Energy Aware Database Updating Protocols for Wireless Sensor Networks

In a classical wireless sensor network, endowed with typical hardware features, especially with high energy level and good stockpiling capabilities, the base station completes the architecture as a required component for a wide range of applications. However, there are some projects where base station deployment should be avoided without reducing network efficiency. A cold storage logistic supervision scheme should use low-budget sensors to monitor items like food products, medicine, etc. Therefore, adding permanent structures like Base Station, inside the truck (used for transport)does not make any sense. Moreover, such applications have to replicate data across all nodes and to maintain same information as well. In this paper , we propose two database updating models for an homogeneous wireless sensor network deployed in a truck without base station. In the first model, a Virtual Base Station (VBS) is elected periodically to act as classical base station for a specific period of time. VBS election algorithm is based on the remaining energy level of each node at the time of selection of the VBS. The second idea deals with Energy aware Wait and See (WaS) protocol which manages update requests to avoid collisions. Like VBS, this protocol is also based on energy. Simulation results (using MATLAB) show that VBS and WaS models introduce very low overhead with respect to the classical network.