Long term vision for the UHF TV band

As the related article 'UHF Battleground' in this edition of our Newsletter explains, the ECC set about its technical background work on the 700 MHz band as a short-term priority, even though some of the policy implications remain a matter of debate, and positions in Europe are quite diverse. We also considered it important to create a better understanding of the technical possibilities which could drive the future use of the remaining part of the UHF broadcasting band, especially in the range below 694 MHz. We set out the reasons for this in our Newsletter article on the subject last year, where we described the establishment of the ECC’s Task Group 6 (TG6), chaired by Jaime Afonso of Portugal, the ECC Vice-Chair.

TG6’s report is a necessary step towards providing clarity and certainty for all stakeholders about the future use of this band – stakeholders who need a stable environment for future investment. Since its establishment TG6 has attracted a very large participation from the broadcasting and mobile sectors, as well as from the administrations. Meetings typically have about 80 participants. The group also developed an interesting dynamic, tending to focus more on what would be possible rather than arguing about what wouldn't.

It is well-known that 'High-Power-High-Tower' broadcast services, which seen through the mobile services' lens are essentially large-scale downlinks, are incompatible with mobile service uplinks. Co-channel reuse distances can be many hundreds of kilometres; and this is the core problem in seeking to accommodate a heterogeneous European approach. But that is only a part of the story.

The fact that terrestrial TV remains the dominant means of delivering the heavily-used public free-to-air services underlines that it needs adequate provision for the foreseeable future. A simple extrapolation of numerical reductions in its use in recent years would not be an adequate predictor of future spectrum demand. Another complicating factor is the evidence that growth of non-linear video consumption (You Tube, catch up TV etc.) is not balanced by a corresponding reduction in linear TV consumption.

TG6 was not set up to quantify what that means, nor to estimate the impact of different bandwidth availability on the development of mobile broadband. It would be very damaging, but not without precedent, to make regulatory allocation decisions based on a current or short-term appreciation of consumer behaviour and technology, extrapolated into an era where these have changed. Therefore, at the heart of TG6’s mission was to identify the likely scenarios for trends in mobile and broadcast use, and particularly to consider – but not to predict definitively – the extent to which the applications and technologies would converge over time.

The convergence issue is particularly worthwhile to explore, given that the predicted source of traffic demand both for wireless broadband, and of course for broadcasting, are generally agreed to be in the area of some form of audiovisual material. This in itself suggests an increasingly asymmetric distribution of spectrum requirement for downlink and uplink components of wireless broadband. This is in parallel with some increasing interest in greater interactivity in the broadcasting world.

Against this background, TG6 was set up to:

  • be forward-looking;
  • set out frequency management options;
  • address the flexibility which may be required in different countries, particularly considering the cross-border issues;
  • consider how broadcast-mobile convergence might evolve (not how it will evolve) and to try to develop an understanding of its implications and role; and
  • to maintain a technical focus.

TG6 has now produced its draft ECC Report (no. 224), which has been subject to public consultation; the results of which will enable it to finalise its work and publish the final report in November 2014. The report includes a large amount of data gathered by administrations and elsewhere, particularly about video consumption by different media, as well as practical considerations such as existing rights of use in the band, and the impact of technology development in both broadcasting and mobile domains.

The draft Report sets out four alternative scenarios.

  • Class A: Primary usage of the band by existing and future DVBi terrestrial networks
  • Class B: Hybrid usage of the band by DVB and/or downlink LTEii terrestrial networks
  • Class C: Hybrid usage of the band by DVB and/or LTE (including uplink) terrestrial networks
  • Class D: Use of the band by future communication technologies (not just 'mobile as we know it')

The group did not offer these scenarios as individual 'one-size-fits-all' solutions; the Report includes an analysis of the extent to which they might co-exist, especially given technical constraints of mutual radio interference.

It further concluded that the long-term usage of the band 470-694 MHz would mainly be foreseen for downstream audiovisual content distribution. These services may be linear or non-linear, with a huge variation in the number of receiving users served by a particular content provider: from one up to several million users, and that in turn would influence the technology used.

But even with differences in the technology and the network density used, downlinks, including broadcasting, are much more technically compatible with each other than they are with mobile uplinks. And this will - or should - be the dominant consideration in future planning and evolution of the band.

Another important part of the group’s work was to identify indicators of progress towards any of the various case scenarios, testing the assumptions used to develop them. These centred mainly around patterns of consumption (e.g. linear and non-linear) and equipment (e.g. product lifecycles). The Report suggests what these might be, although it recognises that further work is required to develop ways to measure and monitor the indicators with more confidence. It also identified a long list of 'non-binding' but very practical factors which would determine how the scenarios would evolve.

In order to facilitate the different scenarios considered by the Report, TG6 identified that it could be necessary to introduce more flexibility in the regulatory environment governing the use of this band. This may entail seeking corresponding changes in the Radio Regulations (the ITU framework), notably where technological advance blurs the historic distinctions between the mobile and the broadcasting service. There is also significant flexibility in the ITU regulations and the GE06 agreement, which could be used in the shorter term.

ECC Report 224 is timely. The subject of UHF and its future is receiving close attention in a number of fora and the Report is a useful contribution to inform and influence these processes. At the global level, there is the WRC-15 agenda item 1.1 seeking increased allocations for mobile broadband. Within the EU, the European Commission has also identified the need to clarify the long-term vision for UHF. A 'High-Level Group' of senior industry figures set up by outgoing Commissioner Kroes has already delivered its reportiii. The Commission has also commissioned a study from consultants (Plum Consulting) on some of the dynamics and possible economics of broadcast-mobile convergence. This attempts to be more predictive than TG6's study on some specific convergence propositions, but tentatively concludes that the economic case for convergence is not yet persuasive. In addition, the Radio Spectrum Policy Group, a high-level advisory group of EU member states to the Commission, has also started work to develop a report on the subject of a UHF long-term vision.

So far, the common theme in all of these activities is to develop a good understanding of evolution and dynamics. But there seems to be a wide recognition that it is too early to pick specific winners and scenarios at this point in time.

Mark Thomas
Director of the ECO

i Digital Video Broadcasting
ii Long Term Evolution
iii The 'Lamy report' recommends (a) dedicating 700 MHz to wireless broadband by approximately 2020,(b) safeguarding frequencies below 694 MHz for terrestrial broadcasting (presumably to the extent required) until 2030, and (c) reviewing the market position in (about) 10 years' time.

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