Performance Comparison of DWT Based MIMO OFDM and FFT Based MIMO OFDM

Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) are two combined technologies to provide the spectral efficiency and high data rate required for 4G wireless systems. Discrete Wavelet Transform (DWT) is presented as an alternative for the Fast Fourier Transform FFT since there is no necessity for Cyclic Prefix (CP) due to the overlapping properties of DWT. By a simple replacement of the FFT with DWT in MIMO OFDM system, an improvement of performances has been detected which leads to a new system scenario DWT based MIMO OFDM. In this paper, such a system is simulated and the performance Bit Error Rate (BER) is analyzed to determine the different types of wavelets in various channel conditions with different modulations (QAM 4, 16, 64) and conventional symbol detection techniques such as zero forcing (ZF), minimum mean square error (MMSE) and maximum likelihood (ML).