The Design and Implementation of Energy-aware Data Gathering Techniques (EDGE) for In-building Wireless Sensor Networks

In wireless sensor networks, application-dependent protocols are usually needed. In our application, each room in a building is equipped with a sensor node which can detect a fire and transmit its identifier to a monitoring station. In addition, the monitoring station needs to monitor the current status of each room periodically. To support such an application using the wireless sensor network, a data gathering technique with energy savings is needed because of the limited battery life in sensor nodes. In this paper, we propose EDGE, which consists of EAGAR (energy-aware data gathering routing) and OHIO (opportunistic hop-in aggregation). EAGAR provides energy-savings and resilience to node failures, while OHIO prolongs the network lifetime through data aggregation. In addition, our OHIO technique determines aggregation points dynamically and opportunistically. This is different from other aggregation techniques that use fixed or static aggregation points. OHIO does not assume the existence of a limited number of source nodes. Hence, EDGE is very suitable for applications where all sensor nodes can be source nodes. We designed and implemented EDGE into MicaZ motes sensors running TinyOS. We have successfully realized the test-bed and demonstrated that our EAGAR and OHIO techniques provide significant improvement in energy-savings of sensor nodes and in the extension of network lifetime.