Performance Evaluation of ZigBee and UWB Wireless Sensors under Doppler Effect in Rotating Mechanical Structures

Wireless sensors are expedient for an increasing range of applications, including the ones intended to operate in the industrial environment. Among the critical challenges characteristic to this scenario can be listed complex multipath propagation caused by the refractions from the metallic enclosures, mobility of the objects and presence of the rotating structures (e.g., engine components, windmills, gearboxes). The effect of the latter on the performance of the two wireless communication technologies, namely ZigBee and IEEE 802.15.4-based Ultra-Wide Band (UWB), is studied by the means of real-life experiments. The measurements were carried out in the laboratory environment with the transmitter installed on a rotating stand and the static receiver. The purpose of the experiments was to estimate the effect of the tangential speed on the number of packets lost by each of the focused technologies. The maximum tangential speed achieved in our experiments was over 52 m/s, which is far beyond the ones tested and reported in the previous studies. The results of the experiments show that even for the tangential speed of 52.4 m/s, which corresponds to the linear speed of 188.6 km/h, the Packet Error Rate (PER) for ZigBee and UWB did not exceed 4% and 7% respectively. These results confirm that both technologies are potentially capable of operating in highly dynamic environment, thus enabling novel applications and use cases.