<p>An IP packet mapping method includes: a step for generating MAC-PDU directly if an IP packet is smaller than a predetermined size or after dividing the IP packet into a plurality of parts if it exceeds the predetermined size; a step for adding a header containing the IP packet division information and a CRC code to the MAC-PDU; a step for channel-encoding the MAC-PDU having the header and the CRC code so as to generate a channel coding block; and a step for mapping the channel coding block to a radio frame.</p>