Systems, methods and computer program products for averaging learned levels in the presence of robbed-bit signaling based on proximity

• US 6,792,004 B1
• Filed: 10/29/1999
• Issued: 09/14/2004
• Est. Priority Date: 10/29/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Ware, Malcolm Scott, Davis, Gordon Taylor
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Boakye, Alexander O.
• Application Number:
  US09/430,603
• Time in Patent Office: 1,782 Days
• Field of Search: 370/523, 370/525, 370/526, 370/524, 370/479, 370/252, 370/522, 370/458, 370/466, 370/467, 375/222, 375/220, 375/285, 375/326, 375/233, 375/242, 708/323, 708/229, 708/230
• US Class Current: 370/479
• CPC Class Codes: H04L 25/061 providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset removal of dc offset in coupling arrangements H04L25/029, H04L25/0296
• CPC Class Codes: H04L 25/4927 using levels matched to the quantisation levels of the channel

Abstract

Methods, systems and computer program products for averaging measured levels from differing intervals and differing code points based on their proximity with other measured levels are provided. Such proximity averaging may be provided by methods, systems and computer program products for averaging measured levels of code point sequences from a plurality of frame intervals in the presence of robbed-bit signaling by comparing a first measured level of a first code point from a first of the plurality of frame intervals and a measured level of a second code point from the plurality of frame intervals so as to provide a first comparison result. The measured level of the second code point is incorporated into an average of the measured levels for the first code point from the plurality of frame intervals based on the first comparison result and a threshold value. The measured level of the second code point may then be replaced with the average of the measured levels of the first code points if the measured level of the second code point is incorporated into the average of the measured levels of the first code point. Preferably, the first and second code points are adjacent code points in the code point sequence.

Claims

1. A method of averaging measured levels of code point sequences from a plurality of frame intervals, the method comprising the steps of:

comparing a first measured level of a first code point from a first of the plurality of frame intervals and a measured level of a second code point from the plurality of frame intervals;

responsive to a difference between the measured level of the first code point and the measured level of the second code point being less than a threshold value, incorporating the measured level of the second code point into an average of the measured levels for the first code point from the plurality of frame intervals; and

replacing the measured level of the second code point with the average of the measured levels of the first code point if the measured level of the second code point is incorporated into the average of the measured levels of the first code point.

2. A method according to claim 1, wherein the steps of comparing, and incorporating are carded out for each frame interval in the second code point so as to evaluate each of the measured levels of the second code point and wherein the step of replacing is carried out after each of the measured levels of the second code point are evaluated.

3. A method according to claim 1, further comprising the step of excluding the measured level of the second code point from the average of the measured levels of the second code points from the plurality of frame intervals if the measured level of the second code point is incorporated into the average of the measured levels for the first code point.

4. A method according to claim 1, further comprising the steps of:

comparing the first measured level of the first code point from the first of the plurality of frame intervals and a second measured level of the first code point from a second of the plurality of frame intervals;

incorporating the second measured level of the first code point into the average of the measured levels for the first code point from the plurality of frame intervals based on the comparison of the first measured level of the first code point from the first of the plurality of frame intervals and the second measured level of the first code point from the second of the plurality of frame intervals and a threshold value; and

replacing the second measured level of the first code point with the average of the measured levels of the first code points if the second measured level of the first code point is incorporated into the average of the measured levels of the first code point.

5. A method according to claim 4, wherein the steps of comparing the first measured level of the first code point from the first of the plurality of frame intervals and a second measured level of the first code point from a second of the plurality of frame intervals, incorporating the second measured level of the first code point into the average of the measured levels for the first code point from the plurality of frame intervals based on the comparison of the first measured level of the first code point from the first of the plurality of frame intervals and the second measured level of the first code point from the second of the plurality of frame intervals and a threshold value and replacing the second measured level of the first code point with the average of the measured levels of the first code points if the second measured level of the first code point is incorporated into the average of the measured levels of the first code point are carried out for each frame interval in the first code point other than the first of the plurality of frame intervals.

6. A method according to claim 4, wherein the steps of comparing a first measured level of a first code point from a first of the plurality of frame intervals and a measured level of a second code point from the plurality of frame intervals and the step of incorporating the measured level of the second code point into an average of the measured levels for the first code point from the plurality of frame intervals based on the comparison of the first measured level of a first code point from the first of the plurality of frame intervals and the measured level of a second code point from the plurality of frame intervals and a threshold value are carried out for each frame interval in the second code point so as to evaluate each of the measured levels of the second code point and wherein the step of replacing the measured level of the second code point and the step of replacing the measured level of the first code point are carried after each of the measured levels of the second code point and the measured levels of the first code point are evaluated.

7. A method according to claim 1, further comprising the step of determining the threshold value based on the measured levels of the code point sequence.

8. A method according to claim 7, wherein the step of determining the threshold value based on the measured levels of the code point sequence comprises the steps of:

determining an average spacing for measured levels of the code point sequence consecutive with the first code point; and

setting the threshold value based on the determined average spacing.

9. A method according to claim 8, wherein the average spacing is determined based on the difference between the first measured level of the first code point and a measured level of a third code point which is four code points lower in the code point sequence than the first code point.

10. A method according to claim 8, further comprising the step of:

establishing the threshold value based on the first measured level of the first code point; and

wherein the comparing step comprises the step of comparing the measured level of the second code point to the threshold value.

11. A method according to claim 10, wherein the step of establishing the threshold value based on the first measured level of the first code point comprises the steps of:

weighting the average spacing to provide a weighted average spacing; and

combining the weighted average spacing and the first measured level of the first code point to provide the threshold value.

12. A method according to claim 10, wherein the first measured level of the first code point comprises the smallest measured level of the first code point.

13. A method according to claim 12, wherein the step of establishing the threshold value based on the first measured level of the first code point comprises the steps of:

weighting the average spacing to provide a weighted average spacing; and

adding the weighted average spacing and the first measured level of the first code point to provide the threshold value.

14. A method according to claim 13, wherein the step of comparing the measured level of the second code point to the threshold value comprises the step of determining if the measured level of the second code point is less than or equal to the threshold value.

15. A method according to claim 10, wherein the first measured level of the first code point comprises the largest measured level of the first code point.

16. A method according to claim 15, wherein the step of establishing the threshold value based on the first measured level of the first code point comprises the steps of:

weighting the average spacing to provide a weighted average spacing; and

subtracting the weighted average spacing from the first measured level of the first code point to provide the threshold value.

17. A method according to claim 16, wherein the step of comparing the measured level of the second code point to the threshold value comprises the step of determining if the measured level of the second code point is greater than or equal to the threshold value.

18. A method according to claim 1, wherein the first and second code points are adjacent code points in the code point sequence.

19. A system for averaging measured levels of code point sequences from a plurality of He intervals, the system comprising:

means for comparing a first measured level of a first code point from a first of the plurality of frame intervals and a measured level of a second code point from the plurality of frame intervals;

means, responsive to the means for comparing, for incorporating the measured level of the second code point into an average of the measured levels for the first code point from the plurality of frame intervals when a difference between the first measured level of the first code point and the measured level of the second code point is less than a threshold value; and

means for replacing the measured level of the second code point with the average of the measured levels of the first code points if the measured level of the second code point is incorporated into the average of the measured levels of the first code point.

20. A system according to claim 19, wherein the means for comparing comprises means for comparing a first measured level of a first code point from a first of the plurality of frame intervals and each of the measured levels of a second code point from the plurality of frame intervals.

21. A system according to claim 19, further comprising means for excluding the measured level of the second code point from the average of the measured levels of the second code points from the plurality of frame intervals if the measured level of the second code point is incorporated into the average of the measured levels for the first code point.

22. A system according to claim 19, further comprising:

means for comparing a first measured level of a first code point from a first of the plurality of frame intervals and a second measured level of the first code point from a second of the plurality of frame intervals;

means for incorporating the second measured level of the first code point into the average of the measured levels for the first code point from the plurality of frame intervals based on the comparison of the first measured level of the first code point from the first of the plurality of frame intervals and the second measured level of the first code point from the second of the plurality of frame intervals and a threshold value; and

means for replacing the second measured level of the first code point with the average of the measured levels of the first code points if the second measured level of the first code point is incorporated into the average of the measured levels of the first code point.

23. A system according to claim 22, wherein the means for comparing comprises means for comparing a first measured level of a first code point from a first of the plurality of frame intervals and each of the measured levels of the first code point from the plurality of frame intervals other than the first of the plurality of frame intervals.

24. A system according to claim 19, further comprising means for determining the threshold value based on the measured levels of the code point sequence.

25. A system according to claim 24, wherein the means for determining the threshold value based on the measured levels of the code point sequence comprises:

means for determining an average spacing for measured levels of the code point sequence consecutive with the first code point; and

means for setting the threshold value based on the determined average spacing.

26. A system according to claim 25, wherein the average spacing is determined based on the difference between the first measured level of the first code point and a measured level of a third code point which is four code points lower in the code point sequence than the first code point.

27. A system according to claim 25, further comprising:

means for establishing the threshold value based on the first measured level of the first code point; and

wherein the means for comparing comprises means for comparing the measured level of the second code point to the threshold value.

28. A system according to claim 27, wherein the means for establishing the threshold value based on the first measured level of the first code point comprises:

means for weighting the average spacing to provide a weighted average spacing; and

means for combining the weighted average spacing and the first measured level of the first code point to provide the threshold value.

29. A system according to claim 27, wherein the first measured level of the first code point comprises the smallest measured level of the first code point.

30. A system according to claim 29, wherein the means for establishing the threshold value based on the first measured level of the first code point comprises:

means for weighting the average spacing to provide a weighted average spacing; and

means for adding the weighted average spacing and the first measured leveld of the first code point to provide the threshold value.

31. A system according to claim 30, wherein the means for comparing the measured level of the second code point to the threshold value comprises means for determining if the measured level of the second code point is less than or equal to the threshold value.

32. A system according to claim 27, wherein the first measured level of the first code point comprises the largest measured level of the first code point.

33. A system according to claim 32, wherein the means for establishing the threshold value based on the first measured level of the first code point comprises:

means for weighting the average spacing to provide a weighted average spacing; and

means for subtracting the weighted average spacing and the first measured level of the first code point to provide the threshold value.

34. A system according to claim 33, wherein the means for comparing the measured level of the second code point to the threshold value comprises means for determining if the measured level of the second code point is greater than or equal to the threshold value.

35. A system according to claim 19, wherein the first and second code points are adjacent code points in the code point sequence.

36. A computer program product for averaging measured levels of code point sequences from a plurality of frame intervals, the computer program product comprising:

a computer-readable storage medium having computer readable program code embodied in said medium said computer-readable program code comprising;

computer-readable program code for comparing a first measured level of a first code point from a first of the plurality of frame intervals and a measured level of a second code point from the plurality of fame intervals;

computer-readable program code, responsive to the computer-readable program code for comparing, for incorporating the measured level of the second code point into an average of the measured levels for the first code point from the plurality of frame intervals when a difference between the measured level of the first code point and the measured level of the second code point is less than a threshold value; and

computer-readable program code for replacing the measured level of the second code point with the average of the measured levels of the first code points If the measured level of the second code point is incorporated into the average of the measured levels of the first code point.

37. A computer program product according to claim 36, wherein the computer-readable program code for comparing comprises computer-readable program code for comparing a first measured level of a first code point from a first of the plurality of frame intervals and a measured level of each of the frame intervals of a second code point.

38. A computer program product according to claim 36, further comprising computer-readable program code for excluding the measured level of the second code point from the average of the measured levels of the second code points from the plurality of frame intervals if the measured level of the second code point is incorporated into the average of the measured levels for the first code point.

39. A computer program product according to claim 38, wherein the first and second code points are adjacent code points in the code point sequence.

40. A computer program product according to claim 36, further comprising:

computer-readable program code for comparing a first measured level of the first code point from the first of the plurality of frame intervals and a second measured level of the first code point from a second of the plurality of frame intervals;

computer-readable program code for incorporating the second measured level of the first code point into the average of the measured levels for the first code point from the plurality of frame intervals based on the comparison of the first measured level of the first code point from the first of the plurality of frame intervals and the second measured level of the first code point from the second of the plurality of frame intervals and a threshold value; and

computer-readable program code for replacing the second measured level of the first code point with the average of the measured levels of the first code points if the second measured level of the first code point is incorporated into the average of the measured levels of the first code point.

41. A computer program product according to claim 40, wherein the computer-readable program code for comparing comprises computer-readable program code for comparing a first measured level of the first code point from the first of the plurality of frame intervals and each of the measured levels of the first code point other than the first of the plurality of frame intervals.

42. A computer program product according to claim 36, further comprising computer-readable program code for determining the threshold value based on the measured levels of the code point sequence.

43. A computer program product according to claim 42, wherein the computer-readable program code for determining the threshold value based on the measured levels of the code point sequence comprises:

computer-readable program code for determining an average spacing for measured levels of the code point sequence consecutive with the first code point; and

computer-readable program code for setting the threshold value based on the determined average spacing.

44. A computer program product according to claim 43, wherein the average spacing is determined based on the difference between the first measured level of the first code point and a measured level of a third code point which is four code points lower in the code point sequence than the first code point.

45. A computer program product according to claim 43, further comprising:

computer-readable program code for establishing the threshold value based on the first measured level of the first code point; and

wherein the computer-readable program code for comparing comprises computer-readable program code for comparing the measured level of the second code point to the threshold value.

46. A computer program product according to claim 45, wherein the computer-readable readable program code for establishing the threshold value based on the first measured level of the first code point comprises:

computer-readable program code for weighting the average spacing to provide a weighted average spacing; and

computer-readable program code for combining the weighted average spacing and the first measured level of the first code point to provide the threshold value.

47. A computer program product according claim 45, wherein the first measured level of the first code point comprises the smallest measured level of the first code point.

48. A computer program product according to claim 47, wherein the computer-readable program code for establishing the threshold value based on the first measured level of the first code point comprises:

computer-readable program code for weighting the average spacing to provide a weighted average spacing; and

computer-readable program code for adding the weighted average spacing and the first measured level of the first code point to provide the threshold value.

49. A computer program product according to claim 48, wherein the computer-readable program code for comparing the measured level of the second code point to the threshold value comprises computer-readable program code for determining if the measured level of the second code point is less than or equal to the threshold value.

50. A computer program product according to claim 45, wherein the first measured level of the first code point comprises the largest measured level of the first code point.

51. A computer program product according to claim 50, wherein the computer-readable program code for establishing the threshold value based on the first measured level of the first code point comprises:

computer-readable program code for weighting the average spacing to provide a weighted average spacing; and

computer-readable program code for subtracting the weighted average spacing and the first measured level of the first code point to provide the threshold value.

52. A computer program product according to claim 51, wherein the computer-readable program code for comparing the measured level of the second code point to the threshold value comprises computer-readable program code for determining if the measured level of the second code point is greater than or equal to the threshold value.