Wireless Fine Time Measurement Implementation and Analysis in Indoor Factory Environments

Positioning and accurate time delay measurement techniques have been used with the Internet of Things (IoT) and embedded systems due to their importance in providing location information for the communicating nodes. In the last two decades, positioning techniques were introduced using the Received Signal Strength Indicator (RSSI) of Wi-Fi signals and time-based techniques. Fine Timing Measurement (FTM) is the most important time-based technique, which relies on the captured timestamps during the messaging between nodes. Thus, in addition to its originally intended application for wireless localization, it can be used for the future of Wi-Fi Time Sensitive Networking (WTSN), where low latency, low jitter, and precise time synchronization play an important role in Industrial IoT (IIOT)-oriented applications.The presented work considers FTM’s behavior and performance measurements, especially in a factory environment with different room sizes. An Automated Physical Test Bed (APTB) and emulated multipath propagation model based on ITU-R radio wave propagation standard for the factory environment are considered in the work. The results show that the FTM performance is noticeably affected by multipath signal propagation, thus increasing RTT, delay, and fluctuation in jitter and resulting in a noticeable degradation in RSSI. In contrast, the total number of correctly received frames is not affected, indicating the efficiency and reliability of the Wi-Fi FTM technique.