A method for soliciting a trigger-based, TB, physical layer protocol data unit, PPDU, transmission in a wireless local area network, WLAN, the method comprising: receiving, by a station, STA, a trigger frame which is used to solicit a type of TB PPDU transmissions from a plurality of STAs in the WLAN, wherein the type of TB PPDU transmissions comprises high efficiency, HE, trigger-based, TB, PPDU transmissions, or extremely high throughput, EHT, TB PPDU transmissions, and one or two subfields in the trigger frame indicate a bandwidth, BW, of the solicited TB PPDU, and transmitting, by the STA, the solicited TB PPDU in the BW indicated by the one or two subfields in the trigger frame; wherein a common info field of the trigger frame comprises an uplink, UL, bandwidth, BW subfield indicating a BW of the solicited HE TB PPDU; wherein the common info field of the trigger frame further comprises an enhanced trigger frame flag subfield which indicates whether the trigger frame is an 802.11ax trigger frame or an enhanced trigger frame; characterized in that when the enhanced trigger frame flag subfield indicates that the trigger frame is an enhanced trigger frame, both the UL BW subfield and a Delta EHT UL BW subfield indicate a BW of the solicited EHT TB PPDU; wherein the UL BW subfield occupies 2 bits in the common info field of the trigger frame and the Delta EHT UL BW subfield occupies 2 bits of the enhanced trigger frame. receiving, by a station, STA, a trigger frame which is used to solicit a type of TB PPDU transmissions from a plurality of STAs in the WLAN, wherein the type of TB PPDU transmissions comprises high efficiency, HE, trigger-based, TB, PPDU transmissions, or extremely high throughput, EHT, TB PPDU transmissions, and one or two subfields in the trigger frame indicate a bandwidth, BW, of the solicited TB PPDU, and transmitting, by the STA, the solicited TB PPDU in the BW indicated by the one or two subfields in the trigger frame; wherein a common info field of the trigger frame comprises an uplink, UL, bandwidth, BW subfield indicating a BW of the solicited HE TB PPDU; wherein the common info field of the trigger frame further comprises an enhanced trigger frame flag subfield which indicates whether the trigger frame is an 802.11ax trigger frame or an enhanced trigger frame; characterized in that when the enhanced trigger frame flag subfield indicates that the trigger frame is an enhanced trigger frame, both the UL BW subfield and a Delta EHT UL BW subfield indicate a BW of the solicited EHT TB PPDU; wherein the UL BW subfield occupies 2 bits in the common info field of the trigger frame and the Delta EHT UL BW subfield occupies 2 bits of the enhanced trigger frame. wherein a common info field of the trigger frame comprises an uplink, UL, bandwidth, BW subfield indicating a BW of the solicited HE TB PPDU; wherein the common info field of the trigger frame further comprises an enhanced trigger frame flag subfield which indicates whether the trigger frame is an 802.11ax trigger frame or an enhanced trigger frame; characterized in that when the enhanced trigger frame flag subfield indicates that the trigger frame is an enhanced trigger frame, both the UL BW subfield and a Delta EHT UL BW subfield indicate a BW of the solicited EHT TB PPDU; wherein the UL BW subfield occupies 2 bits in the common info field of the trigger frame and the Delta EHT UL BW subfield occupies 2 bits of the enhanced trigger frame.