HFC cable system with shadow fiber and coax fiber terminals

摘要

System and method to extend the upstream data capacity of an HFC CATV system by extending a “shadow” optical fiber network deeper into the various CATV cable neighborhoods, with coax fiber terminals (CFT) spaced roughly according to the distribution of CATV active devices such as RF amplifiers. The CFT can intercept local upstream data from various neighborhood sub-regions and transform this upstream data into upstream optical data, thus relieving upstream data congestion in the 5-42 MHz CATV frequency region. The system can produce an order of magnitude improvement in upstream capability, while maintaining high compatibility with legacy HFC equipment. The CFT may exist in multiple embodiments ranging from low-cost “dumb” CFT to sophisticated CFT that can additionally provide GigE to the home (GTTH) service. Methods to maintain good compatibility with legacy CMTS devices, and methods to utilize DOCSIS MAP data for more efficient data transmission are also discussed.

主权项

1. A method for enhancing the upstream data carrying capacity of a hybrid fiber cable (HFC) network with a cable head, at least one trunk optical fiber, at least one trunk optical fiber node terminating on at least one CATV trunk cable, said CATV trunk cable connected to a plurality of CATV active devices, with at least one branch CATV cables connected to said plurality of CATV active devices, thus forming a CATV Tree and Branch Network, and a plurality of cable modems or Ethernet terminals connected to said CATV Tree and Branch Network, said method comprising:
operating at least one shadow optical fiber from said trunk optical fiber to Coax Fiber Terminals associated with at least some of said plurality of CATV active devices, wherein said Coax Fiber Terminals are connected to said CATV cable and intercept local upstream CATV RF signals being transmitted by said plurality of cable modems or Ethernet terminals connected to said trunk or branch CATV cables; using said Coax Fiber Terminals to remove at least some of said intercepted upstream CATV RF signals from said trunk or branch CATV cables connected to said CATV active devices; and using said at least one shadow optical fiber to backhaul at least the information carried by the removed upstream CATV RF signals.