Patent ID: 8238474

Claim:
A communication apparatus to implement a process of two-directional communication of data over a transmission line, the communication employing a bandwidth partitioned into a number of bands and including at least one band associated with each of the two directions, the apparatus including: a signal generation section for generating a signal by encoding the data carried in each direction by modulation of a plurality of tones defined within the at least one band associated with that direction, the tones being grouped into a plurality of groups of tones, each group of tones including a plurality of the tones, the signal generation section including: an input section for receiving data; an encoder for Trellis encoding together a portion of the data to be encoded by modulation of that group of tones; and a modulator for modulating the tones of the group using the respective portion of Trellis encoded data; a signal transmission section for transmitting the generated signal, wherein each of the plurality of groups include tones from multiple bands; a quality determination unit for deriving a measure of a quality of transmission of each of the tones; and a processor for determining for each group of tones, in dependence on said measure of the quality of the transmission for each of the tones of the group, a scheme for modulating the tones of the group to encode a respective portion of data associated with the group of tones, and for controlling the modulator in accordance with the determined modulation scheme.