunication line, the telecommunication line having a time varying anomaly causing a resistance at a point on the telecommunication line to fluctuate over time thereby degrading the digital signals; and

anomaly detection logic configured to detect the anomaly and to provide an indication of a location of the anomaly.

31. The system of claim 30, wherein the anomaly detection logic is configured to detect the anomaly based on coefficients of an echo canceler.

32. The system of claim 30, further comprising an echo canceler having a plurality of taps respectively associated with a plurality of tap coefficients, wherein the anomaly detection logic is configured to perform a comparison of a first tap coefficient associated with one of the taps and a second tap coefficient associated with the one tap, the anomaly detection logic further configured to detect the anomaly based on the comparison.