Method and apparatus for transmitting or receiving ppdu in improved format for short frame in wireless lan system

A first station (STA) comprising:

• at least one transceiver;
• and
• at least one processor connected to the at least one transceiver,
• wherein the at least one processor is configured to:
• generate a physical layer protocol data unit (PPDU) related to a short frame, which includes a first long training field (LTF) field, or which includes the first LTF field and a second LTF field of at least one symbol;
• and
• transmit, through the at least one transceiver, the PPDU to a second STA,
• wherein based on at least one of a plurality of streams being transmitted through the PPDU or a bandwidth of the PPDU being greater than 20 MHz, the second LTF field of the at least one symbol is included in the PPDU.

A second station (STA) comprising:

• at least one transceiver;
• and
• at least one processor connected to the at least one transceiver,
• wherein the at least one processor is configured to:
• receive, through the at least one transceiver, from a first STA, a physical layer protocol data unit (PPDU) related to a short frame, which includes a first long training field (LTF) field, or which includes the first LTF field and a second LTF field of at least one symbol;
• and
• based on at least one of the first LTF field, or a second LTF symbol of the at least one symbol, decode data included in the PPDU,
• wherein based on at least one of a plurality of streams being transmitted through the PPDU or a bandwidth of the PPDU being greater than 20 MHz, the second LTF field of the at least one symbol is included in the PPDU.