Space-time coded MIMO-OFDM for high capacity and high data-rate wireless communication over frequency selective fading channels

This paper presents a space-time block coded multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) scheme over frequency selective fading channels. The system provides spectrally efficient transmissions to increase system capacity or system throughput for individual users. The proposed technique utilizes OFDM to transform frequency selective fading channels into multiple flat fading sub channels on which space-time block coding is applied. We consider a multi-user environment with K synchronous cochannel users, each equipped with n transmit antennas. The receiver is equipped with m(≥K) receive antennas. At the receiver, signals from K users are decoded using minimum mean squared error (MMSE) interference cancellation followed by maximum likelihood (ML) decoding. It is shown that the proposed scheme, with two cochannel terminals, doubles the data rate while maintaining the frame error rate (FER) performance as a single user scheme with some additional decoding complexity.