Monitoring instability and resetting an equalizer

• US 8,284,828 B2
• Filed: 11/11/2009
• Issued: 10/09/2012
• Est. Priority Date: 11/11/2009
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Cooper, Michael J., Moran, John L.
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US12/616,337
• Publication Number:
  US 20110110415A1
• Time in Patent Office: 1,063 Days
• Field of Search: 375230-235, 375/346, 375/350, 708/322, 708/323
• US Class Current: 375/232
• CPC Class Codes: H04L 2025/037 Detection of convergence state
• CPC Class Codes: H04L 2025/03707 Detection or avoidance of local extrema
• CPC Class Codes: H04L 2025/0377 during the reception of training signals
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference

Abstract

Instability resulting from non-linear impairments is detected and an equalizer of an end device is reset. An equalization instability threshold is retrieved from a data storage device. An equalization parameter for the end device is monitored and, if the equalization parameter exceeds the equalization instability threshold, the equalizer is reset.

Claims

1. A communications device for detecting instability resulting from non-linear impairments and resetting at least one equalizer of an end device, the communications device comprising:

a data storage device configured to store an equalization instability threshold; and

a processor configured

to monitor an equalization parameter for the at least one equalizer of the end device,

to determine whether the equalization parameter exceeds the equalization instability threshold, and

in response to the equalization parameter exceeding the equalization instability threshold, to reset the equalizer, wherein the equalization instability threshold comprises one of a maximum power threshold for total power in all secondary equalizer taps and a predetermined percentage of secondary equalizer taps exceeding a maximum power threshold.

2. The communications device of claim 1, wherein the equalization parameter comprises one of an equalizing filter and an equalizing filter update.

3. The communications device of claim 1, wherein the processor is further configured:

to perform a Data Over Cable Service Interface Specification (DOCSIS) load command to reset the equalizer.

4. The communications device of claim 1, wherein the processor is further configured:

to command a frequency change of the equalizer, wherein the frequency change is within one of a same frequency band and a different frequency band, to reset the equalizer.

5. The communications device of claim 4, wherein the processor is configured:

to command the frequency change of equalizers in all end devices connected to the communications device using a primary channel.

6. The communications device of claim 5, wherein the processor is configured:

to command the frequency change of the equalizer in a particular end device using a secondary channel with an upstream channel descriptor (UCD), wherein the secondary channel is identical to the primary channel except for frequency.

7. The communications device of claim 4, wherein the processor is configured:

to determine whether the equalization parameter exceeds the equalization instability threshold for one of a particular end device and all end devices connected to the communications device;

in response to the equalization parameter exceeding the equalization instability threshold for all the end devices connected to the communications device,

to command the frequency change of the equalizer using a primary channel; and

in response to the equalization parameter exceeding the equalization instability threshold for the particular end device,

to command the frequency change of the equalizer using a secondary channel with an upstream channel descriptor (UCD).

8. The communications device of claim 1, wherein the processor is further configured:

to reschedule station maintenance messages for an immediate update of the end device.

9. A method for detecting instability resulting from non-linear impairments and resetting at least one equalizer of an end device using a communications device, the method comprising:

retrieving an equalization instability threshold from a data storage device;

monitoring an equalization parameter for the end device; and

determining whether the equalization parameter exceeds the equalization instability threshold, and

in response to the equalization parameter exceeding the equalization instability threshold, resetting the equalizer, wherein the equalization instability threshold comprises one of a maximum power threshold for total power in all secondary equalizer taps and a predetermined percentage of secondary equalizer taps exceeding a maximum power threshold.

10. The method of claim 9, wherein monitoring the equalization parameter comprises:

monitoring the equalization parameter for all end devices connected to the communications device.

11. The method of claim 9, wherein monitoring the equalization parameter comprises one of receiving an equalizing filter from the at least one end device and determining an equalizer update.

12. The method of claim 9, wherein determining whether the equalization parameter exceeds the equalization instability threshold further comprises:

determining whether the equalization parameter exceeds the equalization instability threshold for all of the end devices or for a particular end device; and

in response to the equalization parameter exceeding the equalization instability threshold for all of the end devices, resetting the plurality of end devices, and

in response to the equalization parameter exceeding the equalization instability threshold for the particular end device, resetting the particular end device.

13. The method of claim 9 wherein resetting the equalizer comprises:

commanding a frequency change of the equalizer of the end device.

14. The method of claim 13, wherein resetting the equalizer further comprises

commanding the frequency change in of one a secondary channel with a UCD connected to a particular end device and a main channel connected to all the end devices.

15. The method of claim 13, further comprising:

rescheduling station maintenance messages for an immediate update of the end device.

16. A computer readable storage device storing at least one computer program that when executed by a computer system performs a method comprising:

retrieving an equalization instability threshold from a data storage device;

monitoring an equalization parameter for at least one end device; and

determining whether the equalization parameter exceeds the equalization instability threshold, and

in response to the equalization parameter exceeding the equalization instability threshold, resetting the equalizer, wherein the equalization instability threshold comprises one of a maximum power threshold for total power in all secondary equalizer taps and a predetermined percentage of secondary equalizer taps exceeding a maximum power threshold.

17. The method stored on the computer readable storage device of claim 16, wherein resetting the equalizer further comprises

commanding the frequency change in of one a secondary channel with a UCD connected to a particular end device and a main channel connected to all the end devices.

18. The method stored on the computer readable storage device of claim 16, wherein monitoring the equalization parameter comprises one of receiving an equalizing filter from the at least one end device and determining an equalizer update.