Disclosed are a data transmission method, device, and system, which are used for resolving the problem of large overhead if an existing manner of sending a public message periodically is used in an ultra-dense network. The method comprises: user equipment sends an uplink request message, the uplink request message being used for requesting for obtaining public information of a first access node in an area in which the user equipment is located; and the user equipment receives the public information sent by the first access node. Because an access node in an area in which user equipment is located does not need to broadcast and send public information periodically, the access node can send, based on an uplink request of the user equipment, the public information, thereby improving the resource utilization and reducing the energy consumption.