A method and device for transmitting an EHT PPDU in a
wireless LAN
system is proposed. Specifically, a transmission STA generates an STF
signal for a 320 MHz band. The transmission STA transmits an EHT PPDU including the STF
signal to a reception STA. The STF
signal is generated on the basis of an EHT STF sequence. The EHT STF sequence is a first sequence in which preconfigured sequence M is repeated, and is defined as {M 1 −M 0 −M 1 −M 0 −M −1 M 0 −M 1 −M 0 −M −1 M 0 M −1 M 0−M −1 M 0 −M 1 −M}*(1+j) / sqrt(2). Sqrt( ) represents a square root. Preconfigured sequence M is defined as M={−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1}.