Time Synchronization in 5G Wireless Edge: Requirements and Solutions for Critical-MTC

The wireless edge is about distributing intelligence to wireless devices wherein the distribution of accurate time reference is essential for time-critical machine-type communication (cMTC). In 5G-based cMTC, enabling time synchronization in the wireless edge means moving beyond the current synchronization needs and solutions in 5G radio access. In this article, we analyze the device-level synchronization needs of potential cMTC applications: industrial automation, power distribution, vehicular communication, and live audio/video production. We present an overthe- air synchronization scheme comprising 5G air interface parameters and discuss their associated timing errors. We evaluate the estimation error in device-to-base-station propagation delay from timing advance under random errors and show how to reduce the estimation error. In the end, we identify the random errors specific to dense multipath fading environments and discuss countermeasures.