Patent ID: 11894925
Assignee: NTT DOCOMO, INC.
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 3:
4. A base station comprising:
a transmitter that transmits configuration information using radio resource control (RRC) signaling, an aperiodic Channel State Information Reference Signal (CSI-RS) to be used for a terminal group comprising a plurality of terminals which is grouped in a cell, and a trigger signal using a downlink control information (DCI) field which indicates the CSI-RS; and
a processor that controls to transmit the DCI field as the trigger signal which indicates the CSI-RS in a frequency domain in a bandwidth that is the same as a bandwidth for a time and frequency resource that is used for data transmission to a terminal of the terminal group,
wherein if the terminal receives the trigger signal then the terminal, based on the configuration information and the trigger signal, specifies a time and frequency resource for the aperiodic CSI-RS from a plurality of time and frequency resources, and
the terminal performs rate matching related to the specified time and frequency resource based on the trigger signal, and
wherein if the terminal does not receive the trigger signal and the terminal receives the configuration information, the terminal determines not to use the aperiodic CSI-RS.