Method and apparatus for handling multiple numerologies in wireless communication system

A user equipment (UE) in a wireless communication system, the UE comprising:

• a memory;
• a transceiver;
• and
• a processor, operatively coupled to the memory and the transceiver, that:
• configures at least one data subband set within a carrier;
• and
• communicates with a base station using the at least one data subband set,
• wherein each of the at least one data subband set comprises at least one data subband, and wherein a maximum number of the at least one data subband is 4 and only one data subband among the at least one data subband is an active data subband,
• wherein each of the at least one data subband comprises a set of consecutive physical resource blocks (PRBs),
• wherein each of the at least one data subband set is configured per numerology,
• wherein based on at least two data subband sets and based on overlapping data subbands belonging to different overlapping data subband sets, the UE transmits UE capability information informing the base station whether the overlapping data subbands are capable of simultaneous activation by the base station,
• wherein based on a request that the UE a report channel state information (CSI) measurement for each of the overlapping data subbands, the UE performs the CSI measurement for one of the overlapping data subbands and reuses a result of the CSI measurement for remaining overlapping data subbands,
• wherein the at least one data subband includes a control resource set (CORESET) for scheduling in the at least one data subband,
• wherein based on the CSI measurement being requested outside of the active data subband, the UE reports a necessary retuning gap to the base station based on the request of the CSI measurement, and performs the CSI measurement within a measurement gap and does not monitor the CORESET for the active data subband during the CSI measurement, and
• wherein the UE receives information on the measurement gap which is determined based on the necessary retuning gap from the base station, where the measurement gap is determined per each of the at least one data subband.