Local clock-based timestamp synchronization for multihop ad hoc and sensor networks

Many applications involved in multihop ad hoc and sensor networks demand synchronizations in a local or global range, but most of existing synchronization protocols consume too much energy of sensor nodes due to periodical synchronization operations. This paper proposes an on demand mechanism, in which a sensor node uses its local clock to generate timestamps for events that it senses, and then the timestamps can be synchronized to a reference time base. By decoupling the synchronization operations from the data communication, the transformation of timestamps can be optimized independently from the delivery of data packets. The simulation demonstrates that the proposed scheme can achieve a tradeoff between protocol overhead and synchronization accuracy.