The present invention relates to a wireless communication system, and specifically, provides a communication method and a device therefor, the communication method comprising: transmitting, to a terminal, an uplink grant comprising first information for changing a timing advance (TA) value; receiving, from the terminal, a first uplink signal which is based on the first information; and receiving a first downlink signal from a base station, wherein the transmission timing of the first uplink signal from the terminal is determined on the basis of the first information so that the first uplink signal and the first downlink signal may be received simultaneously at a relay node.