Fault detection for subscriber loop repeaters

• US 20030045240A1
• Filed: 04/18/2001
• Published: 03/06/2003
• Est. Priority Date: 04/21/2000
• Status: Active Grant

• Current Assignee: Symmetricom Incorporated (Microchip Technology Incorporated)
• Original Assignee: Symmetricom Incorporated (Microchip Technology Incorporated)
• Inventors: Shenoi, Kishan, Bogardus, Gary, Squadrito, Sandro
• Granted Patent: US 6,842,426 B2
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04B 17/402 using different frequencies

Abstract

Systems and methods are described for fault detection for subscriber loop repeaters. A method includes monitoring an upstream signal on a digital subscriber loop for a fault detection signal that is added to said upstream signal at a repeater; and determining if a fault has occurred. An apparatus includes a digital subscriber loop fault detection system including: a receiver circuit that monitors an upstream signal on said digital subscriber loop for a fault detection signal that is added to said upstream signal at a repeater; and a logic circuit that determines whether a fault has occurred.

Claims

1. A method, comprising:

monitoring an upstream signal on a digital subscriber loop for a fault detection signal that is added to said upstream signal at a repeater; and

determining if a fault has occurred.

2. The method of claim 1, wherein said upstream signal is monitored for said fault detection signal at a digital subscriber line access multiplexer that composes said digital subscriber loop.

3. The method of claim 1, further comprising, before monitoring said upstream signal,

monitoring a downstream signal at said repeater, determining whether a signal strength within a frequency band of said downstream signal is above a threshold and

adding said fault detection signal to said upstream signal at said repeater, if said signal strength within said frequency band of said downstream signal exceeds said threshold.

4. The method of claim 1, wherein said fault detection signal is locally generated at said repeater.

5. The method of claim 1, further comprising generating an alarm if said fault has occurred.

6. The method of claim 1, further comprising sending a query to said repeater, if said fault has occurred.

7. The method of claim 1, wherein monitoring said upstream signal includes determining if an intensity of said fault detection signal changes.

8. The method of claim 1, wherein said fault detection signal includes a tone having a center frequency.

9. The method of claim 8, wherein said center frequency of said tone is selected from the group consisting of approximately 12.9375 kHz, approximately 17.25 kHz, approximately 21.5625 kHz and approximately 25.875 kHz.

10. The method of claim 8, wherein said tone is locally generated by said repeater.

11. The method of claim 10, wherein said tone is assigned to said repeater prior to installation of the repeater.

12. The method of claim 11, wherein said tone is chosen by adjusting a dip-switch that is included in said repeater.

13. The method of claim 10, further comprising monitoring said upstream signal for another tone that is added to said upstream signal at said repeater.

14. The method of claim 13, wherein detection of only one tone indicates deteriorating conditions at said repeater.

15. The method of claim 1, wherein a plurality of repeaters are monitored.

16. The method of claim 15, wherein a lower frequency tone is assigned to said repeater and a higher frequency tone is assigned to another repeater that is further downstream.

17. An apparatus, comprising:

a digital subscriber loop fault detection system including;

a receiver circuit that monitors an upstream signal on said digital subscriber loop for a fault detection signal that is added to said upstream signal at a repeater; and

a logic circuit that determines whether a fault has occurred.

18. The apparatus of claim 17, further comprising said repeater.

19. The apparatus of claim 18, wherein said repeater locally generates said fault detection signal.

20. The apparatus of claim 19, wherein said fault detection signal includes a tone having a center frequency.

21. The method of claim 20, wherein said center frequency of said tone is selected from the group consisting of approximately 12.9375 kHz, approximately 17.25 kHz, approximately 21.5625 kHz and approximately 25.875 kHz.

22. The method of claim 20, wherein said tone is assigned to said repeater prior to installation of the repeater by adjusting a dip-switch that is included in said repeater.

23. The apparatus of claim 17, wherein said receiver and said circuit composes a digital subscriber line access multiplexer.

24. The apparatus of claim 17, wherein said receiver circuit monitors said upstream signal to determine if an intensity of said fault detection signal changes.

25. The apparatus claim 17, wherein said receiver circuit monitors said upstream signal for another tone that is added to said upstream signal at said repeater.

26. The apparatus of claim 17, wherein said receiver circuit monitor a plurality of repeaters.

27. A kit, comprising:

a digital subscriber loop repeater fault detection system to be retrofitted into an existing digital subscriber loop.

28. The kit of claim 27, further comprising software adapted to run on said existing digital subscriber loop.

29. The kit of claim 27, further comprising instructions.