The sky’s the limit: new wireless connection record - 382 kilometres
By AL for APCNews
MONTEVIDEO, URUGUAY, 04 June 2007
“This is a technology that works, a proven technology, and what it needs is a bit more promotion,” said Ermanno Pietrosemoli just days after reaching a new wireless connection record of 382 kilometres. The president of Venezuelan APC member EsLaRed spoke with APCNews by conference call about this low-cost solution that is impacting the world’s rural communities.
APCNews: What prompted the idea to set a new record?
Ermanno Pietrosemoli: In October 2006, I participated in Air-Jaldi, the Wireless Summit in Dharamsala, India, courtesy of APC. There I presented the results of the experiment we carried out in April, in which we established a 279-kilometre link between two points in Venezuela. At this same event, Professor Eric Brewer, of the University of California at Berkeley, presented his latest research: his team had successfully modified Wi-Fi system software to improve output (transmission rate) over long distances.
Professor Brewer approached us about testing this new equipment along the path we had identified, since it is not easy to find places that will allow for experiments at great distances (due to the curvature of the earth). After obtaining the systems, we repeated last year’s experiment, and on 18 April installed antennas in El Baúl, Cojedes and in El Águila, Mérida. Once again we were able to establish the link, but this time the transmission speed was significantly increased, reaching three megabits per second in each direction and 6 megabits of total traffic.
APCNews: And so the big day arrived…
EP: Yes, I had been anxious to reach even greater distances. Using digital maps, I studied several possible sites for greater distance and found one at 382 kilometres. Maps are used for this calculation and there is always a great deal of uncertainty about viability. On 29 April we repeated the tests between El Águila and Platillón Mountain, 382 kilometres away. Although the quality was not the same, we also established communication—even transmitting video and audio! We did it with Berkeley’s system but also with the Linksys equipment (which costs less than USD 60) used the previous year.
APCNews: How easily could this experiment be replicated?
EP: I don’t want to raise false hopes but there are many places, particularly in rural areas, where mountains can be taken advantage of, or towers can even be built to guarantee the line of sight between communication stations. In cases like these it is a truly economical solution not at all like installing optical fibre or satellite links.
Right now we are exploring the possibility of working with wireless networks using different technology. Mesh networks allow for connectivity at short distances in populated areas. For example, if a town is 100 kilometres from an internet connection, we can reach it with long distance links, but then it is not economically viable to connect the school, hospital, community centre, etc., with separate links. The cost of long distance antennas is much too high. However, with mesh technology it is very inexpensive to share that link with the entire local community using low-cost antennas.
APCNews: It seems like there are no limits to possibilities with this type of connection. Could you give us a specific example of its application?
At the recent International Summit on Wireless Community Networks of Maryland, I organised a panel precisely to let people know about this type of application. I invited people from Enlace Hispanoamericano de Salud (Latin American Health Link), an organisation headquartered in Madrid which has been applying this technology for many years. In Peru’s rain forest, they have links installed up to 70 kilometres long which are being actively used to provide connectivity to isolated health clinics.
I also invited the people from Berkeley who have several projects operating in Africa and India. The wireless connection in India allows tiny rural locales to access an ophthalmologist’s services from a distance. The local clinics have a link that connects them to the central hospital. A nurse wields a webcam and the specialist makes a distance diagnosis. 95% of the cases can be treated locally after this initial diagnosis. This low-cost technology has a direct impact on people’s health.
APCNews: After logging so many successes, what is the next goal?
The first one is to consolidate the results through a campaign of long-term measures. To begin this, one of Eric’s colleagues will come to Venezuela in July. We will spend two weeks doing experiments so they can verify the operation of their systems in this type of environment and at these distances. Then we will put together a manual that can be used by anyone. This work is based on free and open source software, without any restrictions. We plan to publish and circulate them as widely as possible so they can be utilised in every community. This is a technology that works, a proven technology, and what it needs is a bit more promotion.
The EsLaRed team in Platillón, 382 km from the antenna with which they connected to El Águila: Ermanno Pietrosemoli, Leonardo González V, Leonard González G. and Alejandro González.