Spectrum 101

Spectrum management

What is PolicyTracker about? Spectrum management is the answer, but what is it and why is it important? This is the first of a series of articles which considers these issues.
| Martin Sims

It’s how you call for help at sea and how air traffic controllers stop plane crashes

Let’s start with the who rather than the what.

Who are spectrum managers? The people who are in charge of a nation’s airwaves, and they usually work for arms-length government agencies known as regulators, like Ofcom in the UK or the NCC in Nigeria.

But what do they do? Look at regulators’ websites and you’ll struggle to find a definition of spectrum management, so here’s mine: it’s controlling the airwaves for the benefit of society.

But this simple definition raises as many questions as it answers:

  1. Do we need to control spectrum?
  2. If so, why?
  3. What are these benefits?
  4. Why might they not be realised?

The benefits of spectrum management

The third question is probably the easiest, so let’s start with that. Spectrum is the raw material for a wide range of commercial and non-commercial services. Mobile phones are an obvious starting point: having moved from the hands of the privileged few in the early 1990s to near-ubiquity within 15 years. Radio broadcasting did the same in the late 1920s, as did TV in the 1950s and satellite services from the 1980s.

These are the three titans in the profit-making sector, but non-commercial uses are equally important. Safety of life services depend on it, it’s how the police and fire brigade co-ordinate their services. It’s how you call for help at sea and how air traffic controllers stop plane crashes. The military could not guarantee national safety without using spectrum for communications, radar and weapon control.

in the early 1990s people started to ask whether regulators needed to exert so much control.

Other commercial services do not directly save lives but are very valuable to society. Our knowledge of weather and global warming relies on spectrum to observe the earth from space and to run networks of terrestrial sensors; in the medical sphere devices like hearing aids and heart monitors all need access to the airwaves. We are trying to conserve energy in our homes, through smart cities and though better management of utilities: many of these services rely on spectrum.

And how is culture passed from one generation to another? Our experience of drama, films, music, literature and art in general come largely though TV and radio, although the internet is of increasing importance. Spectrum is crucial to the delivery of all three via terrestrial TV, satellite or mobile. Crucially, TV is also the most trusted source of political information.

The threats

spectrum management should prevent interference

Interference on a digital TV

So spectrum has a lot of important uses but what could stop this potential being realised?

Interference is the first hurdle. Services operating on the same frequencies can cancel each other out. For example, if two radio stations in neighbouring towns both broadcast on 95.5 FM, midway between the two locations the resulting mess would be unlistenable!

So how do we prevent interference? The simple answer is making sure that several people do not try to use the same – or similar – frequencies at the same time in the same place. In our example, 95.5 FM should not be reused in two towns so close together.

Efficiency is the second issue. Similar types of services need to be grouped together or the spectrum would be used inefficiently. If television’s “high power high tower” transmitters were to operate in the same band as mobiles – based on many low power transmitters reaching only a few kilometres each – phones would not work for hundreds of kilometres around the TV transmitter. On the fringes of the TV reception area mobile use would create interference for viewers. Place them in separate but adjacent bands and the huge area around the TV transmitter can be used for mobile.

This doesn’t just apply to individual counties. A TV transmitter in Luxembourg could sterilise large areas of Germany, Belgium and France, giving spectrum management a necessarily international dimension.

Spectrum management: the how questions

To get the most out of the available spectrum it clearly needs some intervention. But how much and what sort are questions which have dominated policy discussions for decades.

The obvious answer is that experts should decide how to manage services to promote efficiency and prevent interference and then co-ordinate this with colleagues in neighbouring countries. This is what happened from the 1920s onwards and still does to some extent, with the International Telecommunications Union (ITU) as the forum for global cooperation.

‘Benefitting society‘? Meaningless! that’s anything you say it is!

But in the early 1990s people started to ask whether regulators needed to exert so much control. Could the market, not regulators, decide who got what spectrum, echoing the privatisation of fixed line telecoms and other utilities? This is known as spectrum liberalisation and is covered in  more depth in the next article of this series.

The answer to the first question, do we need to control spectrum, is yes, but the extent to which this is needed, and the way it should be done is an ongoing debate among the spectrum management community. And that debate is what we cover here at PolicyTracker, through our newsletter, research and training courses.

Does politics come into this?

My definition of spectrum management was “controlling the airwaves for the benefit of society” and I expect the final word raised some hackles: “‘Benefitting society‘? Meaningless! that’s anything you say it is!”

Decisions about what benefits society are made in the realm of politics in a power struggle between politicians, experts, companies and various interest groups. Spectrum management decisions are often justified on technical grounds, but that is rarely the whole story.

There may be a marginal (and arguable) spectrum efficiency benefit in moving broadcasters out of 700 MHz and 800 MHz to make way for mobile services but the driver for these decisions is the perceived economic benefits of improved mobile broadband.  Politicians decided the impact on broadcasting and associated industries was a price worth paying.

Many spectrum decisions are about future economic benefits as much as technical issues and we assess where the balance lies in the articles which follow.

More articles from the PolicyTracker Spectrum 101

What are the key events which have shaped the evolution of spectrum policy?

The evolution of spectrum auctions 

5G spectrum

5G verticals

A guide to WRC-23