A method includes: generating a physical layer packet of a first protocol version of a wireless local area network, where a first signaling field includes at least two OFDM symbols, the first two OFDM symbols of the first signaling field each comprises five signal segments, and duration of each signal segment is 0.8 microseconds; and five signal segments of a first OFDM symbol are respectively a fourth signal segment, a first signal segment, a second signal segment, a third signal segment, and the fourth signal segment in sequence, and five signal segments of a second OFDM symbol are respectively the first signal segment, the second signal segment, the third signal segment, the fourth signal segment, and the first signal segment in sequence; and sending the physical layer packet to a receive end device, so that the receive end device performs recognition.