Cooperative Multi-tree Sleep Scheduling for Surveillance in Wireless Sensor Networks

Idle listening is a major source of energy consumption in Wireless Sensor Networks (WSNs). Sleep scheduling techniques put nodes into sleep, alleviating this problem. However, this increases the response time of the network. For this reason, these techniques must consider the network requirements. Many advanced WSN implementations manage heterogeneous data with different, and maybe opposite, requirements. In this case, traditional sleep scheduling strategies are not efficient. To solve this, we design a sleep scheduling strategy for heterogeneous traffic based on the division of the network in multiple trees. Each tree manages a specific traffic flow, considering its specific requirements. This strategy is applied to a Wireless Sensor Surveillance Network (WSSN) that includes ambient conditions monitoring, event detection and real-time positioning. The simulations show that the proposed strategy can significantly reduce the idle consumption without degrading the network performance.