Optimising 5G for low latency broadcast production

Public and private 5G networks have proved useful for electronic newsgathering [1-4] where latencies of up to 2 seconds can be tolerated. 5G Networks introduce jitter and delay into the data path as consequences of the uplink scheduling process and retransmission mechanisms that manage transmission errors and packet loss. However, low latency broadcast production and audio applications need much lower delays and more stable performance. The performance depends upon the vendor implementation and its configuration. Previous projects [5] reported significant jitter spikes and concluded that 5G networks cannot readily support the 4 ms target required for audio performances requiring in-ear monitors. Tuning the 5G configuration to reduce latency helps, but there is often a trade-off between latency and spectrum efficiency. This paper examines the collaborative efforts of BBC R&D, TV2 and Neutral Wireless to investigate and optimise 5G for low latency production in TV studio settings and multi-camera outdoor broadcasts, which in many aspects differ from newsgathering. We discuss the performance and optimisation of the scheduler, along with the latency/capacity trade-off. Achieving an 80 ms latency for video production using commercial hardware is now feasible, and we explore the potential for further reduction. 5G remains an attractive option for future bi-directional PMSE (Programme Making and Special Events) technology, and we identify areas for future research.