The present invention relates to a method for adaptively controlling a transmission radiation pattern. The flat panel display includes a housing, a panel module and a main bracket. Each of the branches of the first tree ends in a leaf node. In another embodiment of the present invention, an authentication server transmits proactive keys needed for roaming to neighbor APs to which the STA is likely to move, so that when the STA moves to one of the neighbor APs, a reassociation is carried out between the STA and the neighbor AP using the already provided proactive key.