Specifically, that the base station 1 sends retransmission data to the UE includes: if the base station 1 receives the NACK sent by the UE, sending, by the base station 1 to the user equipment, at least one of the physical downlink control channel that is for retransmission and in the second resource set group, where the at least one of the physical downlink control channel for retransmission carries second control information, and the second control information includes scheduling information of downlink data corresponding to the at least one of the physical downlink control channel for retransmission; and sending the retransmission data to the UE according to the scheduling information.
608. The UE receives the retransmitted data.