How 'white spaces' could change the world - TechCentral

How ‘white spaces’ could change the world

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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