A method of an access point device is disclosed. A first indication message is sent to a terminal. The first indication message is used to indicate that the terminal is allowed to access a current channel or to indicate that the terminal has downlink data on the access point device or to indicate that the terminal is allowed to send uplink data. A second indication message is sent by the terminal according to the first indication message. The second indication message is used to indicate that the terminal is to send uplink data. After receiving the second indication message, a third indication message is sent to the terminal. The third indication message carries channel use time information. The channel use time information is used to indicate time for using the channel to send the uplink data by the terminal.