  Emerging industrial applications involving robotic collaborative operations
and mobile robots require a more reliable and precise wireless network for
deterministic data transmission. To meet this demand, the 3rd Generation
Partnership Project (3GPP) is promoting the integration of 5th Generation
Mobile Communication Technology (5G) and Time-Sensitive Networking (TSN). Time
synchronization is essential for deterministic data transmission. Based on the
3GPP's vision of the 5G and TSN integrated networking with interoperability, we
improve the time synchronization of TSN to conquer the multi-gNB competition,
re-transmission, and mobility problems for the integrated 5G time
synchronization. We implemented the improvement mechanisms and systematically
validated the performance of 5G+TSN time synchronization. Based on the
simulation in 500m x 500m industrial environments, the improved time
synchronization achieved a precision of 1 microsecond with interoperability
between 5G nodes and TSN nodes.
