Method and system for a high capacity cable network

摘要

A cable modem termination system (CMTS) may communicate with a plurality of cable modems using a plurality of orthogonal frequency division multiplexed (OFDM) subcarriers. The CMTS may determine a performance metric of each of the cable modems. For each of the OFDM subcarriers and each of the cable modems, the CMTS may select physical layer parameters to be used for communication with that cable modem on that OFDM subcarrier based on a performance metric of that cable modem. The parameters may be selected for each individual modem and/or each individual subcarrier, or may be selected for groups of modems and/or groups of subcarriers. The parameters may include, for example, one or more of: transmit power, receive sensitivity, timeslot duration, modulation type, modulation order, forward error correction (FEC) type, and FEC code rate.

主权项

1. A method comprising:
in a cable modem termination system (CMTS) which communicates with a plurality of cable modems using a plurality of orthogonal frequency division multiplexed (OFDM) subcarriers, executing instructions for:
selecting physical layer parameters to be used for communication such that there is excess signal-to-noise ratio (SNR), relative to a threshold SNR required for said communication, on a first subset of said OFDM subcarriers, and a SNR deficit, relative to said threshold SNR, on a second set of said OFDM subcarriers, wherein said selecting said physical layer parameters includes selecting whether to use hierarchical modulation for said communication with said one of said cable modems; andtransmitting, on said first subset of said OFDM subcarriers, error correction data for packets sent on said second subset of said OFDM subcarriers.