QUALCOMM Incorporated
Hybrid class B FD-MIMO

Abstract:

A hybrid class B channel state information (CSI) reference signal (CSI-RS) scheme is discussed which configures one cell-common beamformed CSI-RS resource for beam tracking and another UE-specific beamformed CSI-RS resource for CSI feedback. The cell-common beamformed CSI-RS resource may be transmitted at a longer periodicity and shared by user equipments (UEs) in the cell. The beamforming may be cycled over a set of predefined weights transparent to UE. The UE-specific beamformed CSI-RS may be transmitted at a shorter periodicity and can be activated dynamically to allow resource sharing among multiple UEs. The UEs will report a CSI for the cell-common beamformed CSI-RS resource which provides a quality indicator for the associated cell-common beam and is utilized by the base station to determine the precoding weight for the UE-specific beamformed CSI-RS resource. Both resources can be configured with different parameter sets, such as number of ports, codebook type, and CSI reporting parameters.