Time-domain signal detection based on second-order statistics for MEMO-OFDM systems

In this paper, a time-domain signal detection algorithm based on second-order statistics (SOS) is proposed for multiple input-multiple output (MIMO)-orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channels. A new system model in which the ith received OFDM block is left shifted by J samples is introduced. Based on some structural properties of the new system model, an equalizer is designed using SOS of the received signals to cancel most of the intersymbol interference. The transmitted signals are then detected from the equalizer output. In the proposed algorithm, only 2P (P is the number of transmit antennas/users in MIMO-OFDM systems) columns of the channel matrix need to be estimated, and channel length estimation is unnecessary, which is an advantage over existing algorithms. In addition, the proposed algorithm is applicable irrespective of whether the channel length is shorter than, equal to or longer than the cyclic prefix (CP) length. Simulation results verify the effectiveness of the proposed algorithm, and show that it outperforms the existing ones in all cases.