Performance Evaluation of DWT-FDM and FFT-OFDM for Multicarrier Communications Systems using Time Domain Zero Forcing Equalization

Other than the conventional fast Fourier transform (FFT) for multicarrier modulation, a new approach for multicarrier modulation (MCM) has been known. Meanwhile, multicarrier modulation involves dividing the broadband channel into many orthogonal but overlapping narrowband carriers. In an OFDM modulation based multicarrier system using the FFT, a cyclic prefix (CP) is inserted after each symbol frame to combat the effects of inter symbol interference (ISI). By inserting the CP, which results in spectral inefficiency OFDM schemes trades up to 25% of the transmit bandwidth. A new MCM approach that is void of the expense is the wavelet transform-based systems. These systems also have very suppressed side-lobes and exhibit improved BER performance. In wavelet based systems, the latest challenge in its implementation is in the channel estimation. In this work we have studied the performance of the FFT based OFDM system against wavelet transform (WT) based multicarrier system using a simple zero forcing (ZF) equalization in time domain. The studied system shows some improved BER performance.