Quasi co-location assumptions for aperiodic channel state information reference signal triggers

A method for wireless communications by a base station (BS), comprising:

• determining a quasi-co-location (QCL) relationship of an aperiodic channel state information (CSI) reference signal (CSI-RS) to a physical channel, wherein:
• the determination of the QCL relationship is based on:
• an offset parameter related to the aperiodic CSI-RS and a downlink control information (DCI) scheduling the aperiodic CSI-RS, and
• a threshold value of a time for a user equipment (UE) to switch between receive beams, and
• determining the QCL relationship comprises determining to use a QCL relationship of a physical downlink control channel (PDCCH) of a control resource set (CORESET) having a lowest identifier (CORESET-ID), when the offset parameter is lower than the threshold value;
• and
• transmitting, to the UE, the aperiodic CSI-RS according to the determined QCL relationship.

An apparatus for wireless communications by a user equipment (UE), comprising:

• a memory;
• and
• at least one processor coupled to the memory, the memory and the at least one processor configured to:
• determine a quasi-co-location (QCL) relationship of an aperiodic channel state information (CSI) reference signal (CSI-RS) to a physical channel, wherein:
• the determination of the QCL relationship is based on:
• an offset parameter related to the aperiodic CSI-RS and a downlink control information (DCI) scheduling the aperiodic CSI-RS, and
• a threshold value of a time for the UE to switch between receive beams, and
• the memory and the at least one processor are further configured to determine the QCL relationship by determining to use a QCL relationship of a physical downlink control channel (PDCCH) of a control resource set (CORESET) having a lowest identifier (CORESET-ID), when the offset parameter is lower than the threshold value;
• and
• process the aperiodic CSI-RS according to the determined QCL relationship.

An apparatus for wireless communications by a base station (BS), comprising:

• a memory;
• and
• at least one processor coupled to the memory, the memory and the at least one processor configured to:
• determine a quasi-co-location (QCL) relationship of an aperiodic channel state information (CSI) reference signal (CSI-RS) to a physical channel, wherein:
• the determination of the QCL relationship is based on:
• an offset parameter related to the aperiodic CSI-RS and a downlink control information (DCI) scheduling the aperiodic CSI-RS, and
• a threshold value of a time for a user equipment (UE) to switch between receive beams, and
• the memory and the at least one processor are further configured to determine the QCL relationship by determining to use a QCL relationship of a physical downlink control channel (PDCCH) of a control resource set (CORESET) having a lowest identifier (CORESET-ID), when the offset parameter is lower than the threshold value;
• and
• transmit, to the UE, the aperiodic CSI-RS according to the determined QCL relationship.