Multi-input Multi-output Orthogonal Frequency Division multiplexing system (MIMO-OFDM) using Wavelet Transform

Abstract

Multiple Input Multiple Outputs Orthogonal Frequency Division Multiplexing technique (MIMO-OFDM) has high performance over multipath channel environments and is used in many wireless communication applications, Combination between OFDM and multiple input multiple output (MIMO) known as (MIMO- OFDM) system. In OFDM the data is transmitted using several narrow-band orthogonal sub-carriers, traditional MIMO-OFDM system based on fast Fourier transform (FFT), this transform however has the drawbacks such as it is a high peak average to power ratio(PAPR) and FFT uses a rectangular window, which creates rather high side lobes. Moreover, the pulse shaping function used to modulate each subcarrier extends to infinity in the frequency domain this leads to high interference and lower performance levels MIMO-OFDM system based on discrete wavelet transform (DWT) has a lot of advantages compared to the FFT based OFDM there is no need for cyclic prefix so that higher data rates can be possible achieved , OFDM-DWT is almost suitable in most of the arenas of wireless communication and next generation of wireless communication. the simulation model has been created to examine the performance of proposed system compared to traditional system using different type of modulation scheme (BPSK,QPSK,16QAM,64QAM) in additive white Gaussian noise channel (AWGN) environment. The PAPR, BER and the capacity has been used as performance metric parameters in order to compare between the conventional OFDM and that based on the DWT. Simulation shows that the use of OFDM- DWT based outperforms the use of OFDM-FFT based in term of PAPR, BER and capacity.