In addition, when the wireless communication terminal reports as the BSR that the buffer for the corresponding AC is empty with respect to one or more ACs to the base wireless communication terminal, the wireless communication terminal receives an ACK for transmission of data of the corresponding AC, and terminates the MU EDCA parameter set application. In the embodiment of FIG. 14(b), the wireless communication terminal reports to the base wireless communication terminal that the buffer for TID1 is empty while transmitting the trigger-based PPDU. Therefore, when the wireless communication terminal receives the M-BA frame for the last transmission of the MPDU corresponding to TID1, the wireless communication terminal converts the MU EDCA parameter set into a general EDCA parameter set Legacy. In another embodiment, the wireless communication terminal sets a first MU EDCA timer according to reception of the trigger information, and sets the MU EDCA timer according to the reception of the response to the trigger-based PPDU transmission. At this time, the period of the second timer may be shorter than the period of the first MU timer. Specifically, the wireless communication terminal may set a first MU EDCA timer when receiving the trigger information and set an MU EDCA timer when receiving a response to the trigger-based PPDU transmission. In the embodiment of FIG. 14(c), when the wireless communication terminal receives the trigger frame TF, it sets the first MU EDCA timer option1. Also, the wireless communication terminal sets a second MU EDCA timer option2 that expires earlier than the expiration time set by the first MU EDCA timer option when receiving the M-BA frame.
