[aaron42net]

That was an explicit goal of OpenBTS when I was following it years ago. The GSM vendors want something like $250k per base station, which is unreasonable for third-world or very-rural applications. OpenBTS thinks they can get the radio hardware costs down to a tiny fraction of that to serve low volumes, backed by a Linux box running this software.

Interestingly, their first large-scale field tests were at Burning Man (http://openbts.sourceforge.net/FieldTest/), where there were thousands of active GSM handsets but no cell coverage. They were able to provide limited SMS support between local participants and in later tests allowed some outgoing VoIP calls.

[sortof]

Great,the only concerns I could think of were legal, around ownership of frequency ranges abd interference.

[chemeris]

The answer is to work with legal spectrum owners (aka cellular carriers), which is what we (https://fairwaves.co) and other in the space are doing.

Someone mentioned that building a full networks (or even a full base station) is much harder than just apt'ing some software and snapping some cheap SDR. So we spent couple years developing an SDR which is more expensive than your typical hobbyist one (http://umtrx.org) - btw even hardware of the simple version of our SDR is open-source - and then couple years building a base station which complies with all regulations and has open-source in its heart (based on Osmocom obviously). And now we've added a bit of (unfortunately proprietary) glue and we can run fully fledged cellular networks for carriers - mostly in developing countries, as was mentioned before, because demand for simple voice communications is through the roof there. At the same time you can buy one of our stations for your lab and play with it as much as you want (get your test license first though).

So yes, you can't stop progress and technology gets cheaper and more accessible. Which is very exciting.

[sortof]

Any idea what the largest opeb source or non commercial gsm network is?

There must be some widely used ones in developing regions.

[qpsk88]

The price for BS alone is down below $10k (afaiu, LTE oder Multi-system BS are at $20k). But to run this as a system you need more boxes than the BS only.