正交轉換用於OFDM傳輸系統之研究

Abstract

The research and development of orthogonal frequency division multiplexing (OFDM) system has already been more than 30 years. Also, using discrete Fourier transform (DFT) to implement multicarrier modulation (MCM) has been proposed.In this thesis, OFDM systems based on several orthogonal transforms are studied. DFT-, discrete Hartley transform (DHT)-, wavelet packet transform (WPT)-, and cosine-modulated filter bank (CMFB)-based OFDM systems are compared in some digital communication channels. From these comparisons, DFT-based OFDM system has the advantages in easy implementation of equalizers and better immunity of frequency offset effect. It is the best choice among these orthogonal transforms for implementation of an OFDM system.