The present invention relates to a wireless communication system, and specifically, to a method and a device therefor, the method comprising the steps of: repeatedly receiving a PDCCH including scheduling information, wherein the scheduling information includes time delay information; and repeatedly transmitting a PUSCH indicated by the scheduling information, after a time point indicated by the time delay information from the time point when the repeated receiving of the PDCCH ends, wherein a time resource in a time region includes a fixed DL time unit having a transmission direction fixed to a DL, and a time resource includes a fixed uplink (UL) time unit having a transmission direction fixed to a UL, and a floating time unit having a variable transmission direction, and the time point indicated by the time delay information is calculated on the basis of the fixed UL time unit.