A method includes: An access point generates an NDPA frame, where the NDPA frame includes a station information field, and the station information field includes an AID subfield indicating an association identifier AID of a station; the station information field further includes a partial bandwidth information subfield; the partial bandwidth information subfield indicates an RU that is in a bandwidth corresponding to the NDPA frame and for which the station needs to feed back channel state information; and the bandwidth corresponding to the NDPA frame is greater than 160 MHz. The access point transmits the NDPA frame.