Description

In this research work the contribution is on mission-critical applications such as battlefield reconnaissance or industrial safety and security, a large number of sensor nodes are deployed in a large area to detect and report event related information to the end-users. When a critical event in the monitoring region is detected by a node, alarm should be broadcast to all the other nodes in the neighborhood. As the sensor nodes are expected to work for a long time without recharging their batteries, a sleep scheduling is always used. During the monitoring process two determined traffic paths are used. If a critical event occurs, an alarm is quickly transmitted along one of the traffic paths to a center node, and then it is immediately broadcast by the center node along another path without collision. Here the broadcasting delay is independent of the density of nodes and its energy consumption is low. The upper bound of the broadcasting delay is only 3D +2L where D is the maximum hop of nodes to the center node, L is the length of sleeping duty cycle. For the transmission of alarm message the Quadrant-based Directional Routing for achieving the power consumption, and level-by-level offset based wake-up pattern according to the paths, respectively.