Methods for canceling interfering wireless signals in cable customer premises equipment devices and outside plant

• US 9,054,782 B2
• Filed: 02/14/2014
• Issued: 06/09/2015
• Est. Priority Date: 09/20/2013
• Status: Active Grant

• Current Assignee: Cable Television Laboratories Incorporated
• Original Assignee: Cable Television Laboratories Incorporated
• Inventors: Hunter, David F.
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US14/181,373
• Publication Number:
  US 20150085909A1
• Time in Patent Office: 480 Days
• Field of Search: 375/346, 375/284, 375/285, 375/350, 375/229, 375/232, 455/570, 455/296, 455/302, 455/307
• US Class Current: 1/1
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 3/46 Monitoring; Testing
• CPC Class Codes: H04B 3/462 Testing group delay or phase shift, e.g. timing jitter

Abstract

A noise reduction device for use with a cable signal distributed by an outside plant of a cable system. The device includes an antenna and a signal processing system. The outside plant receives an interfering radio frequency (“RF”) signal generated by one or more external wireless signal sources and combines the interfering RF signal with the cable signal to produce a noisy cable signal. The antenna receives the interfering RF signal as a copy signal. The signal processing system modifies the copy signal to produce a processed copy signal, and combines the noisy cable signal and the processed copy signal to produce a combined signal. The signal processing system also monitors error rate values of the combined signal, and adjusts the copy signal such that the copy signal at least partially cancels the interfering RF signal in the combined signal thereby reducing the error rate values of the combined signal.

Claims

1. A device for use with a cable signal distributed by an outside plant of a cable system, and an interfering radio frequency (“

RF”

) signal generated by one or more external wireless signal sources and received by the outside plant, the outside plant combining the interfering RF signal with the cable signal to produce a noisy cable signal, the device comprising;

an antenna configured to receive the interfering RF signal as a copy signal; and

a signal processing system comprising;

a signal processing chain configured to receive the noisy cable signal and the copy signal,

at least one signal adjustment component configured to modify at least one signal parameter of the copy signal to produce a processed copy signal, the signal processing chain being configured to combine the noisy cable signal and the processed copy signal to produce a combined signal,

an error detection component configured to determine error rate values for the combined signal,

a monitoring component configured to monitor the error rate values of the combined signal, and determine when the error rate values are increasing, and the copy signal comprises more than a threshold amount of signal energy, the monitoring component being further configured to instruct the at least one signal adjustment component to adjust the at least one signal parameter of the copy signal after the monitoring component has determined that the error rate values are increasing, and the copy signal comprises more than the threshold amount of signal energy, the at least one signal adjustment component adjusting the at least one signal parameter of the copy signal such that the copy signal at least partially cancels the interfering RF signal in the combined signal thereby reducing the error rate values of the combined signal.

2. The device of claim 1, wherein the signal processing system is further configured to output the combined signal to the outside plant.

3. The device of claim 1, wherein the at least one signal parameter of the copy signal comprises an amount of phase shift;

and

the at least one signal adjustment component comprises a phase adjustment component configured to adjust the amount of phase shift of the copy signal.

4. The device of claim 3, wherein the amount of phase shift of the copy signal is adjusted to shift the copy signal to be approximately 180 degrees out of phase with respect to the interfering RF signal.

5. The device of claim 1, wherein the at least one signal parameter of the copy signal comprises amplitude;

and

the at least one signal adjustment component comprises an amplitude adjustment component configured to adjust the amplitude of the copy signal.

6. The device of claim 5, wherein the at least one signal parameter of the copy signal comprises an amount of phase shift;

and

the at least one signal adjustment component comprises a phase adjustment component configured to adjust the amount of phase shift of the copy signal.

7. The device of claim 6, wherein the amount of phase shift of the copy signal is adjusted to shift the copy signal to be approximately 180 degrees out of phase with respect to the interfering RF signal;

and

the amplitude of the copy signal is adjusted to approximately match the amplitude of the interfering RF signal.

8. The device of claim 1, wherein the at least one signal parameter of the copy signal comprises an amount of attenuation;

and

the at least one signal adjustment component comprises an adjustable attenuation component configured to adjust the amount of attenuation of the copy signal.

9. A device for use with a cable signal distributed by an outside plant of a cable system, and an interfering radio frequency (“

RF”

) signal generated by one or more external wireless signal sources and received by the outside plant, the outside plant combining the interfering RF signal with the cable signal to produce a noisy cable signal, the device comprising;

an antenna configured to receive the interfering RF signal as a copy signal;

at least one signal adjustment component configured to adjust at least one signal parameter of the copy signal to produce a processed copy signal;

a signal processing chain configured to receive and combine the noisy cable signal and the processed copy signal to produce a combined signal;

at least one processor; and

a memory connected to the at least one processor, the memory storing instructions executable by the at least one processor that when executed thereby implement a method comprising;

determining error rate values for the combined signal;

determining when the error rate values are increasing;

determining when the copy signal comprises more than a threshold amount of signal energy; and

when it is determined that the error rate values are increasing, and the copy signal comprises more than a threshold amount of signal energy, instructing the at least one signal adjustment component to adjust the at least one signal parameter of the copy signal such that the error rate values for the combined signal decrease.

10. The device of claim 9, wherein the at least one signal parameter of the copy signal comprises an amount of attenuation, and

the at least one signal adjustment component comprises an adjustable attenuation component configured to adjust the amount of attenuation of the copy signal.

11. The device of claim 9, wherein the at least one signal parameter of the copy signal comprises an amount of phase shift;

and

the at least one signal adjustment component comprises a phase adjustment component configured to adjust the amount of phase shift of the copy signal.

12. The device of claim 11, wherein the at least one signal parameter of the copy signal comprises amplitude;

and

the at least one signal adjustment component comprises an amplitude adjustment component configured to adjust the amplitude of the copy signal.

13. A cable system for use with interfering radio frequency (“

RF”

) signals generated by one or more external wireless signal sources, the cable system comprising;

an outside plant, each of a plurality of different portions of the outside plant combining at least a portion of the interfering RF signals with the cable signal to produce a noisy cable signal, each of the plurality of different portions of the outside plant comprising a corresponding different noise reduction device comprising;

an antenna configured to receive a portion of the interfering RF signals as a copy signal; and

a signal processing system comprising;

a signal processing chain configured to receive the copy signal from the antenna, and the noisy cable signal produced by the portion of the outside plant corresponding to the noise reduction device,

at least one signal adjustment component configured to modify at least one signal parameter of the copy signal to produce a processed copy signal, the signal processing chain being configured to combine the noisy cable signal received thereby with the processed copy signal to produce a combined signal,

an error detection component configured to determine error rate values for the combined signal,

a monitoring component configured to monitor the error rate values of the combined signal, and determine when the error rate values are increasing and the copy signal comprises more than a threshold amount of signal energy, the monitoring component being further configured to instruct the at least one signal adjustment component to adjust the at least one signal parameter of the copy signal to reduce the error rate values of the combined signal after the monitoring component has determined that the error rate values are increasing, and the copy signal comprises more than the threshold amount of signal enemy.

14. The system of claim 13, wherein the signal processing system is further configured to output the combined signal to the portion of the outside plant.

16. The system of claim 13, wherein the at least one signal parameter of the copy signal comprises an amount of phase shift;

and

the at least one signal adjustment component comprises a phase adjustment component configured to adjust the amount of phase shift of the copy signal.

17. The system of claim 16, wherein the amount of phase shift of the copy signal is adjusted to shift the copy signal to be approximately 180 degrees out of phase with respect to the interfering RF signal.

18. The system of claim 13, wherein the at least one signal parameter of the copy signal comprises amplitude;

and

the at least one signal adjustment component comprises an amplitude adjustment component configured to adjust the amplitude of the copy signal.

19. The system of claim 18, wherein the at least one signal parameter of the copy signal comprises an amount of phase shift;

and

the at least one signal adjustment component comprises a phase adjustment component configured to adjust the amount of phase shift of the copy signal.

20. The system of claim 19, wherein the amount of phase shift of the copy signal is adjusted to shift the copy signal to be approximately 180 degrees out of phase with respect to the interfering RF signal;

and

the amplitude of the copy signal is adjusted to approximately match the amplitude of the interfering RF signal.

21. The system of claim 13, wherein the at least one signal parameter of the copy signal comprises an amount of attenuation;

and

the at least one signal adjustment component comprises an adjustable attenuation component configured to adjust the amount of attenuation of the copy signal.

15. A method for use with a cable signal provided by a cable system, and an interfering radio frequency (“

RF”

) signal generated by one or more external wireless signal sources, the cable system comprising an outside plant that combines the interfering RF signal with the cable signal to produce a noisy cable signal, the method being performed by a device connected to the outside plant, the device comprising a memory, a processor, signal processing components, and an antenna, the method comprising;

receiving, at the antenna of the device, the interfering RF signal as a copy signal;

processing, by at least a first portion of the signal processing components, the copy signal to produce a processed copy signal;

receiving, by at least a second portion of the signal processing components, the noisy cable signal;

combining, by at least a third portion of the signal processing components, the cable signal and the processed copy signal to produce a combined signal;

outputting the combined signal to the outside plant;

determining, by the processor, error rate values for the combined signal;

determining, by the processor, whether the error rate values are increasing;

determining, by the processor, whether the copy signal comprises more than a threshold amount of signal energy; and

when the processor determines that the error rate values are increasing and the copy signal comprises more than the threshold amount of signal energy, instructing, by the processor, the first portion of the signal processing components to modify the processing of the copy signal to change a value of at least one signal parameter of the copy signal to reduce the error rate values of the combined signal.