Proposed realization of modified FRAT based OFDM transceivers

The rapid expansion in digital Wireless communications results in a demand for systems that are reliable and have a high spectral efficiency. To fulfill these demands, the multicarrier modulation scheme, often called Orthogonal Frequency Division Multiplexing (OFDM), has drawn a lot of attention in mobile radio communications. The Finite Radon transform (FRAT) was chosen in the OFDM structure to serve as a data mapper instead of the conventional data mapping techniques like QPSK and QAM schemes. The Fourier domain approach was found to be the more suitable way for obtaining the forward and inverse FRAT. This structure has result in a more suitable realization of FFT-based OFDM. It was shown that it increased the orthogonality significantly due to the use of IFFT twice, in the data mapping and in the sub-carrier modulation. As a result, a modification has been performed in this Work by replacing (ID and 2D-FFT) by (ID and 2D-Discrete Wavelet Transform (DWT)) in FRAT and IFRAT. The proposed structure with OFDM gave a significant improvement in the BER performance in comparison with the conventional OFDM when tested for different channel types. The modified OFDM is more secure than conventional OFDM structure.