Wavelet based OFDM for wireless channels

The main objective of this paper is to replace the conventional Fourier based complex exponential carriers of the OFDM system with some orthonormal wavelets in order to reduce the level of interference. The wavelets are derived from multistage tree-structured Haar and Daubechies orthonormal quadrature mirror filter (QMF) bank. Compared with the conventional OFDM, it is found that the Haar and Daubechies-based orthonormal wavelets are capable of reducing the power of intersymbol interference (ISI) and intercarrier interference (ICI), which are caused by the loss in orthogonality between the carriers as a result of the multipath wireless channel.