An indirect data transmission method may include: calculating an estimated arrival time of a next poll data request of a terminal device according to a receipt time of a poll data request, after the poll data request is received from the terminal device; transmitting data for the terminal device to a cache of a Media Access Control (MAC) layer module at a time point which is a predetermined time length ahead of the estimated arrival time responsive to a determination that there is the data for the terminal device in a network layer module; and transmitting, to the terminal device, an acknowledgement packet indicating that there is the data to be transmitted in the cache of the MAC layer module and the data for the terminal device, responsive to receiving the next poll data request.