A non-iterative solution to implement interference alignment and cancellation scheme for the three-user MIMO X-channel model

In this paper, we propose a closed-form interference alignment and cancellation scheme for the three-user multiple-input multiple-output (MIMO) X-channel network without symbol extension. We first demonstrate the basic principle of how to design the beamforming matrices for this set-up, then we estimate the sum rate achievable under perfect and imperfect channel state information. It is shown that this scheme can achieve over 64 bits/s/Hz. We also derive its computational complexity.