This paper analyzes a new and accurate overthe-air time synchronization (TS) method for industrial LiFi networks which achieves synchronization via the exchange of timestamps between nodes. The necessity for accurate TS will become increasingly important with future networks due to its connection with industrial applications. Over-the-air TS vision is to achieve accuracy of the order of 1 µs. In this technique, timestamps are transmitted using optical signals which are used for the estimation of the time-of-arrival (TOA). To this end, the Cramer-Rao Lower Bound (CRLB) is computed as the theoretical limit on the performance and accuracy. In this way, the effects of distance, optical power, and semi-angle at half illuminance of the transmitter are investigated. Calculations and comparison show that the proposed technique can be efficiently used for TS in future wireless networks.