In a wireless local area network (LAN) system, a sharing access point (AP) may transmit a first selection frame to a first shared AP and transmit a second selection frame to a second shared AP on the basis of information relating to channels between a reception station (STA) and the first shared AP and between the reception STA and the second shared AP. The sharing AP may receive a first selection response frame from the first shared AP. The sharing AP may determine to use the first shared AP in multi-AP transmission on the basis of the first selection response frame.