If you google “televisions white spaces”, you’ll see a small storm of news generated last week by the FCC’s finalising the rules for the use of television white spaces spectrum in the U.S. TV white spaces spectrum was first announced in Nov 2008 by the FCC but was bitterly protested broadcasters and wireless microphone manufacturers, among others that the devices would interfere with television broadcast and wireless microphone use alike.

So what are the television white spaces? Back when radio spectrum was first allocated for television broadcast in the early part of the 20th century, broadcast and broadcast reception technology was crude by today’s standards. In essence, broadband transmitters had to “shout” because the reception devices were a bit deaf. In order to cope with these loud services, regulators decided that gaps should be left in spectrum assignments as “guard” bands to prevent television signals from interfering with each other. These “guard” bands are also known as television white spaces because of the “white” noise signal that appears on a television in these unused bands. Aside: this makes sense but it really, really doesn’t resonate in South Africa where a call for “white spaces” just says all the wrong things. Sigh. Can’t we call them something else?

So anyway things have changed. Wireless technology has evolved a great deal and now devices can be designed that operate efficiently within these “guard” bands without interfering with television broadcast. The original idea was that the devices would be able to sense what television channels were in use and serendipitously use the empty “white spaces” wherever they were available.

The Nov 8 2008 policy decision has been hanging fire while the FCC have debated the various objections to white spaces spectrum use. On 23 Sep 2010 the FCC finally set down clear rules for white spaces operation. Instead of spectrum sensing, the FCC have decided that all television white spaces (TWS) devices must register online with a centrally managed database which tells TWS devices what spectrum they may use in the area that they are being activated. While this removes some of the serendipitous possibilities for innovation, it directly addresses the concerns of broadcasters that spectrum sensing technology was not sensitive enough to ensure an interference-free environment for broadcasters. The door was left open however for spectrum sensing in the future.

So why is TWS spectrum important?

  1. You don’t need a spectrum license! Or at the very least licensing is very, very lightweight. This means that you you can deploy TWS technology in a very similar manner to other unlicensed wireless technologies such as WiFi. This means more market entrants, more competition, and ultimately more service and better prices for consumers.
  2. You don’t need to re-farm spectrum! Re-farming spectrum which involves moving existing spectrum holders from one band to another band is notoriously painful and long-winded. Just look as the pain-in-the-behind that iBurst and Sentech’s spectrum holding in the 2.6GHz range has been for that process. TWS spectrum can re-use unused television spectrum without moving any existing spectrum holders.
  3. It’s lovely spectrum! Television spectrum is capable of penetrating obstacles such as trees and building much more easily than WiFi spectrum or WiMax for that matter. This means that it will be MUCH easier to deploy this technology and it can be deployed a lot more affordably. It is not without downsides. You don’t get as much throughput through TWS spectrum, probably more like 2Mb/s but frankly that is plenty for loads of applications.
  4. This is such an opportunity for Africa. Pundits are estimating that the TWS market may be worth 4 billion dollars in the U.S. This is a country that already has broadband and is packed with television broadcasters. Here in South Africa it would be hard to find a place where more than a half dozen television channels were in use. Likewise the need for affordable connectivity is so much greater. This is SUCH an opportunity!

So What Needs to Happen?

Blog about it. Tell your regulator. Tell some journalists. Tell your politicians. Bug Google and Microsoft who have been champions of this technology in the U.S. but mute about it in Africa. The Google Public Policy Blog trumpets this decision but no mention of it on the Google Africa Blog. <disclaimer>Sorry Google, I just want more from you on this continent. </disclaimer>

Right now manufacturers are gearing up for mass production of TWS devices. If we can put appropriate TWS regulation in place, we can seize the day as these devices become available.  Otherwise,  this opportunity will pass and mobile operators and broadcasters will lock down this space.

Posted by Steve Song

@stevesong local telco policy activist. social entrepreneur. founder of @villagetelco #africa #telecoms #opensource #privacy #wireless #spectrum #data