Prescriptive and diagnostic system and method for combined RF/optical transmission management

• US 20060218616A1
• Filed: 02/09/2006
• Published: 09/28/2006
• Est. Priority Date: 02/09/2005
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Broadband Royalty Corporation (CommScope Holding Company, Inc.)
• Inventors: Zenkus, William John, Harbert, Roy Allen, Schemmann, Marcel Franz Christian, Mutalik, Venkatesh Gururaj
• Granted Patent: US 7,809,264 B2
• Time in Patent Office: Days
• US Class Current: 725/129
• CPC Class Codes: H04B 10/2575 Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
• CPC Class Codes: H04N 7/173 with two-way working, e.g. subscriber sending a programme selection signal

Abstract

A diagnostic and prescriptive system and method for management of a combined optical and RF cable plant system. In an exemplary embodiment the method and system uses optical receivers in a hub or headend to determine a variety of cable plant parameters such as the OMI of the received signal and automatically facilitated prescriptive service through prioritization and automatic recalibration. In another exemplary embodiment the method allows doing such signal OMI measurements in a closed loop system (that is a fully operational system). In addition, a further exemplary method and system allows storing of standard receiver calibration information such that from thereon signal OMI measurements that can be performed without signal interruption.

Claims

1. A method of diagnostic and prescriptive management of hybrid fiber-coax network, comprising:

collecting network performance parameters related to a network circuit;

comparing the collected network performance parameters with predetermined thresholds corresponding to the collected network performance parameters to grade circuit performance;

selecting a circuit, based on the comparing step, in which at least on of the network performance parameters falls below the respective threshold;

determining at least one additional network performance parameter to be analyzed on the selected circuit, the additional network performance parameter comprising at least an RF power measurement; and

outputting a recommended prescribed modification to the selected circuit based on the at least one additional tested network performance parameter.

2. The method of claim 1, further comprising:

establishing the thresholds of the performance parameters to grade circuit performance.

3. The method of claim 1, wherein:

the RF power measurement includes a measurement of an optical modulation index (OMI) of the signal.

4. The method of claim 1, wherein:

the circuit comprises a customer modem, a RF plant, optical node, reverse transmitter, reverse headend receiver and CMTS;

5. The method of claim 3, wherein:

the measurement of the OMI is performed on a calibrated receiver.

6. The method of claim 5, wherein:

the calibration of the receiver includes using a reference transmitter, and establishing an optical power into the calibrated receiver to compute RF power at an RF test point.

7. The method of claim 4, further comprising the steps of:

determining a received signal power relative to an ingress power;

adjusting a modem power level if the signal power is below a predetermined threshold relative to the ingress power; and

adjusting power of other signals in the system if modem power can not be increased.

8. The method of claim 4, further comprising the steps of:

determining the RF power measurement relative to an expected power for a predetermined OMI;

adjusting the modem output power by changing an attenuator corresponding to the CMTS such that the CMTS sets the modem at a desired output power through automatic power gain control; and

adjusting gain in the RF plant if the modem power has reached a limit.

9. A method of diagnostic and prescriptive management of hybrid fiber-coax network, comprising:

collecting network performance parameters relating to a network circuit;

comparing the collected network performance parameters with predetermined thresholds corresponding to the collected network performance parameters to grade circuit performance;

selecting a circuit, based on the comparing step, in which at least one of the network performance parameters falls below a respective threshold;

outputting a recommended prescribed modification to the selected circuit based on the at least one of the network performance parameters falls below a respective threshold.

10. The method of claim 9, further comprising:

establishing the thresholds of the performance parameters to grade circuit performance.

11. The method of claim 9, wherein:

the RF power measurement includes a measurement of an optical modulation index (OMI) of the signal.

12. The method of claim 9, wherein:

the circuit comprises a customer modem, a RF plant, optical node, reverse transmitter, reverse headend receiver and CMTS;

13. The method of claim 11, wherein:

the measurement of the OMI is performed on a calibrated receiver.

14. The method of claim 13, wherein:

the calibration of the receiver includes using a reference transmitter, and establishing an optical power into the calibrated receiver to compute RF power at an RF test point.

15. The method of claim 12, further comprising the steps of:

determining the received RF signal power relative to an ingress power;

adjusting a power level of the modem if the RF signal power is below a predetermined threshold relative to the ingress power; and

adjusting power of other signals in the system if modem power can not be increased.

16. The method of claim 12, further comprising the steps of:

determining the received RF signal power relative to an expected power for a predetermined OMI;

adjusting a power level of the modem by changing an attenuator corresponding to the CMTS such that the CMTS sets the modem at a desired output power through automatic power gain control; and

adjusting gain in the RF plant if the modem power has reached a limit.

17. A method of diagnostic and prescriptive management of hybrid fiber-coax network, comprising:

collecting network performance parameters relating to a network circuit comprising a customer modem, a RF plant, optical node, reverse transmitter, reverse headend receiver and CMTS;

comparing the collected network performance parameters with predetermined thresholds corresponding to the collected network performance parameters to grade circuit performance;

selecting a circuit, based on the comparing step, in which at least on of the network performance parameters falls below a respective threshold;

comparing the variation of at least one of the network performance parameter over a long term and at least one of another parameters over a short term; and

outputting a recommended prescribed modification to the selected circuit based on the comparison of the at least one of the network performance parameter over a long term and the at least one of another parameters over a short term.

18. The method of claim 17, wherein:

the short term parameter and the long term parameters are the same parameter.

19. The method of claim 17, wherein:

the short term parameter and the long term parameters are different parameters.

20. The method of claim 17, wherein:

the at least one of the network performance parameter over a long term and at least one of another parameters over a short term are different network performance parameters.

21. The method of claim 17, wherein:

the at least one of the network performance parameter over a long term and at least one of another parameters over a short term are the same system network performance parameters.

22. The method of claim 17, wherein:

at least one of the network performance parameter over a long term and at least one of another parameters over a short term comprise at least one of a reported error rate and a reported carrier-to-noise ratio.

23. The method of claim 17, wherein:

ingress is estimated based on the difference between the at least one of the network performance parameter over a long term and at least one of another parameters over a short term, and a theoretical error estimation based on the reported CNR.

24. The method of claim 17, wherein:

ingress is estimated based on the difference between the at least one of the network performance parameter over a long term and at least one of another parameters over a short term, and a theoretical CNR estimation based on the reported error rate.

25. A system of diagnostic and prescriptive management of hybrid fiber-coax network, comprising:

means for collecting network performance parameters relating to a network circuit;

means for comparing the collected network performance parameters with predetermined thresholds corresponding to the collected network performance parameters to grade circuit performance;

means for selecting a circuit, based on the result of the means for comparing, in which at least on of the network performance parameters falls below the respective threshold;

means for determining additional network performance parameters to be tested on the selected circuit, the additional network performance parameter comprising at least an RF power measurement; and

means for outputting a recommended prescribed modification to the selected circuit based on the additional tested network performance parameters.

26. A computer readable carrier including computer program instructions that cause a computer to implement a method of diagnostic and prescriptive management of hybrid fiber-coax network, said program comprising the steps of:

collecting network performance parameters relating to a network circuit comprising a customer modem, a RF plant, optical node, reverse transmitter, reverse headend receiver and CMTS;

comparing the collected network performance parameters with predetermined thresholds corresponding to the collected network performance parameters to grade circuit performance;

selecting a circuit, based on the result of the comparing step, in which at least on of the network performance parameters falls below the respective threshold;

determining additional network performance parameters to be tested on the selected circuit, the additional network performance parameter comprising at least an RF power measurement; and

outputting a recommended prescribed modification to the selected circuit based on the additional tested network performance parameters.

27. A computer readable carrier including computer program instructions that cause a computer to implement a method of diagnostic and prescriptive management of hybrid fiber-coax network, said program comprising the steps of:

collecting network performance parameters relating to a network circuit comprising a customer modem, a RF plant, optical node, reverse transmitter, reverse headend receiver and CMTS;

comparing the collected network performance parameters with predetermined thresholds corresponding to the collected network performance parameters to grade circuit performance;

selecting a circuit, based on the comparing step, in which at least on of the network performance parameters falls below a respective threshold;

comparing the variation of at least one of the network performance parameter over a long term and at least one of another parameters over a short term; and

outputting a recommended prescribed modification to the selected circuit based on the comparison of the at least one of the network performance parameter over a long term and the at least one of another parameters over a short term.