Block transform OFDM: A robust power and bandwidth efficient system with improved frequency diversity performance

Block transform orthogonal frequency division multiplexing (BT-OFDM) — a system sitting in-between two extreme data transmission schemes, i.e., the conventional OFDM system and the single-carrier system, with a balanced system performance is proposed in this paper. Through data symbol grouping and block transformation, the BT-OFDM uses reduced size inverse fast Fourier transform to take the advantages of the single-carrier system to overcome the disadvantages of the conventional OFDM system. Frequency domain representation of the BT-OFDM signal reveals that the block transformation implicitly realizes a precoding or block spreading of the transmitted data symbols. When suitable IFFT size is selected, the BT-OFDM also offers the lowest overall system complexity.