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 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.