Shared hybrid fiber-coax network having reduced ingress noise in the upstream channel transmitted via a repeater

• US 5,765,097 A
• Filed: 05/20/1996
• Issued: 06/09/1998
• Est. Priority Date: 05/20/1996
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Dail, James E.
• Primary Examiner(s): Grant, Christopher C.
• Application Number:
  US08/650,683
• Time in Patent Office: 750 Days
• Field of Search: 348/6, 348/7, 348/10, 348/11, 348/12, 348/13, 348/14, 348/15, 348/16, 348/17, 348/18, 455/3.1, 455/4.1, 455/4.2, 455/5.1, 455/6.1, 455/6.2, 455/6.3, 455/14
• US Class Current: 725/125
• CPC Class Codes: H04H 20/12 Arrangements for observation, testing or troubleshooting
• CPC Class Codes: H04H 20/76 Wired systems
• CPC Class Codes: H04L 25/4921 using quadrature encoding, e.g. carrierless amplitude-phase coding
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

A hybrid fiber-coax network (100) includes at least one repeater (220₁) dispersed within a coax trunk (22₁) that carries video information downstream to a subscriber (14) and subscriber-originated information upstream to a fiber node (18). The repeater serves to digitally regenerate the subscriber-originated information to reduce ingress noise that would otherwise aggregate at the fiber node.

Claims

1. A method for reducing aggregated ingress noise in a shared fiber-coax network that carries information from a head end to a plurality of subscribers via at least one main coax trunk and for carrying information originated by said plurality of subscribers to said head end via said main coax trunk using a repeater, the method comprising the steps of:

aggregating onto the main coax information generated by said plurality of subscribers;

digitizing the aggregated subscriber-originated information; and

digitally regenerating the digitized aggregated subscriber-originated information to reduce the incidence of noise in the aggregated subscriber-originated information on the main coax.

2. The method according to claim 1 wherein the step of regenerating the subscriber-originated information includes the steps of:

filtering the digitized subscriber-originated information to pass the information in a preselected band;

demodulating the information within the preselected band;

receiving the demodulated information via a receiver having a prescribed modulation format

transmitting the information received by the receiver in accordance with said prescribed modulation format;

modulating the transmitted information; and

injecting the transmitted information into the trunk coax.

3. The method according to claim 2 wherein the filtering step includes the step of bypassing subscriber-originated information that is not within the preselected band.

4. The method according to claim 2 wherein the filtering step includes the step of blocking information within the preselected band for non-regeneration to allow use of such information by a second repeater without adding any noise at said second repeater.

5. The method according to claim 2 wherein the prescribed modulation format is Quadrature Phase Shift Keying.

6. The method according to claim 2 wherein the prescribed modulation format is Quadrature Amplitude Modulation.

7. The method according to claim 2 wherein the prescribed modulation format is Carrierless Amplitude Modulation.

8. The method according to claim 2 wherein the prescribed modulation format is Digital Multi-Tone.

9. The method according to claim 2 wherein the prescribed modulation format is Digital Wavelet Multi-Tone.

10. The method according to claim 1 wherein the subscriber-originated information is regenerated in multiple frequency bands.

11. The method according to claim 1 wherein the subscriber-originated information is regenerated by receiving the information via a single receiver and then transmitting the received information via a single transmitter.

12. The method according to claim 1 wherein the subscriber-originated information is regenerated by receiving the information with multiple receivers and then transmitting the information via multiple corresponding transmitters.

13. The method according to claim 1 wherein the subscriber-originated information is regenerated at a preset output level.

14. The method according to claim 1 wherein the subscriber-originated information is regenerated at an output level dependent on the input level of the received information.

15. The method according to claim 1 wherein the subscriber-originated information is regenerated in a particular frequency band in at least one time slot associated with said main coax trunk.

16. The method according to claim 1 wherein the subscriber-originated information is regenerated in a particular frequency band in time slots shared with multiple repeaters on at least one coax trunk.

17. The method according to claim 1 further including the step of utilizing downstream signal information for clock and framing reference purposes.

18. The method according to claim 1 wherein the digitally regenerated subscriber information passes on said coax and is digitally regenerated by a second repeater.

19. The method according to claim 2 wherein the said information having said prescribed modulation format comprises a burst, multiple access signal and wherein said signal is converted into a continuous point-to-point signal.

20. The method according to claim 19 wherein the continuous point-to-point signal has a modulation format the same as said burst, multiple access signal.

21. The method according to claim 19 wherein the continuous point-to-point signal has a different modulation format from said burst, multiple access signal.

22. The method according to claim 1 including the step of deriving a downstream signaling channel received by the repeater for the purpose of operations, performance monitoring, repeater configuration control and repeater software download.

23. A method for reducing aggregated ingress noise in a shared fiber-coax network that carries information from a head end to a plurality of subscribers via a main coax and for carrying information originated by said plurality of subscribers to said head end via said main coax, the method comprising the steps of:

aggregating information originated by said plurality of subscribers onto the main coax;

digitizing the aggregated subscriber-originated information;

extracting the digitized aggregated subscriber information lying within a first prescribed bandwidth; and

digitally regenerating the digitized aggregated subscriber-originated information within said first prescribed bandwidth to reduce the incidence of noise in the aggregated subscriber-originated information on the main coax.