An approach of pilot contamination reduction based on power control and orthogonal identification

Massive multiple input multiple output (MIMO) cellular cells with small radius can satisfy the communication requirements where communication traffic is high. Since the radius of the cell is small, the large-scale fading interference of the second-circle cells outside the central cell still exists. However, it is not realistic that the traditional pilot power control method ignores the interference from the second-circle cells outside the central cell. In fact there is still a large pilot contamination problem. To solve the problem of pilot contamination in the traditional pilot power control method, this paper combines the uplink pilot power control and the orthogonal cell identification. All cells are classified by pilot power control, the cells of each class are grouped again by assigning orthogonal cell identification and the corresponding identifications are added to the head of pilot sequence which is transmitted by the mobile terminals of the local cell. Making sure that the BS identifies the pilots from different groups of cells. The experimental results show that the method of this paper is not only simple, but also can reduce the pilot contamination in multi-cell system effectively.