Wireless sensor network consists of a large number of low-power, short-lived, unreliable sensors. One fundamental issue in this kind of networks is the textbf{coverage} problem, that reflects how well the target area is monitored by sensors. According to the coverage concept, many works have introduced nodes-scheduling methods to increase the system lifetime, as well as to maintain sufficient coverage and reliability. Node-scheduling allows to turn off redundant sensors. In this paper, we propose a node-scheduling algorithm, that reduces system overall energy consumption, therefore increasing system lifetime, by turning off redundant nodes. The proposed scheduling method is based on one-hop remaining energy neighbouring knowledge. This algorithm gives an optimal node-schedul that maintains the original sensing coverage after turning off redundant nodes.