I fail to understand the point to this. People have been building GSM base stations with $1,500 USRPs for years (not knocking the USRP, awesome piece of test equipment; it has been on my wish list for years now). So someone tacked a $35 Raspberry Pi to it.
Now turning a Raspberry Pi into a USRP for $35, that would be disruptive.
You probably know this already, but you can use a cheap DVB-T usb dongle with a RTL2832U chipset to do a lot of things that used to require an USRP [1]. You can't transmit though.
Which is, unfortunately, a pretty big prerequisite for a GSM station. Raspberry Pi + DVB stick is a great combination for reception though, I've seen it used on autonomous model planes.
So they are using a DVB stick to broadcast the video stream back to monitor the autonomous model airplane, which is awesome. I tried looking for a site where hobbyists are doing this without luck. Can you link to a site where I can learn more about this specific use case?
Isn't the Raspberry Pi performing a lot of SDR signal processing in this case? The fact that it's powerful enough to do so seems interesting and newsworthy to me.
I have worked for a moment in company writing some GSM infrastructure sofware, and my first thought after reading the article is that it neglects the fact, that nodes of mobile network are expected to pass broad and comprehensive reliability tests (both the software and the hardware). That, I'd say, can make a ton of a difference, compared to a simple proof-of-concept.
On the other hand, any proof-of-concept is always welcome, interesting, and can lead to new great developments.
I think having the "I'm paying a million dollars for certification?" conversation is a step up from the old days of enterprise or carrier equipment where they'd essentially say "It costs a million dollars. Take it or leave it." Projects like Asterisk and OpenBTS have revealed that there's not as much magic there as people thought.
IIRC OpenBTS was developed by a small group of GSM software experts, with many years GSM experience between them, and GSM essentially being a frozen standard now.
Still an achievement, sure... makes me wonder why pico cells aren't everywhere offering an alternative carrier. (Guess WiFi stayed good enough, and we have moved to over the top apps that don't need cell network).
Isn't the reason mostly that the spectrum is licensed? So the only ones that can actually set up a picocell are the ones that own spectrum, and they don't have a good reason to do so (except in remote areas / on boats).
Seeing some of the hype of raspi is kindof sad. It's a linux box. It's a small, cheap linux box, but it's just a linux box.