The present disclosure provides a method for receiving a downlink signal on the basis of a random-access channel procedure (RACH procedure) by a terminal in an unlicensed band. Specifically, the method may comprise: on the basis of a power ramping counter, configuring transmission power for message A including a first physical random-access channel (PRACH) and a first physical uplink shared channel (PUSCH); on the basis of the transmission power, transmitting message A to a base station; and receiving contention resolution-related message B from the base station in response to message A, wherein an increase is made on the basis that a transmission spatial beam for transmission of message A is configured to be identical to a transmission spatial beam related to transmission of a PRACH preceding message A.