Method for transmitting and receiving uplink acknowledgement signal in wireless lan system and apparatus therefor

A station, STA, for transmitting an acknowledgement signal in response to downlink data in a wireless local area network, WLAN, system, the STA comprising:

• a transceiver configured to receive a downlink physical protocol data unit, PPDU, including:
• a control information subfield for uplink scheduling information, and
• downlink data
• from an access point, AP;
• and
• a processor configured to process the uplink scheduling information and control the transceiver to transmit an uplink PPDU including an acknowledgement signal in response to the downlink data to the AP,
• wherein the processor is configured to process the uplink scheduling information by assuming that the control information subfield includes:
• length information of the uplink PPDU,
• resource unit (RU) allocation information for the uplink PPDU,
• modulation and coding scheme (MCS) information for the uplink PPDU,
• transmit power of the AP, and
• target receive signal strength indicator (RSSI) information of the AP,
• wherein when the downlink PPDU is received, the processor is configured to disable spatial reuse of the uplink PPDU by assuming that the control information subfield does not include spatial reuse information.

A method for receiving an acknowledgement signal in response to downlink data from a station, STA, by an access point, AP, in a wireless local area network, WLAN, system, the method comprising:

• transmitting a downlink physical protocol data unit, PPDU, including:
• a control information subfield for uplink scheduling information, and
• downlink data
• to the STA;
• and
• receiving, from the STA, an uplink PPDU including an acknowledgement signal in response to the downlink data according to the uplink scheduling information,
• wherein the control information subfield includes:
• length information of the uplink PPDU,
• resource unit, RU, allocation information for the uplink PPDU,
• modulation and coding scheme, MCS, information for the uplink PPDU,
• transmit power of the AP, and
• target receive signal strength indicator, RSSI, information of the AP,
• wherein the control information subfield does not include spatial reuse information, and wherein the AP process signals from the STA assuming that the STA is configured to disable spatial reuse in response to receiving the downlink PPDU.