Low complexity precoded OFDM system

In this work, a new low complexity linear precoded orthogonal frequency division multiplexing (LP-OFDM) system, called Haar-OFDM (H-OFDM), is proposed. The proposed system employs a fast precoder, denoted as inverse D-precoder (IDP), which is derived by merging the operations of the fast Haar precoder (FHP) and inverse fast Fourier transform (IFFT) as one transform. Interestingly, the number of arithmetic operations required by the H-OFDM system are noticeably smaller than the conventional OFDM. Furthermore, extensive simulation results demonstrate that the H-OFDM system is robust against the frequency-selectivity of the channel.