Method and apparatus for reporting data status in mobile wireless communication system

A terminal in a wireless communication system, the terminal comprising:

• a transceiver configured to transmit and receive a signal, and
• a controller configured to control the transceiver to:
• trigger a buffer status report (BSR) in case that uplink data for a specific logical channel becomes available,
• determine a format of the BSR based on an amount of a specific data at a first time point,
• determine a value to be set in a specific bit of the BSR based on the amount of the specific data at a second time point in case that the BSR is first format, and
• transmit a medium access control (MAC) protocol data unit (PDU), wherein the MAC PDU comprises the BSR,
• wherein:
• the amount of the specific data at the first time point is amount of the specific data when the MAC PDU is to be built;
• and
• the amount of the specific data at the second time point is amount of the specific data after resource to be allocated to logical channel is determined, and
• wherein:
• a first buffer size table is used for a specific logical channel group in case that the specific bit is set to a first value;
• a second buffer size table is used for the specific logical channel group in case that the specific bit is set to a second value;
• the specific bit is associated with the specific logical channel group;
• and
• the specific logical channel belongs to the specific logical channel group.