Lecture Series in Mobile Telecommunications and Networks (1583KB)

evidence that people give in favour of this is approach is that they huge innovation took place in the ISM bands.
The availability of unlicensed spectrum gave rise to a huge amount of innovation and a huge amount of growth in the
wireless industry.
The way that we typically define a commons today, is by some kind of power limitation, i.e. we do not permit devices
that are unlicensed to radiate too much, so they can’t cause too many problems. However, the proponents of the
commons argue that you could take a much more advanced approach and develop etiquettes and more complex
ideas around how you can encourage behaviour through using a shared resource in a way that you all appreciate each
other’s needs. John Crowcroft (computer scientist) and Bill Lehr (economist) wrote a very interesting paper on how you
would go about thinking in a more advanced way about spectrum commons. This work is a really good example of
technologists and economists working together and thinking through these problems.
The big problem that people talk about when they talk about a commons is the notion of the ‘tragedy of commons’.
Essentially the tragedy occurs when somebody behaves selfishly and overuses the commons resource to the detriment
of others.
This slide shows quite an interesting piece of work by artist Jonah Brucker-Cohen called Wifi Hog. In this work he was
challenged this Utopian idea that wifi is a fantastic thing and easily available to all. You go to your hotspot and get the
access you want. In Wifi Hog the system, as the name suggest, hogs the whole of the spectrum and stops other people
from entering. This illustrates the concept of the tragedy of the commons very nicely.
The overall point I am making here is that spectrum
management has continued for years in a particular
direction. Many people – and the number of voices is
growing – are challenging the way we look at how spectrum
is managed. Whether the challenge is from the point of
view of taking a commons approach or from the point of
view of property rights, or whether the focus is dynamic
spectrum access the challenge is growing and this is a
hugely exciting field of study.
Spectrum management approaches are also being challenged from an application perspective. Here I have a picture of
fire-fighters. Public safety spectrum is often considered differently from other spectrum – you cannot put a value on
people’s lives – hence the spectrum for these services is very important. However, we now hear people talking about
the notion of the ‘interruptible spectrum’. One example of this is when a public safety service provider uses gets access
to commercial spectrum in emergency scenarios. Hence some of the spectrum resources are therefore transferred from
the commercial users to the public safety users. Thinking from an application perspective helps think of how we should
access spectrum.
Let me move on to my Utopia, the way in which I think spectrum should be managed. To a certain extent, this takes
many of the ideas already discussed and puts them together .
To express this Utopia, I will use these diagrams that are
based on the Rubik’s cube, which a couple of people will
have seen and heard before. To a certain extent, they sum
everything up in the best way of describing what is
happening here.
To understand what I am about to explain, you now need to
think of spectrum from this kind of cube point of view. In the
diagram you have frequency, space and time. The X,Y,Z
coordinates of space are represented as one and I have
placed some places around Ireland on the diagram. If we
look at spectrum like this we can begin to see other things.
For example, this could be Vodafone in Ireland, and this could
be their GSM licence – the space between frequencies is
26 The Royal Academy of Engineering