A method for supporting a sporadic high-capacity packet service by a terminal may comprise the steps of: receiving, from a base station, control information including pre-defined timing information for synchronization and resource allocation information associated with the terminal; when uplink traffic occurs, performing transmission synchronization on the basis of the pre-defined timing information for synchronization; selecting a resource for uplink data transmission on the basis of the resource allocation information; and transmitting uplink data through the selected resource.