A wireless station that belongs to a communication cell includes a receiver which, in operation, receives a trigger frame transmitted from an access point that belongs to an interference cell and a controller which, in operation, determines, based on at least one parameter included in the trigger frame and reception power value of the trigger frame received at the wireless station, whether the wireless station is allowed to transmit to other wireless station that belongs to the communication cell, wherein the at least one parameter includes a value set based on transmit power value of the trigger frame transmitted from the access point.