Time Synchronization for 5G and TSN Integrated Networking

TL;DR

The paper addresses the need for deterministic wireless data transmission in industrial settings by enabling precise time synchronization across integrated 5G and TSN networks. It proposes an IEEE 1588/802.1AS-based solution implemented in NG-RAN with hardware-assisted timestamping, dual-clock counters, and HARQ-aware synchronization to overcome multi-gNB competition, retransmission, and mobility challenges. Key contributions include: (1) high-precision timestamp acquisition in 5G, (2) collision-aware synchronization schemes and Dual Clock Counter Mode, (3) HARQ-aware timing adjustments, and (4) comprehensive OMNeT++ validation showing ~$1\,\mu s$ accuracy under realistic industrial conditions. The results demonstrate interoperability between 5G and TSN with deterministic performance suitable for industrial automation, detailing practical parameter bounds for maintaining sub-$1\,\mu s$ precision under mobility and load."

Abstract

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.

Figures (22)

• Figure 1: The 5G and TSN Integrated Networking architecture proposed by 3GPP. the TSN network is connected to the device-side TSN network through a 5G transparent bridge. The 5G Core Network is wired to the Network-Side TSN network, and the Device-Side TSN network is wired to the 5G terminal. The Device-Side TSN network realizes the connection with the Network-Side TSN network through the NG-RAN.
• Figure 2: Operation flow of time synchronisation protocols in IEEE 1588 and 802.1AS protocols, implemented using a Peer-to-Peer Transparent Clock Mechanism.
• Figure 3: Clock Frequency Synchronization Mechanism. It is used to calculate the difference in clock frequency between master and slave nodes from the time synchronization information of two adjacent times.
• Figure 4: Sampling Result for Time Synchronization when using the same clock counter for generating message timestamps and applying time synchronization offset. $4.282\mu s$ is the maximum value of sync errors in the results, and each sync error persisted for some time before being eliminated.
• Figure 5: Synchronization Collision Scenario 1: The transparent clock first transmitted the Sync message to the slave node and later responded to its peer delay measurement request.