Low complexity implementation of Alamouti space-time coded OFDM transmitters

Space-time and space-frequency coded orthogonal frequency division multiplexing systems employing the Alamouti scheme were proposed by Lee and Williams. Straightforward implementation of these systems requires separate inverse discrete Fourier transform (IDFT) processing blocks for each of the two transmit antennas. In this letter, DFT/IDFT symmetry properties are utilized to approximately halve the computational load of these systems at the transmitter.