Shared hybrid-fiber coax transmission system having increased bandwidth in the upstream and downstream directions

• US 5,822,677 A
• Filed: 08/26/1996
• Issued: 10/13/1998
• Est. Priority Date: 08/26/1996
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Peyrovian, M. Javad
• Primary Examiner(s): GRANT, CHRISTOPHER C
• Application Number:
  US08/697,474
• Time in Patent Office: 778 Days
• Field of Search: 455/3.1, 455/4.1, 455/5.1, 455/6.1, 455/6.2, 455/6.3, 348/6, 348/7, 348/10, 348/11, 348/12, 348/13
• US Class Current: 725/126
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

Bandwidth is increased and noise may be reduced in a shared hybrid fiber-coax transmission system (10) by digitally modulating upstream information onto a high frequency band (e.g., 750-1000 MHz) and thereafter digitally regenerating both the high frequency upstream information as well as a portion of the downstream information not used for broadcast video (i.e., the 500-750 MHz band).

Claims

1. For use with a shared hybrid-fiber coax transmission system that transmits downstream information within a first frequency band from a head end to individual subscribers on a main coax and which transmits upstream information generated by individual subscribers to a head end on the main coax, a method for increasing the bandwidth and reducing noise, comprising the steps of:

aggregating the upstream information onto the main coax digitally modulating at least a portion of the upstream information into a second frequency band above the downstream information;

digitally regenerating the upstream information; and

digitally regenerating a portion of the downstream information lying in a frequency band immediately below the second frequency band.

2. The method according to claim 1 wherein the downstream information that is digitally regenerated lies in a frequency band of 500-750 MHz.

3. For use with a shared hybrid-fiber coax transmission system that transmits across a main coaxial cable downstream information within a first frequency band to individual subscribers and that transmits upstream information generated by individual subscribers, a method for increasing the bandwidth and reducing noise, comprising the steps of:

aggregating the upstream information onto the main coax

digitally modulating at least a first portion of the upstream information via a carrier to a second frequency band above the first frequency band prior to transmission on the main coaxial cable;

separating the first portion of the upstream information from other information on the main coaxial cable;

digitally regenerating the upstream information;

re-injecting the upstream information onto the main coaxial cable;

separating a first portion of the downstream information of the main coaxial cable;

digitally regenerating the first portion of the downstream information; and

re-injecting the downstream information onto the main coaxial cable.

4. The method according to claim 3 wherein said first portion of the upstream information is modulated into a frequency band of 750-1000 MHz and wherein the first portion of the downstream information lies in the frequency band of 500-750 MHz.

5. The method according to claim 3 wherein the upstream and downstream information is regenerated within at least one location within the hybrid fiber-coax system.

6. The method according to claim 3 wherein the upstream and downstream information is regenerated at multiple locations within the hybrid fiber-coax system.