A method performed by an access point, AP, in a wireless local area network, comprising: generating (601, 801, 1001), by the AP, a physical layer protocol data unit, PPDU, wherein the PPDU comprises a signal field; and sending, by the AP, the PPDU (602, 802, 1002) to a station, STA; wherein the signal field comprises a common field, and the common field comprises a plurality of resource unit allocation subfields; each of the plurality of resource unit allocation subfields corresponds to one 242-tone resource unit, RU, in a frequency domain resource; a resource unit allocation subfield of the plurality of resource unit allocation subfields comprises an index, and wherein the index indicates information of a multiple resource unit, MRU, in which the 242-tone RU corresponding to the resource unit allocation subfield is located, and indicates a quantity of user fields contributed to a user specific field corresponding to the resource unit allocation subfield in a content channel in which the resource unit allocation subfield is located; and the MRU is formed by two or more RUs whose sizes are greater than or equal to 242 tones, and is one of the following MRUs: an MRU formed by a 484-tone RU and a 242-tone RU; an MRU formed by a 484-tone RU and a 996-tone RU; an MRU formed by a 484-tone RU and a 2*996-tone RU; an MRU formed by a 484-tone RU and a 3*996-tone RU;wherein the information of the MRU comprises a RU number of a corresponding 242-tone RU, 484-tone RU, or 996-tone RU forming the MRU, and the RU number indicates a frequency location of the corresponding 242-tone RU, 484-tone RU, or 996-tone RU, and one or more 242-tone RUs, 484-tone RUs, or 996-tone RUs are respectively sequentially numbered in an ascending order of absolute frequencies. generating (601, 801, 1001), by the AP, a physical layer protocol data unit, PPDU, wherein the PPDU comprises a signal field; and sending, by the AP, the PPDU (602, 802, 1002) to a station, STA; wherein the signal field comprises a common field, and the common field comprises a plurality of resource unit allocation subfields; each of the plurality of resource unit allocation subfields corresponds to one 242-tone resource unit, RU, in a frequency domain resource; a resource unit allocation subfield of the plurality of resource unit allocation subfields comprises an index, and wherein the index indicates information of a multiple resource unit, MRU, in which the 242-tone RU corresponding to the resource unit allocation subfield is located, and indicates a quantity of user fields contributed to a user specific field corresponding to the resource unit allocation subfield in a content channel in which the resource unit allocation subfield is located; and the MRU is formed by two or more RUs whose sizes are greater than or equal to 242 tones, and is one of the following MRUs: an MRU formed by a 484-tone RU and a 242-tone RU; an MRU formed by a 484-tone RU and a 996-tone RU; an MRU formed by a 484-tone RU and a 2*996-tone RU; an MRU formed by a 484-tone RU and a 3*996-tone RU;wherein the information of the MRU comprises a RU number of a corresponding 242-tone RU, 484-tone RU, or 996-tone RU forming the MRU, and the RU number indicates a frequency location of the corresponding 242-tone RU, 484-tone RU, or 996-tone RU, and one or more 242-tone RUs, 484-tone RUs, or 996-tone RUs are respectively sequentially numbered in an ascending order of absolute frequencies. an MRU formed by a 484-tone RU and a 242-tone RU; an MRU formed by a 484-tone RU and a 996-tone RU; an MRU formed by a 484-tone RU and a 2*996-tone RU; an MRU formed by a 484-tone RU and a 3*996-tone RU;wherein the information of the MRU comprises a RU number of a corresponding 242-tone RU, 484-tone RU, or 996-tone RU forming the MRU, and the RU number indicates a frequency location of the corresponding 242-tone RU, 484-tone RU, or 996-tone RU, and one or more 242-tone RUs, 484-tone RUs, or 996-tone RUs are respectively sequentially numbered in an ascending order of absolute frequencies.