Fine-Grained Network Time Synchronization Using Reference Broadcasts

Recent advances in miniaturization and low-cost, lowpower design have led to active research in large-scale networks of small, wireless, low-power sensors and actuators. Time synchronization is critical in sensor networks for diverse purposes including sensor data fusion, coordinated actuation, and power-efficient duty cycling. Though the clock accuracy and precision requirements are often stricter than in traditional distributed systems, strict energy constraints limit the resources available to meet these goals. We present Reference-Broadcast Synchronization, a scheme in which nodes send reference beacons to their neighbors using physical-layer broadcasts. A reference broadcast does not contain an explicit timestamp; instead, receivers use its arrival time as a point of reference for comparing their clocks. In this paper, we use measurements from two wireless implementations to show that removing the sender's nondeterminism from the critical path in this way produces high-preci...

• Type: Conference
• Year: 2002
• Where: OSDI
• Authors: Jeremy Elson, Lewis Girod, Deborah Estrin
• Keywords: Nodes Send Reference, Operating System, OSDI 2002, Sensor Data Fusion, Strict Energy Constraints