Reverse path multiplexer for use in high speed data transmissions

• US 6,137,793 A
• Filed: 12/05/1997
• Issued: 10/24/2000
• Est. Priority Date: 12/05/1997
• Status: Expired due to Fees

• Current Assignee: Arris International, Inc. (CommScope Holding Company, Inc.)
• Original Assignee: Com21, Inc.
• Inventors: Raissinia, Ali, Laubach, Mark E., Gorman, Kenneth
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): HO, DUC CHI
• Application Number:
  US08/985,571
• Time in Patent Office: 1,054 Days
• Field of Search: 370/537, 370/389, 370/395, 370/420, 370/486, 370/487, 370/360, 455/3.1, 455/4.1, 455/4.2, 455/5.1, 455/8, 455/12, 348/12, 348/13, 348/16
• US Class Current: 370/360
• CPC Class Codes: H04H 60/97 using uplink of the CATV systems
• CPC Class Codes: H04J 2203/0012 Switching modules and their interconnections
• CPC Class Codes: H04J 2203/0041 Star, e.g. cross-connect, concentrator, subscriber group equipment, remote electronics
• CPC Class Codes: H04J 2203/0089 Multiplexing, e.g. coding, scrambling, SONET
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A two-way hybrid fiber-coax cable networks offering high-speed broadband communications delivered via a cable modem service. Bi-directional transmissions of packets between the head-end controller (Cable Modem Terminal System) and cable modems (subscriber terminal units) is accomplished using a cable television Media Access Control (MAC) protocol. In Hybrid Fiber-Coax (HFC) networks, the invention provides a Reverse Path Multiplexing (RPM) function permitting the coupling of a large number of return path (plant) RF ports (return ports) to be coupled to a receiver card in the CMTS. One aspect of this invention is that one or more upstream traffic schedulers reside within the CMTS equipment with the responsibility of scheduling the upstream transmissions from cable modems. The cable modems are distributed across many return ports. The data from each cable modem must be successfully received by the head-end controller without being compromised by the effects of noise funneling. The knowledge of when a cable modem will transmit is used to open an RF switch in the RPM.

Claims

1. An apparatus for upstream signal selection, comprising:

a first equalization circuit for processing a first upstream signal from a first port generating a first processed signal;

a reverse path multiplexer comprising;

a first switch for selecting the first processed signal;

a second equalization circuit for processing a second upstream signal from a second port generating a second processed signal;

a second switch for selecting the second processed signal;

a first signal selection controller for controlling the first switch and the second switch;

a first gain circuit for controlling signal gain of the first processed signal;

a first port manager for instructing the first signal selection controller for controlling signal selection;

a first traffic scheduler which identifies a port for receiving signals from a designated cable modem.

2. The apparatus of claim 1, wherein the identified port is associated with the designated cable modem during a registration process.