Method for transmitting and receiving acknowledgment/negative-acknowledgment signal for uplink multi-user data in wireless LAN system and apparatus therefor

A method of receiving, by a first station (STA), an ACK/NACK signal from an access point (AP) in a wireless local area network (WLAN) system, the method comprising:

• receiving a trigger frame transmitted to a plurality of STAs including the first STA;
• transmitting a plurality of data frames to the AP through an uplink multi-user scheme or an OFDMA scheme in response to the trigger frame;
• and
• receiving a single ACK frame from the AP,
• wherein, when the single ACK frame includes an All ACK indication, the single ACK frame represents ACK for all the plurality of data frames transmitted to the AP, without information on successfully received data frames among the plurality of data frames, and
• wherein, when the single ACK frame does not include the All ACK indication, the single ACK frame includes the information on successfully received data frames among the plurality of data frames.

An access point (AP) apparatus for transmitting an ACK/NACK signal for multiple data frames received from a plurality of stations (STAs) in a wireless local area network (WLAN) system, the apparatus comprising:

• a transceiver configured to transmit a trigger frame to the plurality of STAs, to receive the multiple data frames from the plurality of STAs in response to the trigger frame and to transmit a single ACK frame for the ACK/NACK signal;
• and
• a processor connected to the transceiver and configured to process the trigger frame, the received multiple data frames and the ACK/NACK signal,
• wherein the processor is configured to transmit the single ACK frame including an All ACK indication to represent ACK for all the multiple data frames received from the plurality of STAs without information on successfully received data frames among the multiple data frames and
• wherein the processor is configured to transmit the single ACK frame not including the All ACK indication, but including the information on successfully received data frames among the multiple data frames to represent ACK for the successfully received data frames.

An apparatus operating as a first STA for receiving an ACK/NACK signal from an access point (AP) in a wireless local area network (WLAN) system, the apparatus comprising:

• a transceiver configured to receive a trigger frame transmitted to a plurality of STAs including the first STA, to transmit a plurality of data frames to the AP through an uplink multi-user scheme or an OFDMA scheme in response to the trigger frame and to receive a single ACK frame from the AP;
• and
• a processor connected to the transceiver and configured to process the trigger frame, the plurality of data frames and the single ACK frame,
• wherein, when the single ACK frame includes an All ACK indication, the single ACK frame represents ACK for all the plurality of data frames transmitted to the AP without information on successfully received data frames among the plurality of data frames, and
• wherein, when the single ACK frame does not include the All ACK indication, the single ACK frame includes the information on successfully received data frames among the plurality of data frames.