With SDR (software defined radio) would it not be
possible to design /
develop a cheap GSM basestation?
See OpenBTS. It uses the USRP wich brings down to ~1000 eur.
Several company are working on custom hardware for OpenBTS, but for a
really low price, you need large quantity ...
I am a total noob on hardware development but I
suppose there is a large
market for this.
You need a license ... so I'd assume the bulk of the market is
operators. And for them 2-5k EUR is already dead cheap for a BTS.
Or maybe somebody already working on reverse
engineering other base stations
like the nanobts?
There are not that many IP based BTS on GSM (not talking 3g here).
Or might something simpler be possible with modifying
a router and with a
different antenna on 1800mhz?
Not a chance, you need either:
- custom hw dedicated to GSM: Doesn't exist cheap yet because of qty.
(might happen since some company are working on it using openbts, but
no price/data yet).
- or something flexible enough like the USRP (but then, it's not a
'consumer' product and so not _that_ cheap).