Noise suppression in a hybrid fiber coaxial network utilizing selective enabling/disabling of signal paths
View Patent ↗A coupling device for use in a hybrid fiber coaxial (HFC) network may be configured to disable an upstream path through it when there is only noise incident on the upstream path, and enable the upstream path through it when a desired transmission from a cable modem downstream of the coupling device is incident on the upstream path. The coupling device may be a trunk amplifier, a distribution amplifier, a splitter, or the like. The coupling device may comprise a single upstream interface coupled to a plurality of downstream interfaces. The enabling and/or disabling may be in response to a signal strength indicated by the SSI being below a threshold and/or in response to one or more control messages indicating whether any downstream cable modem is, or will be, transmitting.
1. A system comprising:
a coupling device for use in a hybrid fiber coaxial (HFC) network, said coupling device configured to:
disable an upstream path through said coaxial portion of said HFC network when there is only noise incident on said upstream path;
enable said upstream path through said coaxial portion of said HFC network when a desired transmission from a cable modem downstream of said coupling device is incident on said upstream path; and
detect control messages in said HFC network, wherein each of said disable and said enable is in response to a respective one of said control messages.
2. The system of claim 1 , wherein said coupling device is a trunk or distribution amplifier.
3. The system of claim 1 , wherein said coupling device comprises a single upstream interface, and a plurality of downstream interfaces, wherein said single upstream interface is coupled to said plurality of downstream interfaces.
4. The system of claim 1 , wherein:
said coupling device comprises a signal strength indicator (SSI);
said disable is in response to signal strength indicated by said SSI being below a threshold;
said enable is in response to said signal strength indicated by said SSI being above said threshold.
5. The system of claim 1 , wherein a first one of said control messages indicates a service group of said cable modem that is, or will be at some determined time in the future, transmitting.
6. The system of claim 1 , wherein said coupling device comprises a pair of cross-coupled amplifiers for each downstream interface.
7. The system of claim 1 , wherein said coupling device comprises a switching element and a circulator.
8. The system of claim 1 , wherein said circuitry comprises a switch and said disabling comprises opening said switch.
9. The system of claim 1 , wherein said circuitry comprises an amplifier and said disabling comprises reducing a gain of said amplifier.
10. A method comprising:
performing in a coupling device of a hybrid fiber coaxial (HFC) network:
disabling an upstream path through said coaxial portion of said HFC network when there is only noise incident on said upstream path;
enabling said upstream path through said coaxial portion of said HFC network when a desired transmission from a cable modem downstream of said coupling device is incident on said upstream path; and
detecting control messages in said HFC network, wherein each of said disabling and said enabling is in response to a respective one of said control messages.
11. The method of claim 10 , wherein said coupling device is a trunk or distribution amplifier.
12. The method of claim 10 , wherein said coupling device comprises a single upstream interface, and a plurality of downstream interfaces, wherein said single upstream interface is coupled to said plurality of downstream interfaces.
13. The method of claim 10 , wherein:
said coupling device comprises a signal strength indicator (SSI);
said disabling is in response to signal strength indicated by said SSI being below a threshold;
said enabling is in response to said signal strength indicated by said SSI being above said threshold.
14. The method of claim 10 , wherein a first one of said control messages indicates a service group of said cable modem that is, or will be at some determined time in the future, transmitting.
15. The method of claim 10 , wherein said coupling device comprises a pair of cross-coupled amplifiers for each downstream interface.
16. The method of claim 10 , wherein said coupling device comprises a switching element and a circulator.
17. The method of claim 10 , wherein said circuitry comprises a switch and said disabling comprises opening said switch.
18. The method of claim 10 , wherein said circuitry comprises an amplifier and said disabling comprises reducing a gain of said amplifier.