Hello,

SagiSys LLC is a VoIP provider, and we would like to help with this project, so long as SIP to SIP calls remain free between villages. I'd like to speak with you about this project and see how we can help. Please email us at philanthropy (at) sagisys (dot) com

Justin

How about Ultra wideband? UWB should require even less power than Wifi, since communication channels typically have a power/bandwidth tradeoff.

Since it is a rural area, you do not have to worry about interfering with anybody else's channels, and so the biggest drawback to UWB is not an issue.

Intermediate length links and a mesh network with digital voice is a fine approach - that's the heart of the "ARTS" (Advanced Rural Telephone System) phone network designed for Indonesia by the now-defunct Nusantara Telecommunications Corp. See US Patents 5845201 and 5918171 for details. Of course, in the early 1990s we didn't have inexpensive off-the-shelf wireless networks to build on so the whole works was designed from scratch.

Go for it - you are working on a wonderful project. Best to you!

Jim Horn (one of the names on the patents), Salem, Oregon

ok. several things...
1) expecting to do 100km over a wifi link is pushing it a little, particularly with average atheros hardware (there's only so much it can do, you'd need boosters and the like to go further)
you'll be better trying 20/30km on average for decent performance (hope you have villages and stuff on the way
2) there are several applicable routing programs. here at wireless-fr.org (which you probably don't know yet, because it's all in french), we've been using olsrd (from the freifunk package). so far, we have installed a prototype network in a mountain area (with houses sprinkled in the mountain here and there) and 5.5 km main links.
we are however experimenting with a new mesh routing protocol called babel that you may find interesting ( http://www.pps.jussieu.fr/~jch/software/babel/ )
3) you probably would be better off using 802.11a, as it allows for many more frequencies, particularly in areas where the band over 3.5G isn't regulated (ubiquity hardware can do 4.9 to 6.1 GHz)
4) viewing the picture above, I noticed you set up your antennas (the source) in vertical polarization. you should try horizontal instead, as it's much less sensitive to vertical things such as poles and trees.

pm me for more information :)

The majority of my PhD thesis is on developing a MAC protocol named FLASHR to support VoIP calls over multi-hop mesh networks. I see that you are using very long, direct links, but this may not always be practical depending on the terrain, etc. If you have a need for multi-hop calls, nearly all MAC protocols will result in very high end-to-end delays (easily approaching that of using satellite if you have more than a few hops or more than a few active calls) and poor capacity. I have a brief poster about these issues and my solution at http://www.cis.udel.edu/~yackoski/papers/flashr_poster_july_2007.pdf. I may be interested in helping your project, please contact me if you think this could be useful to you.

HF, VHF, and UHF radios require special licensing and are by their nature one-to-many.

In spite of my namesake, I'd like to suggest something else than a modern, wi-fi network.

I thought only channels 1-4 required a license. There are like, 22 channels with 20 or so sub-channels each, and with reasonably cheap technology, you can have radios that use a smattering of channels in a unique sequence.

I don't know. Call me crazy but, I think good ol' radio and HAM radio might be the most economical, sensible approach. I mean, we're talking really rural, right? Without much buildings in the way, you could probably get pretty good range walking around with just a half-watt radio. And a 2-watt? Oh, you'd be set.

for each installation, how long would you expect it to run before it needs to be serviced?

does an installation need to be servicable locally, or will you expect to have to ship parts/equipment to and from the install location?

Could the mobile phones themselves for a network? This may be still i the future but it would be a kind of p2p mobile phone network with capacity increasing automatically as the number users increased.