A novel space-time-frequency coded system design for OFDM over fast fading channels

The paper is concerned with a transmitter diversity technique for wireless communications over frequency selective fading channels. The proposed technique utilizes orthogonal frequency division multiplexing (OFDM) to transform a frequency selective fading channel into multiple flat fading subchannels on which space-frequency processing is first applied and then additional space-time coding is applied in order to increase the diversity. In order to improve the performance of the system, a convenient trellis coding scheme is investigated and design criteria are established. Performance of the proposed space-time-frequency OFDM (STF-OFDM) transmitter diversity technique has been examined by computer simulations and compared with existing schemes.