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by Swannie 4836 days ago
Right, call control with asterisk, and GSM stack in software.

As far as I was aware, the GSM processing isn't much more intensive than equivalent: Ethernet packet assembly + TCP/IP + HTTPS?

I thought all the DSP happened in USRP. So out of that, you get a bit stream, that is sliced into frames, and then processed like any network stack?
1 comments
noselasd 4835 days ago
No, OpeBTS does the GSM related DSP. You get a stream of I/Q samples from the USRP, which is more or less just the digitalization of the baseband. OpenBTS carves the time slots and "frames" out of this, does the GMSK de-modulation and similar stuff.

Note that the lower layers of GSM is very different from e.g. ethernet. Once you get past all the very gory stuff up to layer 2, the concepts are pretty much the same though.

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