Method of handling time alignment command during a random access procedure

A terminal for performing a random access procedure in a wireless communication system, the terminal comprising:

• a transceiver that receives a command for starting a time alignment timer that is used to control how long the terminal is considered uplink time aligned,
• wherein the command is a time advance command (TAC), and the time advance command is received in a random access response message;
• and
• a processor that determines whether a random access preamble in the random access procedure was explicitly signaled and an index of the random access preamble was not 00000,
• wherein if it is determined that the random access preamble was explicitly signaled and the index of the random access preamble was not 00000, the time advance command is applied, and the time alignment timer is started or restarted,
• wherein if it is determined that the random access preamble was not explicitly signaled and if the time alignment timer is not running, the time advance command is applied, and the time alignment timer is started,
• wherein the timer alignment timer is stopped when a contention resolution is considered not successful, and
• wherein if it is determined that the random access preamble was not explicitly signaled and the time alignment timer is running, the received command is ignored.