Performance of Discrete Wavelet Transform based on OFDM and Adaptive Modulation

In the mobile environments, the channel will be highly hostile at high data rate transmission. To combat with this problem, many designs were proposed and developed, such as, Orthogonal Frequency Division Multiplexing (OFDM) system. Adaptive modulation improves the system efficiency by matching transmission parameters to channel variations, so that, OFDM system with Adaptive modulation technique will be achieved an efficient bandwidth transmission technique in wireless fading environments. In this paper, Discrete Wavelet Transform (DWT) is used in OFDM system and illustrates the improvement of Bit Error Rate (BER) and throughput performances compared with used Discrete Fourier Transform (DFT). DWT with Zero Padding (DWT-ZP) is also used as addition technique which supports high performances for the system, all tested in frequency selective fading channel. The obtained results show that a significant improvements in BER and throughput can be achieved demonstrating the superiority of use DWT compared with use traditional DFT in Adaptive OFDM system.