  Recent advances in micro-sensor and communication technology have enabled the
emergence of a new technology, Wireless Sensor Networks (WSN). WSN have
emerging recently as a key solution to monitor remote or hostile environments
and concern a wide range of applications. These networks are faced with many
challenges such as energy efficiency usage, topology maintenance, network
lifetime maximization, etc. Experience shows that sensing and communications
tasks consume energy, therefore judicious power management can effectively
extend network lifetime. Moreover, the low cost of sensor devices will allows
deployment of huge number nodes that can permit a high redundancy degree. In
this paper, we focus on the problem of energy efficiency and topology
maintenance in a densely deployed network context. Hence we propose an energy
aware sleep scheduling and rapid topology healing scheme for long life wireless
sensor networks. Our scheme is a strong node scheduling based mechanism for
lifetime maximization in wireless sensor networks and has a fast maintenance
method to cover nodes failure. Our sentinel scheme is based on a probabilistic
model which provides a distributed sleep scheduling and topology control
algorithm. Simulations and experimental results are presented to verify our
approach and the performance of our mechanism.
