Perfect discrete multitone modulation with optimal transceivers

Recently, discrete Fourier transform (DFT)-based discrete multitone modulat ion (DMT) systems have been widely applied to various applications. In this paper, we study a broader class of DMT systems using more general unitary matrices instead of DFT matrices. For this class, we will show how to desig n the optimal DMT systems over frequency-selective channels with colored no ise. In addition, asymptotical performance of DFT-based and optimal DMT sys tems will be studied and shown to be equivalent, However, for a moderate nu mber of bands, the optimal DMT system offers significant gain over the DFT- based DMT system, as will be demonstrated by examples.