A novel interference alignment scheme for two-cell MIMO downlink channels

In this work, we propose a novel interference alignment (IA) scheme for two-cell MIMO downlink channels. With this scheme the interference will be aligned to the same directions with the desired signals when the transmitters are sending out the same symbols, otherwise, the interference will be aligned to the orthogonal directions of the desired signals as the traditional IA scheme does. As a result, it outperforms the traditional IA schemes in terms of capacity and mutual information, which is verified by simulation results. Numerical results also show that the mutual information improvement will decrease as the modulation level goes high.