In this paper, we propose to apply adaptive loading principles to linear precoded digital multitone (LP-DMT). This new approach can especially be exploited in the powerline context, since it requires the knowledge of the channel at the transmitter. We first show that maximal waveform capacity is achieved when orthogonal matrices are used to linearly precode the multitone signal. A practical loading algorithm based on tone clustering is then developed to handle the configuration of the system. This algorithm assigns tones, size of precoding matrices, bits and energies in order to maximize the total throughput of the system. The optimization procedure is led under power spectral density (DSP) limitations and finit order modulations constraint. Through simulations over power line channels, it is shown that the new adaptive LP-DMT system takes advantage of the carrier merging effect offered by the precoding function and then outperforms the non-precoded DMT system.
