Distributed CCAP cable modem termination system

Patent metadata

Field	Value
Publication number	US-9692612-B2
Application number	US-201615083215-A
Country	US
Kind code	B2
Filing date	Mar 28, 2016
Priority date	Jan 22, 2010
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

Distributed CMTS device for a HFC CATV network serving multiple neighborhoods by multiple individual cables, in which at least some and often all of the QAM modulators that provide data for the individual cables are remote QAM modulators ideally located at the fiber nodes. A CCAP set of IP/on-demand data is transmitted to the nodes using an optical fiber, often using digital protocols such as Ethernet protocols. Optionally a basic set of legacy CATV QAM data, transmitted using RF waveforms transposed to optical frequencies, may also be transmitted to the nodes using either the same or different optical fiber. The nodes extract the data specific to each neighborhood, and inject this data into unused cable QAM channels along with any optional legacy CATV QAM waveforms as desired, thus achieving improved data transmission rates through finer granularity. A computerized “virtual shelf” control system for this system is also disclosed.

First claim

The invention claimed is:

1. A remote CMTS fiber node (CMRTS) system for a Hybrid Fiber Cable (HFC) network, comprising:
a first optical to radio frequency (RF) conversion device that directly converts a first set of RF modulated optical fiber signals to a first set of CATV RF signals;
at least one QAM modulator device capable of encoding selected portions of digitally encoded second optical fiber signals into a second set of RF QAM waveforms;
at least one software controllable switch that can be remotely directed to select at least some of said second optical fiber signals (selected second optical signals) and direct said at least one QAM modulator device to encode said selected second optical signals into said second set of RF QAM waveforms at a selected set of frequencies (remotely generated QAM signals); and
at least one remotely software controllable RF packet processor capable of detecting upstream data carried by CATV RF upstream signals generated by at least one cable modem, and digitally repackaging and said upstream data and retransmitting said upstream data as a third upstream digital optical fiber signal, wherein said at least one software controllable switch and/or said software controllable RF packet processor are capable of being remotely configured by software to implement additional non-DOC SIS functionality, a full set of DOC SIS functionality, or a subset of the standard DOC SIS upstream and downstream functions, in which the functioning of said at least one software controllable switch and the functioning of said at least one remotely software controllable RF packet processor are controlled by a remote virtual shelf manager system.

2. The system of claim 1 further comprising an RF to optical conversion device that directly converts a first set of upstream CATV RF signals to RF modulated optical fiber signals and sends said RF modulated optical fiber signals upstream to said device.

3. The system of claim 1 , wherein the first set of CATV RF signals and the second set of RF QAM waveforms are combined by a diplex RF signal combiner device.

4. The system of claim 1 , wherein the DOCSIS upstream functions are DOCSIS Time Division Multiple Access (TDMA) and DOCSIS Synchronous Code Division Multiple Access (SCDMA) upstream channels, wherein said SCDMA upstream channels are handled by said software controllable RF packet processor, and wherein said DOCSIS TDMA upstream channels not handled by said software controllable RF packet processor, and instead are handled by a RF (radio frequency) to optical conversion device that directly converts a first set of upstream CATV RF signals to RF modulated optical fiber signals.

5. The system of claim 1 , wherein said non-DOCSIS functionality includes functionality to transmit downstream digital video, and/or ability to handle non-DOCSIS compliant upstream signals from set-top boxes.

6. The system of claim 1 , wherein said virtual shelf manager system sends data packets to said remotely software controllable RF packet processor(s) to detect upstream cable modem identification data transmitted by at least one newly initialized cable modem and transmit said modem identification data to said remote virtual shelf manager system.

7. The system of claim 1 , wherein said virtual shelf manager system looks up said cable modem identification data in said device configuration database, and determines the privileges of the user associated with said cable modem identification data, and depending upon the value of the user privilege field, available DOCSIS channels, and available IP addresses, sends data packets to the CMRTS unit associated with said cable modem identification data to configure said software controllable switch and said available IP address so as to transmit downstream data to said cable modem on a first available DOCSIS channel, and configure said software controllable RF packet processor to receive upstream data from said cable modem on a second available DOCSIS upstream channel and IP address and retransmit said upstream data as a third upstream digital optical fiber signal.

8. The system of claim 1 , wherein said virtual shelf manager system handles the IP addresses for said cable modem through the proxy Dynamic Host Configuration Protocol (DHCP) service.

9. The system of claim 1 , wherein the data packets sent by the virtual shelf manager system to the CMRTS unit to configure said software controllable switch and said software controllable RF packet processor are transmitted by the socket based inter-process communication (IPC) protocol.

10. The system of claim 1 , wherein said virtual shelf manager system is in turn managed by an Operational Support Systems (OSS) network configuration management processor and OSS software system, wherein said OSS software stores data pertaining to the state of the HFC network in a network configuration database, and in which said OSS network configuration management processor and OSS software system can be managed by protocols selected from the group consisting of NETCONF, CLI, SNMP or Web interface protocols.

11. A method for enhancing the data carrying capacity of a hybrid fiber cable (HFC) network with a cable head, an optical fiber network, a plurality of optical fiber nodes, a plurality of individual CATV cables connected to said plurality of optical fiber nodes, and a plurality of individual cable modems, each with differing data requirements, connected each of said individual CATV cables, comprising:
transporting a first set of data from said cable head to said optical fiber nodes using a plurality of QAM waveforms capable of being directly injected into individual CATV cables by an optical to RF converter (first RF QAM waveforms);
transporting a second set of data from said cable head to said optical fiber nodes, said second data not being capable of being directly injected into individual CATV cables by an optical to RF converter, and converting a selected portion of said second set of data into RF QAM waveforms at said optical fiber nodes (second RF QAM waveforms); and
combining said first RF QAM waveforms and said second RF QAM waveforms and injecting the combined RF QAM waveforms into said individual CATV cables,
wherein for each individual CATV cable in said plurality of said individual CATV cables, said first RF QAM waveforms and said second RF QAM waveforms are selected so that the combined RF QAM waveforms do not exceed the available bandwidth of said each said individual CATV cable, and
wherein said second set of data and the selected portion of said second set of data are selected to satisfy said differing data requirements for said plurality of cable modems, so that different individual CATV cables in said plurality of individual CATV cables can carry at least differing second RF QAM waveforms.

12. The method of claim 11 , wherein identical copies of said first RF QAM waveforms are injected into to multiple individual CATV cables,
wherein said second RF QAM waveforms are selected to satisfy the differing requirements of individual cable modems connected to said multiple individual CATV cables, and
wherein said second RF QAM waveforms differ between individual CATV cables in said multiple individual CATV cables.

13. The method of claim 11 , wherein said second set of data is transmitted on an optical fiber that is different from the optical fiber used to transmit said first set of data.

14. The method of claim 13 further comprising:
transporting a third upstream set of data from said plurality of individual cable modems upstream to said cable head by transporting said third upstream set of data by a third set of RF waveforms alo

Assignees

• Gainspeed Inc
• Alcatel Lucent Usa Inc

Inventors

• Rakib Shlomo Selim

Classifications

• H04N7/10

  Adaptations for transmission by electrical cable (H04N7/12 takes precedence) · CPC title

• H04N21/64322

  IP · CPC title

• H04N21/2396

  characterized by admission policies (admission control, resource allocation in open networks H04L12/5692; arrangements for network security using user profiles for access control H04L63/102; access security in wireless networks H04W12/08) · CPC title

• H04N21/2221 Primary

  being a cable television head-end (CATV in broadcast systems H04H20/78) · CPC title

• H04N21/239

  Interfacing the upstream path of the transmission network, e.g. prioritizing client {content} requests (hybrid fiber coaxial [HFC] networks for upstream channel allocation for video distribution H04L12/2801; flow control in data networks H04L47/10; real-time communication protocols in data switching networks H04L65/00; scheduling or organising the servicing of application requests H04L67/60) · CPC title