Abstract. Wireless sensor networks (WSNs) consist of a large number of entities that collaborate in order to provide given services. Unfortunately, due to their tiny size, these entities cannot be equipped with a long-life battery. In order to minimize overall energy consumption and maximize the lifetime of the network a widely accepted approach is to implement a duty cycle. Specifically, in order to save battery life, sensors are not active all the time, and switch off their capabilities according to a specific schedule. In this paper, we propose a generic method to schedule these duty-cycles, taking into account two important challenges in WSNs: strong reliability of the network and fairness between sensors. To achieve these aims, we ensure reliability by deploying several k-connected overlays, which became active one after the other. The fairness rule is ensured by spreading the sensors into overlay according to specific characteristics as energy consumption, network density, etc. We then propose different heuristics and probability models to achieve our outcome, and finally evaluate them through simulation experiments.