A frame transmission method, for receiving data in a wireless local area network. A destination station establishes a direct link with a source station. The destination station receives a first physical layer protocol data unit (PPDU) from the source station via the direct link. The destination station receives a second PPDU from a relay station via a relay link. In addition, the second PPDU is received by the relay station from the source station and is forwarded by the relay station to the destination station. Furthermore, the first PPDU includes a sequence field indicating that the second PPDU is to be transmitted via the relay link.