S-MAC is a MAC (Medium Access Control) protocol as specialized for the wireless sensor network in order to sacrifice transmission delay and extend the working life of the whole sensor nodes. The wireless sensor network using S-MAC performs is to find a neighbor node, and then choose and broadcast its own schedule. In the existing paper on S-MAC, this problem is solved by placing a border node to adopt schedules which are different from one another. However, compared with other nodes, the border node consumes energy more, and its efficiency of data transmission according to the broadcast type is lower. This paper suggested a method for unifying schedules through the H-SYNC (Heartbeat-SYNC) method for solving such problem of the diversified scheduling of S-MAC, and as a result of comparing and evaluating its performance through simulation, it was found that the border node consumed energy less.