The method includes generating, by an access point (AP), signaling that includes an AP identifier (ID) field, a bandwidth (BW) field, a guard interval (GI) field, a cyclic redundancy check (CRC) field, and a tail field, the AP ID field is used to indicate an ID of the AP, the BW field is used to indicate bandwidth required for data transmission subsequent to the signaling, the GI is used to indicate a length of a cyclic prefix (CP) required for data transmission subsequent to the signaling, the CRC field is used to guard a field before the CRC field in the signaling, and the Tail field is used to empty an encoder and a decoder, where the CRC field and the Tail field are the last two fields of the signaling. The method also includes sending, by the AP, the signaling.