In a process of beam change, the base station transmits a beam change instruction to a user equipment to confirm a change from a current beam to another beam. The base station determines to change from a first beam to a second beam. The base station generates a beam change instruction to indicate the determination to change from the first beam to the second beam. The base station transmits, to a UE, the beam change instruction in a downlink control information (DCI). The base station determines whether or not the beam change instruction is detected by the UE.