Can satellite technology bridge the digital divide?
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CTA. 2003. Can satellite technology bridge the digital divide?. ICT Update Issue 10. CTA, Wageningen, The Netherlands
Permanent link to cite or share this item: http://hdl.handle.net/10568/57609
External link to download this item: http://ictupdate.cta.int/en/content/download/578/27330/file/10_EN.pdf
by Michiel Hegener The big Internet-by-satellite plans of the mid-1990s have been largely replaced by new, relatively efficient technologies, which may lift objections against satellite as a viable connectivity solution.
Too difficult, too expensive, too far fetched - there have been many objections to satellite as a means to link up small offices, schools, Internet cafes or even individual households to the Internet. In response to some of these objections, during the mid-1990s dozens of plans were put forward (mainly by satellite builders) to design, build and launch satellites for the specific purpose of bringing cheap and easy connectivity to Internet users in areas without cables. This applies to most of Africa. Lack of money meant that most of these plans for Internet-by-satellite had to be shelved, and they were replaced by new technologies for end user equipment. Companies such as Armstrong Electronics in Ireland and Hughes Network Systems in the US soon developed systems such as WebSat and DirecWay, which use run-of-the-mill satellites, some of which have been in orbit for many years. All the innovation resides in the software and hardware on the ground - partly in the large terrestial stations of the satellite service providers, partly in the equipment on the premises of the end users. What you get at home is basically a kit consisting of a dish antenna and some hardware, to be linked to a PC. Normally, the dish is only 60 cm in diameter, unless you are near the periphery of the ´footprint´ of the satellite that´s being used, or in tropical areas with a lot of rainfall. Dishes of up to 1.2 metres in diameter may be needed in such cases. The rest of the hardware consists of either two cards to be plugged into your PC, or two boxes, each the size of an external modem, between the PC and the dish. So what´s so attractive about these new satellite systems? First, their price is falling rapidly. Small satellite links have been available for decades, but they could easily cost between $10,000 and $25,000. The current prices of hardware range from $1,000 to $2,000. Second, the systems are ´demand assigned´ and you ´pay as you go´. For instance, WebSat - which is available in West Africa on the PanAmSat 1Rsatellite - has a 64 kilobit/second uplink speed and 400 kilobit/second downlink. In old-fashioned arrangements you would rent that capacity round the clock, even when asleep or on holiday. That made satellite technology hugely expensive. Now providers charge at the end of the month for the megabytes you uploaded and downloaded, although there is usually a minimum charge of, say, $200 per month. Third, what you get is an Internet link and, as with ADSL, you are always online because the satellite provides a wireless link to the Internet backbone. Usually, two separate technologies are used for the downlink (Digital Video Broadcasting, DVB) and the uplink (Return Channel via Satellite, RCS), which makes these systems unsuitable for Internet telephony. Systems like DirecWay, WebSat, Tachyon and others are becoming more popular in Europe and the US, and they are now being expanded towards Africa and other under-served parts of the world. To offer such services in Africa, however, providers will first have to overcome a number of hurdles. For example, a billing system must be in place. Staff will be required on the spot to help install the dish, which must be trained at the satellite very accurately (much more so than a TV dish). If the dish is just one degree out of alignment, the data transfer speeds will drop drastically. Finally, and most importantly, the service providers must hire capacity on a satellite targeting Africa - where the would-be users are - as well as the North, in order to link up those users to the Internet backbone. Michiel Hegener is a journalist who frequently writes about Internet developments Africa and satellite communications (email: email@example.com).
SubjectsICT FOR AGRICULTURE;
- CTA ICT Update