Couche MAC adaptative pour les applications critiques de surveillance à base d’un réseau de capteurs d’image
Muhammad Ehsan · HAL (Le Centre pour la Communication Scientifique Directe) · 2015
Wireless Sensor Networks (WSNs) are designed for the purpose of completing different monitoring tasks under various environmental conditions. The small electronic devices called sensors are capable of sensing, processing and communicating the environmental data through multi-hop communication and coordination. These devices have limited resources (memory, computing capabilities) and usually run on batteries. This is the reason the research on wireless sensor networks have been focused on energy efficiency and self-organization of the network. We consider mission-critical surveillance applications in our research work. These applications can have different requirements than traditional WSNs. In addition, we use image sensor nodes, whose activity is defined based on criticality of the application. The criticality-based scheduling scheme defines sentry nodes with faster capture rates, to have higher probability to detect intrusions and to alert neighbor nodes. At Medium Access Control (MAC) Layer level, duty cycled approaches are used to preserve energy and prolong the network lifetime. However, while conserving energy, mission-critical surveillance applications cannot compromise on quality of surveillance and the network should still be able to quickly propagate the alert messages. In this thesis, we propose a low latency, energy efficient adaptive MAC protocol. We first propose an original approach to dynamically determine the duty-cycle length of sensor nodes to increase the probability of quick propagation of alerts. Simulation results confirmed that our approach succeeds in improving the system responsiveness when compared to a static duty-cycling approach. At the same time, our proposition considerably reduces the energy consumption of the network. Then, we implemented our approach on sensor node hardware and results were found to be very close to our simulation results.