Comparison of approaches to time-synchronous sampling in wireless sensor networks

• Two approaches to synchronized sampling are suggested: proactive and reactive.
• The proactive approach integrates better with regular communication schemes.
• The reactive approach is better suited for irregular communication.
• At high signal frequencies the proactive approach yields better results.
• Software interdependencies are reduced in the reactive approach.

Time synchronization is required in many data acquisition applications for sensor networks. A large variety of time synchronization protocols for wireless sensor networks has been suggested. Yet, setting up a sensor network for synchronized data acquisition based on those algorithms is not a trivial task. This paper outlines different approaches to time synchronous sampling in wireless sensor networks. The approaches are implemented on a wireless sensor network. Experiments are done to compare the signal quality of the signals acquired with the different approaches in terms of frequency error, signal-to-noise ratio (SNR) and total-harmonic-distortion (THD). Furthermore, the approaches are compared in terms of the effort required for communication and implementation.