Abstract : Recent advances in micro-electro-mechanical systems (MEMS) have enabled the development of low cost, low power, multi functional sensor devices. These devices can operate autonomously to gather, process and transmit information about their deployment area. A sensor network is a set of nodes in which a battery, a sensing module and a wireless communication device are embedded. Densely deployed over hostile or remote environments, the self-organization of the sensors should provide full monitoring and pertinent data collection at base stations. Once deployed in a field, battery power of sensors cannot be easily replaced or refilled. Energy is therefore the system's most important resource. Sensors are allowed to turn into sleep mode depending on a given critrion. For instance, if too many nodes are deployed, only some of them are really needed for monitoring. The area coverage problem is about sensors making decisions whether or not to turn off so that the whole area remains fully covered. We proposed several activity scheduling protocols that preserve area coverage. Their performances are competitive with existing solutions. We addressed the two problems of coverage and connectivity as a unified one, while considerably reducing the communication overhead and increasing the reliability of our algorithms. We then proposed various methods allowing to extend existing solutions to handle multiple coverage (each physical point of the area must be monitored by a given number of active sensors). We finally integrated more realistic communication models and we have shown that our solutions were still performing great, unlike other existing algorithms, which should facilitate their future implementation on real wireless sensors.