So called white-space is comprised of the little 'off-cuts' that are left lying around after big holes have been punched into the radio spectrum by existing users. For example, high powered television transmitters punch great big holes into the spectrum, occupying big pieces of spectrum over very large areas. But the nature of such high powered broadcast services is that transmitters on the same frequency have to be separated by large physical distances so as to avoid neighbouring transmitters interfering with each other. At points roughly half-way between two such transmitters, neither transmitter will provide a signal that is strong enough to deliver a useful service, but the frequency can not be re-used for more broadcasting as doing so would cause interference to viewers in the coverage area of the two transmitters. But a different service (in particular one with much lower power) could be squeezed in without causing such interference. These small off-cuts can, in theory, be sewn together to form a patchwork quilt of spectrum that might just be useable.
For many years, organisations including Google and Microsoft have poured large amounts of money into finding the right thread to stitch the pieces together to make a piece of spectrum big enough to be useful. Thousands of man-hours of research have been poured into radio spectrum white-space and millions of pounds of investment into technology and standards (including Huawei's recent purchase of white-space gurus Neul) have been made, but so far, other than a few technology trials, no 'killer app' for white-space has been found.
Kudos then, to Ofcom and Google, who have launched 'ZooCam' in which live pictures of animals at London Zoo are being transmitted from their cages directly to somewhere or other using white-space technology and then streamed onto the internet. When Wireless Waffle popped by to share in the excitement, the Otters were asleep, the Meercats were nowhere to be seen and the Galapagos Tortoise was moving so slowly that a daily photo update would have been just as informative as a live feed.
Philip Marnick, group director of Ofcom's Spectrum Policy Group is quoted as saying:
In a world where consumers' demand for data services¹ is experiencing huge growth, it is essential we find the most efficient ways to share the airwaves. White space technology could be one way of meeting this demand.
¹For 'data services' read 'pictures of furry animals on the internet' (which are known to account for over 85% of all internet traffic).
Might we be so bold as to suggest some other uses for this high-cost, leading-edge technology:
- 'BergCam' - participate in a thrilling, spill-a-minute live stream of global warming in action as the ice caps slowly melt.
- 'DecorCam' - in which a group of decorators position a camera somewhere different each day after painting a wall so can you watch it dry.
- 'HerbiCam' - a live-action feed from Lords Cricket ground focussing on a few blades of grass so that you can watch them grow.
- 'CymruCam' - share the excitement as someone in rural Wales tries to perform Windows updates using their dial-up internet connection.