Development of a time-synchronized wireless sensor network

Network-based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of buildings or civil engineering structures, which often requires vibration measurement. For vibration measurement via a wireless network, time synchronization is indispensable. In this paper we introduce a newly developed time-synchronized wireless sensor network system. The system employs an IEEE 802.11 standard-based TSF counter and sends the measured data with the counter value. It makes possible consistency on a common clock among different wireless nodes. We describe the accuracy evaluation by simulation studies as the size of the nodes is increased. The hardware and software specifications of the developed wireless system are presented. The experiments were conducted in a three-story reinforced concrete building and the results showed that the system performance significantly exceeds requirements.