Combining unitary space-time codes and blind interference alignment for two-user heterogeneous X channel

In this paper, we present a combining transmission scheme of unitary space-time codes(USTC) and blind interference alignment(BIA) over two-user heterogeneous X Channel where one of two transmitters undergoes time-selective fading channel and another one undergoes frequency-selective fading channel. Even if neither the transmitters nor the receivers know the channel state information, the receivers can effectively implement the interference alignment and decoding. Using the constellation design based on Discrete Fourier Transformation(DFT), when the number of signal constellations is larger than or equals to 16, the data rate of our proposed scheme is comparable under the action of interference alignment. Our simulation result shows that, compared with USTC without BIA, the proposed scheme has higher diversity gain and lower error rate in high SNR region.