OFDM Based New Transform with BER Performance Improvement across Multipath Transmission

This paper introduces a new multicarrier system that uses a low computational complexity transform developed by Boussakta to combine the Walsh-Hadamard Transform (WHT) and Discrete Fourier Transform (DFT) into a single orthogonal transform or as a transition from one transform domain to another. The proposed transform is used in a new orthogonal frequency division multiplexing (T-OFDM) system, across fixed and mobile multipath channel models. Use of the proposed transform with OFDM has been found to achieve high diversity gain by spreading each subcarrier with all the others. Consequently, severe distortion arising from channel fading on the subcarrier power is minimised. Simulation results confirm that the proposed T-OFDM system outperforms the conventional OFDM system when utilizing the minimum mean square error (MMSE) equalizer. The main, merits of such a transform are low computational complexity, no bandwidth expansion, the same average transmitted power, and a high ability to mitigate the influence of multipath channel dispersion.