Data transmission method, apparatus, and device

A data transmission device, comprising a processor, a memory, a transmitter, and a bus, wherein the processor, the memory, and the transmitter are connected by using the bus to perform data transmission, and the memory is configured to store data processed by the processor;

• the processor is configured to determine, according to a maximum power value detected by performing a clear channel assessment CCA on a primary channel in one or more processing time periods, a power value interval to which the maximum power value detected by performing the CCA belongs, wherein the determined power value interval is one of one or more power value intervals that do not overlap each other;
• and obtain a transmit power spectral density according to the determined power value interval, wherein there is a one-to-one correspondence between the one or more power value intervals and one or more transmit power spectral densities;
• and
• the transmitter is configured to:
• when a transmit opportunity TXOP is obtained, perform data transmission on a transmission channel by using a power spectral density that is not greater than the transmit power spectral density obtained by the processor.