A data transmission method, an electronic device and a device having a base station function, wherein, a channel sensing sub-frame is arranged in a frame structure used only for downlink transmission frequency division duplexing; within any period, downlink data is sent via a downlink sub-frame in the frame structure when the channel sensing sub-frame senses that the downlink channel is in an idle state, or otherwise downlink data is not sent. Therefore, on the premise that normal operation of the LTE system by means of the supplemental downlink mode in the unlicensed frequency band can be ensured, the LTE system is prevented from generating significant interference with regard to other systems when operating in the unlicensed frequency band.