Abstract: In a sensor network including a sink node and a plurality of sensor nodes, the sink node receives a routing message including routing information from the sensor nodes, analyzes a structure of the sensor network based on routing information, and calculates a transmission schedule of each sensor node based on the analyzed network structure. Schedule information according to the calculated transmission schedule includes a wakeup time of the sensor node, a time interval that is consumed for packet transmission, and a standby time for preventing a packet collision based on the time interval.