Vibration measurement with routing-free multihop wireless sensor networks and its application to a long-span bridge

The use of wireless sensor networks for long span bridge monitoring has been expected to remove large portions of sensor installation cost and time. However, the large size of such structures poses difficulties. The communication distances are oftentimes shorter than the bridge scale. Elaborated plans on RF transmission and installation locations are often required. The authors proposed the use of efficient flooding scheme exploiting constructive interference phenomena. This approach does not require routing. Even when the RF communication environment is not stable, the path information does not need to be updated. As a result, the multihop communication becomes simple and robust, allowing to realize easy and inexpensive sensor networks covering large structures. This communication method is first introduced and then applied to a long-span suspension bridge vibration measurement. The identified dynamic characteristics of the target bridge are discussed.