Low-Complexity Detection Exploiting Subcarrier Correlation in Multi-Layer STBC OFDM

We propose a multi-layer space-time block coded orthogonal frequency division multiplexing (multi-layer STBC OFDM) scheme. It combines the spatial diversity and spatial multiplexing in order to exploit the benefits of both techniques. The transmit antennas are divided into several layers and each layer is encoded by STBC. The antennas transmit OFDM signals in order to deal with frequency-selective fading channels. In addition to exhaustive detection scheme which applies the same detection at each subcarrier independently, we exploit the subcarrier correlation to develop a subcarrier-grouping based detection scheme (SGD scheme). The subcarriers bound into the same group share the same detection parameters, e.g., layer detection order which is obtained at the center subcarrier of that group. This feature can significantly reduce the detection complexity with very small performance loss. The simulation results show that compared with exhaustive detection scheme, the proposed SGD scheme is capable of reducing 36.13% complexity with less than 1.0 dB performance loss for 4times4 system, and reducing 52.44% complexity with about 1.3 dB performance loss for 6times6 system, respectively