EVER since the early 1990s, when it moved out of universities and was embraced by the general public, the internet has grown relentlessly. Only 2% of the world?s population was online in 1997. By 2014 the proportion had risen to 39%, or about 3 billion people (see chart below). But that still leaves another 4 billion who live an internet-free existence.
Most of the bereft are in the developing world, where only 32% of people are online, compared with 78% in rich countries. And those numbers disguise plenty of local variation. Just 19% of people in Africa were internet users in 2014. Like most infrastructure, the internet is easiest to provide in cities. People scattered in the countryside?even those in rich countries?must often do without.
Yet that may be about to change. Four technology companies are pursuing ambitious plans that could, eventually, provide reasonably fast, high-quality connections to almost everyone on Earth. Google dreams of doing so with a globe-circling flock of helium balloons. Facebook?s plan requires a fleet of solar-powered robotic aircraft, known as drones. And two firms?SpaceX, a rocket company, and OneWeb, a startup based in Florida?aim to use swarms of cheap, low-flying satellites. By providing an easy route to the internet at large, local telecoms firms should be able to provide high-speed, third- or fourth-generation mobile-phone coverage to areas far away from the big cities.
The top-down approach makes sense, for the familiar terrestrial technologies are not well-suited to covering the globe with lots of fast connections. Providing the sort of cabling common in rich cities to every home on Earth would be prohibitively expensive. Mobile-phone masts do away with much of the wiring, but the masts themselves still require ?backhaul??a high-bandwidth connection to the internet. As a result, fast mobile networks are far from ubiquitous even in rural parts of the rich world. They are almost unheard of in poor-country villages. ?
A satellite, however, can see (and be seen from) huge chunks of the planet?s surface. In theory, that allows the provision of data to millions of people at once. And satellite internet services are already widely available, but prices tend to be high, bandwidth limited and data allowances small. Many existing communications satellites fly in geostationary orbits, some 36,000km high, where they stay over a fixed point on the Earth?s surface. This has two unavoidable drawbacks. The strength of a radio signal falls off rapidly with distance, so beefy transmitters and good power supplies are needed to contact them. The second problem is called latency, which is a delay in the signal. It can take at least half a second for a request for, say, a webpage to travel from the ground to the satellite and back down again, and then the page itself to make the same trip in reverse. That may not sound like much, but it is a tenth or less of the speed of a wired connection, even before other internet latencies. ?No one uses a geostationary satellite and says ?I?ve solved my problem for ever,?? says Greg Wyler, the founder of OneWeb.
Lower they go
Mr Wyler?s firm plans to launch 648 small, relatively simple satellites into much lower orbits of 1,200km. This will provide a latency similar to that offered by a fixed-line connection. And it will allow the use of much less-powerful aerials on the ground. OneWeb will offer its services to airlines and military customers, as well as emergency services and disaster-relief organisations, although it plans to attract individual customers, too, through deals with local telecoms firms. Because a single satellite will be able to provide backhaul to dozens of villages at a time, Mr Wyler hopes that local operators will be able to afford to build phone masts or internet base-stations in rural schools, village centres and the like. In the most remote areas, the masts might be powered by solar panels. Those who are still disconnected in the rich world could sign up, too.
But although low orbits offer much better latency, they are also more complicated. Unlike geostationary satellites, low-flying ones move relative to the ground, so hundreds of them would be required to provide reliable coverage across the entire planet. When one satellite disappears over the horizon, radio equipment on the ground needs swiftly to connect to another one in view without the user noticing (rather as mobile phones do when they move out of the range of one mast and into the range of another). Doing that successfully requires a lot of tricky signal processing, says Mr Wyler. It is only in recent years that aerials and chips have become so sophisticated and cheap enough to make such a system possible. OneWeb is helped in this by Qualcomm, an American firm that makes chips for mobile phones and has the necessary expertise?and is one of its early investors.
Read more at THE ECONOMIST