Triggering of aperiodic channel state information reference signals with mixed numerology

A user equipment (UE) for receiving an aperiodic channel state information reference signal (CSI-RS) on a first carrier, where the first carrier uses a first orthogonal frequency division multiplexing (OFDM) numerology, the UE comprising:

• an antenna configured to send and receive wireless signals;
• radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry;
• the processing circuitry being configured to perform operations comprising:
• receiving a downlink control information (DCI) message carried by a Physical Downlink Control Channel (PDCCH) on a second carrier, wherein the second carrier uses a second OFDM numerology;
• obtaining an aperiodic CSI-RS slot offset from the DCI message;
• determining, on the first carrier, a reference slot in the first numerology;
• determining the slot of the aperiodic CSI-RS based on the reference slot and the aperiodic CSI-RS slot offset;
• and
• receiving the aperiodic CSI-RS in the determined slot of the aperiodic CSI-RS or transmitting an associated CSI-RS report in the determined slot;
• and
• a battery connected to the processing circuitry and configured to supply power to the UE.

A communication system comprising:

• processing circuitry configured to provide user data;
• and
• a communication interface configured to forward the user data to a cellular network for transmission to a user equipment (UE),
• wherein the cellular network comprises at least a first base station and a second base station, the first and second base stations having radio interfaces and processing circuitry, wherein the first base station transmits via a first carrier and the second base station transmits via a second carrier the processing circuitry being configured to:
• transmit a downlink control information (DCI) message carried by a Physical Downlink Control Channel (PDCCH) on the first carrier, wherein the DCI message includes an aperiodic CSI-RS slot offset;
• transmitting the aperiodic CSI-RS in the determined slot of the aperiodic CSI-RS on the second carrier according to an aperiodic CSI-RS slot offset.