Linear precoder designs for interference alignment in constant MIMO interference channels

In this paper, interference alignment (IA) achieved from one side is considered in the K-user constant multiple-input multiple-output (MIMO) interference channel (IC). Different from most existing algorithms which need alternating between the transmitter and receiver, our algorithm runs at transmitters only, thereby avoiding vast information exchanged between the transmitter and receiver. The essential aim of IA is overlapping the interference subspaces and maximizing the dimensionality of interference-free subspaces reserved for the desired signals. Based on this, we design the precoders by the steepest descent algorithm at transmitters only to minimize the spatial distance between different interference subspaces. Different interference subspaces are overlapping when the spatial distance between them is small enough. The simulation results illustrate that compared with existing alternating algorithm, the performance of the proposed one-sided algorithm does not degrade in a proper system, moreover, in a improper system, the proposed algorithm achieves better performance. Furthermore, compared with “Least Squares” and “One-sided Algorithm” which are existing one-sided approaches for IA, the proposed algorithm is more robust dealing with different systems.