Clock Synchronization for Wireless Time-Sensitive Networking: A March From Microsecond to Nanosecond

Industrial control systems in the era of Industry 4.0 present significant challenges from a communication perspective, that is, low latency, ultrahigh reliability, and accurate synchronization. Time-sensitive networking (TSN) has emerged as the main solver of these challenges. As a research trend, TSN and wireless technologies are expected to converge in the wireless TSN paradigm. This convergence starts with the adoption of accurate clock synchronization over wireless systems. In this article, we review the existing wireless clock-synchronization approaches and their attainable performances, and we discuss their feasibility to enable wireless TSN. We conclude that the existing clock-synchronization techniques are enough to enable wireless TSN, although significant implementation efforts are required to incorporate accurate clock synchronization over wireless systems.