Realization of Carrier Interferometry OFDM Systems by Wavelet Transform

Nowadays, orthogonal frequency division multiplexing (OFDM) is attracting a great deal of attention. However, the many advantages responsible for the widespread application of OFDM systems are limited by multipath fading. To enhance the performance of OFDM, many models utilize channel coding. Recent studies have focused on carrier interferometry coding for OFDM. In this paper, we present a novel design of carrier interferometry (CI) spreading codes by using a wavelet transform instead of a fast Fourier transform (FFT) which is widely used for realizing carrier interferometry in OFDM systems. The performance of the proposed technique is simulated over Rayleigh fading and Rician fading channels. In the simulations, the performances of OFDM, FFT-based CI/OFDM, and wavelet transform-based CI/OFDM over multipath channels are compared. The simulation results show that the wavelet-based CI codes are more robust at SNR larger than approximately 10 dB over the Rician fading and 7 dB over the Rayleigh fading channels.