Impact of Indoor Multipath Channels on Timing Advance for URLLC in Industrial IoT

摘要

In 5G radio access networks, emerging machine type communication in industrial automation, smart grids, automotives, and other applications has increased the importance of establishing accurate time reference up to the device level. For instance, executing real-time isochronous operations in collaborating robots, monitoring, and fault localization in smart grids require ultra-tight synchronization among the devices. To establish time synchronization, however, the time dissemination procedure must accurately estimate and compensate for the base station (BS) to user equipment (UE) propagation delays. In this paper, we use the timing advance (TA) mechanism as an estimator for the time of arrival (TOA) for adjusting the effects of propagation delay in synchronization procedures. We study the impact of TA binning on TOA estimation, and analyze how multipath channels deteriorate the estimation accuracy. Our analysis shows that multipath channels could introduce large errors in TOA, however, averaging the multiple consecutive TA values, in static device deployments, can bring the errors to an acceptable level, i.e., less than 1 microsecond.