Practicalities and Analysis of Using PTP over 5G Systems with Dedicated Time Synchronization Support for Media Production

The 5G system is becoming more and more a multi-purpose wireless network. Several industry verticals have started using 5G networking technology for their purposes. 3GPP has defined a set of dedicated features relevant to one or more industry verticals. These new features make 5G more suitable for different media production scenarios, such as remote production or mobile studio scenarios, extending the local OB Van facilities and replacing the traditional RF cameras. 5G systems support bi-directional communication by nature, using Time Division Duplex (TDD) or Frequency Division Duplex (FDD). This would allow replacing multiple existing RF transmitters and receivers with a single RF solution. Further, the 5G radio network simultaneously shares the available spectrum with many devices by scheduling small radio resource units. However, some of these 5G systems concepts can become tricky to use for high-performance media over IP due to inherited jitter (due to scheduling and TDD), throughput variations, and path asymmetries (due to capacity allocation for uplink and downlink). The time synchronization between media sources can be challenging in 5G environments due to varying latencies of the radio transmissions. The paper explores the possibility of using IEEE 1588, Precision Time Protocol over a 5G system for media production applications. With 3GPP TS 23.501 Release 16, the 5G System specifications started to include dedicated time synchronization support. 3GPP Release 16 added specific time synchronization support for Time-Sensitive Networks (TSN), i.e., acting as a Time-aware system. With 3GPP Release 17, the support for IEEE 1588 is extended with several additional features. It becomes possible to use PTP according to the SMPTE ST 2059-2 PTP Profile reliably over 5G for media device synchronization. The paper describes lab sessions performed by the 5G RECORDS consortium members, testing the performance of PTP over 5G with and without the dedicated time synchronization support. A trial with a real camera supporting SMPTE ST 2110-22 with JPEG XS was conducted to experiment with synchronization and packet pacing precision. The paper also describes the testing setup based on the open-sourced software used by the team and the methodology developed. The paper concludes on the performance and synchronization quality when using PTP over various 5G systems and analyzes the results from the lab trials.

Published

2022-10

Content type

Original Research

DOI

10.5594/M001966

ISBN

978-1-61482-963-8