Low-Complexity Detection by Exploiting Suboptimal Detection Order and Subcarrier Grouping for Multi-Layer MIMO-OFDM

By combining the transmit diversity and space multiplexing, the multi-layer multiple-input multiple-output orthogonal frequency division multiplexing (multi-layer MIMO-OFDM) system can exploit the potentials of both techniques. The transmit antennas are divided into several layers and each layer is encoded by a certain multi-antenna coding. The antennas transmit OFDM signals in order to deal with frequency-selective fading. In addition to exhaustive detection which applies the same detection at each subcarrier independently, we exploit the subcarrier correlation to develop a subcarrier-grouping based low-complexity detection scheme. The subcarriers bound into the same group share the same layer detection order which is obtained by the post-nulling signal power comparison at the center subcarrier of that group. The simulation results show that compared with exhaustive detection, the proposed low-complexity detection scheme is capable of reducing 50.7% complexity with only 0.8dB performance degradation for 6x6 system, and reducing 60.7% complexity with about 1.0dB performance degradation for 8x8 system, respectively.