The present specification provides a method by which an integrated access and backhaul (IAB) node performs a mobile terminal (MT) operation and a distributed unit (DU) operation in a wireless communication system, the method performing initial access operations with a parent node and a child node, respectively, an MT operation with the parent node, and a DU operation with the child node, wherein a first demodulation reference signal (DMRS) is applied to the MT operation, a second DMRS is applied to the DU operation, and DMRS ports belonging to different code division multiplexing (CDM) groups are applied to the first DMRS and the second DMRS, respectively.