Methods, gating devices, and computer program products for determining a noise source in a communication network
A communication network is operated by attenuating signal transmission on an upstream path between a cable modem and a cable modem termination system (CMTS) during a noise test interval. The attenuation on the upstream path is removed at times outside of the noise test interval.
1 . A method of operating a communication network, comprising:
attenuating signal transmission on an upstream path between a cable modem and a cable modem termination system (CMTS) during a noise test interval; and
removing attenuation on the upstream path outside of the noise test interval.
2 . The method of claim 1 , wherein attenuating signal transmission on the upstream path comprises:
attenuating a portion of the signal transmission spectrum associated with the upstream path; or
high-pass filtering signal transmission between the cable modem and the CMTS so as to block signal transmission on the upstream path and to allow signal transmission on a downstream path between the CMTS and the cable modem.
3 . The method of claim 1 , further comprising:
using diplex filters to separate the upstream path from a downstream path between the CMTS and the cable modem; and wherein attenuating signal transmission on the upstream path comprises:
attenuating a portion of the signal transmission spectrum associated with the upstream path; or
severing the upstream path so as to block signal transmission thereon.
4 . The method of claim 1 , wherein attenuating signal transmission on the upstream path comprises:
attenuating signal transmission on the upstream path between the cable modem and the cable modem termination system (CMTS) during the noise test interval responsive to a signal from the CMTS.
5 . The method of claim 4 , wherein the signal is a Data Over Cable System Interface Specification (DOCSIS) signal.
6 . The method of claim 1 , further comprising:
scheduling the test interval based on a defined maintenance schedule.
7 . The method of claim 6 , wherein the maintenance schedule is a Data Over Cable System Interface Specification (DOCSIS) maintenance schedule.
8 . The method of claim 7 , wherein the test interval comprises a DOCSIS station maintenance interval for the cable modem.
9 . The method of claim 8 , wherein the test interval further comprises a time interval between a beginning of the station maintenance interval for the cable modem and a beginning of a station maintenance interval for another cable modem.
10 . The method of claim 8 , wherein the test interval further comprises a time interval between a beginning of the station maintenance interval for the cable modem and a beginning of a scheduled upstream transmission by the cable modem.
11 . The method of claim 8 , wherein the test interval further comprises a time interval that is a greater of a first time interval between a beginning of the station maintenance interval for the cable modem and a beginning of a scheduled upstream transmission by the cable modem and a second time interval between an end of a scheduled upstream transmission by the cable modem and an end of the station maintenance interval for the cable modem.
12 . A method of operating a communication network, comprising:
sequentially attenuating signal transmission on respective upstream paths between a plurality of cable modems and a cable modem termination system (CMTS) during respective noise test intervals;
removing attenuation on the respective upstream paths outside of the respective noise test interval; and
determining a source of noise in the communication network based on a variation in noise measured in the communication network during the respective noise test intervals.
13 . The method of claim 12 , wherein sequentially attenuating signal transmission, removing attenuation on the respective upstream paths, and determining the source of the noise are performed responsive to detecting a defined noise level in the communication network.
14 . The method of claim 12 , further comprising:
scheduling the respective test intervals based on a defined maintenance schedule.
15 . The method of claim 14 , wherein the maintenance schedule is a Data Over Cable System Interface Specification (DOCSIS) maintenance schedule.
16 . A gating device, comprising:
a control module that is configured to generate a control signal responsive to a signal from a cable modem termination system (CMTS); and
a gating element comprising a switch that is operable to attenuate signal transmission on an upstream path between the CMTS during a noise test interval and to remove attenuation on the upstream path outside of the noise test interval.
17 . The gating device of claim 16 , wherein the switch is configured to attenuate a portion of the signal transmission spectrum associated with the upstream path in a first position and to high-pass filter signal transmission between the cable modem and the CMTS so as to block signal transmission on the upstream path and to allow signal transmission on a downstream path between the CMTS and the cable modem in a second position.
18 . The gating device of claim 16 , further comprising:
diplex filters that are configured to separate the upstream path from the downstream path between the CMTS and the cable modem; and
wherein the switch is configured to attenuate a portion of the signal transmission spectrum associated with the upstream path in a first position and to sever the upstream path so as to block signal transmission thereon in a second position.
19 . The gating device of claim 16 , wherein the signal from the CMTS is a Data Over Cable System Interface Specification (DOCSIS) signal.
20 . A computer program product for operating a communication network, comprising:
a computer readable storage medium having computer readable program code embodied therein, the computer readable program code comprising:
computer readable program code configured to attenuate signal transmission on an upstream path between a cable modem and a cable modem termination system (CMTS) during a noise test interval; and
computer readable program code configured to remove attenuation on the upstream path outside of the noise test interval.
21 . The computer program product of claim 20 , wherein the computer readable program code configured to attenuate signal transmission on the upstream path comprises:
computer readable program code configured to attenuate a portion of the signal transmission spectrum associated with the upstream path; or
computer readable program code configured to high-pass filter signal transmission between the cable modem and the CMTS so as to block signal transmission on the upstream path and to allow signal transmission on a downstream path between the CMTS and the cable modem.
22 . The computer program product of claim 20 , further comprising:
computer readable program code configured to use diplex filters to separate the upstream path from a downstream path between the CMTS and the cable modem; and wherein the computer readable program code configured to attenuate signal transmission on the upstream path comprises:
computer readable program code configured to attenuate a portion of the signal transmission spectrum associated with the upstream path; or
computer readable program code configured to sever the upstream path so as to block signal transmission thereon.
23 . A method of operating a communication network comprising a plurality of gating devices, each gating device comprising a Data Over Cable System Interface Specification (DOCSIS) module connected in series between an associated gating element and a cable modem termination system (CMTS), comprising:
determining that at least one of the DOCSIS modules is unable to initialize on the communication network;
configuring the gating elements so as to block transmission to the CMTS during intervals that DOCSIS modules transmit to the CMTS, respectively.
24 . The method of claim 23 , further comprising:
identifying a source of noise in the communication network based on one of the DOCSIS modules being able to initialize on the communication network when the gating element associated with the one of the DOCSIS modules is configured to block transmission.
25 . The method of claim 23 , further comprising:
determining the existence of multiple noise sources in the communication network based on multiple DOCSIS modules being unable to initialize on the communication network;
configuring the gating elements so as to block transmission to the CMTS at all times;
initializing the DOCSIS modules on the communication network;
configuring the gating elements so as to allow transmission to the CMTS only when the gating device transmits after the DOCSIS modules have initialized; then monitoring the noise in the communication network to identify a rise in the noise floor when at least one gating device that is associated with the noise source transmits.