Method and apparatus for performing communication in wireless communication system

A UE (user equipment) for performing communication in wireless communication system, the UE comprises:

• a transceiver;
• and
• at least one processor coupled with the transceiver and configured to:
• control the transceiver to transmit through a physical random access channel (PRACH,) a message A, including uplink data and a UE contention resolution identifier (ID),
• monitoring a message B, and
• determine whether contention based RACH process is successfully performed, based on a UE contention resolution ID included in the message B being corresponding to the contention resolution ID of the UE.

A base station for performing communication in wireless communication system, the base station comprises:

• a transceiver;
• and
• at least one processor coupled with the transceiver and configured to:
• control the transceiver to receive through a physical random access channel (PRACH,) a message A, including uplink data and a user equipment (UE) contention resolution identifier (ID),
• determine a UE among at least one UE in a contention based RACH process, and
• control the transceiver to transmit a message B including a UE contention resolution ID corresponding the determined UE.