26, Jun, 2009
ISEP-IPP, Porto, Portugal

We present a novel low-power hardware module for achieving global clock synchronization by tuning to the electromagnetic energy radiating from existing AC power lines. This signal can be used as a global clock source for battery-operated sensor nodes to eliminate drift between nodes over time even when they are not passing messages. The frequency of the AC voltage is very stable over time and geographic area; and synchronization based on AC signal, in an ideal case will make sure that two nodes in an area under one common power grid may remain in sync for a long duration of time without exchange of any synchronizing message. There are three major issues which we address in the design of this module: 1. Hardware should consume as low power as possible 2. Eliminate Jitter in the received signal 3. Compensate for phase offset across different nodes in the tuned signal.
When: 12:00
Where: Meeting Room at 1st floor, Building E ("Sala de Reuniões")

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