Issues of signal strength of wireless sensors for civil infrastructure monitoring

Research was conducted using simulated civil infrastructure system conditions to evaluate issues pertaining to signal strength. This research evaluated the performance of the wireless MICA2 sensor motes developed by Crossbow Technology, Inc. The data collected is intended to demonstrate how the motes would perform in a typical civil infrastructure application when placed in a large network of sensors. Specific to signal strength, the strength, quality, and reliability of the signal originating from remote sensor was assessed as a function of its distance from the Gateway Sensor. These experiments encompassed several factors that relate to signal strength and distance such as single motes, multiple motes, single hop, and multi-hop. Experimentation was also performed to evaluate the mote performance for buried applications. The results of the experimentation show that in all cases the quality, reliability and strength of the transmitting signal is a function the distance of the Gateway Sensor from the obstruction and the amount of signal scattering caused by the material surrounding the mote.