Hybrid fiber-coaxial (HFC) cable communication systems having well-aligned optical and radio-frequency links to facilitate upstream channel plans having high aggregate data capacity

A hybrid fiber-coaxial (HFC) cable communication system, comprising:

• a cable modem termination system (CMTS) having associated therewith at least one first attenuator to attenuate at least one upstream signal applied to the CMTS;
• an optical link communicatively coupled to the CMTS, the optical link having a dynamic range and comprising:
• an optical receiver having associated therewith at least one second attenuator to attenuate the at least one upstream signal;
• and
• an optical transmitter having associated therewith at least one third attenuator to attenuate the at least one upstream signal;
• a coaxial radio frequency (RF) link communicatively coupled to the optical link, the coaxial RF link comprising at least one RF amplifier having associated therewith at least one fourth attenuator to attenuate the at least one upstream signal, wherein the coaxial RF link includes an ingress-mitigated hardline cable plant;
• and
• at least one subscriber modem, communicatively coupled to the coaxial RF link, to generate from an output of the at least one subscriber modem the at least one upstream signal at a transmit RF signal level,
• wherein:
• the CMTS implements a long loop automatic level control (ALC) to set the transmit RF signal level of the at least one upstream signal generated from the output of the at least one subscriber modem, based at least in part on a received RF signal level of the at least one upstream signal as applied to the CMTS;
• and
• respective values for the at least one first attenuator, the at least one second attenuator, the at least one third attenuator, and the at least one fourth attenuator are selected based at least in part on the dynamic range of the optical link so as to facilitate implementation of the long loop ALC and effective transmission to the CMTS of upstream information carried by the at least one upstream signal, and
• wherein the at least one RF amplifier of the coaxial RF link further has associated therewith at least one equalizer, and wherein the at least one equalizer and a value of the at least one fourth attenuator associated with the at least one RF amplifier are selected and/or configured such that at least a portion of the coaxial RF link including the at least one RF amplifier provides essentially flat gain for the at least one upstream signal across a substantial portion of an upstream path bandwidth for the at least one upstream signal.

A hybrid fiber-coaxial (HFC) cable communication system, comprising:

• a cable modem termination system (CMTS) having associated therewith at least one first attenuator to attenuate at least one upstream signal applied to the CMTS;
• an optical link communicatively coupled to the CMTS, the optical link having a dynamic range and comprising:
• an optical receiver having associated therewith at least one second attenuator to attenuate the at least one upstream signal;
• and
• an optical transmitter having associated therewith at least one third attenuator to attenuate the at least one upstream signal;
• a coaxial radio frequency (RF) link communicatively coupled to the optical link, the coaxial RF link comprising at least one RF amplifier having associated therewith at least one fourth attenuator to attenuate the at least one upstream signal;
• and
• at least one subscriber modem, communicatively coupled to the coaxial RF link, to generate from an output of the at least one subscriber modem the at least one upstream signal at a transmit RF signal level,
• wherein:
• the CMTS implements a long loop automatic level control (ALC) to set the transmit RF signal level of the at least one upstream signal generated from the output of the at least one subscriber modem, based at least in part on a received RF signal level of the at least one upstream signal as applied to the CMTS;
• respective values for the at least one first attenuator, the at least one second attenuator, the at least one third attenuator, and the at least one fourth attenuator are selected based at least in part on the dynamic range of the optical link so as to facilitate implementation of the long loop ALC and effective transmission to the CMTS of upstream information carried by the at least one upstream signal;
• the at least one subscriber modem includes a plurality of subscriber modems communicatively coupled to the coaxial RF link, the plurality of subscriber modems generating a corresponding plurality of upstream signals respectively having corresponding transmit RF signal levels according to the long loop ALC;
• each upstream signal of the plurality of upstream signals includes at least one encoded carrier wave having a carrier frequency in an upstream path bandwidth of the coaxial RF link and being modulated, using quadrature amplitude modulation (QAM), with voice and/or data information;
• at least some of the plurality of upstream signals have different carrier frequencies to respectively define a plurality of upstream physical communication channels in the upstream path bandwidth;
• and
• a first upstream signal defining a first upstream physical communication channel of the plurality of upstream physical communication channels has a first carrier frequency of less than 19.6 MHz.

A hybrid fiber-coaxial (HFC) cable communication system, comprising:

• a cable modem termination system (CMTS) having associated therewith at least one first attenuator to attenuate at least one upstream signal applied to the CMTS;
• an optical link communicatively coupled to the CMTS, the optical link having a dynamic range and comprising:
• an optical receiver having associated therewith at least one second attenuator to attenuate the at least one upstream signal;
• and
• an optical transmitter having associated therewith at least one third attenuator to attenuate the at least one upstream signal;
• a coaxial radio frequency (RF) link communicatively coupled to the optical link, the coaxial RF link comprising at least one RF amplifier having associated therewith at least one fourth attenuator to attenuate the at least one upstream signal;
• and
• at least one subscriber modem, communicatively coupled to the coaxial RF link, to generate from an output of the at least one subscriber modem the at least one upstream signal at a transmit RF signal level,
• wherein:
• the CMTS implements a long loop automatic level control (ALC) to set the transmit RF signal level of the at least one upstream signal generated from the output of the at least one subscriber modem, based at least in part on a received RF signal level of the at least one upstream signal as applied to the CMTS;
• respective values for the at least one first attenuator, the at least one second attenuator, the at least one third attenuator, and the at least one fourth attenuator are selected based at least in part on the dynamic range of the optical link so as to facilitate implementation of the long loop ALC and effective transmission to the CMTS of upstream information carried by the at least one upstream signal;
• the at least one subscriber modem includes a plurality of subscriber modems communicatively coupled to the coaxial RF link, the plurality of subscriber modems generating a corresponding plurality of upstream signals respectively having corresponding transmit RF signal levels according to the long loop ALC;
• each upstream signal of the plurality of upstream signals includes at least one encoded carrier wave having a carrier frequency in an upstream path bandwidth of the coaxial RF link and being modulated, using quadrature amplitude modulation (QAM), with voice and/or data information;
• at least some of the plurality of upstream signals have different carrier frequencies to respectively define a plurality of upstream physical communication channels in the upstream path bandwidth constituting a channel plan;
• and
• the dynamic range of the optical link is based at least in part on the channel plan.

A hybrid fiber-coaxial (HFC) cable communication system, comprising:

• A) a cable modem termination system (CMTS) having associated therewith at least one first attenuator to attenuate a plurality of upstream signals applied to the CMTS;
• B) an optical link communicatively coupled to the CMTS, the optical link having a dynamic range and comprising:
• an optical receiver having associated therewith at least one second attenuator to attenuate the plurality of upstream signals;
• and
• an optical transmitter having associated therewith at least one third attenuator to attenuate the plurality of upstream signals;
• C) a coaxial radio frequency (RF) link communicatively coupled to the optical link, the coaxial RF link comprising:
• an ingress-mitigated hardline cable plant;
• and
• at least one RF amplifier having associated therewith at least one fourth attenuator to attenuate at least some of the plurality of upstream signals;
• and
• D) a plurality of subscriber modems, communicatively coupled to the coaxial RF link, to generate from respective outputs of the plurality of subscriber modems the corresponding plurality of upstream signals at respective transmit RF signal levels,
• wherein:
• each upstream signal of the plurality of upstream signals includes at least one encoded carrier wave having a carrier frequency in an upstream path bandwidth and being modulated, using quadrature amplitude modulation (QAM), with voice and/or data information from at least some of the plurality of subscriber premises;
• at least one first upstream signal of the plurality of upstream signals has a QAM modulation order of 32 and a first carrier frequency of between approximately 5 MHz and 19.6 MHz;
• the CMTS implements a long loop automatic level control (ALC) to set the respective transmit RF signal levels of the plurality of upstream signals generated from the respective outputs of the plurality of subscriber modems, based at least in part on respective received RF signal levels of the plurality of upstream signals as applied to the CMTS;
• and
• respective values for the at least one first attenuator, the at least one second attenuator, the at least one third attenuator, and the at least one fourth attenuator are selected based at least in part on the dynamic range of the optical link so as to facilitate implementation of the long loop ALC and effective transmission to the CMTS of upstream information carried by the plurality of upstream signals.

A hybrid fiber-coaxial (HFC) cable communication system, comprising:

• A) a cable modem termination system (CMTS) having associated therewith at least one first attenuator to attenuate a plurality of upstream signals applied to the CMTS;
• B) an optical link communicatively coupled to the CMTS, the optical link having a dynamic range and comprising:
• an optical receiver having associated therewith at least one second attenuator to attenuate the plurality of upstream signals;
• and
• an optical transmitter having associated therewith at least one third attenuator to attenuate the plurality of upstream signals;
• C) a coaxial radio frequency (RF) link communicatively coupled to the optical link, the coaxial RF link comprising at least one RF amplifier having associated therewith at least one fourth attenuator to attenuate at least some of the plurality of upstream signals;
• and
• D) a plurality of subscriber modems, communicatively coupled to the coaxial RF link, to generate from respective outputs of the plurality of subscriber modems the corresponding plurality of upstream signals at respective transmit RF signal levels,
• wherein:
• each upstream signal of the plurality of upstream signals includes at least one encoded carrier wave having a carrier frequency in an upstream path bandwidth and being modulated, using quadrature amplitude modulation (QAM), with voice and/or data information from at least some of the plurality of subscriber premises;
• at least some of the plurality of upstream signals have different carrier frequencies to respectively define a plurality of upstream physical communication channels in the upstream path bandwidth constituting a channel plan;
• a first upstream signal defining a first upstream physical communication channel of the plurality of upstream physical communication channels has a first carrier frequency of less than 19.6 MHz;
• the channel plan includes at least four physical communication channels respectively defined by upstream signals having a QAM modulation order of at least 64;
• the CMTS implements a long loop automatic level control (ALC) to set the respective transmit RF signal levels of the plurality of upstream signals generated from the respective outputs of the plurality of subscriber modems, based at least in part on respective received RF signal levels of the plurality of upstream signals as applied to the CMTS;
• respective values for the at least one first attenuator, the at least one second attenuator, the at least one third attenuator, and the at least one fourth attenuator are selected based at least in part on the dynamic range of the optical link so as to facilitate implementation of the long loop ALC and effective transmission to the CMTS of upstream information carried by the plurality of upstream signals;
• and
• the dynamic range of the optical link is based at least in part on the channel plan including the at least four physical communication channels respectively defined by upstream signals having a QAM modulation order of at least 64.

A hybrid fiber-coaxial (HFC) cable communication system, comprising:

• A) a cable modem termination system (CMTS) having associated therewith at least one first attenuator to attenuate a plurality of upstream signals applied to the CMTS;
• B) an optical link communicatively coupled to the CMTS, the optical link having a dynamic range and comprising:
• an optical receiver having associated therewith at least one second attenuator to attenuate the plurality of upstream signals;
• and
• an optical transmitter having associated therewith at least one third attenuator to attenuate the plurality of upstream signals;
• C) a coaxial radio frequency (RF) link communicatively coupled to the optical link, the coaxial RF link comprising at least one RF amplifier having associated therewith at least one fourth attenuator to attenuate at least some of the plurality of upstream signals;
• and
• D) a plurality of subscriber modems, communicatively coupled to the coaxial RF link, to generate from respective outputs of the plurality of subscriber modems the corresponding plurality of upstream signals at respective transmit RF signal levels,
• wherein:
• each upstream signal of the plurality of upstream signals includes at least one encoded carrier wave having a carrier frequency in an upstream path bandwidth and being modulated, using quadrature amplitude modulation (QAM), with voice and/or data information from at least some of the plurality of subscriber premises;
• at least some of the plurality of upstream signals have different carrier frequencies to respectively define a plurality of upstream physical communication channels in the upstream path bandwidth constituting a channel plan;
• the channel plan occupies a substantial portion of the upstream path bandwidth that includes carrier frequencies in a range of from approximately 5 MHz to at least approximately 42 MHz;
• the CMTS implements a long loop automatic level control (ALC) to set the respective transmit RF signal levels of the plurality of upstream signals generated from the respective outputs of the plurality of subscriber modems, based at least in part on respective received RF signal levels of the plurality of upstream signals as applied to the CMTS;
• the dynamic range of the optical link is defined by an input RF power window for the plurality of upstream signals as applied to the optical transmitter of the optical link, the input RF power window determined by at least one intersection of 1) a target carrier-to-noise (C/N) value for a highest QAM modulation order of at least one upstream physical communication channel of the channel plan and 2) a Noise Power Ratio (NPR) curve for the optical transmitter of the optical link;
• a target operating power point for the optical transmitter is selected within the input RF power window;
• a first attenuation value of the third attenuator associated with the optical transmitter is selected based at least in part on the target operating power point for the optical transmitter;
• a second attenuation value of the at least one fourth attenuator associated with the at least one RF amplifier is selected and/or adjusted such that a signal level of the at least one upstream signal at a junction of the coaxial RF link and the optical link corresponds to a predetermined input RF reference signal level to be applied to the optical link;
• and
• respective values for the at least one first attenuator and the at least one second attenuator are selected so as to facilitate implementation of the long loop ALC and effective transmission to the CMTS of upstream information carried by the plurality of upstream signals.