Lecture Series in Mobile Telecommunications and Networks (1583KB)

The second aspect of my comment is that, when we made the transition with Ofcom from the very ‘command and
control’ approach to the ‘let the market decide’ approach, my understanding from the presentation that I attended
about that was that there was a third way. The one thing that has not happened is that there has not been any more
unlicensed spectrum, but I think there is a role for that as well. I am not sure where that ended up – in the bin,
probably.
My question is that, if the future should pan out – and hopefully soon – in the way that you have described, I would say
that in terms of the social ends of these technologies, what I have learned at the BBC is that there are often many
different ways to skin a cat. Society, for whatever reason, no longer feels that it is capable of delivering cathedrals that
take 200 years to build and yet we still provide social ends associated with those kinds of constructs. What would
happen in this world to the actual applications, that people might actually use? Are there any trends? Is it a trend away
from broadcasting to more point-to-point applications? Is it a trend towards social applications or broadcast
applications? I am interested in your views on that.
Linda Doyle: You have made a range of very interesting comments. Starting with your last point, there is a trend away
from broadcasting as we know it anyway, and I think everyone sees that. The whole idea of you having an entity that
radiates out a signal, and a thing that just receives – those days are gone, in the sense that everything is a two-way
thing now. I have to say that I completely object to the term ‘broadcast spectrum’, because spectrum is spectrum, and
labelling it in an ownership way like that would go against my views of that.
How general applications will go – I have to say that there is a whole variety of things. There is more disruption tolerant
networking ideas, and all the social networking. However, I am not the best person to pick the applications and this is
what this is saying – that you do not have to pick them in advance.
You mentioned the licence-exempt approaches and it is very true that that is the way of going about things. A number
of the things I spoke about could be implemented, like the dynamic spectrum access, for example, at the beginning.
There are models where you can have dynamic spectrum access in an unlicensed way and some of the technologies
that are being suggested for the TV – the interleaved spectrum, the TV white spaces – would be an unlicensed
approached, but there are licensed approaches that you can take to it as well.
In terms of general, common type approaches, Ofcom – according to their figures – say that there is really very little
need to increase the amount of spectrum hugely that is devoted to that. There might be other people who would
disagree with that approach and think that it should be completely freed up but the figures that they would report on
the basis of research and evidence that they have show that there is only about six per cent of the spectrum here in the
common space, and that will only grow to seven per cent in the future. That is the kind of demand that they foresee.
They have some very interesting work on suggestions for licensing frameworks, in which you take different approaches
to having different kinds of these regions, with different applications working under different rules and different
etiquettes as they call it.
Professor Jonathan Chambers (Loughborough University): My question is technology orientated. You mentioned
briefly about interference and that will be a major issue in terms of dynamic spectrum allocation. There is much
concern about the so-called ‘hidden terminal’ problem. Could you offer a little more insight into where you feel
solutions might come from, in terms of handling such interference?
Linda Doyle: The common belief, with regard to dynamic spectrum access and hidden terminal is that you need to
collaborate, so nodes in a network have to collaborate in some way in order to overcome the interference. There is
interesting research in collaboration on sensing and the fusing of information, and the sharing of that information.
That seems to be a sensible way to progress in that.
There are challenges, too, in the sense that to have the right level of collaboration, you need the right distribution of
devices, but I do not think I expressed this very well earlier. I put up the slide about spectrum monitoring, but there are
also people who are also thinking in external services that exist, and those external services would provide information
40 The Royal Academy of Engineering