Spatio-Temporal Event Detection and Reporting in Mobile-Sink Wireless Sensors Networks

Spatio-temporal events are used to model various events such as animal movement, storms (tornadoes, hurricanes, etc.), traffic control, and oil or chemical leakage. Wireless Sensor Networks (WSNs) have been widely used in event monitoring for many applications. Depending on the application, network energy can be a constraint when sensors are battery powered and their batteries cannot be replaced or recharged. In this paper we propose an anchor-based routing protocol for detecting and reporting spatio-temporal events. Anchor nodes are nodes closer to the sink and they act as relays between the convergecast tree and the sink. The sink is assumed to be mobile. We use several mechanisms to save energy: reactive event reporting, constrained route request flooding with a shortcut mechanism, a shortcut mechanism for data reporting, and dynamic clustering for minimizing the number of active clusters in the network. The performance of our protocol is analyzed using WSNet simulator, which is specially designed for event based WSNs. Various metrics such as the average residual energy, the number of active clusters, and the percentage of events processed successfully at the sink are measured.