A method for resuming data transmission in a data transmission system including multiple information processing units and at least one mobile device, the multiple information processing units and the mobile device each including a wireless communication component, the method includes: transmitting data, by a first one of the multiple information processing units, to the mobile device; recording atransmission status of the mobile device, the transmission status including information regarding an unfinished data transmission by the first information processing unit to the mobile device; and resuming transmitting data relating to the unfinished data transmission, by a second one of the multiple information processing units, to the mobile device based on the recorded transmission status.