Patent ID: 6680979
Filing Date: 2004-01-20
Classification: H04B,H04L

Abstract:
A communication method of adopting a multi-carrier modulation-demodulation mode as a communication mode for data communication to be held among a plurality of communication devices connected to a transmission line, and selecting tones less influenced by noise and thereby maintaining fixed communication quality, the method comprising:a first tone set changing step of monitoring the transmission line while the communication is held in a steady state, and judging that the communication quality cannot be maintained and changing a tone set by a predetermined method if there are no tones securing a specific standard; a second tone set changing step of judging that the certain communication quality can be maintained and not changing the tone set if the number of tones securing the specific standard is equal to or higher than a predetermined number, and changing the tone set by the predetermined method if the number of the tones securing the specific standard is less than the predetermined number and it is judged that the communication quality can be maintained by changing the tone set in a same tone group; and a tone group movement step of changing the tone group by a predetermined method if it is judged that the communication quality cannot be maintained even by changing the tone set in the same tone group.