Patent ID: 6700879
Filing Date: 2004-03-02
Classification: H04L

Abstract:
A method of setting a downstream communications rate on a communications line, comprising:where no downstream communications rate is established on said communications line, establishing a base downstream communications rate on said communications line; determining a downstream signal to noise ratio (SNR) on said communications line; based on said downstream SNR, predicting an acceptable downstream communications rate; if said predicted acceptable downstream communications rate is greater than said established downstream communications rate, sending an indication of a new downstream communications rate on said line based on said predicted downstream communications rate and thereafter attempting to establish said new downstream communications rate on said line, wherein said establishing a base downstream communications rate comprises: silencing said communications line in the downstream direction for a pre-determined time; transmitting downstream at a pre-determined downstream base communications rate; monitoring for upstream energy on said communications line; on detecting upstream energy, messaging in downstream transmissions a requested upstream communications rate and an upstream high power level; on detecting upstream transmissions at said requested upstream communications rate, synchronising to said upstream transmissions; and at least once: reading an upstream SNR and upstream power level from said upstream transmissions, determining whether said upstream SNR exceeds a threshold, and, if said upstream SNR exceeds said threshold, messaging in downstream transmissions a requested upstream power level which is lower than said read upstream power level.