Intra-cell performance aware uplink opportunistic interference alignment

In this paper, we consider a K-cell multi-user interference network, where S single-antenna users are selected within each cell to carry out the uplink transmission with their M-antenna home base station, where 2 ≤ S ≤ M <; KS. For the considered scenario, a novel intra-cell performance aware opportunistic interference alignment (OIA) scheme is proposed to mitigate the inter-cell interference while reducing the intra-cell power loss caused by zero-forcing receiving. Unlike the traditional OIA schemes, the proposed scheme reuses the reference signal subspace (RSS) to balance not only the inter-cell interference but also the desired signal power and the intra-cell power leakage. It is shown that the refined selection further improves the achievable sum rate as compared to the existing schemes, and this observation is theoretically analyzed. Finally, numerical results validate that our scheme outperforms the existing uplink OIA schemes.