Method and apparatus for channel state information reference signal (CSI-RS)

A base station (BS) comprising:

• a processor configured to:
• generate configuration information to configure a user equipment (UE) with channel state information reference signal (CSI-RS) resource;
• and
• a transceiver operably connected to the processor, the transceiver configured to:
• transmit, to the UE, the CSI-RS resource configuration information, uplink-related downlink control information (DCI), and a CSI-RS associated with a selected CSI-RS resource in a same subframe as the uplink-related DCI;
• and
• receive, from the UE, an aperiodic CSI reporting on an uplink channel;
• wherein the aperiodic CSI reporting is determined in response to a CSI request included in the uplink-related DCI and in reference to the CSI-RS;
• wherein the CSI-RS resource configuration information is transmitted via higher-layer signaling and includes K CSI-RS resources where K is larger than one;
• and
• wherein N out of the K CSI-RS resources are selected for activation and the selection of the N out of the K CSI-RS resources is signaled as a part of a medium access control (MAC) control element (CE).

A method for operating a user equipment (UE), the method comprising:

• receiving, by the UE, information indicating a channel state information reference signal (CSI-RS) resource configuration, uplink-related downlink control information (DCI), and a CSI-RS associated with a selected CSI-RS resource in a same subframe as the uplink-related DCI;
• in response to receipt of a CSI request included in the uplink-related DCI, determining, by the UE, an aperiodic CSI in reference to the CSI-RS;
• reporting the aperiodic CSI by transmitting the aperiodic CSI on an uplink channel;
• and
• wherein the information indicating the CSI-RS resource configuration is received via higher-layer signaling and includes K CSI-RS resources where K is larger than one;
• and
• wherein N out of the K CSI-RS resources are selected for activation and the selection of the N out of the K CSI-RS resources is signaled as a part of a medium access control (MAC) control element (CE).