A method includes receiving a first higher-layer signal from a base station, wherein the first higher-layer signal enables the use of single PDCCH scheduling PDSCH(s) in two or more serving cells; receiving a second higher-layer signal from the base station, wherein the second higher-layer signal enables the use of cross-carrier HARQ management within the serving cells; receiving DCI in one of the serving cells to obtain the scheduling information of PDSCH(s) in the serving cells; receiving the scheduled PDSCH(s) in the serving cells based on the received DCI to obtain downlink transport blocks carried in the scheduled PDSCH(s); and sending downlink transport blocks to a HARQ entity of the serving cell indicated in the DCI carried in a PDCCH for HARQ management based on a HARQ process number indicated in the DCI carried in the PDCCH.