This application provides a data transmission method and a related apparatus. The method includes determining, by a first node, a transmission periodicity, where the transmission periodicity includes a first time unit and a second time unit. In the transmission periodicity, data of a first service is transmitted in only the first time unit, and a physical signal is transmitted in the second time unit. The method further includes transmitting, by the first node, the data of the first service in the first time unit, and/or transmitting the physical signal in the second time unit.