Narrowband - one solution for African connectivity
Dozens of interesting experiments are taking place around the world using WiFi to provide voice and data connectivity in areas of the world where it's difficult to build conventional infrastructure, from Inveneo's work in Uganda with VOIP over WiFi to Nepal Wireless's project to provide connectivity in the Himalayas. Wireless hackers like working with WiFi because the hardware is cheap, the frequency WiFi broadcasts on (2.4Ghz) is usually unlicensed, and because brilliant antenna hackers have been able to send WiFi signals over 100 miles.
From a technical perspective, WiFi probably isn't the best choice to transmit data over long distances. WiFi is ultimately limited by line of sight considerations - barriers like mountains, buildings and forests can block signals. And WiFi signals can be affected by moisture in the atmosphere... which helps explain why the world WiFi record was achieved in the dry, flat Nevada desert.
To send data over longer distances without needing line of sight, engineers use lower freqencies than the microwave frequencies used by WiFi. Generally speaking, you can't send as much data at lower frequencies than at higher, but you can send the signals farther. And while netheads in the US and elsewhere are getting excited about the possibility of "fiber-speed" broadband data over wireless at very high frequencies, there's exciting developments in long-distance, lower-bandwidth "narrowband" communications in the developing world.
