Page:Wireless Networking in the Developing World (WNDW) Third Edition.pdf/22

XVIII The method of choice today is likely a three tier strategy. First and foremost Aipotu should try to roll out optical fibre lines wherever possible. Fibre lines offer the capability to transport a "sea of bandwidth". The cost of optical fibre is very low, considering the capacity. By upgrading the optical transceivers the capacity of a optical fibre line can be upgraded without laying new cable. If Aipotu can afford to establish a fibre connection to every household there is no reason not to go for it. This would make our three tier model obsolete and we could stop here.

However, there are probably areas in Aipotu that cannot afford fibre lines. The second tier that the people of Aipotu can use in order to connect remote villages or small cities are high speed point-to-point links between high points. It is possible to establish high speed links (40 Mbps) of 30 km or more between towers of 30 metre height on flat terrain. If mountain tops, high buildings or hill tops are available, even longer links are possible. The network technology experts of Aipotu don't have to worry too much about the wireless technology that they are mounting on top of their towers - the cost lies mostly in building the towers, proper lightning protection, power supplies, power back-up and theft protection, rather than in the actual wireless equipment and antennas. Like the technology of optical transceivers, wireless transceivers also keep advancing, but a wireless link will always be orders of magnitude slower than the capacity of optical fibre.

The third challenge for Aipotu is to solve the problem of the last mile(s): Distributing access to all the individual households, offices, production facilities and so on. Not too long ago the method of choice was to run copper wires but now there is a better choice. This third tier of our network model is clearly the domain of wireless networking technology.

'Purpose of this book The overall goal of this book is to help you build affordable communication technology in your local community by making best use of whatever resources are available.

Using inexpensive off-the-shelf equipment, you can build high speed data networks that connect remote areas together, provide broadband network access in areas where even dialup does not exist, and ultimately connect you and your neighbours to the global Internet.