Performance Evaluation of the Precision Time Protocol (PTP) over a Commercial 5G Campus Network

Sammanfattning

Accurate time synchronization is a fundamental requirement for industrial systems, particularly applications relying on deterministic communication and coordinated control. While the Precision Time Protocol (PTP), or IEEE 1588, can achieve a sub-microsecond accuracy in wired local networks, its performance over wireless networks such as Fifth Generation Mobile Network (5G) remains challenging due to signal propagation effects and varying wireless delays from radio scheduling. This thesis presents an experimental evaluation of PTP performance over a commercial 5G campus network in an industrial research environment. A wired Ethernet network is used as the baseline to benchmark the impact of wireless connectivity. The study focuses on two primary key performance indicators: syn- chronization accuracy, represented by the mean of the time offset between PTP master and slave, and synchronization precision, represented by the standard de- viation of the offset. The obtained results show that PTP over 5G can maintain synchronization accuracy close to zero microseconds under the evaluated test sce- narios. However, the precision is significantly degraded as compared to wired Ethernet due to the 5G network’s lack of support to compensate for the transit delay and packet delay variations. Further analysis reveals that the dominant factor affecting time-sync perfor- mance is packet delay variation from 5G resource configuration and scheduling. The impact of message timestamping, radio signal conditions, and downlink-uplink delay asymmetry is found to be secondary as compared to the delay variability in- troduced by the 5G network. The findings indicate that, although PTP over 5G is able to support applications requiring microsecond-level synchronization accuracy and precision, its current performance is not sufficient for time-critical industrial applications which require a sub-microsecond precision. This work provides ex- perimental insights into the limitations of wireless-based time synchronization and highlights the need for network-level enhancements to support deterministic com- munication over 5G.