Low-power clock synchronization using electromagnetic energy radiating from AC power lines

Clock synchronization is highly desirable in many sensor networking applications. It enables event ordering, coordinated actuation, energy-efficient communication and duty cycling. This paper presents a novel low-power hardware module for achieving global clock synchronization by tuning to the magnetic field radiating from existing AC power lines. This signal can be used as a global clock source for batteryoperated sensor nodes to eliminate drift between nodes over time even when they are not passing messages. With this scheme, each receiver is frequency-locked with each other, but there is typically a phase-offset between them. Since these phase offsets tend to be constant, a higher-level compensation protocol can be used to globally synchronize a sensor network. We present the design of an LC tank receiver circuit tuned to the AC 60Hz signal which we call a Syntonistor. The Syntonistor incorporates a low-power microcontroller that filters the signal induced from AC power lines ge...

• Type: Conference
• Year: 2009
• Where: SENSYS
• Authors: Anthony Rowe, Vikram Gupta, Ragunathan Rajkumar
• Keywords: Clock Synchronization, Sensor, Sensor Networks, Sensor Nodes, SENSYS 2009