Method and apparatus for determining modulation and coding scheme feedback in wireless local area network system

A wireless device for link adaptation in a wireless local area network, the wireless device comprising:

• a transceiver;
• and
• a processor operatively coupled to the transceiver and configured to:
• receive, from a requesting station, a request frame indicating a request for a modulation and coding scheme feedback (MFB),
• in response to the request frame, configure the MFB,
• wherein a frame used by the responding station for configuring the MFB is differently determined based on whether the request frame is a physical layer protocol data unit (PPDU) carrying the request for the MFB or a null data packet announcement (NDPA) frame,
• wherein the MFB is configured based on the PPDU if the request frame is the PPDU,
• wherein the MFB is configured based on a null data packet (NDP) frame transmitted following the NDPA frame if the request frame is the NDPA frame,
• wherein the PPDU includes a Very High Throughput (VHT) signal (VHT-SIG) field,
• wherein the VHT-SIG field includes a group identifier, a beamforming indicator, and a space-time block coding (STBC) indicator indicating whether an STBC is used for the PPDU,
• wherein the group identifier indicates whether a single user multiple-input and multiple-output (SU-MIMO) scheme is applied to the PPDU or a multiple user MIMO (MU-MIMO) scheme is applied to the PPDU,
• wherein the beamforming indicator indicates whether a beamforming is applied to the PPDU, and
• wherein if the request frame is the PPDU, the MFB is configured at least based on the group identifier, the beamforming indicator, and the STBC indicator, and
• transmit, to the requesting station, the MFB.