The present description relates to a method in which a terminal in an idle mode performs network reentry in a wireless access system, wherein the method comprises: a step of receiving, from a base station, control information containing a first parameter and a second parameter for determining a frame in which uplink ranging is to be performed; and a step of performing uplink ranging for network reentry with the base station on the basis of the control information, wherein the first parameter indicates the location of a superframe in which uplink ranging is to be performed, and the second parameter indicates the frame duration in the superframe which is indicated by the first parameter and in which uplink ranging is performed.