Abstract:

Massive multiple-input multiple-output (MIMO) is a potential technology to improve spectrum efficiency and energy efficiency, and deemed to be a key technology for the next generation of wireless communication. As the active antenna system (AAS) technology develops, the base station equipped with twodimensional (2D) antenna array can control the beams in the three-dimensional (3D) space,which makes 3D MIMO become a research hotspot. In the downlink single-user MIMO (SU-MIMO) system, two limited feedback schemes based on rank adaptation for 3D MIMO are proposed. Scheme I adopts rank adaptation in the horizontal domain and supports rank 1 in the vertical domain. On the contrary, scheme II adopts rank adaptation in the vertical domain and supports rank 1 in the horizontal domain. System-level simulations are conducted to test the performance of the two schemes under the 3D-urban macro (3D-UMa) and 3D-urban micro (3D-UMi) scenarios. Simulation results reveal that, compared with the scheme which only supports rank 1 in both horizontal and vertical domains, the two schemes achieve performance gain. Also, scheme I outperforms scheme II.