System and method for digitally monitoring a cable plant

• US 20050198688A1
• Filed: 02/28/2005
• Published: 09/08/2005
• Est. Priority Date: 09/19/2000
• Status: Abandoned Application

• Current Assignee: At Home Bondholders Liquidating Trust (At Home Corporation)
• Original Assignee: At Home Bondholders Liquidating Trust (At Home Corporation)
• Inventors: Fong, Thomas Kin Tak
• Application Number:
  US11/069,575
• Publication Number:
  US 20050198688A1
• Time in Patent Office: Days
• US Class Current: 725/129
• CPC Class Codes: H04N 17/004 for digital television systems
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/2408 Monitoring of the upstream path of the transmission network, e.g. client requests monitoring data switching networks utilization H04L43/0876; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/173 with two-way working, e.g. subscriber sending a programme selection signal
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

The present invention provides systems and methods for digitally certifying and monitoring a hybrid fiber coaxial (HFC) cable plant. The present invention may be used to automate the characterization of the upstream and/or downstream channels of the cable plant and provide a path for establishing a performance baseline for the cable plant. After certification of the plant, the present invention provides for monitoring of cable plant performance and the use of a performance baseline to provide warnings and alerts prior to system downtime. The present invention also discloses cable plant characterization and monitoring functions being provided from a single site to a plurality of remote cable plant operators.

Claims

1. A method for digitally testing a hybrid fiber coaxial cable plant, comprising:

sending a query to a plurality of cable modems the query including a request for information;

receiving a plurality of replies from the plurality of cable modems wherein a reply includes a unique identifier portion;

storing the plurality of replies in a database;

correlating each of the plurality of replies in the database to a specific cable modem using the unique identifier portion in each reply; and

developing a performance baseline report from data in the database.

6. The method of claim 1 wherein sending the query is automated.

7. The method of claim 1 wherein the receipt of the plurality of replies is automated.

8. The method of claim 1 wherein developing the performance baseline report comprises evaluation of packet error rate.

9. The method of claim 8 wherein the evaluation of packet error rate occurs over a spectrum of frequencies.

10. The method of claim 8 wherein the evaluation of packet error rate occurs over a spectrum of power levels.

11. The method of claim 1 wherein developing the performance baseline report comprises evaluation of nonlinearity and noise

12. The method of claim 1 wherein developing the performance baseline report comprises determining the upstream path of each cable modem-cable modem termination system.

13. The method of claim 1 wherein developing the performance baseline report comprises determining an optimal set of receive conditions.

14. The method of claim 1 wherein developing the performance baseline report comprises validating the alignment of reverse path amplifiers.

15. The method of claim 1 wherein developing the performance baseline report comprises identifying the nature of any physical impairments.

16. The method of claim 1 wherein developing the performance baseline report comprises evaluating signal-to-noise ratio.

17. The method of claim 1 wherein developing the performance baseline report comprises evaluating tilt and channel distortion.

18. The method of claim 1 wherein the request for information employs a simple network management protocol.

19. The method of claim 18 wherein a management information base provides information in response to the simple network management protocol.

20. The method of claim 1 wherein developing the performance baseline report comprises evaluating forward error correction rates.

2. A method for digitally testing a hybrid fiber coaxial cable plant, comprising:

digitally characterizing an upstream frequency band by querying a plurality of cable modems installed within the plant and receiving uniquely identified replies in response to each query;

identifying useful upstream frequencies from the digital frequency characterization wherein the identification corresponds to a predetermined performance baseline; and

restricting use of upstream frequencies to the identified useful upstream frequencies.

3. The method for digitally testing a hybrid fiber coaxial cable plant of claim 2 wherein digitally characterizing the upstream frequency band further comprises:

measuring the dynamic range of the hybrid fiber coaxial cable plant with a digital dynamic range analyzer;

identifying upstream paths where dynamic range is below a predetermined value; and

verifying upstream path alignment of the identified paths.

21. The method of claim 2 wherein the upstream frequency band is approximately 5-50 MHz.

22. The method of claim 2 wherein the replies are at frequencies within the upstream frequency band.

4. A system for digitally testing a hybrid fiber coaxial cable plant comprising:

means for sending a query to a plurality of cable modems, the query including a request for information;

means for receiving a plurality of replies from the plurality of cable modems wherein a reply includes a unique identifying portion;

means for storing the plurality of replies in a database, the plurality of replies being correlated to a specific cable modem using the unique identifier portion in each reply; and

means for developing a performance baseline report from data in the database.

5. A method for maintaining performance of a hybrid fiber coaxial cable system comprising:

establishing a performance baseline, the performance baseline reflecting at least one minimum performance parameter of a cable system;

requesting information from a plurality of cable system components coupled to the cable system wherein the acquired information corresponds to a particular cable system component;

determining whether a cable system component coupled to the cable system fails to meet the at least one minimum performance parameter of the cable system;

requesting further information from the cable system component coupled to the cable system wherein the cable system component fails to meet the at least one minimum performance parameter of the cable system; and

determining whether a maintenance response servicing the cable system component coupled to the cable system is appropriate based on, at least, a correlation of the at least one minimum performance parameter of the cable system component with the performance baseline.

23. The method of claim 5 further comprising:

triggering a notification message in response to determining whether a maintenance response is appropriate wherein the notification message is triggered in anticipation of the cable system not meeting the at least one performance parameter.

24. The method of claim 23 wherein the notification message is unique to a specific cable system component.

25. The method of claim 5 wherein determining whether a maintenance response is appropriate occurs remote from the cable system.