Channel access method, channel access system and stations

The invention discloses a channel access method. A first station acquires a first transmission time frame and sends indication information to a second station in the first transmission time frame, and the indication information is used for informing the second station of acquiring a second transmission time frame; and the second station acquires the second transmission time frame and performs radio frame transmission in the second transmission time frame. The invention also discloses a channel access system and the stations.