Method for determining uplink transmission timing of terminal having plurality of cells configured therein in wireless communication system, and apparatus using the method

An apparatus comprising:

• a memory;
• and
• a processor connected to the memory,
• wherein the processor is configured to receive timing advance (TA) configuration information, and, upon reception of the TA configuration information, the processor is further configured to determine an uplink transmission time for each of two cells among a plurality of cells, wherein the two cells are included in a group, and
• wherein:
• i) based on the two cells comprising a first cell using a frequency division duplex (FDD) frame structure and a second cell using a time division duplex (TDD) frame structure and based on the group including only secondary cells, both the uplink transmission time of the first cell and the uplink transmission time of the second cell are determined by applying a same offset value regardless of frame structures of the first cell and the second cell, and the same offset value is an offset value applied to a cell using the TDD frame structure, and
• ii) based on the two cells comprising the first cell using the FDD frame structure and the second cell using the TDD frame structure and based on the group including a primary cell, an uplink transmission time of the primary cell is determined based on the TA configuration information, and both the uplink transmission time of the first cell and the uplink transmission time of the second cell are determined to be the same as the uplink transmission time of the primary cell.