The present description relates to a method in which a first terminal communicates with a base station via a second terminal in a wireless access system supporting machine-type communication (MTC). The method comprises the following steps: transmitting, to the second terminal, uplink data to be transmitted to the base station; receiving, from the base station, control information corresponding to the quality of a link between the first terminal and the second terminal; and retransmitting the uplink data to the second terminal in accordance with the received control information, wherein the control information includes information on the delay between the second terminal and the base station, and information on the measured quality of the link between the first terminal and the second terminal.