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 0.8 dB performance degradation for 6 × 6 system, and reducing 60.7% complexity with about 1.0 dB performance degradation for 8 × 8 system, respectively.