Narrow Results

A new interspersed orthogonal frequency division multiplexing (OFDM) based on Hadamard coded Discrete Harmonic wavelet transform (DHWT), is proposed for complex modulation under exponential channel model. In this method, real part of complex signal is transformed by DCHWT and imaginary part by DSHWT and summed to form interspersed harmonic wavelet based OFDM (IHWT OFDM). DHWT exploits the useful properties of DCT and DST viz., energy compaction/low leakage, frequency resolution and its real nature, compared to DFT. This wavelet is simple as it has reduced processing due to its harmonic wavelet nature. The harmonic nature has built in decimation, easy interpolation by concatenation of different scales in frequency (DCT and DST) domain without associated anti-aliasing filters for analysis, image rejection filters and complicated delay compensation for synthesis. In this work, we have explored advantages of DHWT to implement IHWP-OFDM for QPSK modulated signals. Hadamard codes are employed in proposed method to further improve BER and PAPR performance. New OFDM provides PAPR reduction of 2.6, 3.8 and 1.4 dB as compared to Haar, Daubechies WT OFDM and DFT, respectively.