Improved and Opportunistic Interference Alignment Schemes for Multi-Cell Interference Channels

We study precoder optimization gains and multiuser diversity gains with interference alignment in a two-cell wireless network. In this paper, we propose algorithms to improve the achievable sum rate by optimizing alignment directions. The proposed iterative algorithm can provide a substantial gain in the achievable rate while it requires only a few iterations. In addition, we investigate interference alignment to exploit multiuser diversity gains. A new criterion of user selection scheduling is proposed. This user selection can be done independently in different cells. Therefore, both the searching space and the information exchanged between base stations are significantly reduced compared to joint user scheduling over two cells.