Method for retransmitting frame in wireless LAN system, and wireless terminal using same

A first station (STA) in a wireless local area network (LAN) system, the first STA comprising:

• a transceiver configured to transmit and receive radio signal via multiple directional antenna modules;
• and
• a processor coupled to the transceiver;
• the processor configured to:
• segment a MAC Service Data Unit (MSDU) received from an upper layer of the first STA into multiple MAC Protocol Data Units (MPDUs),
• wherein the segmented MPDUs include a first MPDU, a second MPDU, and a third MPDU,
• transmit the segmented MPDUs to a second STA,
• wherein each of the segmented MPDUs includes a first information field related to a total number of the segmented MPDUs and a second information field related to a transmission order of the segmented MPDUs;
• after an acknowledgement (ACK) frame for successful reception of the segmented MPDUs is not received from the second STA, transmit a Block ACK Request (BAR) frame to the second STA;
• receive a Block ACK (BA) frame from the second STA in response to the BAR frame,
• wherein the BA frame includes frame information related to a last MPDU successfully received by the second STA among the segmented MPDUs;
• and
• retransmit at least one of the segmented MPDUs to the second STA based on the frame information,
• wherein the second MPDU and the third MPDU are retransmitted for the frame information having a value one (1), and
• wherein the third MPDU is retransmitted for the frame information having a value two (2).