Ian Wagdin (BBC R&D)
Over recent years, news crews have increasingly relied on mobile networks to get pictures from the heart of the action: they offer a great way to get to places that you just can’t reach with a satellite truck or cables. This means that there is computer hardware and kit available to broadcast from anywhere you can get a mobile signal. While this is OK most of the time, at big events the large mobile networks can get saturated with data very quickly, as everyone tries to upload content to social media and journalists compete to send their pictures back to news channels.
For such events the mobile network operators can add capacity, but this is aimed at their customers and is generally spread over a wide area. This means that broadcasters cannot rely on this provision when they most need it; so they use other technologies to support their output, leaving all the kit that supports news contribution unused.
BBC News approached BBC Research & Development following our successful trial of 5G Non-Public Networks (NPNs) at the Commonwealth Games last year and asked if we could help solve this issue. It was a big challenge: could we provide a private 5G network that was available for the days leading up to the event and during the coronation itself? The requirement was high uplink capacity, over a large area, which could be offered to news broadcasters from around the world. It led to the deployment of the largest temporary private 5G network yet.
While we had trialled and tested smaller scale networks previously, this had been to support only one or two cameras. This would be a much bigger challenge. We planned to support up to 30 devices, all streaming high data-rate video from any point along The Mall in central London. We partnered with Neutral Wireless, a specialist in 5G NPNs that we had worked with previously on our 5G Rural First project on Orkney.
One of the challenges of streaming lots of professional video is the need for a high- capacity uplink. Most public networks are designed for their subscribers to download content. The only way we could deploy a network to support the amount of traffic was to
use spectrum separate from the public networks and available for shared access. Working with Ofcom, the regulatory body in the UK, we were able to secure 80 MHz of radio capacity centred on 3855 MHz.
We deployed eight cells, all with very low transmit power but high receive capability. This provided reliable and constant coverage from Buckingham Palace to Admiralty Arch. Using mobile bonding devices such as LiveU’s LU300 with 5G modems and dedicated SIM cards, we were able to move traffic away from the public networks and onto our private network.
This traffic was then backhauled over fibre to Broadcasting House where it met the internet, and from there to whichever broadcaster was connected. For operators and broadcasters the workflow was pretty much the same as they use every day, but we could be confident that their units would work no matter how busy the public network became. We had over 60 SIMs connected from multiple broadcasters from around the world.
Part of this work also involved Neutral Wireless building a dedicated user interface that enabled us to easily set up and monitor the network and provided special features applicable to the broadcast domain. We were able to identify how many cameras were on each cell and how the cells were performing. This in turn enabled us to identify which cell a particular device was on and whether they had the optimum connection for streaming live video.
5G for production
As part of this work we also wanted to see how we could use 5G networks for production. This requires high-capacity, low-latency networks that can deliver UHD HDR (high dynamic range) pictures with bidirectional control. Working alongside Sony, we had two cameras operating on a separate cell in front of Buckingham Palace. Here we also deployed DQoS (Dynamic Quality of Service), which prioritizes the active camera over others on the network. This has added to our understanding of how these networks may be used in the future.
This article, along with additional photographs, first appeared in issue 57 of EBU tech-i magazine.