A terminal receives a downlink signal on the basis of a random access channel procedure (RACH procedure) in an unlicensed band. In particular, a first physical random access channel (PRACH) preamble is transmitted through message A, in response to the message A, a random access response (RAR) is received through message B related to contention resolution, information on at least one DRX timer for setting a discontinuous reception (DRX) operation is received, and a downlink signal is received during an On duration on the basis of the at least one DRX timer, wherein the first PRACH preamble is a PRACH preamble mapped to a physical uplink shared channel (PUSCH) occasion for the message A, and a window for reception of the message B may start after at least one symbol from the last symbol of the PUSCH occasion.