Channel access indication method and device to avoid unnecessary probe delay

A channel access indication method, comprising:

• receiving, by a first communications device, a channel synchronization request sent by a second communications device, wherein the channel synchronization request requests the first communications device to send a synchronization frame to the second communications device, and a wake-up receiver is configured for the second communications device;
• and
• according to the channel synchronization request and a time at which the second communications device is woken up and that is learned by the first communications device based on preset signaling, sending, by the first communications device when a channel is idle, the synchronization frame to the woken-up second communications device, wherein the synchronization frame instructs the woken-up second communications device to access the channel after receiving the synchronization frame,
• wherein there are a plurality of woken-up second communications devices, and
• the synchronization frame is sent in response to the channel synchronization request based on the time at which the second communications device is woken up, and the synchronization frame carries predetermined information including an identifier of the one or more woken-up second communications device,
• wherein the sending, when a channel is idle, of the synchronization frame to the woken-up second communications device comprises:
• sending, by the first communications device when the channel is idle, a first synchronization frame to one or more of the plurality of woken-up second communications devices;
• and
• sending, by the first communications device when the channel is idle, a second synchronization frame to the plurality of woken-up second communications devices,
• wherein the first synchronization frame includes the identifier of the one or more woken-up second communications device, and the second synchronization frame does not include the identifier,
• wherein a receiver address of the second synchronization frame is a broadcast address.