Csaba,
We use UmTRX routinely to develop GPRS code for OpenBSC and it works well.
I can't say much about other SDR equipment, but we have some timing related
bugs with USRP1 based devices of one of our customers.
Regarding the official OpenBTS GPRS code - we've never tried to run it, but
looking into the code, it lacks quite a few features the OpenBSC
implementation has.
On Fri, Jan 24, 2014 at 1:01 AM, Sipos Csaba <dchardware(a)gmail.com> wrote:
Thanks for the info!
At least now I know, that the GPRS/EDGE is part of the OpenBTS code, so
any hardware is OK for packet data which can run OpenBTS. That is good news.
Anyway, it is just an educated guess, but don't you think your problem
with GPRS is related to timing? My experience with real life networks
clearly shows that even a slight timing related problem or inaccuracy can
led to something like that.
My other experience is with R&S CMW500, which I used with a little
external antenna and encountered the same problem. After a few meters even
the voice calls started to drop with -60 RSSI. The reason was obvious: the
device lacks any filters on the input chain (it is designed for production
mode), and when all the received RF energy hits the receiver from all the
bands, it causes problems like that. And the packet data was way more
sensitive to this than voice calls. After installing proper filters, the
problem is gone.
BR,
Csaba
OpenBTS supports GPRS, but at least for me it does not work very
reliably, I consider this only a proof of concept. While voice/SMS range is
up to 200m, GPRS breaks down after 5m (!) distance, and the connection
stalls after a while, requiring a restart of OpenBTS. I am using an USRP1
with WBX board.
Ralph.
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru