Other articles in this series:

5G Broadcast and Multicast delivery are part of a broader convergence trend around 5G mobile networks for video transport across the lifecycle, from remote production to delivery. Even if broadcasters continue to rely on established digital terrestrial networks for transmission to TV sets in the home, they are going to use 5G Broadcast increasingly for delivery to mobile devices, and 5G for video contribution from the field.

We have discussed various trials of 5G Broadcast and Multicast in an earlier article of this series, focusing then on the delivery aspects. Some of these trials, however, have also involved remote contributions from the field with substantial benefits for the ultimate viewing experience, such as ability to capture multiple camera angles at live outside broadcast events.

Although this series is focused on 5G Broadcast, 5G will really score as a three-way video transport system, switching between broadcast (one to all without the requirement of a SIM), multicast (one to a subscribed group of consumers) and unicast (one-to-one) on the basis of factors such as use case, traffic levels and distribution of users wanting to view particular content. 5G Broadcast is downlink only, it is a one-to-all delivery mechanism regardless of whether that is via a broadcasters’ tower infrastructure (whether or not the receiver has a cellular SIM) or via the cellular network. Multicast and unicast require a data return path for the service to operate, so necessitates the use of a cellular network. This technical constraint drives the need to create a dynamic delivery infrastructure, but this also means that the same system can use the 5G cellular network for simultaneous contribution during a broadcast.

One of the most comprehensive trials featured at IBC 2023 was conducted by Italy’s national public broadcaster Rai as a prelude to incorporation of 5G Broadcast/Multicast with the existing digital terrestrial transmission network via the mobile High Power High Tower (HPHT) overlay model. This was designed to show off the potential of 5G Broadcast for all the stakeholders involved, broadcasters, mobile operators, device manufacturers, content producers and end consumers.

It included video contribution as a major component, feeding back video streams from the field to the Rai Way Data Centre in Rome during the broadcast. This illustrated the scope of the three fundamental delivery options for a 5G ecosystem.

Optimization of this process is ongoing, with further developments coming in 2024 through the next Release of the 3GPP 5G standards, which will be discussed fully in the next and final article in this 5G Broadcast series. One challenge that has been at least partially addressed lies in ensuring that when receiving selective multicast deliveries, users’ service is undisrupted as they move between mobile cells, even at the relatively high speeds of cars or trains. Another challenge lies in devices being ready to receive multicast transmissions while being in an inactive state, in order to conserve their batteries.

Video contribution will often be point to point and therefore require unicast delivery, but this could easily be established alongside a broadcast infrastructure. Rai’s Italian trial also featured other applications, or use cases as they are called, such as transmission of emergency warnings, over the air software updates, and serving automobiles with content. The trial therefore established the potential of a broadcaster’s infrastructure to serve new applications and derive additional revenues as a result.

Many broadcasters lack their own DTT infrastructure and so do not have a network that can be extended or integrated with 5G to serve new applications. For them the role of 5G will be to reach devices they otherwise could not serve directly, and to increase the scope of remote broadcasting and contribution from the field affordably.

Mobile networks began to come of age for remote broadcast contribution under 4G, even if at that stage performance was not good enough for some applications. The emergence of 4G backpack systems initially provided a cost-effective alternative to expensive SNG vans for newsgathering, and for roaming cameras for live sport. The bandwidth of bonded 4G is HD capable but struggles with 4K UHD. With 4K resolution already coming for streaming over fixed IP networks using adaptive bitrate techniques, 4G was unable to sustain the desired QoS (Quality of Service). There was also a technical constraint, the need for source content to be at high enough quality to survive re-encoding multiple times through the editing process and then primary distribution. The increased bandwidth and reduced latency of 5G bring use of cellular 4K UHD contribution systems within reach.

5G bonded cellular contribution systems are already widely available, benefiting from the increased bandwidth and reduced latency, of the first phase of the roll out of consumer 5G networks using 5G NSA (Non Stand Alone), which deploys 5G using 4G core infrastructure. Phase 2 of the cellular roll out will bring 5G SA (Stand Alone) core network infrastructure, with much higher bandwidth and even lower latency, which will open the door to the potential use of 5G for larger multi-camera contribution systems.

Another fascinating use case presents 5G as a flexible means to remotely, simultaneously, connect multiple production studios with less restrictions on their location. Two or more studios spanning locations that are physically separated, might be combined as a single unit for direction. During 2023 a proof of concept project conducted by Abertay University in the UK unified two virtual production studios over a 5G network. The project claimed to have broken new ground by connecting two identical broadcast quality LED wall based virtual production sets, constructed especially for the project in studios in Dundee and Manchester. This allowed two actors to be filmed against a consistent virtual environment, whilst located in two different studios 280 miles apart. Primary video streams, monitoring, comms and LED volume control data were all exchanged. This was achieved using a private 5G network utilizing a core located in Dundee.

Dynamic content delivery models seem set to use 5G Broadcast/Multicast, whilst many of the applications in contribution and production will be unicast. Even so, being able to switch to multicast contribution so that bandwidth is not wasted could be a significant saving when connecting multiple studios for virtual production. Combining 5G Broadcast with 5G cellular contribution will allow producers to blend video from traditional cameras and 5G-enabled smartphones, creating new perspectives. The combination of 5G Broadcast with 5G multicast and unicast delivery and contribution has the potential to disrupt many aspects of the content lifecycle in the years ahead.