Apparatus and method for performing uplink synchronization in multi-component carrier system

A method of performing uplink synchronization by a base station, the method comprising:

• transmitting a medium access control (MAC) message including a time alignment value to a terminal;
• applying the time alignment value to a time alignment group including at least one secondary serving cell configured in the terminal;
• transmitting a MAC message indicating activation of a deactivated serving cell in the time alignment group to the terminal;
• performing activation of the at least one secondary serving cell according to the serving cell in a sub-frame determined based on a sub-frame where the MAC message has been transmitted;
• and
• performing uplink reception according to a time adjusted by the time alignment value,
• wherein the uplink reception is performed in a case where the time alignment value is determined to be valid by the terminal or in a case where the time alignment value is a time alignment value regarding a primary serving cell.

A terminal to perform uplink synchronization, the terminal comprising:

• a terminal receiving unit to receive a medium access control (MAC) message including a time alignment value and a MAC message indicating activation of a deactivated serving cell in a time alignment group from a base station;
• a random access processing unit to adjust a time for an uplink in at least one secondary serving cell configured in the terminal by applying the time alignment value to a time alignment group including the at least one secondary serving cell;
• a terminal transmitting unit to perform uplink transmission according to the adjusted time;
• and
• a radio resource control (RRC) processing unit to perform activation of the at least one secondary serving cell according to the serving cell in a sub-frame determined based on a sub-frame where the MAC message has been received,
• wherein the terminal transmitting unit performs the uplink transmission in a case where the random access processing unit determines the time alignment value as valid or in a case where the time alignment value is identified as a time alignment value regarding a primary serving cell.

A base station to perform uplink synchronization, the base station comprising:

• a base station transmitting unit to transmit a medium access control (MAC) message including a time alignment value and a MAC message indicating activation of a deactivated serving cell in a time alignment group;
• a random access processing unit to apply the time alignment value to a time alignment group including at least one secondary serving cell configured in the terminal;
• a radio resource control (RRC) processing unit to perform activation of the at least one secondary serving cell according to the serving cell in a sub-frame determined based on a sub-frame where the MAC message has been transmitted;
• and
• a base station receiving unit to perform uplink reception according to a time adjusted by the time alignment value,
• wherein the base station receiving unit performs the uplink reception in a case where the random access processing unit determines the time alignment value as valid or in a case where the time alignment value is identified to be a time alignment value regarding a primary serving cell.