Method for replying with response frame, apparatus, and access point system

A method for replying with a response frame, the method comprising:

• receiving, by a radio frequency processing device, a physical layer protocol data unit (PPDU) sent by a station (STA);
• sending, by the radio frequency processing device to a baseband processing device by using a wired medium, a frame obtained based on the PPDU, wherein the radio frequency processing device and the baseband processing device are remotely separated;
• in response to a target signal that is received by using the wired medium and that is from the baseband processing device, generating, by the radio frequency processing device, a target field, and sending the target field to an air interface, wherein the target field at least comprises a first field of a response frame of the PPDU, and the target signal is used to indicate the radio frequency processing device to immediately respond to the PPDU;
• receiving, by the radio frequency processing device by using the wired medium, a part that is of the response frame of the PPDU except the target field and that is from the baseband processing device;
• and
• sending, by the radio frequency processing device, the part of the response frame of the PPDU except the target field to the air interface immediately after sending the target field.