So… what is the verdict on the future of the sub-700 MHz band?

PlumThe short answer is: nobody knows. The slightly more elaborated version is: after the study by Plum consulting, the cost and benefit of deploying a converged platform in sub-700 MJHz band is still unclear because of the uncertainties of the market demand for audio-visual service and the valuation of the sub-700MHz spectrum, so let’s wait another 5 years before drawing any definitive conclusions when these uncertainties somehow become less uncertain.

This is basically the message delivered by Plum consulting in the final EC workshop on Broadband-Broadcast convergence which I attended yesterday in Brussels. Or at least it is my and a few other attendees’ (somewhat pessimistic) impression.

As a short explanation on the background of this discussion: the EU commission is trying to formulate a cohesive strategy on how to deal with the sub-700 MHz band in the future, not least in the upcoming WRC-15. Apparently, EU is trying very hard to avoid the same situation in WRC-12 when it had to passively accept the decision of allocating the 700 MHz band to mobile usage, an agenda pushed by other non-EU countries. The broadcasters who originally have the exclusive access to the UHF band in 470-790 MHz are now pushing for a policy ensuring the safeguard access to the remaining sub-700 MHz band for an extended period of time—possible up until 2030. On the other hand, the mobile operators simply want more spectrums in this attractive frequency range and already hope to get a co-primary allocation in the sub-700 MHz band in WRC-15, however unlikely it maybe. Given the political status of the free-to-access DTT service in Europe and the importance of mobile broadband to digital economy, this is a highly sensitive issue to balance. One option is to develop a converged infrastructure platform that can provide both services efficiently. Plum consulting is hired by the Commission to conduct a cost/benefit analysis for such an option with a 15 years horizon.

Plum consulting has already held two workshops earlier this year, one in March and one in July, where they have presented their objectives and methodology. They focused on analyzing a converged platform based on Low Power Low Tower infrastructure, either using DVB or LTE technology. Convergence on content, application and service level are not included, because they would develop under the market mechanism while the convergence on the infrastructure level requires intervention from policy maker and regulator.

There had been a lot of discussions on their models and assumptions in the last two workshops. But overall I found it a reasonable approach, at least from the technical point of view (our paper studied on a similar subject (called CellTV) was also used as a reference in their study). The main advantage of LPLT network is that it can form large scale SFNs with small guard region in-between than HPHT DTT networks. In fact a recent study from ATDI and Qualcomm states that co-channel SFN could be deployed even without guard region by pointing the receiving antenna at the right direction. In the end it is estimated that 110-170 MHz spectrum in the 470-694 MHz band could be released by replacing the HTHP DTT network with a LPLT network, which sounds very promising.

However, what really complicated the picture is the difficulty in the transition from current DTT system to a converged LTLP network. The simulcast period may require considerably more spectrum than what is available in the sub-700 MHz band. The diversity in the EU member states w.r.t the DTT service penetration makes this process and planning more difficult. The cost for this transition thus varies significantly depends on what assumption you make.

On the other hand, the benefit, or the value of the saved spectrum is not clear either. Plum has estimated it to be in range of 0.1 to 0.45 euro per MHz per population based on previous spectrum auctions in other bands—just another reason to wait and see how much would be paid for the 700 MHz band.

In the end, the results seem to be less sensitive to the technical assumptions but more to the market demand. Both the cost and benefits have a large range of variation depending on the latter assumption. Thus they failed to reach a definitive answer, at least on the EU level. And no one is willing or able to make a strong decision to drive for one direction or the other.

Ending on a slightly positive note, at least Plum’s recommendation is to review this option in 3-5 years when the market gives a clear indication. In contrast, another study by EU High Level Group chaired by Mr. Lamy directly excludes the convergence option and instead sticks to a co-existence approach with an even more conservative timeline (someone comment this report is an admission of the failed attempt, albeit written in a politically correct manner, to reconcile two unreconciled groups, i.e., the broadcasters and the mobile operators). Mr. Lamy wrote in his report, ‘’we should be aware about the pace of changes we face and what is at stake if we just wait and may believe that staying in our comfort zone could last forever’’, but unfortunately, it seems ‘staying in our comfort zone’ for a while longer is just what we are doing.


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3 Responses to So… what is the verdict on the future of the sub-700 MHz band?

  1. Darrin Mylet says:

    You solve wireless capacity issues by building smaller cells, not throwing more and more spectrum at macro sites. EU have done good job of keep mobile carriers from gobbling up all the spectrum and sitting on it. They should continue this and work to make more spectrum below 700 available for shared use, look at the value of WiFi and think how this could be used for not spots, IOT and other ideas not yet invented. US, UK, Singapore all moving forward, EU needs to catch up and build more pilot networks testing potential issues raised by incumbents.

  2. jzander says:

    The options for solving the problems of traditional “linear” broadcasting “over the air”, all seem to be very, very complex – the question is what is the future benefit ? What is the expected lifespan of those systems? Looking at the Scandinavian countries, the number of viewers “over the air” is now down to 15-20% decreasing every year as viewing habits change and with the deployment of more broadband infrastructure. Yes, Plum looks at the UK market – probably together with Spain and Italy the stronghold of linear TV in Europe. But the “tipping point” is likely to be near there as well. When the viewing habits change to the internet way of watching TV, things move fast.

    On the other hand – there is hardly any drama since co-existence seems to be the natural solution. Contrary to previous beliefs, the mobile industry is hardly that interested in spectrum below 600 MHz. Antenna performance becomes so bad in handheld devices which makes this spectrum is not very suitable for capacity expansion. As Darrin points out, high spectrum and small cells is much more suitable for that. This means that the spectrum below 600 is more than enough to broadcast those maybe 10 channels that have a really wide audience (i.e. more than 1% of the population) in rural areas. The rest of the channels you can distribute over IP (mobile or fixed). I support the idea though that the 600 MHz band could be repurposed for wide-area M2M systems, possibly under different licensing regimes.

  3. Lei Shi says:

    I agree, a converged platform is perhaps unnecessarily complex. And in my view, DTT has its place even in the 15-20 yr horizon, but probably would be limited to the delivering of a few THE TV channels. So in any case its spectrum requirement of DTT should be further reduced as the service penetration continue to go down. Then the questions is what is the best use case for this band. And as Jens suggested, M2M should be one candidate. Mobile broadband is hardly the most suitable application here as capacity is not solved by larger coverage in most cases. On the other hand, how about rural broadband coverage? Would 600 MHz band play a role here, if there is a real demand?

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