Filter banks for cyclic-prefixing the nonuniform DMT system

Abstract

The cyclic prefix system is used in discrete multitone channels for frequency domain equalization and is based on the inversion of samples of the channel frequency response at uniformly spaced points (DFT coefficients). In this paper, we consider nonuniformly spaced samples of the channel frequency response, especially octave-spaced. The anticipated advantage is that for channels with rapidly decaying frequency responses, there are relatively fewer equalizer coefficients with unduly large values, and helps to reduce amplification of channel noise at the receiver. We show how to combine a wavelet-like filter bank with traditional DFTs to achieve this goal. While the idea appears to be exciting and opens up interesting problems, its merits still remain to be evaluated.

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