Method of mapping csi-rs ports to antenna units, base station and user equipment

A communication method of mapping channel state information-reference signal (CSI-RS) ports to antenna units arranged in an antenna array system, comprising:

• selecting a group of antenna units to which the CSI-RS ports are mapped in a first CSI-RS transmission period or a first frequency resource region;
• and
• selecting another group of antenna units to which the CSI-RS ports are mapped in a second CSI-RS transmission period or a second frequency resource region.

A base station for mapping channel state information-reference signal (CSI-RS) ports to antenna units arranged in an antenna array system, comprising:

• a processor, which, in operation, selects a group of antenna units to which the CSI-RS ports are mapped in a first CSI-RS transmission period or a first frequency resource region, and selects another group of antenna units to which the CSI-RS ports are mapped in a second CSI-RS transmission period or a second frequency resource region.

A user equipment, comprising:

• a receiver, which, in operation, receives from a base station a message indicating that channel state information-reference signal (CSI-RS) ports are mapped to a group of antenna units in an antenna array in a first CSI-RS transmission period or a first frequency resource region, and the CSI-RS ports are mapped to another group of antenna units in the antenna array in a second CSI-RS transmission period or a second frequency resource region.