Design of wavelet filters for DWMT systems

The paper is concerned with the design of wavelet filters for discrete wavelet multitone (DWMT) systems. DWMT systems suffer from the two main problems of inter-symbol interference (ISI) and inter-carrier interference (ICI). ISI may be considerably reduced via channel equalization. The effect of ICI can be reduced using high order filters, but at the expense of increased system complexity. The analysis presented in the work have showed that the required wavelet filters to reduce the ICI should have autocorrelation function approaching an impulse. The resulting filters are orthogonal and consisting of only two nonzero components for any filter order. These filters are compared to Daubechies and Coiflets filters. The comparisons showed that when the designed filters are employed by a DWMT system, then it is much simpler and a much less number of interfering terms will appear at detection. Therefore, the designed filters seem to be more suitable to be used in DWMT systems compared to other types of wavelet filters.