Optimum design of overlapping discrete multitone filter banks for digital subscriber line channels

A new approach to the design of optimum transmultiplexer filter banks for overlapping discrete multitone (ODMT) multicarrier modulation is presented. ODMT has been proposed for use in high-speed data communications over twisted pair copper wires such as digital subscriber lines (DSL), due to its ability to cope well with channel degradations and noise. We propose a new design technique which minimizes the overall interference. We consider the effect of the time domain overlap between successive symbol waveforms by considering each modulation filter as a series of filter components in time. We explicitly incorporate some knowledge of the digital subscriber line channel into our design technique, to account for the effects of time dispersion and frequency distortion. Numerical simulations show that the optimisation of the components in the mixed time-frequency domain leads to an increase in the signal-to-interference ratio of the order of 0.2-0.3 dB