No mobile phone coverage? No worries, researchers put a tower in a phone
By Darren Quick
July 12, 2010
Unsurprisingly, the Australian outback doesn’t exactly boast the greatest mobile phone coverage in the world. But researchers down under have managed to make mobile phone calls in this remote landscape without the use of towers or satellites. Instead of relying on expensive infrastructure, the researchers created a mesh-based phone network between Wi-Fi enabled mobile phones that allowed them to communicate with each other.
The successful test was part of the Serval Project, led by Flinders University’s Dr Paul Gardner-Stephen, that aims to provide fast, cheap, robust and effective telecommunications in remote areas where conventional phone infrastructure isn’t cost effective or where the existing infrastructure has been damaged by natural disaster, war or terrorism.
The Serval Project – named after the problem-solving African wildcat – consists of two systems. The first is a temporary, self-organizing, self-powered mobile network for disaster areas, formed with small phone towers dropped in by air.
The second, and the one being tested in the outback, is a permanent system that requires no infrastructure and creates a mesh-based phone network between Wi-Fi enabled mobile phones, and eventually specifically designed mobile phones the researchers have called Batphones, that can operate on unlicensed frequencies.
Mesh networking is a type of networking where each node (in this case each mobile phone) in the network can act as an independent router, regardless of whether it is connected to another network or not. It allows for continuous connections and reconfiguration around broken or blocked paths by “hopping” from node to node until the destination is reached.
The researchers have integrated existing mesh network technology developed by Village Telco using unlicensed spectrum with software they developed called Distributed Numbering Architecture (DNA). This software allows people to use their existing phone numbers to enable people to be contacted on numbers they know – something the team says is especially important in disasters.
Off the beaten track
Accompanied by an ABC news team the researchers headed to the remote desert of South Australia to ensure they were far from any mobile phone towers. Since the system relies on the phones’ Wi-Fi capabilities, range is an obvious problem and the tests were only able to transmit calls over a distance of a few hundred meters. But they say the range could be expanded to cover a larger area by adding small transmitters or more devices that relay the calls on.
The need for a decent concentration of devices within an area to provide an extended range suggests the technology probably isn’t overly useful as it stands for sparsely populated areas. But its potential in the area of disaster relief could be significant.
After the Haiti earthquake Ericsson deployed a “container based mini-GSM system,” which is essentially a portable mobile phone network, to enable mobile phone communications in the area. However, this took days and was expensive. The software being developed by the Flinders Universuty researchers could do the same thing but much more quickly and much more cheaply.
"With Haiti what was actually observed was that their mobile phone network and their landline phone network was essentially knocked out for the first 48 hours after the earthquake," Dr Gardner-Stephen told ABC News.
"What research has actually shown is that the vast majority of the response to a disaster is actually from the local people there, so if we can provide them with ease of communications as soon as possible after the earthquake, not 48 hours, not 72 hours but potentially minutes after a disaster, then we can help them to start rescuing people from rubble and generally rebuilding, maintaining law and order."
The researchers will now concentrate on increasing the range and improving the range of their system.
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