1. A wireless communication terminal, the terminal comprising:a transceiver; and
wherein the processor is configured to:
generate an uplink packet, wherein a predetermined field of a MAC header of the uplink packet indicates information on uplink data of the terminal, and
transmit, through the transceiver, the generated uplink packet to a base wireless communication terminal,
wherein the predetermined field of the MAC header individually indicates size information of uplink data corresponding to a first access class set and size information of uplink data corresponding to a second access class set.