A beam determination method, a downlink transmission decoding method performed in a communication system, and corresponding user equipments and base stations are disclosed. The base station has a plurality of transmission beams, and may dynamically select a beam for transmitting downlink control information and downlink data information from a plurality of beams. The downlink transmission decoding method performed by the user equipment includes: determining M preferred beams in the plurality of transmission beams of the base station; and receiving, through one or more reception beams corresponding to any one or more of N preferred beams in the M preferred beams, downlink control information transmitted by the base station, wherein N≤M, the base station transmitting signaling including same downlink control information through the N preferred beams during the transmission time period of the downlink control information. The downlink transmission decoding method performed by the base station comprises: determining M preferred beams in the plurality of transmission beams of the base station; and transmitting signaling including same downlink control information through N preferred beams in the M preferred beams, where N≤M.