How ‘white spaces’ could change the world

The potential social and economic benefits of opening up existing broadcasting spectrum to broadband are huge. By Duncan McLeod.

Duncan McLeod

Duncan McLeod

It has an arcane name and involves complex communications technology, but there’s every reason you and I should be getting very excited indeed about “television white spaces”, the gaps in spectrum between broadcast television channels.

Google and Microsoft are pouring millions of dollars into pilot projects to test the feasibility of exploiting so-called white-spaces spectrum to offer wireless broadband access to consumers at a tiny fraction of the cost of using traditional mobile networks.

Google is backing a white-spaces trial network in Cape Town, while Microsoft is involved in pilot networks in Kenya and Tanzania. The software giant is also planning to build a test network in Limpopo province in conjunction with the Council for Scientific and Industrial Research and backed by the State Information Technology Agency.

Why all the excitement? Proponents of white-spaces technology argue it can be used to slash the cost of accessing the Internet in emerging markets. Microsoft estimates that it can reduce the cost of delivering a 2Mbit/s wireless service and electricity to consumers using solar technology to just $1,50 per month per user.

That figure is stunning: if it’s correct, and governments and regulators give the go-ahead to companies to utilise the white-spaces spectrum commercially, it could help bring billions of people in emerging markets online for the first time. The social and economic impact would be vast.

Though television broadcasters generally oppose the licensing of white-spaces spectrum — at least at first — because they fear interference, Microsoft’s Fernando de Sousa, who heads the software giant’s Africa initiatives, says that no interference whatsoever has been encountered in any of the 23 pilot networks it’s involved in around the world.

In fact, television broadcasting spectrum is hugely underutilised, with most of it simply being wasted. And as countries migrate from analogue to more efficient digital television signals, broadcasters make even less use of it. Cracking it open to wireless broadband is a no-brainer.

Also, the frequency in question has big advantages for delivering broadband. The longer wavelengths of spectrum traditionally used in broadcasting mean signals travel further, requiring less infrastructure investment by service providers.

Steve Song, a proponent of white-spaces technology, points out that the longer wavelengths carry less information than higher-frequency signals, but this is a “very reasonable trade-off” in planning rural networks where cost is a bigger factor than the need to deliver the high speeds demanded in urban centres.

Less electricity is required, too, a key consideration in Africa where the power supply in many countries remains unreliable.

In Kenya, where Microsoft has built the network in collaboration with Indigo, an Internet service provider, the pilot network is making use of solar-powered base stations.

Signals are sent to wireless hotspots — much like the hotspots one finds in airports and coffee shops — and these are then used to provide access to end users who connect using the Wi-Fi found in most modern mobile phones.

The system uses a database to access spectrum dynamically in whatever frequencies happen to be available in a particular area so as not to cause interference. In the future, smarter technology, using “cognitive radio” is planned. A transceiver in a smartphone, for example, will be able to detect automatically which spectrum is free.

There are challenges that have to be overcome before the technology is adopted on a large scale, however. The biggest of these, Microsoft says, is that policy makers and regulators still regard the allocation of spectrum as a revenue-generating opportunity. Auctions for mobile spectrum bring in huge tax receipts, but ultimately slow network deployment and raise costs for users.

Instead of thinking of the short-term windfall from selling spectrum, governments and regulators ought to be thinking of the longer-term picture. Says De Sousa: “The possibility of bringing millions more people online and creating new businesses is where the real economic benefit is.”

Freeing white spaces for wireless broadband, and doing so quickly and without the need for complex licensing, could go a long way in achieving South Africa’s objective of universal broadband access by 2020. But time’s a wasting.

  • Duncan McLeod is editor of TechCentral. Follow him on Twitter
  • This column is also published in the Sunday Times

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  • Nico

    This is all good and well, but it is a few years too late. The digital TV switch over will happen before this gains any real market penetration and with the switch over this technology is rendered useless.

  • Janneman27

    Dude, you got it wrong…after switchover, there’ll be loooots more space available.

  • Nico

    Precisely! The space will be available so it would not have to be shared. It will be totally available space not shared white spaces between channels…

    There is a reason why this technology is not being tested in other more developed countries it simply has no use there and soon it will have no use here. It’s a great skills test but not a long term broadcast method.

  • Vusi Sibiya

    Nico… I’m afraid you’re chewing on the wrong end of the stick on this one.

  • Vusi Sibiya

    Instead of thinking of the short-term windfall from selling spectrum, governments and regulators ought to be thinking of the longer-term picture. Says De Sousa: “The possibility of bringing millions more people online and creating new businesses is where the real economic benefit is.”

    Let’s hope that our government will be looking at where the real economic benefit is… it’s always the thieves that only plan for the 5 years which they’ll be in office who derail projects the have potential to impact our country significantly.


    Agreed 100% Nico. It’s too late. The investment in technology, especially hardware and end-user devices, for such a niche short-lived technology is mostly a waste of time. An interesting project, and perhaps viable in less developed nations, but mostly a waste of time for emerging and developed markets.

  • Vusi Sibiya

    Just how developed do you imagine SA or the rest of the continent to be…? Probably the reason why you’re always scratching your heads after every election trying to figure out where all the votes for the ANC come from. This is just the kind of investment needed to get the majority of our people online.

  • Nico

    We don’t invest in it because we are a 3rd world country we are one since we still invest in outdated technology like this. There is something seriously wrong here. Brazil and Bangladesh are moving up not because they played catch up fast, but because they invested heavily in technology that has a long term future.

  • Nico

    There is nothing short term about creating more spectrum space. That extra spectrum can be used for much faster internet for the masses without the need of limiting it by fitting it into white spaces… Or any other use that will have a much greater return on investment through longevity.

    The only thing short term here is the use of white spaces They will disappear sooner later than later.

  • Greg Mahlknecht

    While I generally agree with you, that if it’s between the mobile networks or white space comms, I’d choose mobile networks any day of the week – but do the two technologies compete 1:1 for spectrum? Couldn’t we use both – prioritize allocation to GSM operators where the two overlap, and let white spaces use the rest (assuming there’s enough left over to make it viable).

  • Nico

    White spaces is the frequency space between two Analogue channels that prevents the two different channels from overlapping with ghost images via physically unpreventable spillover. In this particular case analogue tv channels.

    GSM is digital signals, there is no white space of any real significance between two digital signals. Since any digital signal can provide its own error correction not really possible in a viable allocated space for analogue signals.

    By nature digital is more spectrum friendly. Since it can rely on great compression algorithms already available and developing rapidly. Digital also offer time sharing of a specific band this can be great for some purposes making one frequency available for more than one purpose.

    So i’m sorry if I misunderstood the question but this article was about analogue tv white spaces. GSM and other mobile networks protocols are not involved here.

  • Greg Mahlknecht

    >White spaces is the frequency space between two Analogue channels

    Once Analogue signals are phased out though, don’t “white spaces” simply become unused frequencies? Doesn’t matter if the signals are analogue are digital, surely – it just fits in the unused bits. GSM only spans X to Y in frequencies, and it appears even that has holes in it. There’s tons of spectrum outside that X-Y allocation, which I assume also has lots of holes in it.

  • Nico

    >>Once Analogue signals are phased out though, don’t “white spaces” simply become unused frequencies?

    Yes precisely that’s why this technology is rather pointless. Remember this is not to fill holes in the spectrum that is simply not used like the ones you are talking about. This technology squeezes in between analogue channels that we currently see as being used. The technology here is to do it in such a way that it doesn’t interfere with the existing analogue broadcast. But it is almost inevitable that analogue broadcasting of almost all forms will eventually stop in favor of more efficient digital broadcasting.

  • Greg Mahlknecht

    I understand the technology was created to fill in the holes in the analogue channels, but like most things that are invented, as time goes on, it finds other uses.

    My base question is – what’s the GSM/White Spaces/Digital-TV overlap look like? Is there enough space between it to sustain a White Spaces network? I don’t have the numbers and they don’t seem to be easily discoverable. We need Steve Song to read this thread, he’ll probably know :)

  • Nico

    Like I said there is no real overlap or white space between two digital signals. It is already at the physical allowed minimum. There is no physical way of squeezing in another digital signal between two optimally spaced digital signals. But like I said before it can be simulated via time sharing, which is already a widely used technology.

  • Greg Mahlknecht

    Yes. If and when every bit of spectrum is allocated for digital signals – but how far away are we from that? I think there’s probably enough wiggle room to accept lots of money from giant multinational companies that want to help connect people that the government has failed in getting connected.

  • Nico

    Again that is short term money that will provide many more future problems, expensive buy outs and change overs, when we then try to switch to digital. Invest in long term future technologies like Brazil and Bangladesh and the economy will grow. Make the tough choices now don’t just pay it forward.

  • Greg Mahlknecht

    What did Brazil and Bangladesh invest in?

  • Nico

    Just overall planned for future technologies they didn’t settle for intermediate or short term gap plugs. It’s more complex than just one scenario but go and read up a bit about it and you’ll see why they are two of the fastest growing economies and both were in a similar situation South Africa now is. That’s why I keep comparing. But our economy is weakening while they are going from strength to strength. They became leaders in new technology and didn’t settle. SA is doing the same with the SKA for astronomy but we need to do more in other fields as well.

    Why spend on this when we know it will become absolute rather go for what currently is the best on the market or developing and invest in it. This is not that.

  • Greg Mahlknecht

    >This is not that

    The problem is, you don’t seem to be able to say what “that” is. We need something working now. The White Spaces technology seems incredibly dynamic and scalable. It might serve as a very robust and long-term solution. You may be right, it could be a massive failure and waste of money. But I don’t see any other technology on the horizon which can fill the need to connect millions cheaply.

  • Nico

    Maybe I understand it completely wrong. But using spaces between analogue signals for digital broadcasting is simply not scalable. There are only two major analogue bands left radio and television and both are moving digital. This technology is not for normal white spaces and under utilized digital bands, it only works in analogue bands. They are using the term white spaces incorrectly in my view and that is causing major confusion. But like I said I may be missing the point completely.

    Underutilized digital bands is not solved by new technology but should be controlled better by ICASA.

  • Greg Mahlknecht

    I don’t see “analogue” or “digital” as being important … spectrum allocation is spectrum allocation. Sure, the White Spaces tech was made to fill the spaces between analogue signals, but a space is a space. There’s no reason it couldn’t use the unused spectrum between digital signals, of which there seem to be a lot. Furthermore, I understand that White Space tech means the spectrum allocation is very dynamic, and geographically sensitive, so if you want to connect an outlying community, you could find a space, hook them up, and if, say, MTN was allocated that bit of spectrum at a future stage, you could just hop to another hole.

    I could also be completely wrong, but then this is very mysterious tech at this point – I find it hard to find concise information about its workings.

  • Nico

    Again short term gain versus massive long term future troubles. They will base their newly reduced prices on a model that will not last. Altough what you are saying makes sense (Applying it across the whole band) in theory practically this will still work only in a certain band. No antenna can broadcast over the entire spectrum range. There will have to be 10s of different broadcasters to cover the entire range and then one is left with how to receive this dynamic frequency in a finite handset since again you cant fit 10 antennas in a user end device. Nobody has space for that. So they are focusing on the analogue tv band . Which will be reallocated to digital and if ICASA manages it correctly there should be hardly any under utilized space in that band and this whole broadcast and receiver has to change to a new frequency band. So the whole process and prototype cost starts again and the whole process gets more expensive and it loses the advantages the specific band provides, eg longer wave lengths.

  • Joe Black

    Unfortunately for us ICASA will probably start charging steep license fees on these spectrum gaps to protect their little baby snookums dumpling darling – Telkom.

  • stevesong

    It is worth clearing up a few misunderstandings about TV White Spaces technology.

    1/ It started out as a technology that could operate in the guard bands between television channels but to think of it that way now is misleading. It is a flexible technology that can be used in any free spectrum. The key is that it is a secondary spectrum use technology which means that it can co-exist with a primary license holder such as a television broadcaster. If the broadcaster isn’t using the spectrum in a particular area, then TV White Spaces tech can take advantage of that unused spectrum.

    2/ It’s biggest advantage in a country like South Africa is for rural broadband where there are comparatively few terrestrial broadcast channels and where the economic model for rural broadband is difficult to solve by other means.

    3/ It is not an either / or scenario with other technologies whether digital terrestrial broadcast or mobile spectrum. There is room for everyone.

    4/ Perhaps its greatest advantage is that it doesn’t require a re-allocation of spectrum. As we have seen with the 2.6GHz and 3.5GHz bands and with the digital switchover, the process of effective re-allocation and assignment of spectrum is complex and slow. TV White Spaces can be implemented tomorrow and can adapt flexibly to changing allocation and assignment plans.

  • Nico

    I understand all the points. You say it can be implemented tomorrow but to what end device? If the target market are those in rural areas what devices do they have. Surely that is the true cost. Making them spend on a capable device. Sure it can broadcast tomorrow but what will the market be like? Digital TV can also broadcast already but there is no market ready yet that’s the main delay.

  • Vusi Sibiya

    If analogue switch-off was going to happen in Africa within 10 years then you’d have an argument but the reality, as opposed to the ideal is… that’s never going to happen. What can be gained by getting the masses online through such technology in the interim out-ways your suggested striving for an ideal which is just not possible to achieve.

    The long term future technology you speak of investing in is also subject to change and that was the downfall in the thinking behind trying to create an industry around the migration to digital. The game has changed and all those plans are no longer appropriate since online media is now a more viable option and subsidized digital STBs are now clearly a waste.

    Education and information NOW is what’s going to empower the masses who still can’t afford to be online… that’s how we’ll begin moving up. The situation we’re in is different and it doesn’t help to compare it to elsewhere.

  • stevesong

    Although it uses what has come to be known as broadcast spectrum it is not a broadcast technology; it is a broadband technology. Think of it more as a point-to-multipoint broadband that doesn’t have the line-of-sight issues that point-to-point WiFi does. On other hand, at the endpoint WiFi is an ideal technology to facilitate access. Computers, tablets, and smartphones with WiFi will still be the client devices.

  • Nico

    That is the thing, precisely how many of the target market in rural areas possesses such devices?

  • stevesong

    I’m afraid you’ve lost me. Are you talking about WiFi devices? WiFi chipsets are outshipping mobile phones. No tablet has ever been made without WiFi. Even the humble Nokia C3 has WiFi. I think is reasonable to suppose that soon all phones will be WiFi capable.

    On the other hand if you are talking about TV White Spaces devices, the assumption is that TVWS will tap into the same kind of innovation and market growth that WiFi has through its unlicensed (or at least lightly licensed) status. Obviously that is a big assumption but the great thing is that it is an assumption that can be tested at comparatively low cost. It gives what Nasim Nicholas Taleb describes as optionality. The market can decide and take the risk. Licensed spectrum poses much, much bigger risks.


    OK now that you’ve explained to us a bit more of the detail, I can see how this could be useful in rural areas. End-users will connect via WiFi to a hot-spot which is “backhauled” through white spaces spectrum currently available and unused in that specific location. The expensive equipment is in the network, and not at the edges (end-users).

    However, satellite broadband can be (and is) used in the same way, minus the spectrum-related issues. It should in fact be far cheaper, as the technology is already available. Why are we not connecting the rural areas via satellite dishes connected to WiFi hostpots? What makes TV white spaces technology so special that it could become a “game changer”.

    The fundamental problems we face have nothing to do with technology and spectrum (or even the lack thereof). It has everything to do with political will, and the failures of governments and regulators.

    In RSA, we have the DoC and ICASA. If we can’t even get them to complete processes like DTT, effectively regulating interconnect rates, managing spectrum allocation, collecting licenses fees, or doing ANYTHING for the benefit of the telecoms industry and consumers, what makes you think they will fast-track regulations for white-spaces tech?

    Fixing telecoms in South Africa means fixing the DoC and ICASA, which in turn means fixing government, or rather, changing government.

    The same could be said for most industries in RSA, and most problems we face,.

  • stevesong

    The game-changer is the low cost of market entry. Licensed spectrum now costs millions of dollars just to get in the door. Satellites also cost millions to launch. This puts a natural restriction on competition in these markets which explains why both satellite and mobile are still expensive in South Africa.

    License-exempt spectrum opens the doors to entrepreneurs. I will be a huge leg-up for the WISP industry in South Africa who will have better and cheaper ways of serving rural clients. This is not the whole story though. We also need more unlicensed spectrum in the 5GHz band which offers dramatically higher throughput speeds but is somewhat crowded now, especially in urban areas.

    I think ICASA will move on this because it is basically all upside for them. It doesn’t interfere with existing stakeholders, it is a decision that can be adapted as things evolve, and if it fails, it is the market that has failed not ICASA. Whereas in a spectrum auction, the regulator is much more on the hook for the outcomes.

  • Vusi Sibiya

    Well said… “TV White Spaces can be implemented tomorrow and can adapt flexibly to changing allocation and assignment plans.”

    With what’s going on within the DoC we are in for a long wait, for the alternative technologies, not to mention the time that will taken by existing broadcasters who will be continuing to run dual illumination having thus far demonstrated that they have no compelling new offerings that’s going to push the masses to adopting the digital broadcast technology.

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