Abstract
Orthogonal frequency division multiplexing (OFDM) system has been favourably applied in various aspects of wired and wireless communication systems due to its flexibility, high spectral efficiency, efficient implementation, and robustness against the different types of interferences. In this paper, all the transformation techniques used in the OFDM system were reviewed. Major transformations used in the OFDM system such as Fourier Transform (FT), lapped transform (LT), cosine transform (CT), wavelet transform (WT), and curvelet transform (CvT) were surveyed. The computational complexity of all these transformations techniques was also addressed. The results show that the discrete wavelet transform (DWT), the complex wavelet packet transform (CWPT), and the dual-tree complex wavelet transform (DTCWT) give lower order of computational complexity compared to other types of the transformation techniques. At the same time, the discrete cosine transform (DCT) gives lower order of computational complexity compared to fast Fourier transform (FFT), modulated lapped transform (MLT), wavelet packet transform (WPT) and CvT.