DVB combined with 5G offers an evolved ecosystem for media delivery
Emily Dubs, Head of Technology, DVB Project
Earlier this year I wrote a paper that sheds light on the various initiatives targeting interworking – as opposed to convergence – between second- generation terrestrial broadcast and 3GPP systems. The paper, presented at NAB’s BEIT (Broadcast Engineering and Information Technology) Conference, starts by outlining how DTT standards have embraced IP-based approaches and included mobile broadcasting in scope. It then describes how, at the same time, 3GPP incorporated broadcast technologies in its standards and released LTE-based 5G Broadcast as a new terrestrial solution.
The main intention of the paper, however, was to highlight interworking at the service layer, especially with the recent adaptation of the DVB-I specification to support the different Release-16-based 5G operation modes. These include not only 5G Broadcast – relating largely to infrastructure and networks typically used by broadcasters – but also 5G Media Streaming (5GMS), relating to mobile networks. The paper also touches on potential coexistence at the RF level between 5G Broadcast and ATSC 3.0 or DVB-T2 waveforms.
High interest
It has been gratifying to see so much interest in these topics, on which I have also presented – from various angles – at events in Southeast Asia and Europe. Interesting questions arose around, for example, content monetization opportunities that are enabled by the use of DVB-I as a service layer for 5G technologies. These relate to various use cases like enhanced venue-casting and dynamic offloading of unicast networks to 5G Broadcast. Interest was also generated by the possibility – offered by the coexistence of 5G Broadcast and DVB waveforms on the same RF channel – to operate the Commercial Mobile Alert System (CMAS) on resilient broadcast infrastructure using 5G Broadcast, instead of relying on cellular networks.
Even more questions mushroomed on the topic of how second-generation terrestrial standards like ATSC 3.0 compare with 5G Broadcast for Direct to Mobile (D2M), also known as DTT to Mobile (DTT2M) broadcasting. And on why DVB-NIP/T2 (DVB Native IP used with T2), which would be easy to deploy in countries that already have DVB infrastructure, is not itself proposed as a candidate for DTT2M, despite being effectively the equivalent of ATSC 3.0 both in terms of spectral efficiency and in having a fully IP-based core. Many readers will remember broadcast-to- mobile trials undertaken in several countries, notably India, using DVB-T2/ T2-Lite: while satisfactory technical performance was demonstrated, there seems to be a form of collective amnesia about the reasons why this has never been successful!
Existing challenges
The NAB BEIT paper is, however, only really just the start of the story. For me, it has served as a means of preparing the ground for raising awareness of the fact that DVB now offers a unique solution to help countries to build an integrated broadcast-broadband future: 5G networks can complement DVB ones (both legacy broadcast and new Native IP networks) as 5G coverage rolls out, and in a way that allows networks to be used for their own strengths. As outlined in the final section of the paper, the use of DVB-I on top of 5G technologies also provides a means for bridging 5G with satellite delivery. While satellite was not in scope for the paper – it rather focused on terrestrial broadcast – adding OTT delivery over satellite into the equation makes a huge difference, providing groundbreaking, flexible and scalable solutions that meet the wide-ranging challenges currently faced in DVB markets. Key among these challenges are the following:
- How can operators adopt a flexible use of the most appropriate or cost- effective network according to the popularity of services or to whether services target high-density or more rural areas?
- How can the migration journey to hybrid delivery landscapes evolve at an appropriate pace and include new networks in the content delivery ‘mix’ as they become relevant?
- Above all, how can countries that already have DVB histories, especially those where broadband connectivity is not yet well established, connect today people living in rural areas, reusing existing infrastructure while at the same time paving the way for harmonized media delivery in a future where both 5G Broadcast and forthcoming (5G, 6G) mobile networks also come into play, as both coverage and devices become progressively available?
What DVB offers
DVB-NIP delivery combined with – network-agnostic – DVB-I service discovery is the answer. DVB-NIP allows OTT services to be delivered over existing DVB (satellite or terrestrial) networks, while DVB-I enables the discovery of such services delivered through either DVB broadcast networks, LTE-based 5G Broadcast, or 5G Media Streaming (5GMS) mobile networks.
We see, therefore, that combined solutions involving both 5G and DVB networks can seamlessly coexist thanks to DVB-I. In low connectivity areas, for instance, DVB-NIP over existing satellite links (DVB-S2) can be used to reach legacy devices through DVB-NIP gateways and Wi-Fi hotspots. In this way, indoor coverage is easily ensured simply by leveraging the infrastructure already in place (headends, satellite links) and without requiring any device adaptation on the end-user side, while outdoor coverage is left to either 5G Broadcast or 5G unicast networks as they come on stream, and for devices that progressively support 5G technologies.
Such a combination offers the advantage of alleviating the current spectral efficiency disadvantage of 5G Broadcast by removing the need to take indoor coverage into account in the link budget. This reduces the number of transmission towers that are needed to ensure 5G Broadcast coverage for a given target reception area. Above all, such a 5G/DVB-NIP combination is totally seamless for end users thanks to the interworking between heterogeneous distribution networks, enabled at the service layer through the use of DVB-I. In addition, the relevance of such a scenario is strengthened by the fact that DVB-NIP is also envisioned for feeding 5G base stations.
Solution for India
India is a particularly interesting case. There, stakeholders are actively grappling with the problem of direct mobile broadcasting (the aforementioned DTT2M), including connecting devices in rural areas, and there is clear interest in 5G Broadcast. However, since it will make most sense to roll out 5G Broadcast first in areas of high population density, relying on it to provide coverage in rural areas doesn’t seem realistic. Nevertheless, the huge size of the market naturally encourages companies to put forward various solutions whatever the price might be, and the Indian government is currently focused on assessing candidate solutions for DTT2M (with ATSC 3.0 also under consideration, in addition to 5G Broadcast). However, DTT2M meets only part of the challenge, as the broader need is to connect people beyond the main cities and to serve content (live and on-demand) directly to mobile devices, preferably the existing ones!
Now that DVB-NIP is standardized, and now that DVB-I is better understood and supports 5G technologies, DVB offers the key to a standards-based solution to India’s needs. It is a solution that combines DVB networks with 3GPP ones thanks to DVB-I, that doesn’t require specialized hardware in mobile devices, and that leverages the broadcast infrastructure already in place in India. I believe it is a more appropriate solution when compared with a fully blown 5G Broadcast deployment that would be very challenging considering the huge investments (and amount of time) that would be required to achieve good coverage – including indoors – and to address the legacy base of mobile devices, that may last for a long time yet.
It is noteworthy that my NAB BEIT paper was referenced in a landmark report on “Television Broadcasting to Mobile Handheld Devices” that was published by the Telecommunication Engineering Centre (TEC) of the Government of India. Even if it does include mention of this deployment scenario, whereby DVB-NIP ensures indoor coverage, such a scenario doesn’t yet seem to be fully accepted as being part of the solution. I am glad, in any case, to be in dialogue with the TEC in India and to have opportunities to tell the full story. And it’s a story that is relevant to many other markets, not least in Southeast Asia, where similar discussions are under way.
In conclusion
DVB’s evolved ecosystem is now in place: a modern, standards-based approach that enriches resilient broadcast systems with well-rounded IP-centric solutions, including for the delivery of OTT services, whether over broadband or broadcast; and those networks can be combined and/ or bridged with 3GPP technologies in a flexible and seamless way.
This article first appeared in Issue 64 of DVB Scene magazine.
Emily Dubs is Head of Technology for the DVB Project, leading on technical and standardization activities, representing DVB around the world at conferences and tradeshows, and supporting its modules and working groups.
