Multiple upstream split support in a fiber-deep HFC network
Systems and methods for achieving full duplex bidirectional transmission across coaxial cable in a hybrid fiber-coaxial cable TV network. Some preferred systems and method will attenuate reflections propagated within the coaxial cable. Other preferred systems may echo-cancel reflections propagated within the coaxial cable.
1. A system comprising at least one optical network unit (ONU) receiving upstream content from and delivering downstream content to each of a plurality of subscribers in a single cable service group over coaxial drop cables, the at least one ONU also communicating upstream and downstream content over a common optical link to at least one component upstream from the ONU,
the at least one ONU including:
a diplex filter for communicating upstream and downstream content communicated over a first coaxial drop cable with a first of said plurality of subscribers having a first frequency split, wherein the diplex filter separates upstream content having an overlapping frequency band with the downstream content from upstream content having a non-overlapping frequency band,
a directional coupler for delivering the downstream content to the diplex filter, receiving the upstream content in the overlapping frequency band from the diplex filter, and delivering the upstream content in the overlapping frequency band to a common output with upstream content in the non-overlapping frequency band.
2. The system of claim 1 having a plurality of ONUs, each ONU delivering upstream content from and downstream content to the first of said plurality of subscribers at a frequency split determined independently of respective frequency splits between upstream and downstream content delivered to other ones of said plurality of subscribers.
3. The system of claim 2 where the frequency splits of the first and second subscribers are such that at least one of the upstream and downstream signals from the first subscriber overlaps with the upstream or downstream signal, respectively, of a second subscriber.
4. The system of claim 2 where each ONU has at least one of a diplex filter and a directional coupler that implements the frequency split associated with the ONU.
5. The system of claim 2 where each ONU has a first diplex filter implementing a first frequency split that is interchangeable with a replacement diplex filter implementing a second frequency split different from the first split.
6. The system of claim 2 where each ONU has a plurality of ports, each port implementing a selective one of a plurality of different frequency splits.
7. The system of claim 1 having an ONU that delivers content to each of a plurality of different subscribers, the ONU implementing a first frequency split to at least one of the subscribers different from the frequency split of at least one other one of the subscribers.
8. The system of claim 7 where the ONU includes at least one receptacle capable of receiving a plug-in diplexer.
9. The system of claim 1 where the at least one ONU is configured for identifying passive optical network (PON) content based on wavelength and delivering the PON content to one or more subscribers.
10. An optical network unit (ONU) for receiving upstream content from and delivering downstream content to each of a plurality of subscribers in a single cable service group over at least one coaxial connection, said ONU comprising:
a fiber connection propagating an optical signal from a head end and comprising upstream and downstream cable television (CATV) content, and at least one first coaxial connection to a first subscriber in a service group comprising a plurality of subscribers, and at least one second coaxial connection to at least one other of the plurality of subscribers, the at least one coaxial connection propagating an RF signal comprising the upstream and downstream CATV content; and
a split-setting element that configures a first frequency split between upstream content from and downstream content for the first subscriber in a manner independent of and different from the frequency split between upstream content from and downstream content for the at least one other of the plurality of subscribers, wherein the split-setting element separates upstream content from the first subscriber having an overlapping frequency band with the downstream content for the first subscriber from upstream content for the first subscriber having a non-overlapping frequency band; and
a directional coupler for delivering the downstream content for the first subscriber to the split-setting element, receiving the upstream content from the first subscriber in the overlapping frequency band from the split-setting element, and delivering the upstream content from the first subscriber in the overlapping frequency band to a common output with upstream content of the first subscriber in the non-overlapping frequency band.
11. The ONU of claim 10 where the split-setting element is a diplex filter.
12. The ONU of claim 11 where the diplex filter is a pluggable filter insertable into a receptacle of the ONU.
13. The ONU of claim 10 where the upstream and downstream content propagated into the fiber connection are overlapping.
14. The ONU of claim 10 configured for identifying passive optical network (PON) content based on wavelength and delivering the PON content to one or more of the plurality of subscribers.