Performance of OFDM modem with alternative basis functions

Abstract

Conventional orthogonal frequency division multiplexing (OFDM) systems use discrete Fourier transform (DFT) as the basis function. Recently, it was shown that it is possible to use other sinusoidal transforms, e.g. discrete cosine transform (DCT), as OFDM basis functions. However, relative little is known regarding the performance of these alternative basis functions and how they compare with traditional DFT. This paper investigates the performance of OFDM modems employing alternative basis functions under different fading channel models in both double sideband and single sideband operation modes. A semi-analytical approach is also developed to predict and compare the error performance between different basis functions. The predicted results are close to the simulations thus verifying the simulation model. It was found that in general DFT has a better error performance, but interspersed basis is capable of offering a higher net throughout under certain channel conditions.