A method includes receiving a higher-layer signal from a base station, wherein the higher-layer signal enables the use of 2-stage DCI based cross-carrier scheduling and provides mapping between a scheduling serving cell and one or more scheduled serving cells; receiving a first-stage DCI carried in a PDCCH in a slot in the scheduling serving cell, wherein the first-stage DCI provides the information related to the corresponding second-stage DCI; receiving a second-stage DCI corresponding to the first-stage DCI in a specific set of resource elements in the same slot in the same scheduling cell as the first-stage DCI-based on the information provided in the first-stage DCI, wherein the second-stage DCI provides scheduling information for the scheduled serving cells; and performing data reception or transmission over the scheduled serving cells based on the received 2-stage DCI.