Cable television return link system with high data-rate side-band communication channels

• US 7,222,358 B2
• Filed: 10/30/2002
• Issued: 05/22/2007
• Est. Priority Date: 12/13/1999
• Status: Expired due to Fees

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Lawson, Arthur Michael, Levinson, Frank H., Sage, Gerald F., Mostert, Willem A.
• Primary Examiner(s): VU, NGOC K
• Application Number:
  US10/285,205
• Publication Number:
  US 20030110509A1
• Time in Patent Office: 1,665 Days
• Field of Search: 725/118, 725/119, 725/120, 725/121, 725127-129, 725/105, 725/109, 370/535, 370/539, 370/910, 370/916, 398 66- 67, 398/71, 398/135, 398/138
• US Class Current: 725/121
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0247 Sharing one wavelength for at least a group of ONUs
• CPC Class Codes: H04J 14/0252 Sharing one wavelength for at least a group of ONUs, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0298 with sub-carrier multiplexing [SCM]
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 7/0029 interpolation of received data signal
• CPC Class Codes: H04L 7/005 Correction by an elastic buffer
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/2381 Adapting the multiplex stream to a specific network, e.g. an Internet Protocol [IP] network transmission of MPEG streams over ATM H04L12/5601
• CPC Class Codes: H04N 21/615 Signal processing at physical level signal processing in analog two-way television systems H04N7/173
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications
• CPC Class Codes: H04N 7/22 Adaptations for optical transmission

Abstract

A Cable Television (CATV) digital return link system that provides dedicated, high-speed, full-duplex and point-to-point connections between users and the head end system is disclosed. The CATV digital return link system includes return path transmitters, intermediate hubs and a head end hub coupled to each other via a network of fiber optics cables. The return path transmitters are each coupled to a relatively large number of users via a local CATV-subtree. Signals from cable modems are transmitted via the local CATV-subtree to the return path transmitters for transmission to the head end. A number of users are individually and directly connected to the return path transmitters. Data from these directly connected users is transmitted to the head end via the network of fiber optics cables in conjunction with the RF data from the subtree. Likewise, data from the head end to these directly connected users is transmitted in the forward path direction using the digital return link system.

Claims

1. A return path transmitter for use in conjunction with a local system that generates an analog RF data signal to be conveyed to a head end system, the return path transmitter comprising:

an RF signal receiver configured to receive and convert the analog RF data signal into digitized RF data samples, the RF signal receiver further configured to output a first data stream including the digitized RF data samples;

an Ethernet data receiver configured to receive first Ethernet data from a device external to the return path transmitter, the Ethernet data receiver configured to output the first Ethernet data in a second data stream;

first circuitry coupled to the RF signal receiver and to the Ethernet data receiver to receive and process the first data stream and second data stream and to output a third data stream;

an optical transmitter configured to convert the third data stream into a first optical data signal for transmission over an optical fiber to the head end system;

an optical receiver configured to receive a second optical signal over the optical fiber, the optical receiver configured to convert the second optical signal into a fourth data stream;

second circuitry coupled to the optical receiver, the second circuitry configured to recover second Ethernet data from the second optical signal; and

an Ethernet data transmitter coupled to the second circuitry and configured to transmit the second Ethernet data to the device external to the return path transmitter.

2. The return path transmitter of claim 1, wherein the first circuitry is configured to output data frames in the third data stream, each data frame having Ethernet data and digitized RF data samples.

3. The return path transmitter of claim 1, wherein the first circuitry comprises:

a first memory device configured to buffer the first data stream;

a second memory device configured to buffer the second data stream;

control circuitry configured to monitor a fullness level of the first memory device and to generate control signals based on the fullness level; and

a multiplexor to output the third data stream, wherein the multiplexor, in response to the control signals, outputs data stored in the first memory device in a first mode when the fullness level of the first memory device is more than a predefined threshold level, and outputs data stored in the first memory device and data stored in the second memory device in a second interleaved mode when the fullness level of the first memory device is less than the predefined threshold level.

4. The return path transmitter of claim 3, further comprising:

supplemental channel circuitry coupled to the multiplexor, the supplemental channel circuitry configured to generate maintenance data indicative of an operational state of the return path transmitter, the supplemental channel circuitry further configured to generate a fifth data stream that includes the maintenance data, wherein the multiplexor is configured to include the maintenance data in the third data stream.

5. The return path transmitter of claim 4 wherein the supplemental channel circuitry includes at least one sensor for measuring an operational parameter selected from a group consisting of temperature and supply voltage.

6. The return path transmitter of claim 1, wherein the second circuitry comprises:

circuitry configured to recover control information for the RF signal receiver from the second optical signal and to provide the control information to the RF signal receiver.