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[June 22, 2007]
Point-to-point Wi-Fi brings internet to all
(New Scientist Via Thomson Dialog NewsEdge) CELLPHONE evangelists often claim mobile telephony and internet access are revolutionising life in the developing world. Nations without landlines can leap into the 21st century, pushing their economies into overdrive as they do so.
Like many a convenient orthodoxy, this one does not stand up to close inspection. While the cellphone may be changing lives in the cities of the developing world, the same is far from true in rural areas.
"Economists are head-over-heels in love with cellphones, but so far they have been a largely urban, big-city phenomenon in the developing world," says Eric Brewer, a computer scientist at the University of California, Berkeley. "The fact is that in rural areas, which by definition have a low population density, it's actually very difficult to deploy cellular base stations in an economically viable way."
Cellphone operators need enough users for each radio antenna tower to justify the cost of building and maintaining it. If a network cannot guarantee a threshold revenue per user, the tower will not be built. "That tends to mean all cities will be covered, for sure, and certain roads and railway lines. But not the rural areas. That's the case in India, for example," says Brewer.
There are exceptions. Getting complete coverage is no problem in Bangladesh, for instance, which is a small, densely populated country, while China has made wide rural coverage mandatory.
But cellular technology is unlikely to do much to help the rural population in the rest of the developing world, Brewer believes. It will be at least a decade, he says, before the cost of cellphone masts drops enough to allow rural dwellers access to a cellphone network for telephony or internet connections. Even where networks are up and running, there is no guarantee that the cost of internet access will not be prohibitive for rural users. "The cost of moving data is extremely high on cellular networks," says Brewer.
"What's needed is a technology for rural areas that uses unlicensed spectrum and which is designed for operator-free deployment by grassroots organisations."
To this end, Brewer and his colleagues at TIER, the Technology and Infrastructure for Emerging Regions project at Berkeley, have modified the way Wi-Fi works. They have created a wireless system that can beam the internet to remote communities many hundreds of kilometres away from a dense population centre. Called Wi-Fi over Long Distance Networks (WildNets) the technology is cheap and disarmingly simple.
Standard Wi-Fi beams a 200-milliwatt radio signal in all directions around a stubby antenna the length of your thumb. The signal extends 100 metres in all directions, forming a hotspot. In contrast, WildNets feed the Wi-Fi signal from a PC's regular router card into a rectangular parabolic antenna dish 60 centimetres wide. This focuses the formerly 360-degree signal into a beam 5 degrees wide that travels a very long way but only in line of sight. Antennas can be installed on chimneys and trees.
The result is a cheap point-to-point link that requires no frequency licence, as it uses Wi-Fi's free 2.4-gigahertz band. Wi-Fi cards are also very cheap, as hundreds of millions of them are made for PCs every year, while the necessary software is open-source, costing users nothing.
Early WildNets installations are already up and running in India, Ghana and the Philippines. In tests west of Mrida, Venezuela, last week, the Berkeley team managed their furthest high-speed WildNets transmission yet reaching 380 kilometres between two points in the Andes.
At the Aravind Eye Hospital in Theni, in India's Tamil Nadu state, the technology is being used extensively for doctor-patient videoconferencing. Doctors can contact clinics staffed by a local nurse in 12 remote villages, and diagnose and monitor the eye conditions of 2000 patients each month. Each clinic covers up to 30 villages within a 5-kilometre radius, says R. D. Thulasiraj, executive director of the Lions Aravind Institute of Community Opthalmology, which trains eye centre staff. Some of those villages are up to 85 kilometres from the hospital too far for villagers to trek. Once the problem has been diagnosed, patients are either treated at the clinic or referred to the main hospital for surgery. "This is giving us the platform to reach into remote communities to ensure that everyone has easy access to eye care and no one remains needlessly blind," says Thulasiraj.
The hospital plans to open 14 more clinics by the end of this year. "After seeing about 20,000 patients, Aravind's WildNets have allowed around 3000 people to have their vision significantly improved," says Brewer.
In Ghana, telemedicine will soon reach rural areas via WildNets, while they are already linking universities and hospitals along the country's coast, allowing them to exchange information on disease outbreaks. In the Republic of Guinea-Bissau in West Africa local radio stations are using WildNets to share content such as interviews. WildNets have also been set up in the Philippines and Rwanda to allow schools to connect and share learning resources and to access the internet.
Only 1 billion of the world's 6 billion people have internet connections, so such technologies are desperately needed, says Malcolm Hutty of the London Internet Exchange, a hub for internet service providers. "WildNets sounds like an opportunity for connecting the next billion people."
Copyright 2007 Reed Business Information - UK. All Rights Reserved.
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