Signal detection for MIMO-OFDM wireless communications

In this paper, orthogonal frequency division multiplexing (OFDM) for MIMO channels (MIMO-OFDM) is considered for wideband transmission to mitigate intersymbol interference and enhance system capacity. The MIMO-OFDM system uses two independent space-time codes for two sets of two transmit antennas. At the receiver, the independent space-time codes are decoded using pre-whitening followed by maximum-likelihood (ML) decoding or ML decoding based on successive interference cancellation. Computer simulation shows that for 4-input and 4-output systems transmitting data at 4 Mbits/sec over a 1.25 MHz channel, the required SNRs for a 10% and 1% WER are 10.5 dB and 13.8 dB, respectively, when each codeword contains 500 information bits and the channel's Doppler frequency is 40 Hz.