Signal transmission/reception method in wireless LAN system, and device therefor

A wireless device that is a first station (STA) transmitting a signal by performing multiple-input multiple-output (MIMO) beamforming training in a wireless local area network (WLAN) system, the first STA comprising:

• a transceiver configured to comprise one or more radio frequency (RF) chains and to transmit and receive a signal to and from a second STA;
• and
• a processor configured to be connected to the transceiver and to process a signal transmitted to or received from the second STA,
• wherein the processor is configured to transmit a first MIMO beamforming setup frame to a second STA, to receive a second MIMO beamforming setup frame from the second STA, to transmit beam refinement protocol (BRP) frames to the second STA, and to transmit a signal to the second STA based on the MIMO beamforming training;
• wherein the first MIMO beamforming setup frame, the second MIMO beamforming setup frame, and the BRP frames are transmitted during a service period (SP) based on time division duplex (TDD) in order to perform the MIMO beamforming training;
• wherein the SP comprise a first TDD slot and a second TDD slot;
• wherein, based on all of the BRP frames not being able to be transmitted in the first TDD slot, first BRP frames, which are part of the BRP frames, are transmitted in the first TDD slot, and second BRP frames other than the first BRP frames of the BRP frames are transmitted in the second TDD;
• wherein the second TDD slot is a TDD slot allocated first after the first TDD slot, and
• wherein a code field value of a last BRP frame of the first BRP frames is not 0, and a code field value of a last BRP frame of the second BRP frames is 0.

A method for receiving a signal by performing multiple-input multiple-output (MIMO) beamforming training in a wireless local area network (WLAN) system, the method comprising:

• receiving, by a first station (STA), a first MIMO beamforming setup frame from a second STA;
• transmitting, by the first STA, a second MIMO beamforming setup frame to the second STA;
• receiving, by the first STA, beam refinement protocol (BRP) frames from the second STA;
• and
• receiving, by the first STA, a signal from the second STA based on the MIMO beamforming training,
• wherein the first MIMO beamforming setup frame, the second MIMO beamforming setup frame, and the BRP frames are transmitted during a service period (SP) based on time division duplex (TDD) in order to perform the MIMO beamforming training;
• wherein the SP comprise a first TDD slot and a second TDD slot;
• wherein, based on all of the BRP frames not being able to be transmitted in the first TDD slot, first BRP frames, which are part of the BRP frames, are transmitted in the first TDD slot, and second BRP frames other than the first BRP frames of the BRP frames are transmitted in the second TDD;
• wherein the second TDD slot is a TDD slot allocated first after the first TDD slot, and
• wherein a code field value of a last BRP frame of the first BRP frames is not 0, and a code field value of a last BRP frame of the second BRP frames is 0.