Fault detection for subscriber loop repeaters

• US 6,842,426 B2
• Filed: 04/18/2001
• Issued: 01/11/2005
• Est. Priority Date: 04/21/2000
• Status: Expired due to Fees

• Current Assignee: Symmetricom Incorporated (Microchip Technology Incorporated)
• Original Assignee: Symmetricom Incorporated (Microchip Technology Incorporated)
• Inventors: Bogardus, Gary, Squadrito, Sandro, Shenoi, Kishan
• Primary Examiner(s): HO, DUC CHI
• Application Number:
  US09/838,575
• Publication Number:
  US 20030045240A1
• Time in Patent Office: 1,364 Days
• Field of Search: 370/242, 370/243, 370/252, 370/465, 370/352, 370/356, 370/492, 370/501, 379/100.05, 379/93.08, 379/93.28, 379/338, 375/211, 375/222
• US Class Current: 370/243
• 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, wherein the method further includes, 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.

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, wherein said fault detection signal is locally generated at said repeater.

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

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

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

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

8. The method of claim 7, 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.

9. The method of claim 7, wherein said tone is locally generated by said repeater.

10. The method of claim 9, wherein said tone is assigned to said repeater prior to installation of the repeater.

11. The method of claim 10, wherein said tone is chosen by adjusting a dip-switch that is included in said repeater.

12. The method of claim 9, further comprising monitoring said upstream signal for another tone that is added to said upstream signal at said repeater.

13. The method of claim 12, wherein detection of only one tone indicates deteriorating conditions at said repeater.

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

15. The method of claim 14, wherein a lower frequency tone is assigned to said repeater and a higher frequency tone is assigned to another repeater that is further downstream.

16. 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, wherein said repeater locally generates said fault detection signal, wherein said fault detection signal includes a tone having a center frequency.

17. The method of claim 16, 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.

18. The method of claim 16, 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.

19. The apparatus of claim 16, wherein said receiver and said circuit composes a digital subscriber line access multiplexer.

20. The apparatus of claim 16, wherein said receiver circuit monitors said upstream signal to determine if an intensity of said fault detection signal changes.

21. The apparatus claim 16, wherein said receiver circuit monitors said upstream signal for another tone that is added to said upstream signal at said repeater.

22. The apparatus of claim 16, wherein said receiver circuit monitor a plurality of repeaters.