Performance Analysis of QAM-Modulation on FFT-OFDM, DCTOFDM,and DWT-OFDM in AWGN Channel

Discrete wavelet transform-OFDM (DWT-OFDM) is a new multicarrier modulation (MCM) technique and a promising alternative to the OFDM. DWT-OFDM dose not need to adding cyclic prefix (CP). This, saves bandwidth and increases spectral efficiency. In this paper bit error rate (BER) performance of Fast Fourier Transform OFDM (FFT-OFDM) compared with Discrete Cosin Transform OFDM (DCTOFDM) and Discrete Wavelet Transform OFDM (DWTOFDM) in AWGN channel. We compare the performance of QAM modulation and different wavelets such as Haar, Sym4 and Bior1.3. We found about 4 db improvment in DWT-OFDM compare with FFT-OFDM and DCT-OFDM.