In a wireless local area network (wireless LAN) system, a transmitting STA can transmit, to a receiving STA, a grouping initiation frame for generating a group that is to perform sensing. The grouping initiation frame can include information related to a session identifier (ID) for a sensing session and to the number of transmission times of a sensing signal performed in the sensing session. The transmitting STA can receive a grouping response frame from the receiving STA. The receiving STA can be included in the group on the basis of the reception of the grouping response frame from the receiving STA within a threshold time preset from the transmission time of the grouping initiation frame. The sensing session can include at least one transmission opportunity (TXOP).