Spatial domain method based on 2D-DoA estimation against pilot contamination for multi-cell massive MIMO systems

This paper deals with the pilot contamination problem for multi-cell massive multiple-input and multiple-output (MIMO) mobile communication systems. The pilot contamination effect constitutes a major bottleneck for overall performance. Most of researches on pilot decontamination ignore the fact that different users can be distinguished by the direction of arrivals (DoA), even the users in different cells use the same pilots. We propose a spatial domain method based on two dimensions DoA (2D-DoA) which can distinguish the target user in 3D space. To obtain the desire signal´s DoA, two type of 2D-DoA estimation methods are proposed. Utilizing the estimations to preprocess the received signals the interference can be suppressed effectively. Simulation results show the pilot contamination can be reduced obviously and the system performance can be improved significantly by the proposed method.