DFT based transceivers with-windowing

Abstract

In this paper we consider window designs for DFT (discrete Fourier transform) based multicarrier transceivers without using extra cyclic prefix. As in previous works of window designs for DFT based transceiver, a post processing matrix, generally channel dependent, is needed to have a zero-forcing receiver. We show that post processing is channel independent if and only if the window itself has the cyclic-prefixed property. We design optimal windows with minimum spectral leakage subject to the cyclic-prefixed condition. Moreover, we analyze how post processing affects SNR (signal to noise ratio) at the receiver, an aspect that is not considered in most of the earlier works. The resulting SNR can be given in a closed form. Join optimization of spectral leakage and SNR are also considered. Furthermore, examples demonstrate that we can have a significant reduction in spectral leakage at the cost of a small SNR penalty.