One example according to the present specification relates to a technique related to configuration of a preamble in a wireless LAN (WLAN) system. According to various embodiments, a receiving STA may receive an NDP frame. The NDP frame may comprise a first signal field and a second signal field. The first signal field may comprise first information about a PHY version. The second signal field may comprise second information about transmission of a PPDU, set on the basis of the first information. The receiving STA may perform channel sounding on the basis of the NDP frame.