Interference Alignment Schemes Using Latin Square for K <inline-formula> <tex-math notation="LaTeX">$\times$ </tex-math> </inline-formula> 3 MIMO X Channel

Abstract

In this paper, we study an interference alignment (IA) scheme with finite time extension and beamformer selection method with low computational complexity for X channel. An IA scheme with a chain structure by the Latin square is proposed for K × 3 multiple-input multiple-output X channel. Since the proposed scheme can have a larger set of possible beamformers than the conventional schemes, its performance is improved by efficient beamformer selection for a given channel realization. Also, we propose a condition number-based beamformer selection method with low computational complexity and its performance improvement is numerically verified.INDEX TERMS Beamforming, degrees of freedom (DoF), interference alignment (IA), latin square, multiple-input multiple-output (MIMO), X channel.