Performance Analysis Comparison of FFT and Discrete Wavelet Packet Transform (DWPT) Based MIMO-OFDM Systems

Multiple Input Multiple output (MIMO) antennas can be combined with orthogonal frequency division multiplexing (OFDM) to ensure spatial diversity gain and/or to increase spectral efficiency. MIMO communication system with Alamouti methods can improve the bit error rate (BER) and signal to noise ratio (SNR) thus distortions are reduced for higher data rate. Conventionally OFDM is Fast Fourier Transform (FFT) based system, it uses IFFT (Inverse FFT) blocks in the transmitter and FFT blocks in the receiver. Replacing the FFT with Discrete Wavelet Packet Transform (DWPT) makes the system’s performance further improved. This leads to a new scenario of DWPT based MIMO OFDM system. In this work, the STBC-MIMO-OFDM under the scenario of having multiple antennas system, with QAM in Rayleigh fading channel for different values of Quadrature Amplitude Modulation (QAM) points (8, 32 and 64) are implemented. By evaluating the BER performance and the transmission capacity, it turns out that the DWPT based MIMO-OFDM system is superior compared with the FFTMIMO-OFDM system. BER performance of the system is analyzed under different channel environments to assess the WPT based MIMO-OFDM performance in order to compare it with FFT based MIMO-OFDM system. .In this paper the numerical results of the simulation consist a new contribution and are obtained using MATLAB. The simulation of DWPT-OFDM was accomplished with Haar mother based multicarrier. Whereas for both the latter and the conventional FFT-OFDM were subjected to the same conditions, for the multi-antenna system channel capacity and QAM modulation (8, 32, and 64) points in flat fading channels with AWGN and selective fading channel with AWGN. Computer simulation results demonstrate that the proposed wavelet based MIMOOFDM system outperforms in Alamouti (two transmit antenna and two receive antenna) due to the overlapping nature of DWPT dispensing the addition of cyclic prefix and less hardware complexity as in FFT based MIMOOFDM. Key-Words: DWPT, FFT, OFDM, MIMO, Alamouti STBC. Performance Analysis Comparison of FFT and Discrete Wavelet Packet Transform (DWPT) Based MIMO-OFDM Systems SOUKAINA ETTARFAOUI HAITHAM JABBAR TAHA MOHAMMED MAJID HIMMI LIMIARF, Faculty of Sciences Department of Electrical Engineering LIMIARF, Faculty of Sciences Mohammed-V University University of Technology Mohammed-V University Rabat, Morocco Baghdad/ Iraq Rabat, Morocco [email protected] [email protected] [email protected] WSEAS TRANSACTIONS on COMMUNICATIONS Soukaina Ettarfaoui, Haitham Jabbar Taha, Mohammed Majid Himmi E-ISSN: 2224-2864 267 Volume 14, 2015