Method and apparatus for transmitting uplink

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

• a radio frequency (RF) unit configured to transmit and receive radio signals;
• and
• a processor operatively coupled with the RF unit and configured to:
• determine whether to transmit both a physical uplink shared channel (PUSCH) and a sounding reference signal (SRS) or drop the SRS, and
• transmit only the PUSCH but dropping the SRS when the UE determines satisfaction of all of at least three conditions including:
• a first condition specifying that a plurality of timing advance groups (TAGs) including a first TAG and a second TAG are configured,
• a second condition specifying that at least one symbol of a subframe n which is used to transmit the SRS toward a first cell belonging to the first TAG is overlapped with a subframe n+1 on which the PUSCH is transmitted toward a second cell belonging to the second TAG, and
• a third condition specifying that a total uplink transmission power exceeds a maximum value.