  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 Kx3 multiple-input multiple-output (MIMO) X channel.
Since the proposed scheme can have a larger set of possible beamformers than
the conventional schemes, its performance is improved by the efficient
beamformer selection for a given channel. Also, we propose a condition number
(CN) based beamformer selection method with low computational complexity and
its performance improvement is numerically verified.
