Wideband DOCSIS on catv systems using port-trunking

• US 20040244043A1
• Filed: 05/28/2003
• Published: 12/02/2004
• Est. Priority Date: 05/28/2003
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Terayon Communications Systems Incorporated (Motorola Solutions, Inc.)
• Inventors: Rakib, Belim Shlomo, Lind, Paul Alan, Fanfelle, Robert James
• Granted Patent: US 7,023,871 B2
• Time in Patent Office: Days
• US Class Current: 725/111
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• 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: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Method and apparatus to carry out wideband DOCSIS both upstream and downstream in a point-to-multipoint environment of an HFC system using port trunking concepts. For the downstream, each CMTS has a frame distributor which distributes frames to various transmitters transmitting on downstream channels to be used to transmit downstream data simultaneously to a CM using wideband DOCSIS. The frame distributor adds sequence numbers in some embodiments to guarantee proper order of frames can be restored at the CM, and schedules transmissions according to quality of service considerations to meet guranteed and committed portions of constant bit rate and variable bit rate flows. The CMTS sends and Extended Channel Enable (ECE) message to wideband capable CMs telling them which downstreams to enable. Each CM has a frame collector to which all frames received on various downstream channels are sent. The frame collector makes sure they are all there, puts them into the proper order and delivers them to a NI. Upstream wideband DOCSIS works the same way with a frame distributor in each CM and a frame collector in the CMTS. The CMTS receives bandwidth requests and controls upstream wideband DOCSIS transmissions by sending downstream UCD and MAP and ECE messages to the CMs instructing them which upstream channels to use, describing the parameters of the channel and assigning times for transmission which are simultaneous on multiple channels for upstream wideband capable CMs.

Claims

1. A method for performing downstream wideband DOCSIS in a point-to-multipoint environment comprising a cable modem termination system (CMTS) coupled to a plurality of cable modems (CMs) by a shared transmission medium, comprising:

determining which cable modems are wideband capable and how many downstream channels each can simultaneously use;

sending an extended channel enable message to each wideband capable cable modem telling it which downstream channels to which it should tune for reception of wideband downstream DOCSIS transmissions;

processing incoming frames to be sent downstream to each particular cable modem in a frame distributor to schedule the distribution of frames to the various CMTS transmitters transmitting on the downstream channels to which the CM is tuned so as to meet quality of service requirements, add sequence numbers or do anything else to guarantee the frames can be put into the proper order at the receiver side and distribute the frames to the transmitters;

transmitting the released frames addressed to a particular cable modem to that cable modem on the downstream channels to which said cable modem has been instructed to tune.

2. The process of claim 1 wherein said frame distributor guarantees that the transmitted frames can be placed in the proper order after reception by adding a sequence number to each frame of an IP flow such that different frames of the same IP flow can be transmitted on different downstream channels at different times or with different latencies and the frames can still be put in the proper order at a receiver.

3. The process of claim 1 wherein said frame distributor guarantees that the transmitted frames can be placed in the proper order after reception by restricting transmission of frames from each IP flow to be sent to a CM to transmission on one downstream channel.

4. The process of claim 1 wherein said CMTS also:

receives upstream bandwidth requests from the various CMs so that said CMTS knows how much upstream traffic there is from each CM, and determines how much downstream traffic there is to each CM from the information the frame distributor is receiving from the router;

schedules transmission of downstream frames for each IP flow to a particular CM using a Quality of Service algorithm so as to at least meet guaranteed and committed bit rates of constant bit rate and variable bit rate with committed portion IP flows;

schedules transmission of upstream frames for each IP flow from a particular CM using a Quality of Service algorithm so as to at least meet guaranteed and committed bit rates of constant bit rate and variable bit rate with committed portion IP flows and so as to fulfill as much as possible the bandwidth requests;

generates and transmits MAP messages and UCD messages for each DOCSIS upstream with the grants in the MAP messages allowing simultaneous upstream transmissions on different DOCSIS upstreams from each wideband capable CM so as to implement upstream wideband DOCSIS operations;

releases downstream frames to the various downstream transmitters for the various IP flows addressed to each particular CM at the appointed times per the schedule so as to implement wideband DOCSIS downstream transmissions to wideband capable CMs;

receives upstream wideband DOCSIS frames from various CMs, verifies that all the frames are present in each IP flow from each CM, and puts the frames in the proper order and delivers the frames for further processing.

5. The process of claim 1 further comprising the steps in each cable modem of:

powering up or rebooting and searching for and locking onto a DOCSIS downstream;

ranging using the DOCSIS upstream associated with the DOCSIS downstream to which the cable modem locked, and registering with the CMTS as a CM on the system;

sending information to the CMTS indicating how many tuners the CM has which are capable of use in downstream wideband DOCSIS;

receiving an ECE message from said CMTS indicating how many and which downstream channels will be used for wideband DOCSIS transmissions to said CM and responding thereto by tuning a tuner of said CM to each of the downstream channels designated in said ECE message;

receiving wideband downstream DOCSIS frames simultaneously transmitted on two or more downstream channels designated by said ECE message and verifying that all frames have been received;

putting said received frames into the proper order, and delivering said frames to a peripheral device coupled to said CM for further processing.

6. The process of claim 5 further comprising the following steps:

checking to determine if any new ECE messages have arrived from said CMTS;

if a new ECE message has arrived, determining whether said ECE message adds or drops any downstream channels;

if said ECE message adds a downstream DOCSIS channel, tuning one or more tuners to the newly designated channels and performing ranging on each newly designated DOCSIS downstream using a DOCSIS upstream associated therewith;

sending an acknowledge message indicating success or failure in ranging on each newly enabled DOCSIS downstream;

starting wideband DOCSIS operations on any newly acquired downstreams;

if a new ECE message has arrived that drops a DOCSIS downstream channel, dropping the specified channel and continue DOCSIS downstream operations on any remaining DOCSIS downstreams.

7. The process of claim 1 wherein said step of processing incoming frames to be sent downstream to each particular cable modem in a frame distributor to schedule the distribution of frames is done in using the following steps:

determining the particular downstreams to which each wideband DOCSIS CM is tuned using the registration data and data from transmitted ECE messages and determine the particular IP flows directed to each wideband CM from header data in packets received from a router;

verify which downstreams to which a particular CM is tuned and which has an IP flow to be sent to it are available for transmission and determine the quality of service requirement of each IP flow;

schedule the guraranteed portions of contant bit rate flows and the committed portions of variable bit rate flows on available downstream DOCSIS channels to which CMs are tuned which have IP flows with quality of service requirements which are constant bit rate or variable bit rate flows with guaranteed portions;

generate frame release signals and release and transmit frames at the scheduled times on the appropriate downstream DOCSIS channels to fulfil said guaranteed bit rates of constant bit rate QoS IP flows and to fulfil committed bit rate portions of variable bit rate QoS IP flows; and

for any wideband downstream CMs which have IP flows directed thereto with other than guaranteed bit rate Qos IP flows or variable bit rate QoS IP flows with committed portions, use any times on DOCSIS downstreams to which said CMs are tuned when no releases of frames to said CM or other CMs are scheduled or when there is no traffic to release frames directed to said CMs which have IP flows directed thereto with other than guaranteed bit rate Qos IP flows or variable bit rate QoS IP flows with committed portions.

8. A process carried out in a cable modem (CM) during wideband DOCSIS downstream processing, comprising the steps:

powering up and locking onto a DOCSIS downstream and performing DOCSIS ranging including ranging and equalization and receiving time, frequency, phase and power offsets in a messages from a cable modem termination system (CMTS);

sending an acknowledgement message if said ranging was successful and registering with said CMTS as a CM in the system, said registration message including data regarding the wideband DOCSIS capability of said CM;

receiving an Extended Channel Enable (ECE) message from said CMTS that indicates which DOCSIS downstreams said CM should get ready to receive wideband DOCSIS data upon, and reacting thereto by setting up a plurality of DOCSIS receivers to receive data on the DOCSIS downstream messages designated in said ECE message;

receiving a plurality of frames or packets transmitted simultaneously on a plurality of DOCSIS channels representing one or more IP flows;

verifying that all packets or frames have been received that are supposed to be received; and

putting said frames or packets into the correct order and delivering said frames or packets for further processing.

9. A process for performing wideband DOCSIS transmissions upstream from a cable modem (CM) which is part of a plurality of cable modems coupled to a cable modem termination system (CMTS) via a shared transmission medium, comprising the steps:

broadcasting from said CMTS a plurality of Upstream Channel Descriptor (UCD) messages, each of which defines the frequency, symbol rate, modulation type and other parameters of a DOCSIS upstream identified in said UCD message;

after a CM has locked onto a downstream and sent a ranging burst, the CMTS makes measurements and performs equalization convergence and sends one or more messages downstream to said CM which give it time, frequency and power offsets and upstream equalization coefficients;

after the CM has successfully ranged and sent an acknowledgment thereof and sent a registration message which advertises its capabilities, the CMTS receives these messages and stores at least some of the data therein indicating the CM'"'"'s wideband capabilities and determines whether the CM is wideband capable;

the CMTS receives upstream bandwidth requests from the CMs and uses registration data to determine which CMs are upstream wideband DOCSIS capable and determines how many upstream channels each CM which has requested upstream bandwidth can simultaneously transmit upon;

the CMTS analyzes the requested upstream traffic and registration and subscription data and determines which upstream channels to assign to which CMs for upstream wideband DOCSIS operation;

the CMTS uses a quality of service algorithm to schedule upstream grants for each IP flow from each CM and generates separate MAP messages for each DOCSIS upstream a CM is scheduled to use for upstream wideband DOCSIS, each MAP message scheduling when the CM or CMs having grants in the MAP message may transmit on the DOCSIS upstream to which the MAP message pertains;

the CMTS uses the grants in the MAP messages to determine which CMs that are wideband DOCSIS capable need to use multiple upstream DOCSIS channels, and sends an ECE message to each CM which is being authorized to send upstream wideband DOCSIS transmissions, each ECE message designating which upstream DOCSIS channels the CM may use and sends the MAP messages;

after the CMs which have been enabled for upstream wideband DOCSIS have transmitted data according to the MAP, ECE and UCD messages, the CMTS receives all frames and passes them to a frame collector which makes sure all frames are there and puts them into the correct order for delivery.

10. A process carried out in a cable modem (CM) which is one of a plurality of cable modems coupled by a shared transmission medium to a cable modem termination system (CMTS) for performing upstream wideband DOCSIS transmissions, comprising the steps:

powering up, finding a DOCSIS downstream and locking onto it, and using a DOCSIS upstream to perform conventional DOCSIS ranging including ranging and equalization and sending an acknowledgment message indicating whether or not ranging has been successful, and sending a registration message to said CMTS which advertises the CM'"'"'s wideband upstream DOCSIS capabilities;

receiving a plurality of Upstream Channel Descriptor (UCD) messages, each of which describes the frequency, symbol rate, modulation type and other parameters of a DOCSIS upstream;

receiving requests from user applications to send data upstream and responding thereto by sending upstream bandwidth requests;

receiving an Extended Channel Enable message which indicates which upstream DOCSIS channels to use for wideband DOCSIS upstream operations, and receiving a plurality of MAP messages, each pertaining to a single DOCSIS upstream channel and defining when said CM may transmit on said channel;

setting up the transmitters of said CM to transmit on the upstream DOCSIS channels designated in said ECE messages, and timing the transmission of upstream data on the designated channels per grants in said MAP messages pertaining to said channels.

11. A cable modem apparatus comprising:

a plurality of DOCSIS transmitters, each having an input;

a frame distributor having a plurality of outputs coupled to said inputs of said transmitters and having an input;

a plurality of DOCSIS receivers having inputs for coupled to a hybrid fiber coaxial cable system and a plurality of outputs;

a frame collector having a plurality of inputs coupled to said plurality of outputs of said plurality of DOCSIS receivers and structured to perform the following steps and having an output;

a network interface or bus interface having an input coupled to said output of said frame collector and having an output coupled to said frame distributor; and

control computer coupled to said plurality of DOCSIS transmitters and said plurality of DOCSIS receivers and said frame distributor and said frame collector and programmed to orchestrate coordination of said circuits of said cable modem to perform the following functions;

powering up, finding a DOCSIS downstream and locking onto it, and using a DOCSIS upstream to perform conventional DOCSIS ranging including ranging and equalization and sending an acknowledgment message indicating whether or not ranging has been successful, and sending a registration message to said CMTS which advertises the CM'"'"'s wideband upstream DOCSIS capabilities;

receiving a plurality of Upstream Channel Descriptor (UCD) messages, each of which describes the frequency, symbol rate, modulation type and other parameters of a DOCSIS upstream;

receiving requests from user applications to send data upstream and responding thereto by sending upstream bandwidth requests;

receiving an Extended Channel Enable message which indicates which upstream DOCSIS channels to use for wideband DOCSIS upstream operations, and receiving a plurality of MAP messages, each pertaining to a single DOCSIS upstream channel and defining when said CM may transmit on said channel;

setting up the transmitters of said CM to transmit on the upstream DOCSIS channels designated in said ECE messages in accordance with the parameters in the UCD message pertaining to the appropriate upstream channel, and timing the transmission of upstream data on the designated channels per grants in said MAP messages pertaining to said channels.

12. The apparatus of claim 11 wherein said control computer is also programmed to orchestrate coordination of said circuits of said cable modem to perform the following functions:

receiving an Extended Channel Enable (ECE) message from said CMTS that indicates which DOCSIS downstreams said CM should get ready to receive wideband DOCSIS data upon, and reacting thereto by setting up a plurality of DOCSIS receivers to receive data on the DOCSIS downstream messages designated in said ECE message;

receiving a plurality of frames or packets transmitted simultaneously on a plurality of DOCSIS downstream channels representing one or more IP flows;

verifying that all packets or frames have been received that are supposed to be received; and

putting said frames or packets into the correct order and delivering said frames or packets for further processing.

13. A cable modem termination system capable of wideband DOCSIS operation, comprising:

a plurality of DOCSIS transmitters each having an output for coupling to a hybrid fiber coaxial (HFC) cable system, and each having an input;

a frame distributor having an input and having a plurality of outputs, each said output coupled to an input of one of said DOCSIS transmitters, and having an input;

a plurality of DOCSIS receivers, each having an input for coupling to said HFC system, and each having an output;

a frame collector having a plurality of inputs each coupled to an output of one of said DOCSIS receivers and having an output;

a router having an input coupled to said output of said frame collector and having an output coupled to said input of said frame distributor; and

a control computer coupled to said plurality of DOCSIS transmitters and receivers and to said frame distributor and to said frame collector and to said router, and programmed to orchestrate said circuitry in said cable modem termination system to perform the following functions;

receiving registration message data from said CMs and determining therefrom which cable modems are wideband DOCSIS downstream capable and how many downstream channels each can simultaneously use;

sending an extended channel enable message to each wideband capable cable modem telling it which downstream channels to which it should tune for reception of wideband downstream DOCSIS transmissions;

processing incoming frames from said router to be sent downstream to a particular CM in a frame distributor to schedule the distribution of frames to the various CMTS downstream transmitters transmitting on the downstream channels to which said CM is tuned so as to meet quality of service requirements, and adding sequence numbers or or other processing to guarantee the frames can be put into the proper order at the CM, and distributing the frames to said CMTS downstream transmitters in accordance with said schedule;

transmitting the released frames addressed to a particular CM to that CM on the downstream channels to which said CM has been instructed to tune.