3D MIMO with rank adaptation for LTE-A downlink transmission

In this paper, we investigate three-dimensional (3D) multiple-input multiple-output (MIMO) techniques with dynamic rank selection for long term evolution advanced (LTE-A) downlink cellular networks. To facilitate users to transmit different numbers of data streams, we develop a new structure for designing 3D precoding matrix (PM). Then based on the designed PM, 3D MIMO transmission with rank adaptation is proposed. The performance improvement of the proposed algorithms is demonstrated by system level simulation.