Bit Error Rate Reduction of Dwt Based Ofdm Systems

--In OFDM systems, Fast Fourier transform (FFT) is used for frequency translation, and recently Discrete Wavelet Transform (DWT) has replaced FFT for frequency translation. 16-QAM (Quadrature amplitude modulation) scheme has been used in the OFDM system for both DWT and FFT based models. This work presents a modified OFDM system that is based on a low complexity interleaving process which is applied after the inverse fast Fourier transform (IFFT) in order to reduce the bit error rate (BER) due to Impulsive Noise (IN). Time domain interleaving (TDI) performance has been analysed in frequency selective fading channel where the Zero Forcing (ZF) and Minimum Mean Square Error (MMSE) equalizers are employed. The TDI introduces both time and frequency diversity, which can be used to effectively combat IN. TDI has low computational complexity and BER reduction capability but maintains the spectral efficiency. DWT and Inverse DWT (IDWT) based OFDM transmitter and receiver achieves better performance in terms SNR and BER than the IFFT-FFT implementation.